Dyno faq
 

I Just wanted to get this out in the open because I get this question every single time.

"Do I need to own a wideband to come get my car tuned on the dyno"

No,

Any REPUTABLE dyno will have it's own high quality Wideband WITH data logging on site.

If you guys have any other FAQ for Dyno please post in this thread and I will attempt to answer

Do you have a knock box also? That'd save me a few hundred.

Rb25 project coming to you soon Steve :)

here's one that come up all the time.
whats the difference between:
dynojet
dynapac
dyno dynamics
mustang dyno
etc.

and which is the best/most accurate?

YES I DO HAVE ONE!!!! Ready to use on site - we use on almost every car during the power pulls portion of the run

Here is some basic wrap up

1. how/where is the wideband o2 connected at?
2. do i need additional bung?
3. any experience tuning rotary?
4. for ka-t setup, what "budget" fuel management system do you recommend?(you would be tuning it). 4b. fuel upgrades? injectors, fuel pump, and? fpr??
5. obd1 vs obd2, do I need to know anything if I am obd2?

i have never heard of "Also it will often overheat before you can really nail down a cell or complete a map ." could this be because the person didn't hook up the water hose to the devices?

how much for a baseline dyno pull, and can you tune something called nistune?

Not all Dyna Packs have water cooling. They are starting to come pre-equipt now. They still operate similar to a mustang dyno in regards to the fact that you can't quite hover in each indvivdual cell to do true steady state.

Baseline pull is 75 bucks. 5 runs typically

Nistune? Yes, you just have to bring your laptop/software to synch up and I can tune it

The wideband 02 is conntect to a long pipe that goes into the back of your tail pipe and then routes the exhaust gas from about 3 feet upstream past the wideband sensor.

I have tested it back to back with my old race car using a LM 1 about 3 feet behind the turbo and the AFRs are nearly identical. In most cases the tail band sensor was actually more acurate because the sensor itself is exposed to less ambient heat. High heat around the sensor burns them out and can skew readings

KA-T, depends on what you mean by budget. Most people spend 1000-2000 on their turbo and manifold alone but when it comes to their "EMS Budget" they want to spend a fifth of that. I still think the AEM EMS plug and play is the best unit for the KA-T, from tuning experience.

OB1 vs. OBD2? Doesnt matter if you have an upgraded EMS.

Do you need to know anything if you are OB2? .....? like what?

very good info

I hope it's okay if I post my knowledge about the different dynos.

As far as I'm concerned dynojets read the highest.
Mustang dynos read the next best.
Dyno dynamics read the lowest and are usually give the best sense of where your car lies. If you're making high numbers with dyno dynamics you must have done something right (or wrong!).

Take it for what you will.

Pretty certain that Mustang dynos read the lowest, easily.

Dyno Dynamics read the lowest.

Mustang Dynos are usually the second lowest.

However some units arent properly calibrated or maintained and this can skew readings.

Mike has hauled his DD out to dyno days or festivals and they have done side by side testing at other shops with mustang vs. dd.

Either way at the end of the day the thing that is most important is if the dyno allows you to tune the car in a certain way. Cell by cell, etc.

In my opinion the best way to do it is use the dyno dynamics for the actual tuning of the car and then having a dj in the floor to do the power pull for the best numbers once the car is finished. This is actually what XS engineering did for a very long time! their customers didnt even know it

Sounds like a good business plan. What I would do.

"Tuning to the Left bay, ePeens to the Right bay."

hahah

exactly

It works,

But for me personally I dont mind the lower read out on the DD.

It's more of a reaity check. And hey you always know if you needed to lengthen the epens you could hit the dj

Sorry for the misinformation folks

Interesting, I've never heard of Dynapacks that were not water cooled, if they were not, I would agree, you would have a hard time completing a mapping session without overheating the dyno. Before we bought our Dynapack dyno, we rented dyno time from Church Automotive Testing, and their unit has always been water cooled, so if Dynapack did ever did sell dyno's without water cooling, it was a long time ago.

I disagree with another statement made above about the Dynapack not being able to hold the vehicle well under steady state conditions. Considering I've used Dyno Dynamics, Mustang MD-250, Dynojet with eddy current, and a Mainline, the Dynapack, I've found, has been the most capable at holding steady state, and that's one of the main reasons we decided to purchase one. Under most situations, our Dynapack will hold +/- 5 RPM of the target, even at very high power levels.

Yes all recent dynapacks come with water cooling.
No, a lot of dumbasses at shops do not hook up the water cooling. Which is really common unfortunately
Church automotive stick to hondas...btw... I have had a lot my customers bringing cars in that they "tuned" and had some insane crack pot maps with timing all over the place in random places

Yes the dyna pack will allow some steady state. But what i am talking about is something I like to call ROW WALKING, when you trace down a single row of cells hitting each individual cell one by one in a single RPM row, load point by load point. So far the only dyno that could do it perfectly has been the DD for me.

If I had to buy a dyno other than a DD, I think the Dyna Pack is a good alternative. But I have seen dyna packs that even have the water cooling hooked up overheat...

is there any benefit for running a dyno on the fresh swap stock sr?

if the car is running stock ecu and recieving a knocking code, would running a dyno tell any information about where the knocking happens?

Yes, dyno on a stock swap is actually something I have just recently started to recommend.

A. Most people, even experienced shops, don't get the base CAS timing right. Which even if it's off by a little bit can throw off base HP numbers by 50-100 HP!!!!, I KNOW!

B. TPS, and other parts of the motor are harder to check when they are not under controlled conditions. I can data log your air temps, vacuum and other functions under controlled conditions on the dyno to make sure your stock swap or motor with bolt ons is at it's peak potential mechanically.


PS> I wanted to correct myself earlier.

The Dyno Dynamics actually uses an extremely accurate NARROW band sensor. I also have a Wide Band LM1 with tail pipe mount which we use as a third party sensor on-top of the Dyno Dynamics equipt super accurate Narrow Band. It's ridiculously accurate. Even more so than the bosch wideband.

Also the dyna packs are very capable of steady state. I just prefer the durability of the dyno dynamics and some of the more advanced load simulating capabilties. Just make sure the shop you go to is Nissan specialized or has A LOT of experience. because they are finicky

nice, this is such an important piece of information to know from an expert. I heard you can do a remote dyno/tune, how can you achieve that?

also, do you have any comment of my second part of the questions?

