Mine has an automatic tranny. Last summer my truck was dyno'd (factory stock) on one dynojet at 265 while in 3rd gear. The next week (still completely factory stock) it was dyno'd on a different dynojet but at 280 hp/528 tq while in 4th "od". I think dynoing in 4th was the difference and helped it.

 

On Mustang dyno's we dyno 1:1.
On Dyno Jets its OD gear.

How many times have you dynoed your diesel?

 

PourinD,

IF this question is for me..........that is the only two times it has been dyno'd. I am hoping to go to another Dyno Meet pretty soon and see if the AFE Stage 2 and Magnaflow (kitty delete) helped any too. I am hoping for over 300 next time with no other mods. Haven't run on a Mustang yet. Just the two Dynojets.

 

Nope,
Sounds like you got it down!

 

Ok if the question was about for me I dynoed it 9 times in one day. A couple on stock and each power level and a couple of level 5.

 

Why do you dyno one in 1:1 and the other in OD? I'm just curious.

 

Same question here. I dyno'd on a Dynojet@ 376hp/670tq with just the power pup. The torque I told them seems a little low for the hp#'s. Stock was 264hp/490tq. The Funny thing was in lev.2 @313hp/540tq, I mean I've never seen such a low tq# on a diesel compared to the hp#. I know the tech or the machine wasn't right but they said everything was working properly,and they would't do any more pulls. It cost me $95 for 3 pulls. This is the only chassis dyno in the Memphis, TN area so I don't have much choice when I go back to dyno with the Edge&tranny upgrades. Is there some secret to get better #'s?

 

I dont know thats just the way I have done it and it works well for not just me but most if not ALL others that dyno their diesels.

 

The difference is which way you can achieve boost on the dyno. The Mustang dynos are based on a load from an eddy current retarder and the Dynojet dynos are inertia. The load based dynos will let you achieve max boost during the whole run if you like but the inertia dynos will only let you achieve max boost if you trick them into doing it. On a Dynojet dyno, you need to use the air brake once you get in 5th gear and about 2000 RPM. Hit the red button (brake) and let the dyno drag your truck down to about 1600 RPM then hit the red button again to turn it off and then the green to start the sample of the run. Once you achieve max RPM, hit the green button again to end the run and let off of the throttle.

That being said, the most efficient gear for a drivetrain is the gear set that allows for a 1:1 ratio or as close to that as you can get. The reason you are seeing higher numbers on a Dynojet dyno using 6th gear is because it loads the drivetrain more and your truck achieves the boost lower in the RPM range and carries through the run much better because of the slower acceleration rate.

For the record, I've logged several thousand runs on Dynojet dynos most on gas vehicles but a lot on diesels as well.

 

Good stuff Staarma.

 

Yes, GREAT!!! I'll have to print this out and pass it along to the techs when I go back in for another dyno run. You definately know what you are doing. I knew the HP#'s sounded good but the TQ#'s were way off and you made an easy explanation of why. Thanks.