Tuning on the dyno or street?

[Wannabe1989]

If this has been covered 100 times I'm sorry but I just rebuilt my kat. It has a full build and I'm only planning on drifting it as I have been. I don't have plates or insurance on it, I could get them and break in the motor on the street, or do it on the dyno. Which should i do? Benefits? Why? Thanks in advance

[ultimateirving]

dyno costs money but is better for tuning, more accurate, controlled climate to tune. Street is convenient but may cost u more if you get caught driving without plates/insurance. or going too fast..

[[email protected]]

tow it to a dyno please...

[4x4le]

In for the smart people in this thread! I hate it when a question like this is asked and everyone says tune it on the street brah!!1! U dont race on the dyno so why tune on one. Thats bullshit.

Honestly, breaking it in on the street would be ok if it were registered ect but its fine to break it in on the dyno.

[MADE]

I've had cars tune on the street and dyno. IMO the tuner abilities are more important than where they choses to tune it at.

[rocknrollkat]

If this has been covered 100 times I'm sorry but I just rebuilt my kat. It has a full build and I'm only planning on drifting it as I have been. I don't have plates or insurance on it, I could get them and break in the motor on the street, or do it on the dyno. Which should i do? Benefits? Why? Thanks in advance
Dyno tuning gives you repeatable results in a controlled environment. Here's an example.
on the dyno, bring the engine up to 3,000 rpms.
Read the guages on the dyno.
Stop the engine.
Make 1 change to the setup.
Bring the revs up again to 3,000 rpms.
Read the guages again.
What changed ?
That's the scientific approach.
Now try that on the street, cruising at 3,000 rpms, read the dashboard guages, write down the results, dodge that squirrel, watch out for the fuzz, don't hit anything.
Pull over, make one change to the setup, repeat.
Good luck....
Rocky

[MADE]

Dyno tuning gives you repeatable results in a controlled environment. Here's an example.
on the dyno, bring the engine up to 3,000 rpms.
Read the guages on the dyno.
Stop the engine.
Make 1 change to the setup.
Bring the revs up again to 3,000 rpms.
Read the guages again.
What changed ?
That's the scientific approach.
Now try that on the street, cruising at 3,000 rpms, read the dashboard guages, write down the results, dodge that squirrel, watch out for the fuzz, don't hit anything.
Pull over, make one change to the setup, repeat.
Good luck....
Rocky

I know it sounds dangerous but most of the tuners in Japan don't use dyno's. But most only tune in area's they consider safe by their drivers and tuner.

[rocknrollkat]

I know it sounds danerous but most of the tuners in Japan don't use dyno's. But they're an abundance of low traffic expressway's with inclines.Konnichiwa, MADE !! For street tuning, I would pick a stretch of road, measure it, mark it with spray paint at the start/finish points, have a buddy or cutie (preferably) with a stopwatch and notepad, you know the rest. Here in NYC we used to do tuning like that, but the traffic is so bad here now....
Ja Ne,
Rocky

[4x4le]

I street tune for driveability only. Im only worried that the afr stays acceptable and everything feels smooth.
Power is to be made on a dyno. I have had so many dynojet tunes and street tunes come to me so i can put them on a load based dyno dynamics and i have always made more power. More safer power i should say because there have ALWAYS been areas that had too much timing and either too much or not enough fuel. Your engine revvs so quick that your wideband is gathering an average afr in the exhaust, but when slowed down on the dyno where it has to hold at every rpm for a few seconds you can quickly see that 4000 rpms is holding a 13:1 afr and 4250 is holding a 9:1 afr and then 4500 is sitting on 10.8:1 and so on. On the street or on a dynojet this may end up looking like a perfectly acceptible solid 11.5:1 and it was achieved and the truth is your lean and rich during some cycles.

[rocknrollkat]

I street tune for driveability only. Im only worried that the afr stays acceptable and everything feels smooth.
Power is to be made on a dyno. I have had so many dynojet tunes and street tunes come to me so i can put them on a load based dyno dynamics and i have always made more power. More safer power i should say because there have ALWAYS been areas that had too much timing and either too much or not enough fuel. Your engine revvs so quick that your wideband is gathering an average afr in the exhaust, but when slowed down on the dyno where it has to hold at every rpm for a few seconds you can quickly see that 4000 rpms is holding a 13:1 afr and 4250 is holding a 9:1 afr and then 4500 is sitting on 10.8:1 and so on. On the street or on a dynojet this may end up looking like a perfectly acceptible solid 11.5:1 and it was achieved and the truth is your lean and rich during some cycles. Good points. Dyno tuning gives you a great baseline to start with, road testing gives you the real world finishing touches. If you had the time, money and location, you could street test the car, dyno tune it for maximum power, return to the street and compare real world results !!

[4x4le]

What i do is get everything scaled right on the street and driveable, dyno to make power and for the low throttle to wot transitations, and then back to the street usually just to observe and make sure nothing stupid happens.

The information a dyno gives you cannot be given any other way. Most people think a dyno graph is the end result of a tune. To me they are what enabeled me to make the final one.

[4x4le]

Also, i dont get what your talking about the real world gives you finishing touches. Ive already elaberated showing how you cannot gather proper air fuel data on the street and as far as timing goes, well what are you going to do, add more once you get off the dyno?

Dyno is the only way to tune an engine. There is tons of tuning equipment that can make tuning better and more precise such as listening devices, egt sensors ect, but those can be used on the dyno too.

[Wannabe1989]

Ok thanks. I don't need a tune cuz I got a pre programmer jwt ecu. But I'll still go to a dyno to do it cuz it'll cost about the same as if I got plates and insurance for a couple months and all.