"if the car is running stock ecu and recieving a knocking code, would running a dyno tell any information about where the knocking happens?"

The Base Map and Remote Tuning services I offer are for people who own re-programmable fuel and ignition management systems or engine management systems like Power FC, Tomei Reytech, Haltech, AEM EMS, Megasquirt, Autronic, etc, etc etc...

I do not currently do rom or ecu tuning. If you're looking for this strickly I recommend Scot Avoy or Enthalpy Tuning. JWT is ok too, but Scott is a little bit more custom tailored and price savvy.

I still think getting an EMS like a power fc and buying a base map or remote service package from me is better in the long run because you can get a map and tune the car specifically for the exact mods and engine you have. Every engine is different. Even stock to stock every one has it's own little ticks that a custom fit is much better tailored to.

We can check knock with det cans and knock box at the shop on stock motors as well as montor your injector duty cycle and fuel pressure under load if needed.

Tuning by knock is not recommended though. If you have an EMS you should be tuning and checking input vs. MBT, not knock.

i am now learning alot about dyno's. Thanks! Steve!

Steve, I should know this, but what is MBT an abbreviation for?

max best torque

the best torque or power you can achieve with the minimum amount of timing in the tune. MBT can be achieved when you don't want to use more timing than you have to to hit your target output, the less the better.

I feel I need to add to this, while it's nice to be able to tune to MBT, many engines will reach their knock threshold before they get to MBT with pump fuel. This is why knock monitoring is so important. Also, if you carefully monitor knock and creep up on timing, you are generally not going to kill a street engine if it just begins to ping. In practice, on engines that reach their knock threshold before MBT, you cannot tune the engine safely unless you reach the knock threshold, otherwise you would not know the limit of the motor. With a set of knock headphones, it is possible to hear knock just as it begins, well before you would hear it with just your ears . Of course, the more power you make with a given engine, the higher the risk of damaging it with knock. I think of it like a blow torch, you can pass a blow torch over a piece of metal without affecting it one bit, if you hold it there you will start melting things.

- Chris

hello steve,

1.i was wondering if u can tune a chiped sr ecu?what about stock ecu?
2.if im installing bigger injector, fpr, boost cntrlr,and other mods, should i install right before heading to a tuneshop?
3.i notice your in la, where is your shop? im in pasadena

i have my sr that has a shitty tune for about 4 months now, i backfire EVERYWHERE, i figure to invest in tuning to extend my sr lifespan.

here is pic whats in my ecu
http://i391.photobucket.com/albums/o...n/IMG_2280.jpg

thank you sir...

Hi Chris

We use active knock detection such as Det cans and we have a knock box but I have never heard knock before reaching correct timing in each cell and achieving knock...at least yet on a Nissan motor. This is an AGE old tuning debate that was actually discussed even this weekend at the EFI University session we had with Seth from EFI University. The debate and EFI University ended up being a conclusion that tuning off MBT and not being sole focused on knock precautions. Most knock sensors are not even properly configured for the motors they are running on and most oem knock sensors are not designed to pick up the minor knock you are mentioning.

Part of the way to avoid knock while tuning on PUMP gas to begin with is to move towards more rich AFRs than you would commonly expect, especially with the quality of fuels being lower, to actually achieve the same energy out of many of the pump gases today a richer mixture must be used. I honestly have to disagree that most motors will see knock before you reach max best torque. When watching an OEM knock sensor that is actually configured and in working condition for the correct vehicle, at least with Nissan applications, this has not been the case in my experience. With Knock sensors that are aftermarket and not properly calibrated specifically for the voltage range of true inaudible knock this becomes the opposite and it becomes harder and harder to tell if you are actually picking up real knock or supersonic engine air vibration or some other engine condition.

It might also be good to note here that knock IS NOT detonation / extreme engine pressure or typical preignition referred to by most people referring to it...Knock is also not flame fronts meeting in the center of the quench zone of the combustion chamber...

Knock is literally the sound waves of the air inside of the combustion chamber reaching such a pitch and velocity that they explode the fuel air mixture milliseconds prior to TDC during a piston stroke. This vibration is what will actually damage your internals. And also note that on most nissan motors inaudible knock will first start to effect ROD bearings, not pistons in most cases. This is another misnomer.

I think you present an excellent point in that MBT will not always tell you if a motor is tuned in a way to avoid all knock. However tuning with det cans or after market knock senors is an even more risky way to tune off of, based on the fact that most aftermarket knock sensors are extremely hard to properly calibrate due to each individual engine having a different voltage threshold to properly identify actual engine knock and not some other vibration or cam noise in the engine.

In a perfect world you could hook up det cans, knock boxes and an external 3rd party knock sensor and hear knock that would normally be inaudible, see knock on the 3rd party sensor easily without having to spend thousands of dollars on equipment and development to properly configure the sensor to see REAL knock and not some other vibration from engine to engine and also be 100% clear of any detonation before TDC while tuning for MBT. It's an endless debate and I think that honestly it has more to do with engine to engine, vs. tuning method to tuning method. Some engines are much more prone to knock and inaudible det than others. For example many 4G and Subaru engines often see these conditions and their users are very involved in the development or more and more knock feedback and knock based tuning. Age old debate and I hope I shed some light as well

Steve, I agree with you that tuning to MBT is a safer and really, a better way to tune a engine IF that engine reaches MBT before it's knock threshold. That being said, many of the vehicles we tune at our shop reach their knock limit before or very close to MBT, and I am not referring to SR20's. This is why when I tune vehicles, I do both, watch torque and monitor/listen for knock, I'm sure you do the same.

As a side note, many of the late model european turbo cars that come through our shop, straight of the dealer lot, knock. The knock control systems on those vehicles are apparently good enough that the manufactures feel comfortable to calibrate them that way. As an example, we had a brand new Porsche Cayman that was consistently pulling up to four degrees of timing. With the engine cover removed ( the car is mid engine so the engine cover is right behind your head) you could drive it around and hear the engine momentary knock at times as you rolled into the throttle. It was not very loud, but it was definitely there.

