AZG37 thanx for the info man, Also makes me feel a little better about my numbers- Being in the wrong gear, But that will all get ironed out of the 29th we I get my tune..
I just hope a see a lot better of a number..

 

I have 5AT and dynoed in 3rd gear, So that means I dynoed in the wrong gear too? This is retarded, if they do so much **** with cars shouldn't they know what ****ing gear to dyno it in?

 

Agree 100% I guess not with the 7SPD auto..

 

Yes Rhino, they should have been in 4th. Some people, while getting tunes, state that 4th gear causes them to hit the speed limiter before reaching redline like my previous post covered, but that never happened to me. Here's one of my old dyno's showing me hit 7kish rpm's, and it also shows the AF ratio like I went over before. See how the AF starts at about 14.2 and dips to 13 or below under heavy load? Notice how the RED line of the AF was higher than the blue, and once it was adjusted the my HP went up by 11. FYI: use the left side of the graph to read the HP #'s, the right side to read the AF ratio. AF ratio is the lower lines that are not as smooth.

 

VQ's known for making power all the way out to redline which is where I peaked on this 3rd gear tune pull. AFR was set to mid 12's across the band and rev limit to 8150 to take advantage of that fact.

 

So when I get tuned on the 29th I should raise the REV limit to 8k from 7800 so 200 RPMS more?

 

It looks like you peaked at about 7700-7800 rpm. I don't know about you but raising the rev limiter higher and higher is getting close to sketchy, even if you make power all the way until it pops Most people I've seen take it from 7500 to 8k rpm's. The funny thing though is this dyno was done in 3rd I presume to hit redline and get the most hp out of you tune, but since the gearing wasn't 1:1 your HP numbers aren't accurate. I wonder what hp #'s you'd have if you dyno'd in 4th and just went to 7500 rpm's?

 

Took almost 3 pages but finally started to get some good accurate answers. This thread was making me angry until then.

 

The gear does NOT matter, the dyno should be calibrated to the gear ratio.

 

Winnar!

I just posted in another thread, I don't understand everyone's fascination with 1:1 gears. It's still a gear, and it's still a loss. It's just a ratio.

 

I dont know where the 1:1 fascination comes from but look at this
From DynoJet directly:

Also to note here is that, 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."

I know the dyno was done on a dyno dynamics machine which is different than dynojet, but I've also seen several dynos all over other forums where owners posted dynos done in different gears and the 1:1 ratio was always higher than the others.

Im guessing that most shops are calibrated for 1:1 calculations and do not take the time to research specific vehicles gear ratios and make the proper adjustments maybe??

This whole dyno thing is always pointless anyways when you get down to it. Dyno's are meant to calculate gains, not be used as a measuring stick for who has the most HP.

My advice to Rhino, and ANMVQ, as long as you use the same shop, same machine, same gear for your dynos you'll have accurate gains calculated. Thats all that matters. The total HP may not be as high as others, but a 10HP gain over baseline is a 10hp gain over baseline no matter what machine or gear you run. It's all about consistency.

 

THen, please, explain how they account for tire/wheel radius (gearing), final drive ratio (gearing), and secondary reduction if applicable (also gearing).

Dynos don't measure horsepower. They never have and never will. They calculate horsepower from measured torque. The torque measured at the wheels is divided accordingly according to the gearing of the car. Thus, if a lower gear is used, it reads more raw torque, and in a higher gear, less raw torque.

The torque figure you see is calculated using ratios.

 

WOW my head hurts from reading this.. LOL weather or not we did or didnt have the car in the right gear, dyno compensated correctly or what ever the other puzzle is we MADE the same WHP.. I have stillen GEN 3's and CBE he only had CBE.. I'm not to worried about the number I made but the fact that a lower HP with less mods( yes only one) made the same as I did..Yes both autos and yes both AWD's

 

Here's the confounding variables, which can alter the readings.

Tire wear
Tire diameter (byproduct of wear)
Wheel alignment
How tightly the car was strapped down
Tire pressure

I'm assuming SAE corrections were used, so weather shouldn't be a factor.

 

Weather was not a factor we both were at .09 correction, Strapped down?? That matters. I know my car was rock solid on the dyno and his was kinda all over the place? His car was moving alot on the Dyno..

Tire wear not sure but his car was 38k+ miles and mine had 1200.