[rocknrollkat]

Also, i dont get what your talking about the real world gives you finishing touches. Ive already elaberated showing how you cannot gather proper air fuel data on the street and as far as timing goes, well what are you going to do, add more once you get off the dyno?

Dyno is the only way to tune an engine. There is tons of tuning equipment that can make tuning better and more precise such as listening devices, egt sensors ect, but those can be used on the dyno too.Real world finishing touches are outside, on the road, where altitudes vary, air temps and densities vary, driving style comes into play, load conditions vary, tons of variables that don't exist in the 'clean' room. The engine dyno is the best way to get a great starting point, then the real world is where I finish the setup.

[4x4le]

altitudes, air temps and densities = ///

if the computer is working right and you did your part right on the dyno none of that will need adjusted no matter what is thrown at it later.

Driving style? Searously? "hey man I got a drift tune and a drag tune", no its all the same.

I can change load on the dyno dynamics from anything you could see on the street up to as much as things you couldnt see in the natural world. The dyno I use holds back diesel trucks that make 1000whp and 2400lb/ft.

I just dont get it but I guess thats why people come pay me to tune their car, and I guess thats why they dont call me up needing changes made once they go back to where ever they live and drive where ever they drive.

[Zacho]

My process:

-Do math for base map. Don't worry about positive manifold pressure values just worry about driveability.
-Get the car out on the road and work on the tune a bit. Stay out of boost and don't mess with timing much except for @idle. Make the car run well, start reliably and sort out any idle/ignition/ecu outputs and make sure everything is functioning.
-Drive the car for a few days like this. Give it some time for issues to come out.
-Take it to the dyno.
-After the dyno get back on the road and do fine adjustments. In my experience on a dynapack, dynojet, and mustang dyno when you go back out on the street the cells you pass through on the map usually aren't 100% exact to what you hit on the dyno.
-Take car to the track and enjoy.


When you go to the dyno, especially if someone is tuning your car for you, don't bring it with shit that "may" go wrong or "may" need to be fixed. They don't want to deal with it and your wallet won't like you.

[rocknrollkat]

altitudes, air temps and densities = ///

if the computer is working right and you did your part right on the dyno none of that will need adjusted no matter what is thrown at it later.

Driving style? Searously? "hey man I got a drift tune and a drag tune", no its all the same.

I can change load on the dyno dynamics from anything you could see on the street up to as much as things you couldnt see in the natural world. The dyno I use holds back diesel trucks that make 1000whp and 2400lb/ft.

I just dont get it but I guess thats why people come pay me to tune their car, and I guess thats why they dont call me up needing changes made once they go back to where ever they live and drive where ever they drive.Yes, seriously. And no, it's NOT all the same, not even close

[4x4le]

My process:

-Do math for base map. Don't worry about positive manifold pressure values just worry about driveability.
-Get the car out on the road and work on the tune a bit. Stay out of boost and don't mess with timing much except for @idle. Make the car run well, start reliably and sort out any idle/ignition/ecu outputs and make sure everything is functioning.
-Drive the car for a few days like this. Give it some time for issues to come out.
-Take it to the dyno.
-After the dyno get back on the road and do fine adjustments. In my experience on a dynapack, dynojet, and mustang dyno when you go back out on the street the cells you pass through on the map usually aren't 100% exact to what you hit on the dyno.
-Take car to the track and enjoy.


When you go to the dyno, especially if someone is tuning your car for you, don't bring it with shit that "may" go wrong or "may" need to be fixed. They don't want to deal with it and your wallet won't like you.

we do things very similar. I do start out by making sure that all of the sensors are working right, base timing is right, plugs are new and gapped where I estimate they should be and a heat range I estimate they should be.
I have never felt the need to make changes on the street after I started using a dyno dynamics. Check one out.

Yes, seriously. And no, it's NOT all the same, not even close

yea it really is all the same. if your engine is making as much power as it can everywhere then that is what you want.
The only settings I would change based on driving style would be boost settings and if you want no lift shift or not.
engine paramiters, Ill stick to the dyno

You fail to list any examples of anything. Your argument is "yea huh" "no" "seriously no its not"

Tell me an example you would change an engine paramiter once you leave the dyno.

What condition would happen, and what setting would you change.

[rocknrollkat]

we do things very similar. I do start out by making sure that all of the sensors are working right, base timing is right, plugs are new and gapped where I estimate they should be and a heat range I estimate they should be.
I have never felt the need to make changes on the street after I started using a dyno dynamics. Check one out.



yea it really is all the same. if your engine is making as much power as it can everywhere then that is what you want.
The only settings I would change based on driving style would be boost settings and if you want no lift shift or not.
engine paramiters, Ill stick to the dyno

You fail to list any examples of anything. Your argument is "yea huh" "no" "seriously no its not"

Tell me an example you would change an engine paramiter once you leave the dyno.

What condition would happen, and what setting would you change.To begin with, 'tuning', in the realm of racecars, refers to not only engine prep but drivetrain, chassis, suspension and tire prep also. Where would you like me to begin ?

[4x4le]

To begin with, 'tuning', in the realm of racecars, refers to not only engine prep but drivetrain, chassis, suspension and tire prep also. Where would you like me to begin ?

try me

but if you think your going to go off topic by talking about changing foot settings then think again. I work on race cars every week and I know those settings are changed in the real world and then my (dyno) for that is I bring them back to the alinment rack to see what we ended up with.

were talking about engine parameters in this thread
http://www.youthinkyouknowbutyoudont.com/cat%20watermelon.jpg

[rocknrollkat]

try me

but if you think your going to go off topic by talking about changing foot settings then think again. I work on race cars every week and I know those settings are changed in the real world and then my (dyno) for that is I bring them back to the alinment rack to see what we ended up with.

were talking about engine parameters in this thread
http://www.youthinkyouknowbutyoudont.com/cat%20watermelon.jpgI thought the topic was tuning. How is that off topic ?? Foot settings ?? What engineering book did THAT term come out of ??
Alinment ?? Do you mean "alignment" ?? Where do you get this stuff ??
Cute graphic, by the way. I like cats.