- Chris

Exactly. So you agree it is more based on make to make discrepancies vs. tuning method to tuning method in a way.

I do understand what you are saying in your example as well. We used knock box on a couple of vw's that were knocking like pigs however we could still see torque going up. Didnt mean the motor needed more timing (obviously).

This would be a great selling point however to get the customer on 1. meth and water injector 2. or E85. I think this is why this has popped up as a popular route because you can then limit the specific make and models tendancy to see knock prior to MBT and get more out of the motor while decreasing the knock with an octane simulator

Well when we were tuning my ear, if there was a way to detect knock via a eletronic mechanism, my ears would thank them for it... But yeah tuning my car, I had a knock box by phormula which can be tuned for knock frequency as well as sensitivity. I believe all these boxes need to be calibrated, but I think tuning for MBT and really just trying to listen for knock via an ear, imo is really the only way...

But ear and turbo's and boost... not a good thing, so yeah... not doing that for anyone elses car haaha

VERY interesting... thank you

A lot of good information Steve... especially about the base CAS timing... so many idiots out there who think they know how to tune or work on cars.

I have to disagree with you on one point though because personally I have never had any issue with it.

Having tuned on a Mustang Dyno frequently I have never had any problems with the steady state moving around. It has always been rock solid. Other than that everything else is good.

Except for the one dyno being good for NA motors versus turbo... a motor is a motor. If the dyno can handle the power it doesn't matter. Sometimes I don't know where people get these things. They just need to sit down with a couple engineering textbooks and educate themselves as opposed to asking some random person across the internet.

A lot of shops do tune on a Mustang or DD to get a good tune and then run on a cheaper dyno that yields inflated numbers. I know of quite a few personally and I think it is a very dishonest thing to do to the customer.

I always find it personally gratifying when a 300whp/tq car of mine beats a 500whp/tq car from one of those inflated shops though. Something about an idiot will destroy his own stream of revenue and then I don't have to deal with stupid kids... just enlightened ones.

Steve, here's 3 questions for you!

In this coming year, I hope to get some time on a Dyno Dynamics and do some steady state tuning to refine my fuel and timing maps.

1) Once one gets "into the groove" of how to do this, how long would you say nailing down a single cell takes?

If I understand correctly, one would lock in the RPM for the desired cell, and then use the throttle to change the load.

Once locked in on a cell, I would guess you first get the AFRs into check and then start slowly bumping the timing and monitoring the torque output.

...given this is all occurring in "real time", I can't see how it would take any more than a minute or two to nail down a single cell.

...The reason I ask is because I am wondering how long one should expect it to take to do a whole 20x20 map.


2) On a load-bearing dyno, can you also go into cells with a load well below that of where you would be if you were at constant speed or accelerating?

For example, can the dyno apply a load to keep the engine spinning at 5000 RPM but with your foot completely off the throttle so that you can tune the lowest load cell in the map at that RPM level?

2b) Can you get into cells that seem like they are not physically meaningful (i.e. 2000 RPM and 10 psi).....if not, what does one do for these cells? Does the car even ever see them (maybe on fast upshifts?)


3) In practice, if you wanted to do a REALLY good job tuning a car (let's say your own car, for example)....

Do you hit EVERY SINGLE cell....or do you every other (would reduce a 20x20 grid down to 100 cells rather than 400)....or what...?

Hit every single cell in the heavy load areas and interpolate in other areas? Just curious.

Thanks!

You are never going to hit EVERY single cell in a map because every car traces through different regions or collections of cells, depending on build, the amount of load etc.

On a dyno dynamics you can hover in one exact cell, raise the timing up and up while watching tractive effort (or torque) in real time. Once you read the best possible torque in a given cell and your addition of timing to said cell begins to not give you any return in power you know you should back track a couple of degrees lock it in and move onto the next cell in the range.

Thanks for the response....but I am truly interested in my 2nd question....

Can the dyno apply negative and positive load?

Can you hit cells that you would only hit if you were at closed throttle and letting the car decelerate (dyno is applying the power to keep the engine turning, even tho the throttle is closed enough that the car would normally be decelerating)?

Can you hit cells that are in higher boost (i.e. dyno works as a brake.....so you keep builiding boost but the RPMs don't go up)?

j

OEM manufactures use engine dyno's that can do what you are saying, which is to actually motor the engine to simulate deceleration to calibrate those area's. I have not seen a chassis or engine dyno in the aftermarket that can do that. In practice, if I need to calibrate those area's, I can drive the car on the street or decelerate against an inertia dyno. Certainly you cannot do this steady state, so you use your logged information to go back and make changes. As to hitting cells in "higher boost" with a steady state dyno, you can hold the rpm's anywhere you want, therefore you can tune as high in the map as the turbo will spool. In practice, when you are doing calibration work, most tuners will do a combination of power sweeps and steady state to tune a car, not just hold the car in steady state through every cell.

- Chris

Thank you man

Here's a bit from Eric Hsu from cosworth/XS engineering.

"This is an inertia type chassis dynamometer and does not have "load control", but is the absolute most accurate and sensitive dynamometer available. The method of horsepower measurement is fixed and is unaffected by PID closed loop controls from modern chassis dynamometers with eddy current power absorber units. In other words, there is no computer algorithm required to control the load and therefore possibly affect the horsepower measurement. The intertia type Dynojet is very simple and has a pair of 4,000lb rollers (a fixed mass) and the time needed to accelerate this fixed mass is the amount of power the car generates. It is so sensitive that it even measures bent wheels, cylinder misfires, rough engine running conditions, etc. that other chassis dynos cannot measure. If you can tune a car on an inertia type Dynojet with a perfectly smooth dyno graph at 0 smoothing on the graph, you can bet for damn sure that the car will run smoother than a baby's ass. Even to this day, the Dynojet remains my favorite chassis dyno and I've used them all.

