Question about Dyno Numbers

[NismoRacer1]

OK so this past weekend there was a car show in my hometown which I went to with some friends. There was a dyno competition that paid cash prizes to the winners so I entered and won, although my numbers were extremely low. The last time I dynoed was on a DynoJet and made 305 HP & 302 ft/lbs and this time I was on a Mustang Dyno and made 253 HP & 549 ft/lbs. The guy running the dyno said to add 40% to my HP numbers to compare it to DynoJet numbers and that the torque was just fucked up period. I called bullshit on that and just figured he didn't know how to operate the dyno but a C5 Z06 got on an only put down 270 HP which he said he normally makes 360 HP so I'm just confused about the whole thing.


Any comments?

[ThatGuy]

Different dynos have different results. Nothing new there. Google dynos and you will recieve similar information.

[NismoRacer1]

I guess my question is 40% correction accurate cuz that would put me at 354 HP which is kinda high for my setup

[johngriff]

A mustang Dyno is a tuners dyno. People use them for the eddy brakes.

DynoJet is a honda boi dyno, people use them to grab inflated numbers.

If you want the absolute most accurate HP number reading, find somewhere witha a MAHA dyno. Der German Sceintific Specification.

If you want a baller tunning dyno, find a DynoDynamics, Aussie build everything fat, and this has the fattest eddy brakes on the market.

[/thread]

[ThatGuy]

Google search yielded this about DynoJet vs. Mustang Dyno.
Actually...The Mustang Dyno's work slightly different than the Dyno-Jet Dyno's...

Mustang Dyno's apply a load, via eletro-mechanical resistance, then rwhp is calculated based on how your "acceleration/unit of time" of this load occurs...

DynoJet Dyno's simply use a large drum, of know mass, as its rotating resistance...Then rwhp is calculated based on how your "acceleration/unit of time" of the drum occurs...

From what I am told the Mustang dyno gives you a "true" or real world rwhp... i.e. my '00 FRC put down 307 rwhp stock, using 12% drivetrain loss and that is 348 flywheel hp (factory rated 345 hp)...My '02 Z06, on the same Mustang dyno, put down 348 rwhp stock, divide that by 12%, using the same 12% drivetrain loss is 395 fwhp (factory rated at 405 hp)

Dyno Jet Dynos give more of a bragging rights rwhp...

The difference between the two is about 10%...Dyno Jets registering the higher hp readings...

Yours for example...358 rwhp Mustang Dyno vs. 405 rwhp DynoJet...358/405=.884...Pretty close to the 10%...

Last comparison one of the F-body guys posted on LS1.com was the something like the following...338 rwhp Mustang vs. 378 rwhp DynoJet...338/378=.901

On the Mustang dyno that I go to...Stock LS1's in F-body cars dyno in the 280~290 rwhp range...Yet nearly every LS1 F-body that posts rwhp using DynoJet Dynos are in the 310~320 rwhp stock...285/315=0.905

Again...285 rwhp using 12% drivetrain loss gives 324 fwhp, factory rated 320 hp...If you use the DynoJet hp, then you get the following...315 rwhp with 12% drivetrain loss gives 358 fwhp, factory rated 320 hp...So you see, it sound great to think these engines are putting out this kind of power, but it's just not as realistic of a number as you get with the Mustang Dyno...

It really doesn't matter what Dyno you use...Just as long as you keep using the same dyno to check your mods...This will keep variances down to a minimum and tell you truely if any mod is helping or not...

[lucky7]

what about a dynapack hub dyno? the guy that is going to tune my car will use one of those. im sure they arent as accurate as a mustang dyno, since you have to remove your wheels. lol.

[LowNismo17]

it all depends on what settings they enter in too.. also the reason why the tq is so messed was probably because of wheels spin. On the local mustang awd dyno anytime you have wheel spin the numbers go crazy.

[johngriff]

Wheel spin= bad dyno techs. Not knowing how to mount a car... ok.

Steer clear of dynapacks. You are looking to use the dyno to create an artificial load, then measure the total tourqe output of the drivetrain, to assign timing correctly.

You can af/r on a dynapack. You can af/r on a dynojet. You can af/r on the street, that is simple.