[4x4le]

the topic is engine tuning, street vs dyno

you ran your mouth about stuff you know nothing about, got cornered in your own bluff and tried to change the subject.

Still havent shed any insite on anything, nothing based on facts, no examples given for anything.

Anything I say Im fully prepared to back up, as I said earlier, try me.

Foot settings, as a matter of fact it came from initial d, I thought it was catchy and started saying that instead of ALIGNMENT settings for the hell of it. Yea i seen the red squiggly line under the misspelled word and totally didnt give a shit to right click on it to change it.
Engineering book, um no. Ive been having to deal with engineers for the past 6 years and my conclusion with them are they are the dumbest group of stubborn fucking people Ive ever had the pleasure of dealing with. Most likely Im replying to one right now.
If you want to make yourself sound smart just list examples to support your claim and stay on topic. No one is impressed with your spell checker.

the graphic came from google images btw

[rocknrollkat]

The topic is --- "Tuning on the dyno or street? "
The word "engine" does not appear in the topic.
I see the language degenerating and the name calling is starting.
Nobody's going to learn anything here, since you seem to have it all covered.
"Foot settings" and alinmet", honestly, I thought you meant "Liniment" and were complaining about your bad foot !!
Forget that I've been around high performance cars my entire life, you're not going to learn anything, you know it all.
So let's do the "Burger King" thing and have it "Your way".
You can have the last word if you like, and I'm sure you will.
I've got other things to do.

[4x4le]

Your 63, dynos were not something of your time i guess. Maybe thats why you thought anything other than engines were tuned on them?
Last word, im sure others will have cute comments.

[travisty_]

I thought the topic was tuning.

The topic is clearly engine tuning, now back on topic.

[bardabe]

I thought the topic was tuning. How is that off topic ?? Foot settings ?? What engineering book did THAT term come out of ??
Alinment ?? Do you mean "alignment" ?? Where do you get this stuff ??
Cute graphic, by the way. I like cats.

Your an Idiot, we are clearly talking about engine tunning, to the OP. Please spend money on Dyno time, and don't cheap out with a POS Dyno Jet, use a Dyno Dynamics or Dynapack.

[Kingtal0n]

Engine tuning: The eternal question, Street or dyno?

First its important to mention like someone already said, "tuning" refers to the entire vehicle not just the engine. But since this topic is engine specific, it will be ok to examine specifically engine tuning IN PARTICULAR INSTANCES.

For this particular instance we will assume the engine will be daily driven. We will assume it uses pump gas. We will assume it spends most of its time at stop lights and possibly cruising steady around 40mph and 70mph.
What is important then? REALLY Important?


Lets jump to the meat and potatoes of engine tuning: The right chemical reaction. We are trying to apply force to a crankshaft by burning fuel and air- WHILE keeping the amount of fuel burnt to a minimum for the given force applied (fuel economy!) and supplying enough fuel and the right ignition point to prevent engine damage!

IF we prevent engine damage, and minimize the amount of fuel burnt, and maximize the amount of force applied to the crankshaft for any given "cell" of engine parameter... then we have taken care of the fundamental aspects of engine tuning, right? This is where I will focal point my final investigation for the thread "title"...

the original question is street or dyno. Let me start by saying there are many kinds of dynos, engine dynos for instance can tune an engine without even needing a vehicle. I could do all of the engine tuning without even driving the car right? Well, technically... But we are assuming you guys mean CHASSIS DYNO by which the actual tire of a vehicle touches a roller with a (usually) given mass so that a computer can determine the horsepower by measuring how quickly that roller accelerates. AND THATS IT! Thats all a Dyno Does! It has NOTHING to do with tuning AT ALL!!!! Its just a TOOL that can be USED for tuning!So my initial observation for the street or dyno argument is simple: Can you afford this tool? Because clearly, if you can afford to use an obviously helpful tool (When used correctly) then why not?

Lets ask a new question: Is it DESIRABLE to tune an Engine(topic) on a chassis dyno instead of the street? My short answer is NO, the street would be preferred, simply because it represents a more REAL SITUATION for the vehicle. That is, specifically, the load represented by the street is given based on the vehicle's weight and rolling resistance and gravity and all that cool physics stuff, where the load represented by a random chassis dyno roller is represented ONLY by the weight of the roller. So your "perfect dyno tune" can fall to complete $#!T once that heavy vehicle hits the right and your seemingly "perfect" 15 degrees of timing under load that gave such a smooth flat torque curve without a hint of knock blows a hole in the headgasket instantly. So no, a dyno is a TOOL but it is not THE tool, it is not the all important say in how "well" an engine is tuned given the circumstance. It can and should only be used to tune an engine IN ADDITION TO the natural experience of the car driving on a street. I am not saying that is impossible to strict tune a car on a dyno, NO, and experiened tuner may be able to determine that the vehicle will require a few degrees less of timing or a small bump in fuel or the additional loading characteristics observed when a vehicle hits the road... you CAN account for these things but that is off topic! The original question was: Street or dyno? So after all of this we see that simply:

1. A dyno is only a tool that may be used in addition to other tools to tune an engine (or other off topic aspects)
2. A dyno is only capable of giving you the "tune" that the tuner is capable of extracting from it. A dyno by itself does not "tune" anything.
3. Real engine tuning is usually based on knowledge of how an engine works and usually some experience and a good tuner should use ALL tools available to him/her.

and last, #4: Every vehicle is different, every set of tools is different, every calibration of every potential difference is different, every real world calculation back to back even for the same set of variables is going to be different. I blame matter, for matter is discrete and sooo impossibly tiny, the number of electrons moved from place to place during a dyno run even if misplaced by a single elementary charge will give different results. So #4 basically just says that you can only do the best you can do, and you should use every tool available with as much knowledge of how those tools work to maximize the performance (which includes economy) of whatever you are working with, be it cars or computers or people.