While a dyno with load control is certainly convenient for mapping an engine from scratch, it isn't "necessary" for mapping AT ALL. If you want to map specific cells on your ignition or fuel tables, all you need to do is vary the throttle in different gears and you can very easily map entire fuel and ignition tables in no time. If you need more load at part throttle go up a gear. If you need more load at full throttle, go up a gear again. The Dynojet 248C has a 200mph speed limit. Don't let all those young fools or FFF tell you that a Mustang, Dyno Dynamics, or Dynapack is better because "it can control load". If you really think about it, when are you driving on the road and the car is held at a specific rpm or speed? The only time that happens is when you're doing 170mph in top gear on the way to Vegas and your STi is aero and/or gear limited. Otherwise your engine is ALWAYS accelerating and decelerating isn't it? This is also the case on an inertia type Dynojet. How's that for real world conditions?

Anyhow, this may sound like I'm giving a full on sales pitch here, but I'm not. A lot of what Koji and I learned when we were tuning regularly at XS was because of the sensitivity and accuracy of the inertia type Dynojet. While forums and younger tuners may have you thinking that "loading" dynos are better, the reality is that it's how good the tuner is. If you gave Tiger Woods some Wal Mart golf clubs and you had the latest and greatest Ping irons and Callaway drivers, you can bet your ass he'll still smoke your ass in 18 holes (probably even just 1 hole). "

Dynojet 248C Chassis Dynomometer

Some of the points that Eric makes I agree with, however, steady state tuning becomes more important the lower the engine speed and load, due to lower port velocity. Real world, as Eric says, is a combination of various engine loads, speeds and acceleration rates. When you are cruising down the freeway at 75 , that would be considered a steady state load, as you are running at a specific rpm, and are at a specific load. The problem with sweeping through light load lower rpm map area's is that you get transient fueling which will greatly skew what the steady state fueling requirements are at a specific rpm/load site. You can see this clearly on a steady state dyno when you bring the engine up to a specific rpm/load site and hold it there it will take a couple of seconds before the mixture stabilizes. In the real world, I would agree with Eric, that tuning a car on a inertia dyno by someone who knows how to tune, is much better than having an incompetent person tune your car on a steady state dyno.

- Chris

Is this why when I am cruising on the highway in 5th gear and then blip the throttle (just enough to build a psi or 2 of boost), it takes an extra 1/2 second or so for my AFRs to go slightly rich?

.....in other words is there really a noticeable dealy between the engine's operating conditions and when the air-fuel gauge detects the mixture?

If so, this screams for the need to do steady-state tuning in those portions of the map

^^ I believe so, but also in 5th gear, air velocity being driving by exhaust is much slower. Before I brought my car to steve, it was tuned on a dynojet. As far as I can tell it looked like more guess work than anything. I believe doing a steady state and full load sweep is required to do a perfect tune... And most steady state dyno tuners do that.... Its just the lower load areas are where DD's are great! But to adjust from a blank table, DD's are more efficient in doing the work.... at least thats my observation

If this is true then why do I always have cars in the shop FROM OTHER shops who need to use the DD because they are unable to tune portions of their cars maps while trying to simulate load regions?

It's impossible to hit many regions of these maps by just TRYING to simulate load by bouncing in and out of the rollers. It's also impossible to check tractive effort in stead state. To really put things in perspective he is also from a shop that has a reputation for using a load bearing dyno to do the actual map tuning and then throw their cars on the dynojet for big fat numbers to make clients happy...nothing wrong with that but XS used to always use load bearing dynos to tune their cars

We have cars in all the time from Dynojet shops who need to use the dyno dynamics because they have problem regions on their maps that they cannot hit no matter how hard they TRY to simulate it by bouncing in and out on the roller dynos

Just wanted to take a minute and point out that this statement is false, Dynojet makes an entire line of loading dynos, most shops are just too cheap to buy them.


Other than that, this is a very good thread.

Carry on.

Yes they do,

however they are not true brake eddy, they use a BELT or they are ADD - ON design where you add a break to your DRUM to simulate steady state.

Just wanted to correct you on that

:rofl:

:Owned: by Steve

Model 250i Load Control System

* About Model 250i Load Control
* The System includes..

LOAD CONTROL SYSTEM DESCRIPTION

The Dynojet Load Control System was developed through years of experience with over 5,600 dynamometer installations worldwide. The design is easy to operate and provides the function of steady-state load control.

Dynojet's Load Control System uses the latest in eddy current power absorption technology, which combines with our easy-to-use software to give any technician repeatable, consistent results. The Load Control software provides a technician with the ability to control vehicle RPM or speed at any throttle opening. Through our exclusive closed-loop software design, the vehicle is automatically held at the pre-determined setting.

With the addition of the optional torque cell package, the dyno has the capability of a more complete range of tests, including step and sweep tests and wind drag simulation.





Quoted from their site. They are Eddy current load controls, I've used one, and was involved in its install at National Speed in Wilmington NC.


Yep, you are SOOOO right.

That one just happens to be on a Motorcycle dyno, but the same holds for some of their more top end models such as the 424xLC2, which also has an eddy current load control system.

First of all I was just joking, second of all, did you need to post 3 times consecutively?

No, Especially as a premie...

Q: I had my RB25det tuned on DD, got the dyno sheet, and the RPMs were way off. The shop said they only reved the motor to 72, where the soft limiter is set to, but the sheet had it revving up to 9000! I also read of another guy who had the same issue. Is this just laziness on the shop's part?

Sounds like they didn't set-up/isolate the pickup correctly for RPM. Easy to screw up on COP.

Yes they were lazy....

There is a lot of good information posted here
this seems a bit of fear mongering, and totally ridiculous in response to a stock swap question.

It's retardedly easy to line up the CAS - ans setting it to proper timing requires a 3rd grade education.

A properly stabbed CAS, say at 15 deg TDC making 210 rwhp on a stock swap will make +/- 50rwhp b/c of base timing being off?

That information on the Dynojet brand is SO OLD AND INCORRECT that it's not even worth posting. Circa 1996 or 1997? Dynojet has offered load controlled dyno runs on the 224 series automotive chassis dynos for over 10 years!

Wow, where to begin? So much bad info...I'll do my best to give the actual, correct information to refute the outdated, bad or erroneous things here.
Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
Come to find out..
A mustang dyno & dyno dynamics are much much better for tuning

False. Load style dynos do things differently than inertia style dynos, but once you add a PAU (power absorption unit) to an inertia style dyno, it can then do BOTH. Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
here is an excerpt ive taken from another website that really talks about the difference.
Quote:
DynoJets are inertia dynos, and have been around for years, much longer than any type of load cell dyno.


