Underdrive pulley

glass3222 · Jul 7, 2010

Is anyone running an underdrive pulley?

Seems like a fairly cheap and easy mod. I know some of my buddies that ran 5.0 mustangs all had them, I was wandering if it would be worth it in our trucks.

truckin151 · Jul 7, 2010

I've heard mixed results with them, some say they are well worth it and others say they caused more harm than good.

Off_Road_Teacher · Jul 7, 2010

truckin151 said:
I've heard mixed results with them, some say they are well worth it and others say they caused more harm than good.

I believe it was the ASP/Motoblue underdrive pulleys that were causing tone ring failure on guys engines.

AF_Hemi · Jul 7, 2010

if its less than $300 you dont want it. theres very few good companies out there with a solid reputation, and i dont think any of them have the pulley for much less than $300. The key is it MUST be a harmonic balancer as well. If not (or if its not perfectly harmonized) it'll destroy your engine

Hemiguy0302 · Jul 7, 2010

Pass on this mod. You are willing to lose cooling capability, the ability to hold a decent charge at idle, air conditioning performance and the assist provided at low speed by power steering for 10 maybe 15 crank hp. **** that. On mustangs and stuff it makes sense as the guys who run these have minimal electrical load and the ac deleted. IMO put your $ elsewhere.

AF_Hemi · Jul 7, 2010

^^ the truth

glass3222 · Jul 7, 2010

Hemiguy0302 said:
Pass on this mod. You are willing to lose cooling capability, the ability to hold a decent charge at idle, air conditioning performance and the assist provided at low speed by power steering for 10 maybe 15 crank hp. **** that. On mustangs and stuff it makes sense as the guys who run these have minimal electrical load and the ac deleted. IMO put your $ elsewhere.

Makes sense. The more I read about them, the more I think I will pass. If my truck was not my DD and was a street/strip truck, then maybe.

Trupiano · Jul 7, 2010

Yup, I'd leave that one alone. Waste of money, and more problems thatn they're worth IMO.

Hemiguy0302 · Jul 7, 2010

Yeah for a racer it would make some sense. With a DD it gets old. With my mustang I was running an UD crank pulley but with the stock alternator if the E fan kicked on it would not put out enough to properly run both the fuel pumps at idle so when the E fan turned on at idle it got pretty choppy. A 90w alt fixed it. Think about how much more load would be in a truck electrical system especially if you have extra lights at night and an aftermarket stereo.

truckin151 · Jul 8, 2010

See I know guys running the UD and an ALt pully and the combo cut some time off their ET's and they run just fine BUT is it worth it???? IMO unless you're at the track every weekend the answer is no.

OklaHemi · Jul 8, 2010

so i guess this can sit on the shelf next to the TB spacers...lol

OlDirtyJohn · Jul 8, 2010

OklaHemi said:
so i guess this can sit on the shelf next to the TB spacers...lol

id say on the shelf UNDER the TB spacers...... the U/D doesnt make that sweet ass whistle that the spacer does!!! that means its not nearly as cool.

AParrette · Jul 8, 2010

^^^ lol in my last car it had a/c delete, heater delete, power steering delete, interior had as steeringwheel and a drivers seat. ud pulleys full exhaust and a supercharger. was fun as hell and it was my dd

Trupiano · Jul 8, 2010

^^ Sounds very fun to drive... In a straight line... and as long as the temperature stays below 80' degrees or above 50'! lol

AParrette · Jul 8, 2010

in florida's heat. it had a 160 tstat and ran straight water for coolant. sucked in the summer when i had to stop. and winter was iffy since you had to wear a jacket. but it was a heated seat

KGBIGCOUNTRY · Jul 8, 2010

I will agree with everyone else. There is alot that can go wrong with this unbolt bolt mod that makes what lill gain not worth it (ESP for a DD).

RubberFrog · Jul 8, 2010

AParrette said:
in florida's heat. it had a 160 tstat and ran straight water for coolant. sucked in the summer when i had to stop. and winter was iffy since you had to wear a jacket. but it was a heated seat

That's hardcore right there!

talon6 · Jul 8, 2010

i have a asp crank pulley on my truck. the only time i see that it can be a little bit of a problem is when you are sitting still for a long period of time with the a/c on. just sitting still without the a/c on it does charge a little less. but to add there wasnt much of a performance gain. and i donnt have a big stereo or extra lighting. you can tell when my e-fan kicks on. it drops the charging a little. i have yet to have any problems though. as long as you are running atleast 1000rpms it charges just the same as stock. i would say that if i got a different alt pulley all issues would be solved.

truckin151 · Jul 8, 2010

How much of a gain did you see with it on? Do you have any numbers on it (before and after the install)?

I think if I wanted to get a bit more out of mine (during the winter months) i would rather run a short belt and bypass the ac altogether and see how it runs then.

talon6 · Jul 8, 2010

truckin151 said:
How much of a gain did you see with it on? Do you have any numbers on it (before and after the install)?

no numbers. could feel a small gain. i am just guessing here, gonna say about 5hp.

Underdrive pulley

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