[4x4le]

^^^^ I would totally agree with you if every dyno were a dyno jet but they are not.

Do some research. Specifically look at what you can do with a dyno dynamics dyno. It is not inertia based its load based.
But we are assuming you guys mean CHASSIS DYNO by which the actual tire of a vehicle touches a roller with a (usually) given mass so that a computer can determine the horsepower by measuring how quickly that roller accelerates. AND THATS IT! Thats all a Dyno Does! It has NOTHING to do with tuning AT ALL!!!!
Thats how a junky dyno jet works. It knows the weight of a roller and estimates hp based on how quick you spin the roller up and then calculates tq from its hp estimate.
A dyno dynamics applies tq to the rear wheels and knows how much your creating to overcome its tq and can get an accurate hp figure from that. You can raise or lower the tq imput from anything to simulate driving on ice all the way up to trying to pull a building up a mountain (impossible load).


Now I almost agree with everything else you said though, im just assuming you dont know much about load bearing dynos. With one, if you tune each cell, cell by cell, and enter each cell by adjusting load on the dyno, only that type of load will make your engine enter those cells wether its on the dyno, street, race track, or offroad. Scaling your maps right is also important (wether its tuned on a dyno or street) because if there is too much of a gap you can get into the unknown.

Post #9 is one of the single most important reasons tuning on anything other than a load dyno is a no no.

[Kingtal0n]

^^^^ I would totally agree with you if every dyno were a dyno jet but they are not.

Do some research. Specifically look at what you can do with a dyno dynamics dyno. It is not inertia based its load based.

Thats how a junky dyno jet works. It knows the weight of a roller and estimates hp based on how quick you spin the roller up and then calculates tq from its hp estimate.
A dyno dynamics applies tq to the rear wheels and knows how much your creating to overcome its tq and can get an accurate hp figure from that. You can raise or lower the tq imput from anything to simulate driving on ice all the way up to trying to pull a building up a mountain (impossible load).


Now I almost agree with everything else you said though, im just assuming you dont know much about load bearing dynos. With one, if you tune each cell, cell by cell, and enter each cell by adjusting load on the dyno, only that type of load will make your engine enter those cells wether its on the dyno, street, race track, or offroad. Scaling your maps right is also important (wether its tuned on a dyno or street) because if there is too much of a gap you can get into the unknown.

Post #9 is one of the single most important reasons tuning on anything other than a load dyno is a no no.


Yes, all my data is assuming a very specific instance and typical chassis dyno. Change one thing and every word is meaningless. So you agree with me in the specific context with which I Wrote all those words... yes you should because I did cover my ass. Most people do not know what a loading dyno is.

You are still faced with tools vs dollars. To effectively use a load type dyno is still going to cost money and it still does not "tune" anything, that is still the tuner's job.

So let me add the load dyno and comparison contrast it for you now:
Yes you can hit nearly any load spot on your map because you can adjust the throttle valve and "weight" of your roller simultaneously. There is still a discrepancy to the vehicle weight; that is, you are strictly tuning the performance of the engine on those load cells without actually driving the vehicle's own weight around. So the final tune will still change once the vehicle hits the real road, just like it will change when the atmospheric pressure fluctuates and your "0 load" map based tune becomes richer/leaner since a map sensor can not measure the mass of air- its up to the tuner to provide fueling based on what the engine desires at that instant. With this in mind, you can instantly say that there is no such thing as a "perfect tune" because the instant you drive anywhere, up or down, rain or shine, hot or cold, everything changes, and so does the performance characteristics of the engine. These things cannot be helped! So what we are looking at now is simply headroom! Room for changing variables, wiggle room to prevent engine damage and provide maximum performance. As close to the edge of chaos as possible but not over the line!

Which brings us back to the actual street where the car will drive. If I ship the car up north and get it "perfectly tuned" by a load dyno and bring it back- whats the difference between that and a mail order ROM tune based on a similar combination? Ah, Actually having the engine in front of the tuner, being able to adjust the fuel pressure on the spot, noticing that yes, the EGT drops and the torque climbs as I add a few degrees of timing. Can we see this sort of thing on the street? NOT GENERALLY... Thats why dynos are considered TOOLS, they do give us valuable information if used correctly. ALL OF THEM DO. Even a "crappy chassis dyno" without the ability to measure horsepower or torque (lets say its broken today) Is still a valuable tool... We can still accelerate and data-log and make changes right? So there is a place for every tool in the world:

The street is the ultimate tool. This is where and how the car is actually driven. there is no better way to "simulate" actual real world driving than actual real world driving, period, I dont care what kind of dyno you have. Unsafe? If you are being UNSAFE with this then you are doing it WRONG. There is no reason to be "solo tuning and driving" For god's sake have someone drive the car around (um, the owner?) while you do your job and tune that shit- exactly as the owner drives it! THEN take the vehicle to a dyno and run it as it sits! Do some final minor crispy edges tuning but the bulk should already have been done on the street.

And lets also examine a specific instance when there is no one available to drive the vehicle. YOU are the driver AND the tuner now. Dangerous yet? It doesn't have to be! First of all, there is no reason to be driving around with the laptop open. If you are a real tuner you can read data-logs, and with that means that you can drive some, stop and tune, drive some more, stop and tune, drive some more, stop and tune. I have done this and to be honest it is VERY FAST AND EASY IF AND ONLY IF you have the capability to log wideband air/fuel ratios along with load cells. With that one simple capability this job becomes effortless- you know a desired A/F ratio and within 20 minutes those numbers are popping up everywhere.