Incorrect. Load style dynos have been around much longer that Dynojet has. Inertia as a design principle has been around for longer than Dynojet too...we didn't invent the idea - just did a good job of offering it to the public at an affordable cost. Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
Quote:
Inertia dyno's work on the principle of the acceleration of a known mass over time. Their rollers are the known mass. Weighing in at over 2500lbs or so. Your car gets strapped down to the machine, and the dyno collects it's data. It is able to calculate horsepower by measuring the acceleration in rpm of the rollers in regards to RPM.


Most of this is correct, but the acceleration of the drum is measured by TIME, not RPM. The Dynojet inertia dyno will accurately collect data and display HP vs. speed with no RPM input at all. This is the most basic dyno run it can do. Add RPM information from the engine and then it can calculate torque off the well known forumla that TQ = (HP * 5252) / RPM. Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
Quote:
This is why gearing can affect the dyno results, more on that in a bit. Now that the dyno has recorded the horsepower curve, it can take the integral of that curve and get the torque curve. Since the dyno’s power calculations are based on the acceleration of mass over time in regards to RPM, gearing is very important. Since a vehicle with a lower gear ratio can accelerate the mass to a higher speed using less engine RPM, it will show a higher horsepower number than a car with a higher gear ratio. If a car is able to accelerate the dyno’s rollers from 200rpm (roller) to 300rpm (roller)in 1500rpm (engine), then the dyno is going to record more power than a car that did that in 2000rpm (engine).


Also incorrect. Gearing has no bearing in the horsepower/torque figures displayed. Gearing does have a bearing on the FORCE put to the dyno drum, but this is all relative per gear. 2nd gear will have more mechanical advantage and accelerate the drum quicker than 4th gear, but the delta (change in) speed is not as great. If you look at a given RPM range (let's use 2000rpm to 6000rpm for ease), then in 2nd gear that may translate to a dyno run that goes from 20mph to 60mph, where in 4th that may be from 35mph to 100mph. While it takes longer to make the run in 4th, it also has a greater delta speed.

Also to note here is that in our example above, in 2nd gear, more of the HP the engine produces is going to be used to accelerate the inertia of the drivetrain, engine internals, etc. over that shorter timeframe. In doing so, less HP actually gets to the wheels. This is why you will typically see less HP in gears that are not a 1:1 ratio, and the further you get from 1:1, then less power the vehicle will put to the wheels.

The exception to this is large turbo applications with big torque - like turbo diesels - that have far more torque than HP. They need the extra run time of the taller gears to build boost and load the engine over a very short RPM range. Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
Quote:
Now we go to Mustang dyno’s and other loaded dyno’s. Our Mustang MD-1100SE dyno’s rollers weigh 2560lbs. That is the actual mass of the rollers, much like the DynoJet. That’s about where all the similarities end. When we get a car on our dyno, we enter two constants for the dyno’s algorithms. One being the vehicle weight, the other being what’s called “Horsepower At 50mph”. This is a number that represents how much horsepower it takes for the vehicle to push the air to maintain 50mph. This is used as the aerodynamic force. Mustang dyno’s are also equipped with a eddy currant load cell. Think of a magnetic brake from a freight train. This magnetic brake can apply enough resistance to stall a big rig. Off one side of the eddy currant load cell, there is a cantilever with a 5volt reference load sensor (strain gage).


The setup referenced here using a PAU and a strain gauge is exactly the same setup used on the Dynojet 224xLC and 424xLC2 dynos. One MAJOR difference though, is that there are no "constants" that need to be added to the Dynojet software. Giving the operator this control gives them the ability to fudge the numbers. Think I'm full of it? Next time you're on that Mustang dyno, enter a vehicle weight of 3000#, make some dyno runs and then change the weight to 4000#. What happened? The HP went up? Why would it do that? Are you telling me that if I put friends in my car on the way to lunch and the car is heavier, that now my engine makes more HP? How can that be? LOL
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Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
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I like to state it like this. . . I start by asking how much your car weighs, lets say 3500lbs. Now you take your car and you make a make a WOT rip in your tallest non overdrive gear, how much mass is your engine working against? 3500lbs right? Now you strap your car on a DynoJet and you make a WOT in the same gear, how much mass is your engine working against? 2500lbs right?


Yes, OR NO. With the load controlled Dynojet dynos, you can setup sweep tests, step tests or custom load test using the PAU in the same method as the other load style dynos. We actually have one routine that allows the user to input how much load to add versus either engine speed, time or road speed. For instance, we can have the load increase as vehicle speed increases, to simulate wind drag and aerodynamic loads. We even provide our dyno centers a spreadsheet they can use to input the vehicle weight and aerodynamic values (coefficient of drag and frontal area) which calculates the custom load profile for them.

The load is then added during the run. This slows the acceleration of the drums, which means we measure less HP to the drum, but then we record the strain gauge data as to how much torque is being absorbed by the PAU during the run, and do the math to calculate the total HP as if the load had not been applied. Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
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Now you strap your car on a Mustang dyno, how much mass is your engine working against? 2500lbs. Plus the resistance being applied by the eddy current generator. We’ve seen anywhere for 470lbs of resistance to over 700lbs of resistance as measured in PAU force in the data logs. So which one is more accurate? Well they their both accurate. If a DynoJet dyno says you made 460rwhp, then you made 460rwhp. If a Mustang dyno says you made 460rwhp, you also made 460rwhp. Now which one of those numbers best represents what your car is doing when its on the street. That’s a different question.


See, same result - the information quoted here is SO OLD that it doesn't take into account that Dynojet has offered this same technology for over 10 years! Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
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For instance, my 2002 Z28 with a forged internal LS6 Heads/Cam/Intake, makes 460rwhp on our dyno. I thought that was a little low, since I’ve had cam only LS6 Z06 vettes make 450rwhp. So I overlaid the dyno graphs. Guess what, the PAU force for my car was almost 200lbs more than the C5Z06 that made 450rwhp with cam only. So I entered the weight and horsepower at 50 number for a C5Z06 and did another horsepower rip with my car. The only reason I did that was to compare Apples to Apples. This time my car made 490rwhp, no other changes. Now I don’t go around saying my car made 490rwhp, I say what it actually did with the correct information entered into the computer. It made 460rwhp.


