Underdrive pulley dynoed (10hp and 16 ftlb's of torque gain!!)

[mralbuquerque]

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My 06 Viper has the following mods: 3.55 gears, k+n cai, and a sct tune. I was debating if it would be worth purchasing and underdrive crank pulley. Research on this forum indicated most people were saying it would offer zero to a few hp at most and was probably not worth the time or effort. With that assumption and a low budget I thought I would try it anyway. Besides it kind of looks pretty. (justification bling-bling).

My results:

Baseline mods:
3.55 gears
SCT tuned (canned) by Todd A&C performance thanks.
k+n cai
441 hp and 468 ft lb's of torque.

Addition of UDP only with above mods: 451 hp and 484 ft lb's torque.

Installed the underdrive pulley purchased from Jon B. of partsrack. I purchased the crank pulley and went to autozone and found a belt that was approximately 2 inch's shorter than stock. (I'll supply the part number if anyone is interested.)

I took my car back to the dyno and they did three runs. The net result was a 10 hp gain and 16 ft lb of torque increase! All I can say is wow, that's bang for the buck!

For what its worth I looked at the corrections factor and the atmospheric conditions from the first time I dynoed and found the conditions were very similiar (1.19). Some of you guys will find my numbers low. However, I live at a mile high location and the numbers appear to read lower than what i've seen throughout this forum. Viper's with full exhausts on this dyno have only resulted in the high 450 to 460 range.

dynosheets to follow

 

[351carlo]

Very cool. Do you have the before run files so you can overlay the gains and see how it did throughout the RPM Band?

If you have the runfiles from both times I'd be glad to do this for you.

 

[Twister]

Mine pickep up close a a mph in quartermile testing. But also had the findanza flywheel.

I also noticed she shoots through the rpms a bit faster. Thanks for the dyno

 

[mralbuquerque]

351carlo, i'll see if i can can get the run files.

 

[345s-bspinnin]

Looks like some healthy gains. Do you still have stock exhaust/cats? The A/F ratio looks like its creeping on the lean side.

 

[cash84]

You sure you gained torque? 368ft lb? Can i say ouch?' haha I'm sure you have a typo

 

[highsierrahillbilly]

Excellent gains and well worth the buck$$


High Sierra Hill Billy

 

[mralbuquerque]

Oops I meant 468 ftlb's of torque.

345s-bspinnin: My exhaust is currently stock. I'm currently debating the throttle body or rocker arms. I have read mixed reviews on both of these mods as well.

I want to upgrade my exhaust system but I cannot stand louuddd!!! A friend of mine has a stock 06 with the Borla catback and its pretty loud especially in the 2500-3200 rpm range.

I was contemplating american racing headers, and high flow cats with the stock mufflers??? any thoughts..

 

[351carlo]

I think a custom tune would suit you best. With a K&N and Tune my car woke up quite a bit. 471/511 SAE Corrected.

I know you have a canned tune, but at your elevation I think with some finesse there is more power on the table.

 

[RCC]

Oops I meant 468 ftlb's of torque.

345s-bspinnin: My exhaust is currently stock. I'm currently debating the throttle body or rocker arms. I have read mixed reviews on both of these mods as well.

I want to upgrade my exhaust system but I cannot stand louuddd!!! A friend of mine has a stock 06 with the Borla catback and its pretty loud especially in the 2500-3200 rpm range.

I was contemplating american racing headers, and high flow cats with the stock mufflers??? any thoughts..

I to am not a fan of exhaust noise. I recently fnished my exhaust install which consists of ACRX Header/ 3" HF Cats/ and 3"cat back from M&M Performance. The car is deeper sounding at idle but nothing I would call loud. Noise at cruise speeds in a touch louder than stock IMHO. All in all I am very pleased with it.

 

[NVMYVPR]

Has anybody done the underdrive pulley change on a Gen 1? Any gains?

 

[rpm9000]

I just got one for my Gen.1 from Jon B at Parts Rack. I will install it in the next day or so. We did a dyno day today so I have before numbers.

 

[xr4racer]

Anyone interested in an underdrive pulley and belt, new never installed, purchased from Partsrack. $200 shipped.

text 3302890536

matt [email protected]

 

[iownedu]

Same temp and humidity during both dyno's? Both without being heatsoaked?

 

[xr4racer]

Should have added it is the black pulley for the gen 3


matt