musubi

iTrader: (1)

I took my car in a few months back for a dyno run and put down 271 hp and 228 tq. (Graph below) I'm looking at it again and couldn't help but notice my torque numbers are a bit low compared to other HR numbers, even typical stock numbers. I could understand if my hp # was proportionally lower, but others with around the same hp are running around 250+ tq.

Mods are:
Injen Intake
Nismo S-Tune exhaust
UpRev Standard - eTuned (w/ Vince at RT)

The dyno was done on a old Dynojet 248. Weather conditions was probably not optimal, but was done early evening, raining w/ high humidity (it's Hawaii), 75 deg F, sea level.

I did not run my car on the dyno stock.

Any ideas why my torque is low? Or am I looking too much into this?

Graph shows:
Blue: No Tune
Red: V1 Tune
Green: V3 Tune

str8dum1

iTrader: (11)

looking too much into it. dyno variances, motor build variances from the factory, etc etc.

musubi

iTrader: (1)

Dang I hope it's variances from the dyno and other things, because 30 lb-ft due to a variance from the factory is large, in my mind anyways. Thanks.

Any other thoughts out there?

jerryd87

iTrader: (4)

dynojets dont actually measure torque, the only thing they measure is horsepower, the torque numbers you see on a dynojet dyno is nothing but calculated from rpm and hp. looking at the dyno the torque curve matchs up. now with that said if there is a issue with the ignition pickup it will display crazy numbers(showed my car having 1400 ft lbs of torque lol) and alot of dynos have issues picking up the z's ignition signal.

musubi

iTrader: (1)

Thanks for that information, jerryd87. Although I prefer your 1400 ft-lb number compared to mine.

ETK

Horsepower = (Torque x RPM)/5,252

If you know one, you know the other.

Maybe what you are saying is that since a dyno only measures Wheel RPM and Wheel Torque it has to calculate torque at the crank?

str8dum1

iTrader: (11)

no maybe he is saying that Dynojets measure horsepower....

musubi

iTrader: (1)

From what's been mentioned and reading numbers from the graph, it seems my torque really is what it is, around 228 ft-lb (peak) for the hp and rpm curve given, which still seems a bit low. So I gather that it's because my hp isn't peaking sooner is what's causing my torque number to remain lower, and not because the ignition pickup is faulty. Or rather the rate I gain hp over the rpm range is what affects my torque. Shucks, I was hoping for a flaw somewhere.

musubi

iTrader: (1)

One thing to note: There was no external fan running during the runs. Hood was open, but no fan to cool the radiator. Not sure if that plays a factor into anything.

ETK

Thorough explanation, good to know.

str8dum1

iTrader: (11)

only if the car detected knock and threw the map into low timing mode.... You would def be down quite a bit then.

karletto66

Only my impression : there is very small difference between no tune dyno and tuned one. Usually there is more gain also with a "simple" e-tune.
In my opinion this is not normal, may be some problem on dyno "suite test".

This can explain low numbers...

binder

iTrader: (8)

30ftlbs is only 12% difference in that amount of tq. There can be up to 10% variance from factory engines and then between dynos and even runs there can be 5-10% variance.

Since it's an NA car tuned in the winter I wouldn't think going WOT on a dyno for a few pulls would heat it up enough to knock retard the timing. Maybe if the car was doing back to back pulls for a few hours but even then the intake temps on a NA aren't going to skyrocket like boosted setups. Cam timing would optimize the tq curve so if it's a simple a/f tune with no decent changes in cam timing then it can greatly effect the tq curve.

musubi

iTrader: (1)

karletto66, I guess I was expecting a bit more from the eTune than the 4 hp it gave me, but at this point, at least it's a gain (for hp and tq). Not really sure what dyno suite test is.

binder, Looking back through my data logged runs, you're right. My temps were fairly normal during the runs. I compared them to moving data logged runs. Honestly, it seemed a bit hard to get info out of Vince about what he did to the tunes. My guess is he probably was busy and maybe didn't want to spend the time typing that out. All I can recall is he telling me that he advanced timing a bit and adjusted/smoothed out my AFR.

Thanks for the info everyone. Not sure how much things can change from another tune, but I'm thinking it's variances in the dyno and engine which is what str8dum1 and binder have already mentioned.

karletto66

I think that only 4hp is a very low difference with also a "normal" e-tune, also is a normal "variance" in differet runs. Not really relevant.
Using the car in the street you can notice some big difference ?
You can try a different dyno test, seems that this had somenthing wrong, maybe car temperature or other. If the car detect knock it goes in "low timing mode" and that can explain low performance. Also gasoline has to be good to avoid that.
I had a similar problem last year in a my friend dyno test suite, i attach the graph. My car made the same hp with or without map (little more than yours but low for an HR) and we discovered that was a problem of the "hardware" dyno suite, not able to read more than about 250hp of power on single axis. It has also some problem in low rpm as you can see.
Just a possibility.....
Vince usually is very good in tuning, he made my car and a lot of other inside forum

I own Pro version of Osiris so i can look at maps: i compared UPREV and Vince, i'm not expert in this ECU so i cannot say wich is better but are all two quite "well done" also in e-tune version...
Of course a tune made by person is the best but for a NA car with no big mods the differences are not so big...

musubi

iTrader: (1)

I don't feel a big difference on the road. I can see and feel the rpms running without resistance in the higher rpms, but it doesn't feel like it amounts to much. I also notice/feel low end torque is a bit lower than stock. It started feeling lower as I added the exhaust, and then the intake was a noticeable difference.

I'm not knocking Vince for what he did. Seems like he has a good rep around here and good experience with tuning Z's, which is why he's probably so busy. I just wish I could find out what changes were made during the tuning and possibly why they were adjusted as such, generally.
I did try emailing him, but the response was limited. Getting a hold of him over the phone seems impossible and he's the only one knowledgeable there about tunes.

Unfortunately I'm stuck on an island with limited resources and that one dyno was the only one people knew about.

karletto66

Put back original intake if yoy can, car will be better for sure.

HR has no need of bigger intake like DE and usually changing it causes loss of power...
If you wanna change your island with my north Italy ler me know by the way !

binder

iTrader: (8)

Vince from R/T tuning? He's a great tuner.

remote tunes are never going to be night and day. If he was to tune it while you were on the dyno remotely you could get more out of it. Also, the downfall is there isn't a ton to be pulled out of NA cars. Most of that can be through some cam timing which is hard to tune without a car being on the dyno doing multiple pulls.

karletto66

Yes but if a car is "quite stock" and the tuner has some good experience he can makes some "soft" cam tuning using the previous experience.
All car similar are...similar so if i know a good map for a HR (i make only an example..) i can use it in a car with same engine and mods, quite for sure without problems. I'm always speaking of "not extreme" maps of course, last hp has to be taken with "real time" tuning !

So some cam tuning is possible also using e-tune, and i know (and see with Pro version...) it was made on my maps for example.