[rocknrollkat]

Kingtalon said --- "The street is the ultimate tool."
Now we're getting somewhere.
Okay, let's say that the topic is "Engine tuning". It's not in the header, as I poinetd out, but let's move ahead.
If we're discussing engine tuning, then why is there so much talk about chassis dynos ??
If we're tuning engines, let's do it right and use an engine dyno.
It makes the most sense to develop the engine on the test bed, get all your settings correct, then place it in the chassis, track test, etc. to establish a baseline.
That's where we initially evaluate everything in the system from tire pressues to driver attitude.
The chassis dyno (a misnomer, since it's the driveline we're evaluating, NOT the chassis and suspension) is where we can see how the driveline responds to transmission ratio changes, rear drive ratio changes, etc.
There's more, of course....

[Kingtal0n]

I street tune for driveability only. Im only worried that the afr stays acceptable and everything feels smooth.
Power is to be made on a dyno. I have had so many dynojet tunes and street tunes come to me so i can put them on a load based dyno dynamics and i have always made more power. More safer power i should say because there have ALWAYS been areas that had too much timing and either too much or not enough fuel. Your engine revvs so quick that your wideband is gathering an average afr in the exhaust, but when slowed down on the dyno where it has to hold at every rpm for a few seconds you can quickly see that 4000 rpms is holding a 13:1 afr and 4250 is holding a 9:1 afr and then 4500 is sitting on 10.8:1 and so on. On the street or on a dynojet this may end up looking like a perfectly acceptible solid 11.5:1 and it was achieved and the truth is your lean and rich during some cycles.

This is beautiful. Many people do not realize how discrete matter really is, and most of our tools take, as you mention, averages for our single digit simplicity pleasure. There is much more in this post than anyone realizes, I want to pick a few good un-obvious points out though right away;

As you mentioned, the air fuel is jumping in your example because the engine is accelerating too quickly to determine exactly what load cell is what air/fuel and everything is a jumbled up mess. Typical of single wide open throttle runs, right? There are many tools to combat this mess, such as a transient delay wideband data-logging session, and common sense. I know the air/fuel that was picked up in my cell .020 seconds after the cell was being read is behind about .150 seconds because the fuel injected from that cell at 2,000 rpm has to be burnt and read by the O2 sensor. Thats transient delay. The common sense part comes from reading the log and noting that from one cell to the next the number simply change: That is, specifically, If you put the same exact fueling number into every single load cell, then technically, the air fuel ratio should be the exact same for every single load cell also, right? WRONG! Internal combustion engines are generally NOT LINEAR. The air fuel is fluctuating for MANY Reasons, but generally, it fluctuates because volumetric efficiency changes, and with it, so does the mass of air being burnt and the required amount of fuel being injected. But we are skipping the plethora of other changing variables such as; air temperature (as compressor efficiency changes) which affects air mass (you can increase VE and decrease air MASS and make less power because of this and thus require less fuel even though the engine is more efficient... think of a T-25 turned up past 10psi on a 3L engine at almost any RPM), engine flow characteristics (pretend our example engine has a long 28" runner manifold and the VE spikes around 4400rpm drastically then falls off quickly afterwards, like a chevy tuned port injection from 1992).

These things affect engine breathing capability and they require more than just a "line of numbers that makes sense". A good tuner should be able to recognize a 28" runner and should know about the acoustic effects of Helmholtz (thanks scott!). A good tuner should recognize that not every cell in a straight line should have the same fuel and timing value. This is now common sense; but therein lies the ultimate definition of tuning: Technically, I never need to start the engine. Technically, I never need to drive the car. Technically, I can calculate the amount of fuel required by the engine at ALL load spots without even seeing it. If I account for everything; that is, all of the fluctuation of airflow, all of the changes in air temp, all of the rotating mass requirement even the viscosity of the oil and the pumping action of the lifters and the shape of the intake ports and the lengths of the runners and the size of the exhaust inlets and the shape of the turbine and the location of the wastegate and the symmetry of the exhaust manifold and the expected path of the incoming column of air through the calculated velocity of that air at the expected flow rate of the engine at any RPM, even calculate the speed of the injectors at the voltage supplied with math can determine pretty damn close how much fuel is going to be injected and there are some things we MUST assume such as the tightness of the cylinder (we must assume the engine is properly assembled) if EVERYTHING is accounted for with good math then we technically never need to start it to "tune" it.

Which brings me back to the common sense aspect of tuning and the reason air fuel ratio numbers "jump seemingly randomly" as an engine makes a pass through it's fuel map; If the jumping around does not make sense then either you lack the tuning common sense ability, or, there is something wrong with one or more of the components. The Air/Fuel ratio on a Honda S2000 engine will be consistant with the same fuel value in every maximum N/A load box because the volumetric efficiency and atmospheric pressure do not change much as it accelerates during a wide open throttle run (thanks to honda design of course) my point here is simply this common sense aspect; should the tune "jump around" that is, as you mentioned, should the air fuel fluctuate for any reason, we know there is a problem with one or more of the components... because common sense tells me that the VE and therefore torque on this N/A engine should/is flat and so should the fuel requirement be assuming a steady A/F is desirable. We wont even need a wideband if I calculated the injector on-time required at every rpm for the desired A/F ratio.

