I have been looking into underdrive pulleys lately and they seem like a good addition to my 4.0 auto. They claim to increase MPG and power, but I dont really trust what anyone says about their product so I wanted to get a few opinions on them. My car is a daily driver in all weather and my only performance mod is dual exhaust. Later one I plan on going with an 8.8 and better gears and eventually FI. I posted links to 2 different pulleys that I found, if one is better then the other let me know. Any info would help.
Thanks

http://www.stangmods.com/ASP-Underdr...ys-p/00234.htm

http://steeda.com/products/s197_unde..._pulley_v6.php

 

I want to do UDP's....they claim 12.7 whp and 16wtq
Not sure if you will gain quite that much but every little bit helps.

IF you are planning forced induction.....it depends on which type you go with on whether or not it will affect you -or +
Supercharged apps you will technically run lower boost than a stock pulley from what I have experienced on the essex v6's
shouldn't negatively affect turbo or giggle juice applications though

HOpe that helped a little bit

 

Oh and I have had nothing but good things to say about stangmods......I ordered from steeda once and it was a complete pain in my ***.

 

UDP's on the GT frees-up about 5 RWHP (be sure to understand that UDP's are NOT a power adder; they do not add to crank HP but simply reduce some of the parasitic loss) but it's hard to say since few people do a before and after just for a UDP install. But every little bit helps. I consider UDP's a worthwhile mod on either engine.

 

Do UDP's free up or add more torque also or is it just mainly HP?

 

http://www.mustang50magazine.com/tec...ve_pulley.html

dyno tests by 5.0 mag. the explorer guys hve been playing with these for a few years, shop around have seen them for less.

 

http://www.mustang50magazine.com/tec...ve_pulley.html

dyno tests by 5.0 mag. the explorer guys hve been playing with these for a few years, shop around have seen them for less.

 

UDP as stated before do NOT add hp OR torque.....but they FREE it up

 

Lol, well then will they free up more torque or jsut HP

 

tq ...the tq numbers in the sohc engine are already higher than hp....so one should "generally" assume that one will free up more tq

I've seen the dyno sheet for those udp
12.7 hp
16.2 tq at the wheels!

keep in mind those are peak numbers so likely you are freeing up all the way across the power band....that being said.. you may feel a HUGE difference.
it varies from car to car tho