So, the operator changed a number typed into the software and the HP changed? (I think I mentioned that above). So what good is a dyno that the operator has the control over to make it read whatever he wants? The whole point behind the dyno is to have a CONSISTENT and REPEATABLE testing tool that cannot be manipulated to show different power figures. If this rule is not followed, what guarantee does the vehicle owner have that gains shown on the dyno printout were truely made? On a Dynojet dyno, there is no value that can be entered to change the HP displayed. Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
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Now which one is more "real world" is a totally different question. I like to explain it like this..... If you drive your car in a situation in which you have no mass and you're in a vacuum, so basically if you do intergalactic racing in space, use a DynoJet. If your car sees gravity, and has an aerodynamic coefficient, and you race on a planet called Earth, then use a Mustang Dyno.


I think we've now illustrated the point that this is completely false. Don't let the sales mumbo jumbo and 10 year old quoted speeches give you bad information.
__________________


Whew, almost done... http://www.GenCoupe.com/images/smilies/smile.gif

Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
whats the difference between:
dynojet Giant Drum at a given weight, Dyno reads how much energy the car has to use to push against the given weight. Often reads the highest of any dyno due to the fact you cannot apply additional load. The weight is the only resistance on every car for every run/chassis/weight etc of the car- You cannot tune the low end or mid range cells on a dynojet, You can only tune based on straight power pulls or on-off attempts to simulate load.

This has now been proven false as well. Anything you can do with a load style dyno you can do with the Dynojet (properly optioned) as far as loading the car for simulated dyno runs. Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
dyno dynamics
Dyno Dynamics is the best dyno for the money imo. It reads lower than all other mainstream dynos on the market because it uses an Electromagnetic Brake that is slowed by the magnets applying a force to slow the rollers the HARDER the car trys to push against the applied force. This dyno also allows the operator to apply various amounts of load conditions, simulate highway speeds, acceleration and other driving conditions that cannot be simulated with any other dyno.

I think I've also discussed how everything this dyno can do, can be done with the Dynojet dyno as well. Not to mention, Dyno Dynamics is now out of business. Support and repair parts for these dynos are now non-existent.
Quote:
Originally Posted by renzo088 http://www.GenCoupe.com/images/buttons/viewpost.gif
If you want your car tuned properly take it to a Mustang or DynoDynamics dyno

Links
Dyno faq - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

In conclusion, that last statement is completely FALSE. I believe that I've stated all the pertinent facts to show that the Dynojet dyno has all the benefits of a load bearing dyno (as it can be one when optioned with the PAU), and all the benefits of the repeatability and consistency of an inertia dyno. There is a reason why nearly every NASCAR team in the country has a Dynojet inertia dyno. This is why discerning performance shops like Beyond Redline, AMS Performance, Hennessey Performance, Borla, K&N and many others choose a Dynojet dyno. When it comes to testing and getting repeatable and consistent results, you can't beat a Dynojet.

or a link if that is unclear http://www.gencoupe.com/engine/28966...no-tuning.html

So in conclusion the reason why a dynojet is just as good as a load bearing dyno is because Nascar uses it?

Nascar runs PRE TUNED, in many cases CRATE MOTORS!!! bwahahaha

Are you fucking kidding me?

YOU CREATED AN ACCOUNT JUST TO POST THIS LIMP WRISTED BS RESPONSE????

....BECAUSE YOU'RE A DYNOJET REP!!! BWAAHAHAHAHHAHHAAHHAAHHAAHAHAHAHAH

I was looking through that thread you posted, You are spreading the most loaded cattle car pile of BULLSHIT I have ever seen!!!!!

Dyno Dynamics OUT OF BUSINESS? NO SUPPORT?

What the fuck do you think this is FedEx vs. UPS? Totally spread disinformation because you're only interested is that DYNOJET sells more of their shitty toy dynos.

I am a tuner, I have no interest in supporting sales of any particular part. I have however used all of the dynos listed for various different cars over the years and by far, without a second of thinking about it the Dyno Dynamics BLOWs all of the other dynos out of the water. Even if you just compare it to how fast and refined the cars are after tuning alone. It's NIGHT and DAY. The dynojet cars are weak, very peaky power bands with very little mid range and low end power and torque. The DD cars come off feeling like I added 2-4 cylinders to the motor. The amount of free power hidden in the low to mid-range hard to reach cells is AMAZING! So much hidden power in those hard to reach spots. But with the DD I can simulate any fucking cell I want to hit any time and rad tractive effort in read time cell by cell by cell for PERFECT cylinder pressure and power output down to ms and down to a hundreth of a ft lb of torque. Show me a dyno slut jet that can do that, even with the gay-ass shitty fucking add on brake with the belt/ pulley, what a piece of shit

Dyno Dynamics is now combined business with Haltech USA, they work out of the same office and R and D facility in KY. They are alive and well and have complete support for all of their units...

Have you no shame?

Dynojets are good for ONE THING, consistent WOT comparisons.

For actual cell by cell map tuning it's garbage

Sorry but for me I care a whole hell of a lot more about how FAST my car accelerates and handles then how big of a number I can simulate based on a controlled experiment trying to spin a given weight

TKO by Steve

Flawless victory

you cant just waltz into zilvia, start an account then copy and paste some bullshit post from another thread that was posted by a Dyno Jet Sales rep...fail

steve, can i buy u a beer? a stone ale. Tuned to perfection. MMm lol

that was a great reading. lol

Steve, are there any East Coast (specifically GA or surrounding states) tuners that you recommend for the SR20? I suppose I could just have Scott at Enthaply do a mail order ROM-tune when the time comes, but I just wanted to know your thoughts. I do not have a standalone, nor the current budget to purchase one, so ROM tune would have to be my route in the near future.
thanks

great thread... looks like i found somewhere to take my hoop-d as soon as i get some parts i want.. i have a stock rb20det swap just with a FMIC that made the boost lag horrible and a cheap exhaust hahaha.. PM me on what you have seen work best for the RB20's im open to ideas so we can work something out man.. maybe get a total prive so i can drive down there and get my car running at its best!