[Kingtal0n]

Kingtalon said --- "The street is the ultimate tool."
Now we're getting somewhere.
Okay, let's say that the topic is "Engine tuning". It's not in the header, as I poinetd out, but let's move ahead.
If we're discussing engine tuning, then why is there so much talk about chassis dynos ??
If we're tuning engines, let's do it right and use an engine dyno.
It makes the most sense to develop the engine on the test bed, get all your settings correct, then place it in the chassis, track test, etc. to establish a baseline.
That's where we initially evaluate everything in the system from tire pressues to driver attitude.
The chassis dyno (a misnomer, since it's the driveline we're evaluating, NOT the chassis and suspension) is where we can see how the driveline responds to transmission ratio changes, rear drive ratio changes, etc.
There's more, of course....

Well you are out of context here. I said the "ultimate tool..." with regards to my original comparison: "We are assuming daily driver, pump gas, etc..." Keep in mind everything I write is from this aspect (since that is most of our goals, a daily driver performance vehicle with good fuel economy)... In Which Case... The street is the ultimate "tool" simply by virtue of being the place that the vehicle will spend most of its time. If we are talking a strict drag vehicle then a TRACK is the "ultimate tool" because the numbers that appear on the big screen is our "dyno"- its how we know if the car is faster or slower, which is all that matters to a strict drag vehicle.

[rocknrollkat]

Well you are out of context here. I said the "ultimate tool..." with regards to my original comparison: "We are assuming daily driver, pump gas, etc..." Keep in mind everything I write is from this aspect (since that is most of our goals, a daily driver performance vehicle with good fuel economy)... In Which Case... The street is the ultimate "tool" simply by virtue of being the place that the vehicle will spend most of its time. If we are talking a strict drag vehicle then a TRACK is the "ultimate tool" because the numbers that appear on the big screen is our "dyno"- its how we know if the car is faster or slower, which is all that matters to a strict drag vehicle.
No context problems here.
The street gives its own numbers, like fuel economy, if that's what you're set up for. "J" curves, anyone ??
Also, racing is not just drag racing. Yes, the 'clock' at the end of the strip is the "tell-all", but lap times anre the determining factor in road racing.
I agree that the final result is the real world, the dyno is just another tool among many.
More to follow....

[Kingtal0n]

If we're discussing engine tuning, then why is there so much talk about chassis dynos ??
If we're tuning engines, let's do it right and use an engine dyno.
It makes the most sense to develop the engine on the test bed, get all your settings correct, then place it in the chassis, track test, etc. to establish a baseline.

Engine dyno tuning is useful and it has a place but it is not the end-all of engine tuning. The main IMPORTANT thing to keep in mind is resistance- just like resistance on a muscle during strength training, the force of gravity on the mass of a vehicle m, combines to form a vehicle weight, which by the physics of friction and a given tire compound, will exert an opposing force on the drivetrain (and thus the crankshaft/connecting rod/piston) and this opposing force is the MAJOR DIFFERENCE that everyone seems to be missing when comparing engine dyno / chassis dyno / street application tuning.

To illustrate this important let me think up an example:

I have a 6L engine at idle. If I snap open the throttle, it free revs easily to 6000rpm- very fast right? Because there is no load right? Well, actually the rotating assembly represents the load- the weight of the components that are turning and require "work" to move, those components represent an opposing force on our engine, just like a load from the road. Its just significantly LESS than a road would provide.

So enough energy is produced to accelerate the internals. Some energy is used to simply keep the components moving, and the leftover is available to accelerate them as fast as we want- until we run out of energy or until the whole thing flies apart in pieces. Either way, the concept here is whats important: The goal of Free revving an engine is identical to the goal of revving an engine under load- Increase engine RPM, thereby increasing the rotating speed of the components, and in a vehicle, the speed of the tires right?

Now we can hit the nail directly: Think of my 6L Engine free revving and how quickly and easily it does... THEN think of my 6L engine in a VERY HEAVY TRUCK. Now put the truck in fifth gear (at zero MPH) and dump the clutch and go wide open throttle. Clearly, instead of a clean free rev, we get a dead engine or a seriously ruined clutch. THIS IS THE CRITICAL DIFFERENCE! The "WEIGHT" of our rotating assembly increases dramatically when we connect it to the drivetrain of the truck. Suddenly the engine not only has to accelerate its own internals; NOW it has to also accelerate an enormous mass of metals also.

So lets draw a line between the two situations: Lets start to lighten up our truck. As I take weight from the truck, more and more weight, until finally the truck is completely gone all together and we are left with only our engine alone again; AS I REMOVE WEIGHT from both the truck and its rotating components until they are GONE... At some point, at some critical point, our engine becomes "capable" of actually moving the truck, even in fifth gear. This can lead to a tech talk about gearing and torque but lets move past that into the real central idea I want to bring to the table: The resistance experienced by the rotating assembly of the engine directly affects its fuel and timing requirements. . As we lighten up the truck, during a full throttle (0 vacuum) run, it will generally require more and more ignition timing (for the sake economy and burning the most of our dollars) and less and less fuel (as fuel only serves two purposes: burn for energy and prevent engine damage). Same engine, different loads, totally different fueling/timing requirements. To see why you must visualize the piston being forced down by the expanding soon to be exhaust gas. The gas expansion represents the ability to transmit energy to the rotating assembly. If the gas expansion happens TOO QUICKLY engine damage will result. If the expansion happens too SLOWLY we will lose fuel to the exhaust plumbing (EGT should go up!). The same thing applies to the ignition timing; as the load increases we want less and less ignition advance, or engine damage will result (because the burn begins too soon!). So lets jump back to our engine dyno for a minute; Does the load exerted on the flywheel by the engine dyno exactly mimic the load experienced by that engine when it is installed in a vehicle of given mass m? NO. Not unless we set it up to do exactly that job! Therefore, an engine dyno can generally not represent a way to "tune an engine" before it goes into a vehicle, since depending upon the vehicles various components masses (m), the required amount of fuel and the required amount of timing will change. You can get close, but fine tuning will always be required, and nothing is ever perfect. Imagine I want to tow a trailer one day... Did I account for this in my fuel and timing map? I Mean 0psi is 0psi, whether I have a trailer on the back or not, so my truck was fine for years until I decided to pull a trailer one day and my "perfect map" blew my engine because my ignition timing was "perfect" for the truck's exact mass all these years and I had no headroom for the trailer.