Actually pulling real world tq numbers out of engine using ignition timing is tunning. Get what you pay for.

[NismoRacer1]

it all depends on what settings they enter in too.. also the reason why the tq is so messed was probably because of wheels spin. On the local mustang awd dyno anytime you have wheel spin the numbers go crazy.


Yea my friends said they thought i was spinning on the dyno, i felt like it was too but the guys working it said i didn't. All i know is when I caught full boost it revved up real fast like its supposed to and then it just kinda stuck there at 6000 as if it was spinning and then eventually went the rest of the way up.

[steve shadows]

Wheel spin= bad dyno techs. Not knowing how to mount a car... ok.

Steer clear of dynapacks. You are looking to use the dyno to create an artificial load, then measure the total tourqe output of the drivetrain, to assign timing correctly.

You can af/r on a dynapack. You can af/r on a dynojet. You can af/r on the street, that is simple.

Actually pulling real world tq numbers out of engine using ignition timing is tunning. Get what you pay for.

how is timing assigned via dyno read out?

[steve shadows]

Real world numbers? as in read out?

I am only familiar with load point tuning for torque.

But torque is the only reading you can actually (literally) tune for in load by load or torque by lb ft of torque to tune on a dyno meter.

HP is a rate at which is torque is applied over RPM, so it is not the same.

Power is power, whether the car is street tuned or dyno-tuned. I think a measure of a good tuner is having a car set up on paper

or street tune so well that hardly any load point re-fining is needed once on the dyno, saves a lot of time as well.

cheers

[johngriff]

Real world numbers? as in read out?

I am only familiar with load point tuning for torque.

But torque is the only reading you can actually (literally) tune for in load by load or torque by lb ft of torque to tune on a dyno meter.

HP is a rate at which is torque is applied over RPM, so it is not the same.

Power is power, whether the car is street tuned or dyno-tuned. I think a measure of a good tuner is having a car set up on paper

or street tune so well that hardly any load point re-fining is needed once on the dyno, saves a lot of time as well.

cheers

Sounds like my words verbatim.

Minus the tuning of ignition on the street. What, tune tq by the seat of your pants? Or maybe tune off the knock sensor? Cylinder temp a little to hot... BOOM.. =/ sorry bro.

People were asking about dyno's, not the basics of tuning. I am glad you rehashed some of the basics.


All i know is when I caught full boost it revved up real fast like its supposed to and then it just kinda stuck there at 6000 as if it was spinning and then eventually went the rest of the way up.


This bump that you felt was the eddy current brake of the dyno. Either they had set up a 6k load point for you to bump against, or had turned it up to get the total tq output right up to 6k. If you had wheel spin, the "engine would continue to rev up" as the tires slipped over the rollers.

[O3DigitalBath]

wern't dynojets made orginally bikes?

[steve shadows]

Sounds like my words verbatim.

Minus the tuning of ignition on the street. What, tune tq by the seat of your pants? Or maybe tune off the knock sensor? Cylinder temp a little to hot... BOOM.. =/ sorry bro.

People were asking about dyno's, not the basics of tuning. I am glad you rehashed some of the basics.


T his bump that you felt was the eddy current brake of the dyno. Either they had set up a 6k load point for you to bump against, or had turned it up to get the total tq output right up to 6k. If you had wheel spin, the "engine would continue to rev up" as the tiresslipped over the rollers.


this guy "bro" haha


I just finished re building the horrible map you built on luke's car.

everyone knows the nissan knock sensor is garbage... even someone as dumb as me haha:bowrofl:

[johngriff]

I wouldnt exactly say i "built" that map ;)

That would be giving me too much credit, its more of what you would call a "free tune" (meaning he did not pay a dime for it, lol)

OMG: http://www.jandssafeguard.com/

Now we can all tune right up against a knock sensor on the street!! (j/k)

[steve shadows]

john i didnt think youd read this that fast!! !!

haha

APRIL FOOLS!

cheers mate

[steve shadows]

wern't dynojets made orginally bikes?

maybe jet skis

[ctm_motortrends]

maybe jet skis


I met this guy at a Aerodyne event. He was the coolest and has tons of info. I was driving a silvia face hatch with no front bumpper.

