For those who have dyno'd your trucks, what is the best/most accurate way to dyno your truck using a dynojet dyno?


Brent

Best way if you want solidly repeatable numbers so you can track changes is to do everything the same! I would recomend running TH in 4th gear. Letting it upshift to 4th and letting the R's come down to the lowest RPM the truck will hold without downshifting and just wood it. With an auto there is a certian RPM were the truck will want to downshift. The key is playing with it and figureing out how low you can go before that point. It will take some practice.

Isn't it possible to command a gear with a tech2?

Yah i was thinking with the tech 2 would be the best way to get biggest #'s i know they did that in a diesel power challenge and as far as i know you can hold it in 4th or 5th gear with a tech 2

If you had a tech 2 you could command a gear yes. Witch is great becasue then you dont have to worry about the downshift issue. Witch brings up another point. If you cant start your dyno run at a RPM that is BELOW your torque peak your torque numbers are completely useless and you may as well not ever attempt to read them. IIRC the allison wants to downshift around 2200 or so witch is well past your torque peak.

I mentioned not using a tech 2 becasue if you dont always have access to one then you arnt going to be able to conduct your tests the same every time. If you have acess to one then it would be better to use it to comand a gear and then you can start your dyno run at a MUCH lower RPM so you can actualy pull up through your torque peak.

4th gear is 1 to 1 ratio and with TH the converter will be locked.

what about hooking up the tach signal on an LBZ

Optic eye with some tape on the balancer. Useless though unless you have a way to start well below the torque peak though.