[4x4le]

I tend to disagree about the road forces and weight changing (such as towing a trailer) changing what is needed from a tune although when I tune a car on a dyno dynamics I do change the load all the way, even to a point that the engine cannot overcome the load at all.

In theory the max power is going to come from the flame front being extinguished 15* after tdc. So, I do tend to bring some safty margin into my tunes by trying to come close to finding this. If I add 1* of timing across the map and gain 15hp everywhere great, time to add another 1*. Cool, made another 15hp. Add another 1* in 2 different cells (or at certain rpms) I only gained 10hp but gained 15hp in the others. Im going to watch the areas that only gained 10. If I only gain 5 the next time in those areas I have the decision to make to either leave their values there, retard it back 1 in those areas or whatever. Since it was still making gains Ill typically leave it there because if it was still making more power than before it wasnt detenating yet (im listening for that as well). I can then load the dyno up to a higher value and 99% of the time It will make the exact same power as it did on the previous pull, still be entering the same cells too if were still at the same boost or vac level, were just causing the engine to rev slower. The engine will still consume the same air at that rpm per cycle regardless of load and if your igniting the mixture at the same time too ( * btdc) and the piston is moving at the same speed, the flame front will go at at the same time too.

kingtalon, you seem really smart and I cant help but think a dyno dynamics would change your entire outlook on everything and make you a dangerous weapon when it comes to tuning.

[rocknrollkat]

Kingtalon said ---"Engine dyno tuning is useful and it has a place but it is not the end-all of engine tuning.", which is pretty much what I said, which was --- "It makes the most sense to develop the engine on the test bed, get all your settings correct, then place it in the chassis, track test, etc. to establish a baseline."
It may seem simplistic, as you point out, to set up an engine on the dyno, since the engine has no idea where it is.
In a vacuum, that's correct, as an abstract assumption.
However....
As far back as the early 1960s, when Ford was developing the four cam Indianapolis V8, the engineers set the engine dyno to simulate the track conditions at Indy. The automation ran the engine lap after lap and the engine had no idea that it was on an engine dyno, it thought it was in a racecar at Indy.
Here's some info on the engine, enjoy !!
Development of the Quad Cam Ford engine (http://www.quadcamford.com/development.html)

[4x4le]

Here is a t25 ka-t i tuned. It was street tuned by a local tuner, blew up, rebuilt, retuned on the street again. The lower numbers was the tune it came to me with. I didnt advance the timing ANYWHERE i retarded it. Some areas need more fuel, some needed less. Im sure it would have blown up again if I wouldnt have dyno tuned it.
Ill stick to my opinion and ill encourage anyone that likes street tuning an engine to try out a dyno dynamics.

sent from my rooted thunderbolt

[rocknrollkat]

Here is a t25 ka-t i tuned. It was street tuned by a local tuner, blew up, rebuilt, retuned on the street again. The lower numbers was the tune it came to me with. I didnt advance the timing ANYWHERE i retarded it. Some areas need more fuel, some needed less. Im sure it would have blown up again if I wouldnt have dyno tuned it.
Ill stick to my opinion and ill encourage anyone that likes street tuning an engine to try out a dyno dynamics.

sent from my rooted thunderboltThis is too funny !!
Let's see, an engine that you didn't tune blows itself up, and you all but guarantee that if you 'tuned' it, it would be blowup proof !!
Let me fill you in on something that should be obvious.
Drivers blow up engines.
If this driver over-revs his engine with your 'tune', it'll blow up just like it did before, only sooner, because now it's got more power !!

[4x4le]

This is too funny !!
Let's see, an engine that you didn't tune blows itself up, and you all but guarantee that if you 'tuned' it, it would be blowup proof !!
Let me fill you in on something that should be obvious.
Drivers blow up engines.
If this driver over-revs his engine with your 'tune', it'll blow up just like it did before, only sooner, because now it's got more power !!
Do you realize how fucking retarded your making your self sound grandpa? I would never promise someone a bullit proof engine. What i was saying that he wouldnt have even had to do anything stupid at all with that engine and it would blow. Its detenation was so audiable it was sickning. I didnt add 1* of timing in its map anywhere, i pulled at least 5* from everywhere and as much as 15* in some areas. Also the air fuel ratios were wack.

And your not filling me in on a god damn thing either, i know all engines are doomed at some point. Do you think i havent blown my fair share of engines at the track? Never fault of a tune, some got a little hot, some lost oil pressure, my fault for not noticing but not my fault for the tune.
You know, i bet if he drains his oil and goes racing it would probably blow up too huh? Or if he runs out of gas he probably wont be able to get it started.
Usually its the 16 year olds stating stupid things on here, not olds that have but 16 years left to live.


sent from my rooted thunderbolt

[rocknrollkat]

You sound angry.
Let's see, you said --- "Im sure it would have blown up again if I wouldnt have dyno tuned it."
You're pretty much coming in the side door by saying that without your wizardry, the engine was doomed to fail again. in effect, you're saying that you deliver blowup proof engines.
I like the 'grandpa' touch.
I was setting up racecars before you AND your father were born, sonny.
Oh, and by the way, you also mentioned --- "Also the air fuel ratios were wack."
Just what does "wack" mean ??
I couldn't find it in any reference book.
It's not a Japanese word either, in case you're trying to pawn yourself off as "JDM".
Settle down, you'll live longer, trust me.