[NismoRacer1]

I have another question for your guys since you brought up tuning, my roommate kinda stole a fuel and timing map from HKS which was originally for a 2540. He just adjusted it to be more compatible with my turbo, and we noticed after my first dyno session there was a dip in my plot around 4500 rpm, so after checking the timing map there is a dip at 4500 rpm in the timing. At 4000 its 18 degrees, at 4500 its 14 degrees, then it goes back up to 18 at 5000. I asked one of my friends who is pretty decent with this stuff and said that a lot of Japanese tuners will detune it where you make peak torque because torque is a function of knock and they want to be safe. Would I really be risking a lot my changing my timing back to 18 degrees right there? What are you guys running for timing at that point?

[steve shadows]

I have another question for your guys since you brought up tuning, my roommate kinda stole a fuel and timing map from HKS which was originally for a 2540. He just adjusted it to be more compatible with my turbo, and we noticed after my first dyno session there was a dip in my plot around 4500 rpm, so after checking the timing map there is a dip at 4500 rpm in the timing. At 4000 its 18 degrees, at 4500 its 14 degrees, then it goes back up to 18 at 5000. I asked one of my friends who is pretty decent with this stuff and said that a lot of Japanese tuners will detune it where you make peak torque because torque is a function of knock and they want to be safe. Would I really be risking a lot my changing my timing back to 18 degrees right there? What are you guys running for timing at that point?

no, why the hell was it 14 in the first place?

Is it only in that one cell? sounds like a boo boo.

Your making peak torque at 4500 rpms? Are you using a t25?

If its 14 across in a ratio or grid ok...if its just one cell I dont think thats useful at all.

Timing maps should be a linear as possible imo. Helps spool up etc.

18 degree is really really retarded if were talking 14 psi range even , at that rpm on SR unless your runing like 89 freakin octane and you shoudl be taken behind a shed in that case anyways.

should be somewhere in the 26 degrees depending on load point.

I dont think any turbo ever on stock disp sr would even make 25 psi at 4k, except for a turbo that is

having massive compressor surge.

Torque is not a function of knock, that doesnt even make sense.

knock will occur with TOO much advance depending on fuel and quality of ignition or spark however.

[NismoRacer1]

i'm running a GT2871R @ 18psi

here is my first dyno plot, you can see the dip around 4500
http://memimage.cardomain.net/member_images/5/web/257000-257999/257730_74_full.jpg

[steve shadows]

I would dial the timing back up.

If you have your map in excell, ill be willing to re-adjust it for you and smooth it out if you paypal me a little money


PM me if your interested. :wiggle:

[johngriff]

+1 for steve. You can measure how close you are to knocking my measuring the tourqe output. How many cells are effected by this timing "dip"? it looks like 4.1-4.6k from your sheet.

HKS is far from end all be all for the end user, If that is your timing values, that map is retarded (in both uses of the term).

If it is not a mistake, it is what i've been thinking the whole time:
HKS Turbo= Epic Surging Fail (though the over all numbers are a little hyper dramatic).

LOL, @ 2871 Not making over 300 on a dynojet.
That thing needs timing.

[BillKlineVT]

i dont know where the hell you get 26 degrees timing as being safe for this setup? Are you used to tuning NA cars or something? Keep in mind, this is for a STOCK bottom end... plus, this was at 18 psi not 14....

the reason the map had the dip from 18 to 14 to 18 was probably from a spot-tune to reduce some knock heard while tuning. Not the correct way of fixing it, but it was the map we based the tune off of, and the person we were depending on for the timing map tuning was not available during the day of our dyno day, so we just left it. We are going to change it now...

EDIT: did a maptrace of the updated map... at 1.26 bar, it hits 18 degrees from 4000 rpm to 6500, where I ease timing back on to 19 and then to 20 degrees by 8000 rpm (end of map) This is to account for the .64 a/r's top end dropoff

New map feels good, very smooth power delivery. Maybe our "ace in the hole" timing dude (Jeff Taylor) can help us squeeze some more power out of this bitch. I never claimed to be a "tuner," I'm just familiar with the BikiROM software... haha

[steve shadows]

i dont know where the hell you get 26 degrees timing as being safe for this setup? Are you used to tuning NA cars or something? Keep in mind, this is for a STOCK bottom end... plus, this was at 18 psi not 14....

the reason the map had the dip from 18 to 14 to 18 was probably from a spot-tune to reduce some knock heard while tuning. Not the correct way of fixing it, but it was the map we based the tune off of, and the person we were depending on for the timing map tuning was not available during the day of our dyno day, so we just left it. We are going to change it now...

