dankl

iTrader: (1)

Hello,
Just wondering if anyone knows if doing a dyno pull from 4th gear would put up lower numbers?
I was told 3rd gear was the proper gear for the dyno, but mine was always done in 4th. I am not sure what to believe as only the gear ratio changes per gear, not engine power...right?
Your thoughts?

Thanks for your time!

dankl

iTrader: (1)

Also, pulls were done in 90* south Florida summer. Had a fan in front, but not much airflow. Dyno was also STD. Could that result in low power numbers?

ls1curt

iTrader: (31)

stick car?

redbird555

iTrader: (14)

generally you want to get the tranny in the close 1:1 gear ratio you can to get a dyno reading and in a t56 4th it 1:1 so I;d say it was done in the correct gear. what are your mods and what did the car make

Deviant LS1

iTrader: (4)

3rd for a 4L60e and 4th for a T56. If you're dyno shows in STD then yes weather will effect numbers. If you change it to SAE it will show the "standard" that everyone goes by.

S8ER95Z

iTrader: (3)

What's the end result if an M6 car is dynoed in 3rd instead of 4th? Skewed numbers?

JonCR96Z

iTrader: (33)

I've seen cars gain nearly 10rwhp dynoing in 4th over 3rd.

The reason some people use 3rd is that it turns up much quicker, so you're not holding the motor WOT for as long of a time. The important thing to remember is that you use the same gear every time you dyno your car.

S8ER95Z

iTrader: (3)

Thank you, it's always bothered me that my car was done in 3rd (on a dyno dynamics) but I was told it wouldn't matter. Some people claim my numbers were inflated due to the gear.

Made 324rwhp/341rwtrq with just FRA.

itsslow98

iTrader: (18)

My brother made 8 less rwhp dynoing his 2011 5.0 in 4th as opposed to 5th(which is the 2011s 1:1 gear).

I dyno all my stuff in 6th just for the hell of it.


^jk

Slowhawk

iTrader: (12)

If a shop insists to dyno in 3rd gear on a M6 car it is obvious they have no idea about tuning or dynoing.

It will show lower #'s in 3rd.

quik95lt1

iTrader: (7)

regardless of numbers the car should be dyno'd in 4th gear for means of accuracy ........in very fine tuned applications AFR should be also checked in a track/street application, acceleration rates of the engine differ from different gears and loads which can cause effective AFR's to vary slightly....just remember "dyno numbers" mean virtually nothing, a dyno is a TUNING tool. Comparing numbers from one dyno to the next has become more of an internet fad than a means for useful data.....too many variances in not only operators and steups but also maintainence and calibration of weather metering equipment that applies correction factors exsist from one dyno to the next to do this......you never see stories of proud men and their dyno's

Bill00Formula

iTrader: (4)

Even the correction factors do not make up for the heat. Best to do it when it's in the 70s or cooler. But either way, you should get them corrected to SAE. I can't believe a dyno operator would not be familiar enough with these cars to not know which gear to use. Also, a car that has cooled off versus a hot car can make a significant difference as well.

speed_demon24

iTrader: (6)

STD is a correction factor just like SAE. It's generally the correction factor shops use to inflate numbers since it corrects to a higher # than SAE.

S8ER95Z

iTrader: (3)

These were the results of mine... was always in the back of my mind. (No Smoothing on the graph.)
I'm going to get dyno tuned at Speed Inc in a month, so it won't matter I guess.

DynoDR

iTrader: (1)

Like it that lean huh?

S8ER95Z

iTrader: (3)

That was stock tune and pretty low miles... not sure why it was like that to be honest. Car ran solid at the track even. Hoping the numbers don't look like that next time.

quik95lt1

iTrader: (7)

if they used the sniffer that they just jam up the end of the exhaust pipe thats probably a false lean reading............

S8ER95Z

iTrader: (3)

Thats what it was... can't imagine the car was running dangerously lean considering the beating it's taken in the years since I had it done. I could be wrong though.