[rocknrollkat]

Your 63, dynos were not something of your time i guess. Maybe thats why you thought anything other than engines were tuned on them?
Last word, im sure others will have cute comments.Yes, I'm 63, and dynos were around LONG before the early 1960s, when I first got involved with cars.
"You guess ??"
From what I can see, you guess quite a bit.
Instead of guessing, here's a link that will introduce you to dynamometers, from the earliest "Prony Brake" to the latest innovations.
Dynamometer History - A Timeline of Innovation (http://ezinearticles.com/?Dynamometer-History---A-Timeline-of-Innovation&id=1022510)

[4x4le]

All you have done since your stay on zilvia has started is beat around the bush and make yourself look like a douche.
You have impressed me with none of your own knowlege and it seems you have learned how to google stuff and copy and paste links. Look up troll, your picture will be listed.

[rocknrollkat]

All you have done since your stay on zilvia has started is beat around the bush and make yourself look like a douche.
You have impressed me with none of your own knowlege and it seems you have learned how to google stuff and copy and paste links. Look up troll, your picture will be listed.Luckily, I don't exist on this planet to impress you. Obviously your ego gets in the way of any coherent responses, and your 'knowledge' of the topic is pathetic. It's useless to attempt any meaningful dialogue with someone who immediately covers his (her ??) ignorance with foul language, childish attempts at put downs, and name calling.
Engine 'tuning' ?? It's all plug 'n' play to you. Without your laptop you'd be lost. And poking fun at my age ?? Now THAT'S childish !!
My knowledge would be lost on you.
First, you can't shut up long enough to hear anything, and if you did, you haven't shown me enough background knowledge to be able to comprehend anythig I could tell you.
Battery's dead on your laptop ??
'Tuning' session's over !!

[4x4le]

honestly what are you talking about? Yes, tuning efi systems is plug and play. Were not jetting carbs and setting mechanical advance on distributors.

Were not changing chips in 7al's.
Tuning ecu's is very precise work and I have become very good at doing this. I have a good reputation for doing this and I have customers come from all over to have their engines calibrated by me. No horror stories, and plenty of return customers when they change cars or the setups on their cars.

Yea I poked at your age, reason being, you havent brought anything but old school ideas to the table. Should I have kept going with it, no your right.
Do you know about cars? Quite possibly, no one would know though by reading what little you have posted on here. Im 4x4le on every forum im on. Feel free to look me up if you wish, I have helped many many people out.

What keeps me wondering about you is how you dont seem to think that it was a big deal that pulling 15* of timing out of a ka-t and making more power as a result wasnt alarming. That engine WOULD have blow its self to pieces. You also seem to think it will be more likely to blow up now because it makes more power? No, its cyl pressures are now lower but they are just being pressurized at the right times. Im sure you already knew that though.

[rocknrollkat]

honestly what are you talking about? Yes, tuning efi systems is plug and play. Were not jetting carbs and setting mechanical advance on distributors.

Were not changing chips in 7al's.
Tuning ecu's is very precise work and I have become very good at doing this. I have a good reputation for doing this and I have customers come from all over to have their engines calibrated by me. No horror stories, and plenty of return customers when they change cars or the setups on their cars.

Yea I poked at your age, reason being, you havent brought anything but old school ideas to the table. Should I have kept going with it, no your right.
Do you know about cars? Quite possibly, no one would know though by reading what little you have posted on here. Im 4x4le on every forum im on. Feel free to look me up if you wish, I have helped many many people out.

What keeps me wondering about you is how you dont seem to think that it was a big deal that pulling 15* of timing out of a ka-t and making more power as a result wasnt alarming. That engine WOULD have blow its self to pieces. You also seem to think it will be more likely to blow up now because it makes more power? No, its cyl pressures are now lower but they are just being pressurized at the right times. Im sure you already knew that though.Actually, we never got to the point of discussing timing, or anything else relevant for that matter. Now that you seem to be addressing specific topics besides my age (no offense taken), 'timing' is a discussion that gets involved pretty quickly. Fifteen degrees (15) is an arbirary number until we put it in context. If you can hear detonantion from across the street, then obviously there's a problem, and the ignition key is the first step to a solution. Turn the engine OFF !!
If the driver kept 'pushing' the engine with that kind of racket coming from under the hood, then take your pick, 'holed' piston, bent rod, shattered valve ?? It's up to fate at that point. What did the driver think was happening ??
I'd check several things, including timing. Don't forget 'bad' gas. Picking up a bad batch at the pump has happened, and don't overlook that possibility.
Of course you know that timing that is TOO advanced leads to a very quick falloff in power, even if detonantion is not present.
I've seen power increase by RETARDING the timing to a more realistic number (still advanced, but not past the max pwr. point)
That's where a dyno makes life easier, but it sure helps to listen for "engine knock" !! (an 'old school' term for you.).
Regards,
Bill

[mr_eh]

skipped everyones reply.

431whp srt4 tuned on the street most of it's life - it did see some dyno tunes but it was always finalized and checked on the street.

315whp break in tune on my built sr 35r full race kit was on the dyno, and will get it's full tune on the dyno...

I'd prefer all of the dyno tuning be done on the street but it's not always viable, depends on the tuner.

[rocknrollkat]

skipped everyones reply.

431whp srt4 tuned on the street most of it's life - it did see some dyno tunes but it was always finalized and checked on the street.

315whp break in tune on my built sr 35r full race kit was on the dyno, and will get it's full tune on the dyno...

I'd prefer all of the dyno tuning be done on the street but it's not always viable, depends on the tuner.I agree. that's what started this discussion in the first place. I've been doing it this way since 1963, and yes, we had dynos back then. The time slip or the triple stopwatch lap timing board was the end game, not the dyno chart.

Bill