EDIT: did a maptrace of the updated map... at 1.26 bar, it hits 18 degrees from 4000 rpm to 6500, where I ease timing back on to 19 and then to 20 degrees by 8000 rpm (end of map) This is to account for the .64 a/r's top end dropoff

New map feels good, very smooth power delivery. Maybe our "ace in the hole" timing dude (Jeff Taylor) can help us squeeze some more power out of this bitch. I never claimed to be a "tuner," I'm just familiar with the BikiROM software... haha




in reference to 26 degrees advance its not one size fits all.

I highly doubt your making 18 psi of boost at 4k rpms.

*ok so you are just re-read it* right?

Are you? If you are congratulations. The map sucks if you need to drop because your HEARING knock.

If you could actuall post the whole fucking map I might be able to help you but if were going to start arguing about mystery points of data on a mystery 'x' map Im going to have to refrain from nunchucking the ass out of this thread.

Explain how you can "hear" knock and know that thats how you should drop a 4 degree plummet spot in the map.

Ive never heard of "tuning by feel" or feels smooth either. Car should get progressively faster, but tuning timing by hearing doesnt make any freaking sense.

If the car is on boost 18 psi at 4k rpms then timing should be in the range you have I agree. But the drop does not make sense to me. Something else is going on if your seeing knock, this is why a gas analyzer is so much better for dyno tuning as well as using LAMDA readings as direct scaled voltage rather than using AFR off a probe in the exaust pipe.

BTW a 1.5 degree advance to account for drop off is not enough to see any real difference on the dynometer.

oh sweet mother of god your using biki rom... god i hate biki rom haha. to each there own.

[BillKlineVT]

iI highly doubt your making 18 psi of boost at 4k rpms. If you're not familiar with the 2871 .64 a/r turbo, yes, it makes 18psi by like 3500 rpm on the SR... I have 15 psi at 3200 RPM on my KA-T
the map sucks if you need to drop because your HEARING knock. Re-read what I said... I said the person that originally wrote the map that we BASED this map off of PROBABLY did... it was just an assumption for why there was a spot-tune like that.
If you could actuall post the whole fucking map I might be able to help you but if were going to start arguing about mystery points of data on a mystery 'x' map Im going to have to refrain from nunchucking the ass out of this thread. here it is... http://filebox.vt.edu/users/bkline/pics/2871SRmap.JPG
Your input is welcome... like I said, I based it off of a "JDM Tight" tune I found on another rom tuning forum based on a similar setup with a hks turbo of similar size
Explain how you can "hear" knock and know that thats how you should drop a 4 degree plummet spot in the map. Ever heard of det. cans? Knock sensor tuning? HKS even sells a knock amplifier to tune this way. You tune to the threshold of knock, and dial back a bit. A ghetto way of fixing "hearing" knock is to dial back timing in that one spot that you hear it. Ideally it should be linear and smooth, as u said earlier.

Ive never heard of "tuning by feel" or feels smooth either. Car should get progressively faster, but tuning timing by hearing doesnt make any freaking sense. Like you said - to each their own.

If the car is on boost 18 psi at 4k rpms then timing should be in the range you have I agree. But the drop does not make sense to me. Something else is going on if your seeing knock, this is why a gas analyzer is so much better for dyno tuning as well as using LAMDA readings as direct scaled voltage rather than using AFR off a probe in the exaust pipe. Clearly there is a misunderstanding. We are not noticing knock. The only thing I said about knock is an assumption made about why there was a dip in the map that we BASED this map off of

BTW a 1.5 degree advance to account for drop off is not enough to see any real difference on the dynometer.How much do you suggest?
oh sweet mother of god your using biki rom... god i hate biki rom haha. to each there own.The software for bikirom is really lacking support, but its maturing... and it works well for me... meh, whatever

[steve shadows]

Is 95 Load on the map correlating to any specfic boost level in cross over for Load measure? like is that representing AFM values at 20 psi? Just trying to make sure Im looking at this right

I can’t suggest any exact amount because I'm not the one tuning the car in person on the dyno and the system you’re using is not fully familiar with me.

