Page 1 of 1

Which gear to run auto trans in on dyno?

Posted: September 23rd, 2015, 5:13 am
by nicpaige
Going for a baseline dyno on the tired stock engine tonight and was wondering what gear the pull should be done in?

Re: Which gear to run auto trans in on dyno?

Posted: September 23rd, 2015, 5:48 am
by Cheromaniac
Third gear would be preferable but if your tires aren't rated for 100+mph speeds, you might have to use 2nd.

Re: Which gear to run auto trans in on dyno?

Posted: September 23rd, 2015, 6:24 am
by nicpaige
Tires are rated for 100mph.

Re: Which gear to run auto trans in on dyno?

Posted: September 23rd, 2015, 6:43 am
by jeepxj3
3rd is best but when you floor it WOT it will down shift into 2nd. PITA. If you had manual shifting then you could have the trans in 3rd and stay there. Because of this, you might have to use 2nd gear. 3rd you might hit the speed limiter before you hit your max rpm.
Dynoing an auto is a pain. Can't wait to see your numbers.

Re: Which gear to run auto trans in on dyno?

Posted: September 23rd, 2015, 5:47 pm
by nicpaige
BIG NUMBERS... after 247,000 miles this power plant put out 135 HP and 177 TQ to the 31.50 tires on a DynoJet dyno. Stock everything. Now time for this engine to take a well deserved rest.

Re: Which gear to run auto trans in on dyno?

Posted: September 23rd, 2015, 6:09 pm
by SilverXJ
I did my 4.0l in third as well.

With a 60mm throttle body, 0630 head, header, cat back, HAI, 30s and stock gears mine did 149RWHP/183rwtq on a DynoJet with a slightly rich fuel trim.

Re: Which gear to run auto trans in on dyno?

Posted: September 23rd, 2015, 6:28 pm
by nicpaige
This has been a great motor. It will go on the shelf as is for a backup. Burns no oil, runs great just a little noisy on cold startup.

Re: Which gear to run auto trans in on dyno?

Posted: September 24th, 2015, 7:24 am
by Cheromaniac
nicpaige wrote:BIG NUMBERS... after 247,000 miles this power plant put out 135 HP and 177 TQ to the 31.50 tires on a DynoJet dyno.
Sounds just about right for a stock 4.0 automatic in 3rd gear.