Underdrive Pulleys and RWHP ???

[BelueLX]

Ive had a few sets of underdrive pulleys on various Mustangs and seen some pretty good results as far as ET and trap speeds (like .1 / nearly 1.5 mph...). Has anyone actually taken the time and trouble to do a before and after dyno? Just wondering not that its of any importance just wondering if anyone that doesn't sell these for a living has done a dyno run. Thanks,

Cody B

 

[-86GTStang]

Dyno result..

Well, found a dyno test regarding this in a Super FORD ,
5.0 Magazine, April -97.-BOLT ON POWER.
This test was done with a -95 GT, and they used Auto
Specialties pulleys. ... boosted horsepower and torque across the rpm range. They started with a 2hp increase at 2000rpm and ended with a big 11rwhp improvment at
5000rpm (14-degree Timing, 196hp/229Tq before pulley install)

 

[89MustangGX]

Well, found a dyno test regarding this in a Super FORD ,
5.0 Magazine, April -97.-BOLT ON POWER.
This test was done with a -95 GT, and they used Auto
Specialties pulleys. ... boosted horsepower and torque across the rpm range. They started with a 2hp increase at 2000rpm and ended with a big 11rwhp improvment at
5000rpm (14-degree Timing, 196hp/229Tq before pulley install)

Most of the ones I've seen are between 7-9hp in the higher RPM range, so I'd go along with that as well and say it's not uncommon.

 

[90mustangGT]

U/D's were my first mod, made a very noticable difference in a stock 5.0. A few months ago I bought thier 3" Crank pulley, made a good difference even more on a modded car where the rpm's are rising quickly.

 

[WhiteStallionGT]

Do you guys think pullies on my 94 gt AODE would be worth it?

 

[TrickStang37]

Heres some dynos i have:
5.0 - Mods
73mm MAF
Pulleys
March Ram Air

RPM--------Stock----------Pulleys----|
----------HP----TQ-------HP----TQ---|
2500--|--116----244--|--118----248--|
2800--|--136----255--|--138----259--|
3000--|--150----263--|--152----266--|
3300--|--165----262--|--168----268--|
3500--|--177----265--|--180----270--|
3800--|--188----260--|--192----266--|
4000--|--194----254--|--198----260--|
4300--|--198----241--|--203----247--|
4500--|--200----233--|--205----239--|
4800--|--198----217--|--206----226--|
5000--|--197----207--|--204----214--|
5300--|--188----187--|--196----194--|
5500--|--176----168--|--187----179--|

 

[TrickStang37]

on a more modified car:

5.0 - Mods
Extrude Hone Ported Dart Windsor Heads (2.02/1.60 valves)
Extrude Hone Ported GT-40 Intake (upper/lower)
MAC shorty headers
10.6 compression
1.6rr
75mm TB
X303
77 ProM MAF
Pulleys

RPM--------Stock----------Pulleys----|
----------HP----TQ-------HP----TQ---|
2500--|--127----267--|--127----267--|
2800--|--152----285--|--152----284--|
3000--|--165----288--|--165----288--|
3300--|--198----314--|--195----311--|
3500--|--222----333--|--222----333--|
3800--|--241----333--|--243----336--|
4000--|--264----346--|--269----353--|
4300--|--293----358--|--295----361--|
4500--|--307----358--|--311----363--|
4800--|--317----347--|--322----352--|
5000--|--320----336--|--329----346--|
5300--|--325----322--|--334----331--|
5500--|--321----307--|--330----315--|
5800--|--315----281--|--319----289--|
6000--|--303----266--|--318----277--|

 

[TrickStang37]

i wonder why there was no gain till 3800+?

 

[jb89coupe]

i wonder why there was no gain till 3800+?

On the second one they actually killed power at 3300? Is that your car? Same day?

 

[ponycar17]

I've taken mine on and off several times, but I've never noticed any power difference at the seat of the pants, and no ET difference either... Maybe it's just me...

 

[TrickStang37]

the dyno runs are from a book I bought few years ago, "5.0L FORD DYNO TESTS" by Richard Holdener (has written in MM&FF, Car Craft, Super Ford, Mustang Illustrated blah, blah, blah tons of other ones). And that run was from an engine dyno runnin all accessories minus powersteering on the same day/conditions/probably minutes apart really.