That sounds great actually haha

I don't know how, between the dyno dynamics and the mustang dyno that one could be better than the other.
In a sense its up to the dyno tuner to determine load value. Which they ask at the begining of the session. My tuner says that my car drives on the level of a miata so then a factoring number is added to the program and the dyno then sets a predetermined load value.
Thats technically why I don't give a crap between the mustang eddy or the dyno dynamics, there load values depend on the dyno tuner. Any tuner can manipulate those numbers to usually make numbers look higher.
Thats the problem with braking resistance dyno's you can't really determine which one is better, because it is truely determined by the dyno tuner and there experience dealing with cars in general.

True

Which is why it's honestly important to have a good "butt dyno"

Seriously

because cars will read out whatever they damn well want to read out but Ihave seen several cars I have tuned that put out 235 whp womp all over cars tuned on another brake eddy dyno that were putting out 350 whp.

So it's all in the capability to tune efficiently and give the engine what it wants: the most efficient way to get air in and air out as they say

Well thats also manipulation on the engine builders part as well as the dyno tuners. I know from my experience that usually when I'm on the dyno I will do what it takes to exceed real world HP figures. Such as adding toulene and xylene fuel mixtures, or sunoco 110,or manipulating timing as if I was on a race track only.

In any real world situation hypothetically most people are bound to 91 octane unless you can find your local street blaze station with 100 or 101 octane.

I know that the dyno room at BRG racing in pacheco purposely sets up a small fireproof room just big enough to fit the car and dyno, and then a blower fan chills the room between 68*~70*F, with an inlet and exhaust out system.

Now I know that in any real world application most spring and summer days are a good 85*~90*F just the raise in temprature by 3*F for a naturally aspirated engine can drop HP, 10 to 15HP at the wheels and with forced induction depending on timing and boost from 10 to 70HP at the wheels. I actually read that in the book four stroke performance tuning by Graham Bell.

Now we are also talking about ecu tuning which is the key factor here. You can get a car that shows more HP on the dyno than another car that may have less HP using a higher octane blend, as you have pointed out in your example of a 235HP car VS. 350hp car. What they run on the dyno is manipulated as I said before from octane fuel used, timing, boost, etc, and of course the dyno tuners load settings. Infact the car that maybe making less HP may actually be utilizing pump gas more effeciently than the hyped up car tuned for higher octane for HP. Once you take an ecu, and an engine and tune it for higher octanes, it usually isn't as effecient in using lower streetable octane blends, as the cars that are tuned for those lower octane blends. this has alot to do with cam selections and bas etiming more than anything else. Its actually a way of being more deceptive on the dyno than in an instance of real world driving habits and competitive racing.

Last but not least what everyone fails to look at in the dyno is the torque band, most people become to prone to just looking at the peak HP without looking at the entire dyno graph.Torque plays a huge factor in this as well, while most people look at the HP band there are alot of engines out there with less HP, but have a much more superior beefy torque band. This would be more like the debate of the RB25det NEO VS. the RB26det which in most cases some say the RB25det neo is much more superior with its fully counterweighted crank and torque band , VS the RB26dett with its half weighted crank and higher off the wall peak hp rev range.

Just so many X factors that a car with less HP on the dyno can whomp a car with more HP on the dyno.

All very fair points.

Especially the torque curve point.

It's a lot easier to understand when talking tuner to tuner. But talking customer to tuner it's harder to get across.

It is a lot easier though, once they actually drive the car and experience the torque. They get a little less concerned about being 15-20 hp off of their target HP goal.

The other issue is tuning for throttle response and tip in power. This is something that I have been able to get extremely efficient and experienced with thanks to me switching from the dynojet to the dyno dynamics now.

I am able to do things that I could have only dreamed of with the dj 6 years ago. Thanks soo much to Mike Kondo at Canyon Racer Motorsports to letting me rent his dd anytime needed for Nissan Clients.

The other thing is building smooth linear maps. Being able to test out timing in each individual cell - watching the tractive effort in real time, it's awesome. You can find 10-30 ft lbs of torque as low as 2000 RPMS sometimes with this function

Here's a question.

What recommendation can you give to someone that is getting started as a tuner?

Recommended reading?
Recommended tools(hardware/software)?

I continually read this book to cross refrence, and has turned out to be very informative book for beginer and intermediate tuners and engine builders.
There is a chapter that specifically discusses dyno tuning. The book is about 90% engine management and the rest of the chapters get into data logging, dyno tuning, MAP tuning. It how ever is not too specific on the differences of dyno systems.
http://i27.photobucket.com/albums/c1...nie/img024.jpg

Here are some videos on the dynomite Eddy dyno systems.
http://www.land-and-sea.com/videos.htm

Circle track magazine article.
http://www.circletrack.com/techartic...iew/index.html

so whats the best way to make a base tune for a bikirom to get the car to the dyno? It already has a tune for 550cc injectors, t25 and z32 maf, but i have 440cc's and a gt2871r.

I really wish you where an Osiris / Uprev Tuner.

What makes this any different from tuning with an AEM ems? The key factor here is resolution. Uprev is cheap no doubt, but AEM is much more superior as far as resolution is concerned.

UPREV also has its limitations with dyno jet tuners that aren't familiar with osiris/uprev. There is a local shop here in concord that uses the dyno jet and they have no clue how to use osiris.

Some options on the uprev I also don't think are needed such as 5 MAPS per cruise control system.

This is more of a preference I would think. Both have good qualities, but in any instance although the AEM cost more I would prefer it over the uprev/osiris.

What's the difference?

I always get this as well from people. A standalone is a standalone is a standalone. Now mind you some are far superior than others for the money, like Haltech is great, AEM is pretty good (although they basically completely copied the Haltech on their new release), the Power FC is an easy to learn first option...but any other unit is basically the same.

If you can tell me the resolution of the tables and the units on the axis I can write a map for it, end of story.

Any comments for my carb?

I use Dynapack exclusively. I'm more interested in the torque curve than anything else.

Actually I'm most interested in response, but I use the butt dyno for that. I only use the Dynapack for the WOT torque curve to tune the secondary fuel delivery system and timing curve.

