How to Dyno an Automatic Duramax

[Dehorton]

We tried to dyno my brothers 2006 Duramax and we can't keep it from down shifting into 3rd gear. We would like to start the dyno run at a low RPM but we can't. Is there a way to hold the tranny in 4th gear and bring the RPM down to 1500 or so and then start the dyno run? Thanks

Donovan

 

[ripmf666]

The lowest is around 1,800, Use M and shift to 4th let the rpm's settle out then roll into the pedal.

 

[smith6.6]

tech 2 and lock in 4th

 

[McRat]

The Tech2 will kick out at 60mph.

1500rpm is silly. You cannot operate the truck at WOT at 1500 rpm, so why? Put it in T/H, select M, then go 1st, 2nd, 3rd, 4th. Cruise in 4th at 1800rpm, then roll it to the floor. It should stay in 4th.

Racing RPM range is 2500-3600 on a tune-only LBZ. Below or above that is costing you.

 

[JoshH]

I personally like to run in 5th, but others seem to disagree.

 

[McRat]

I personally like to run in 5th, but others seem to disagree.

Casper is normally dyno'd in 5th because that's the gear it spends most of it's time in at the track.

But that pisses folk off for some reason.

The reason to run in 4th on a stock truck is to avoid the speed limiter.

 

[JoshH]

Casper is normally dyno'd in 5th because that's the gear it spends most of it's time in at the track.

But that pisses folk off for some reason.

The reason to run in 4th on a stock truck is to avoid the speed limiter.

That's why I do it too. Plus it makes my numbers higher :rofl:

Just kidding.

 

[McRat]

That's why I do it too. Plus it makes my numbers higher :rofl:

Just kidding.

I wish. On a Dynojet with no retard it can, but on a load cell, you will drop power in fifth, my test showed 10rwhp, no biggie as long as you keep in one gear. It does reduce tirespin on the rollers though.

Casper's 797rwhp test was done in 4th because the Mustang it was on could not go to the MPH necessary in 5th.

 

[smith6.6]

The Tech2 will kick out at 60mph.

1500rpm is silly. You cannot operate the truck at WOT at 1500 rpm, so why? Put it in T/H, select M, then go 1st, 2nd, 3rd, 4th. Cruise in 4th at 1800rpm, then roll it to the floor. It should stay in 4th.

Racing RPM range is 2500-3600 on a tune-only LBZ. Below or above that is costing you.

I've held many trucks in 4th up to 80mph but after each run you need to go back into shift trans mode.

 

[jrkrace]

Iv'e always wondered how to do it and after I saw a portable dyno set up at a local fair, I'm inclined to give it a try. The question I have is what the little handheld button does when the operator pushes it? I'd assume it starts to measure the rollers force on the truck?

 

[TrentNell]

i was on the dyno yesterday and i just changed the tune so it would not shift into 5th i did not have a problem with it downshifting .

 

[Subman]

I try and dyno in 5th with my 6 speed. It wants to down shift as well. These trucks do not dyno near as well as they perform on the track. I can't build near the boost on the dyno that I can on the track. I've kind of given up on dyno's to tell you the truth.

 

[McRat]

I try and dyno in 5th with my 6 speed. It wants to down shift as well. These trucks do not dyno near as well as they perform on the track. I can't build near the boost on the dyno that I can on the track. I've kind of given up on dyno's to tell you the truth.

Dyno Racing is a huge sport back east. Nothing like the roar of a 1200HP Dodge even if it does run 12's...

But I can't afford to go dyno racing.

Seems the highest score goes to whoever can grenade their engine the best. Hopefully someday I will learn the secret to throwing parts across the room on command.

 

[whitetrash21]

Hopefully someday I will learn the secret to throwing parts across the room on command.

500 dry shot @ 3500 rpm.... should do the trick

 

[Samdweezel05]

Dyno Racing is a huge sport back east. Nothing like the roar of a 1200HP Dodge even if it does run 12's...

But I can't afford to go dyno racing.

Seems the highest score goes to whoever can grenade their engine the best. Hopefully someday I will learn the secret to throwing parts across the room on command.

What's up with the "back east" crap?:baby: Some of us don't live real close to Bonneville. Hell I don't even live real close to a dragstrip. It's a 3 hour drive for me to get to the strip. Dyno is 35 minuints.

Phil

 

[juddski88]

So If I am going to Dyno my truck on a Dynojet 248....and i can run in 4, 5, or 6 gear, which would you choose?? hopefully they will let me run the truck so they don't break anything but I dunno. I am not planning on swapping TCM tunes or anything, just using DVT's in Scan Tool. my turbo is only a S64X and builds boost pretty quick so how hard do you think it will be to get a good run?

 

[juddski88]

bump...just curious