But 1.5 is not going to do it. 3 you should see some change and amplification of torque, but that’s just the fuk of using that turbo. Timing cannot counter for the turbos lack of peak efficiency drop after that point. If you want more power up there change cams, adjust CAM timing, re-tune and try again. If you still want to pull torque out higher move to a 3071R with the combination of larger cams (specifically duration) and this should suffice.

I’m not trying to be a dick, I just come off that way. Biki Rom has a lot to be desired, and I dont really want to get into the nitty gritty of how and why etc.

let me trace over your map here while im bored at work Ill post a reply about what I think in a minute.

Ill be getting some more time on the dyno soon and experimenting whit stuff relating to timing etc. I should be able to speak in more specifically regarding exact points and exact changes depending on timing adjustment after i get that out of my system

[steve shadows]

ok as a general rule for 91 octane (not sure if your using 93 octane) for example of one specific load pont I like to run

7.5 PSI load (say from 4k-6500) +28 degrees of Timing
14.4 PSI load (say from 4k-6500) + 21 degrees of Timing.
18.5 PSI Load( same rpm, -----) + 17 degrees of Timing. imo

straight across. Now with the drop off in toruqe. I dont think its that safe to pull up 3 degrees of timing to try to make up for the small turbine housing and lower flow rate of cfms though the head at the rpms up top.

That can be solved with some of the mechanical tuning adjustments I mentioned.

Going back to smoothing out your fuel map in the right places with make a big difference once your timing is dialed in.

I usually go, ruff afr/lamda map, in-put goal timing map, street tune and re-build fuel mpa according to seen values completely for smoothness.

The more the linear the fuel and ign map the better response, gas milage and power you will make in the long run.

Im going to throw up if I talk about this anymore, Im going to take a break, PM me and ill throw some more "crap" i know a little bit about.

[steve shadows]

Ok sorry for multiple posts but I think it helps you see the information in better piece by piece deliniations...

ok..

in the HIGH LOAD portion of the map between 1000-4000 RPMS

I think your timing is far TOO advanced.

In load point 55 you should be more like + 7 or 9 degree advance at most for rule of thumb to scale in your head.

I would have it somewhere around 3 degrees advance at 1000 rpms at pt '95' for exampe and go up slowly like 4, then 6 then 8 then 10 then 13 then 16 then 17 across to 6500 then 17 17 17 in the last three cells after that.

The retard in the low end will help smooth the map and get rid of that snowboarding summit your seeing in 3 D view.

Im a liberal arts major and my brain is hurting (since i was building a map already today haha).

im taking a break

[Brian W.]

We use a Dyno Dynamics dyno and out customers have seen anywhere from 12-30% increase in "HP numbers" by going to dyno days @ places with DynoJets. We bought our dyno to tune cars however and not show off big #s.

[steve shadows]

I like dyno-dynamics, wish you guys were local haha.

[BillKlineVT]

I'll look into more of your comments a bit later, but sorry I forgot to mention the following.

0 psi was at 22-25 Load columns.... 18.5 psi was around the 75 Load column

It was suggested by Scott (Enthalpy) to try the ramping up timing slightly after peak torque... so I thought I'd try it

Running 93 octane

Thank you for the input!

[BillKlineVT]

oops double post

[steve shadows]

Yeah Scott rocks, havent tried taht personally, but allt he turbos I run on cars with tunable ems out here are big compressors.

If scott reccomends it he's prolly got a point. I just dindt think 1 deg would make a diff, 2 deg might though.

good luck man :bow:

[BillKlineVT]

word... also, in response to too high of timing in the high load section before 4k rpm... By watching the maptrace in 2,3,4 gears, that part of the map is never reached, even on a hill climb. It kind of skirts diagonally a cell or 2 away from the green (knock enabled) area of the map. maybe it would reach the green area if we were towing a house? hehe. I'll double check a pull in 5th to make sure its not there, but yeah I suppose I can lower it there just for safety