As you know, the secondary in the carb can only be tuned by finite, incremental jet changes. It has 7 pairs of jets that I can swap out. Not much more tuning than that.

I'm getting the new MSD Programmable 6AL. I have no idea how to tune the ignition curve and GM doesn't have any base guideline.

So I have 2 great tuners that are semi local to me. One has a Mustang dyno and the other a dynojet. What you guys are saying is I'm better off with going to the one with a Mustang dyno?

Just because a shop has a better dyno doesn't mean that's the best choice. I think a bigger part has to do with the actual tuner himself and how much experience he has.

A shop can go buy a dyno dynamics or dynapac dyno easily but what if the tuner sucks.

Ask around about how other people feel about the shop and the tuner and go from there.

Question Steve,

Do you know any reputable tuning shops around Western NY?

Also, which would be better for tunning - AEM EMS or Nistune?

Thanks in advance for your input.

~ Kamil

Fixed that for you, you sexist pig :hug:

Honestly there is nothing like actually doing the darn thing, I have no engineering background (school wise) totally self taught, I did some USAF tech stuff on thermodynamics in my short stint in ROTC and was always around airplanes growing up so I guess that kind of helped. I actually sought out books on thermodynamics, exhaust system design and even fluid dynamics. Also understanding Lambda and lambda correction helps A LOT.

The best way to get a crash course in my opinion is to hit up Seth from EFI university and see when they have a discounted EFI univeristy class near your region. If you get the basics of AFR and can tune and understand the basic idea of an AFC or piggy back you could go straighgt for the second level course they offer.

Real time on the dyno is priceless though, watching you hit one key, then immediately seeing the torque or afr change immediately in real time, starts to click in a pattern an dyou start to get a feel for how everything is applied in practice. I lucked out and partnered up with a great friend who happens to own his own dyno dynamcis, This allowed to be spend hundreds of hours experimenting, writing my own notes and then applying some of my other learning in a controlled enviornment on my own build and a few other show cars we had. I am all about the hands on. I have been tuning for 9 years now, started with an AFC and a wideband in 01-02 and graduated to Haltech and dynos by 03-04. The rest is history. (although I really do want to build another 500-600 whp car in the future).

Go AEM all the way. You need a standalone or EMS that can work instantly in realtime, with no near for an emulator or to burn the emulated tune back onto the actual board or hardware that is actually running the car.

Full real time tuning directly into the unit itself is my preference. So this includes, AEM, HALTECH, MOTEC. Power FC is also semi-capable of this. You just need the FC data logit (which i Prefer to the PFC software personally). You can map watch in real time and then after a pull look at RPM and AFR and go back through and fine tune every single individual cell.

IN real time with FC data logit, you just do map watch, adjust a cell and hit "WRITE" and it writes instantly, same as real time also.

The Tomei Reytech is also a good unit that I never head anyone talk about, although the resolution of the map is not amazing the unit itself is very easy and quick to tune, especially if you are using nissan based equipment, high impedence injectors, and mostly factory gear, but the plus is it operates as a map based system.

If you have to get a map base system and dont want a Haltech or AEM, I suggest the Tomei unit (if they still sell which I think they do). Otherwise stick to the tried and true Power FC L Jetro. Unit is great, really affordable and good soultions for builds with power as high at 500-550 WHP

Nobody sells the tomei unit, it costs as much if not more than the aem and the haltech unit and the instructions are still mostly in japanese. You can buy it from tomei directly but that's it. It's not listed on any nissan online store I've been to.

If you're serious in locking down tuning for the car I suggest going with a PFC L jetro if you're looking for sub 500 WHP. The unit is great and affordable and you can work with it in real time.

I will give you a good price on some dyno time too, I know we've tried to link up in the past but I can do 480 US for a full session.

Thanks for taking some time out of your schedule to answer my question :) My KA24DE was recently rebuilt to get ready for boost. Here's what I got done...

Bottom end:

Bored .020 over and honed
Clevite Main and Rod Bearings
AMS Sportsman Series Rods
Arias 8.8:1 pistons
ARP Main Studs
ARP 10mm Head Studs
Balanced whole rotating assembly

Head:
5 angle job
Brian Crower Stage 2 Cams
Supertech INCONEL Exhaust Valves - 0.7mm oversize
Supertech Intake Valves - 0.5mm oversize
OEM timing rebuild kit & using original cam sprockets
1.5mm Cometic HG - due to resurfacing

Once the time comes and I'm finished builing the car, will I need adjustable cam sprockets for dyno tuning? Let's pretend I do...will a dyno shop go through the trouble of taking a valve cover off and adjust the sprockets as needed or will I have to make seperate trips with the car and do it myself before arriving at the shop?

Thanks again in advance for any input bud.

Kamil

BC's have been known to be cut off center. Just get a dial indicator and make sure the cams match the cam card. If they are off get some adjustable sprockets and dial them in.

The whole advancing and retarding them on the dyno is a Honda thing. They are really meant for dialing in a cam on install.

Thanks bud. So AEM EMS seems to be the popular choice huh?

Does anyone know any good tuning shops around Western NY that have the dyno dynamics?

Once again, thanks in advance for any info!

I suggest Haltech the new units are great to work with and honestly EFI university and some other tuner classes all support Haltech to be no.1 for the money.

AEM would come in second for Full EMS, IMO - they have issues or had issues with the CAS wheel having to be replaced so your timing doenst magically advance and get off map YIKES!!!

Power FC is not really in the class with these two, but it is a great unit for any build up to 400 WHP. The new PFCs are a bit more in line but either way if I was personally doing another S chassis build I would pick up a PFC and drop that in there for sake of ease of tuning and really don't need much more than that function wise on a 300-375 whp type build

Steve over at SRMotorCars sells the Raytec ECU. My buddy is running it on his S14SR currently.

anyone used the logworks app for the itouch/iphone? i downloaded the free version and it was almost spot on as far as dyno hp and 1/8mile/ 1/4mile times

what does it use? Magical powers from Harry Potter to guesstimate?

any info on the nistune product? Looking to do a roots setup, and wondered what you would prefer for a ka with a m62?

lol . . read the title of the thread as 'dyno snip'

hahahaha.