i was thinking of getting a set of underdrive pulleys for my 89 iroc-z what do you guys think?


i kind of like the bling factory it adds if nothing else........


i'm talking a 3 pc polished setup that is, just curious if it's an actual noticable power increase or if any1 has b4 and after dyno results of the mod?

 

IMHO, not worth the very minimal hp increase to have your alternator not charge properly and slow your water pump down.

Just my .


And from the Stewart Components Web site:
"Stewart Components does NOT recommend the use of underdrive pulleys on any STREET application. Stewart high-flow water pumps only consume 2.26 horsepower at 4,000 RPM, so the actual savings in parasitic horsepower loss through the use of underdrive pulleys is minimal. In addition, a properly designed cooling system's flow and efficiency are designed to operate at a given speed. In years of testing, Stewart has consistently proven that the engine will lose more horsepower due to higher operating temperatures than any possible gain from underdrive pulleys."

 

i have them on my bird. all 3 pulleys. my altnerator doesnt really struggle to much. it dips down a lil bit when i have everything on, and im sitting at idle. but for the most part i dont have a problem with them. and my water pump is fine to, my car doestn overheat or anything. as far as h.p. i couldnt really tell ya. ive had them on for a long time. and dont remember if i felt a difference or not. the only reason why i got them was a budy of mine was selling them at the time for really cheap. i would save the money and use it on somehting. and save the pulleys for last.

 

from what ive read or seen from dyno runs they actaully do add a good bit of hp at the wheels. seen a few dyno runs with diff cars before and after pullies. its not gona be like seat in your pants increase but the car should have more pep.

i have a 2 piece set on my car, well i did from MARCHm crank and alt. i had to take the alt pully off bc they sent be 2 diff pullies, crank had 4 rib belt and alt had 5 rib belt. i had it on for a while but eventually wears belt away. i put a smaller pulley than stock so kep charging up, thats the only prob i have still, is charging at idle at a light with accessories on. other than that they are good. no overheating etc.

i did the mod with other intake mods so i couldnt tell u wat hp increases it made. i would say get em, the are better peices than stock

 

blackbird, what part of the country do you live in? Also, the reason your car does not overheat could be bc of your thermostat and fan switch. Maybe pulleys with the therm and fan switch are what allows for a hp increase?

 

Not a good mod for a street driven car.

 

north jersey, 20 min from manhattan.
no i did the underdrive with a 180 state and a 200 on 188 off jet therm fan switch.... still no overheating. i just recently about a yr ago put the 160 in.

our cars temp settings are already set way to high as is, i had good cooling with underdrive pullies,180stat and 200ob 188 off switch.

 

i live in florida, and i have a 180 t-stat, and undrive pulleys. if im cruising down the road above 60, i can shut my fan off and the car wont overheat. it wont even heat up at all. one time i had a coolant hose blow off, and let me tell ya, i had very good flow. so i aint worried about my water pump not being able to cool the engine. and yes i can shut my fan off, i wired it to a switch on my dash because the thermal switch in the block broke and i didnt feel like changin it since i have headers and it makes it a p.i.t.a. to change with headers.

 

so any1 have dyno info.

also the charging wont be a problem i plan to run a bigger alternator anyways down the road for a good sized stereo system.

as for cooling i doubt that will be a problem either. previous owner dropped a 160 t stat in her and 166-176 fan switch. Has a new radiator and will have a new waterpump when i tear it down for a head/cam swap.

hell i ran it with the old factory leaky copper radiator at the track back to back 5 passes in a row and only got up to 200*, this is with pure rusty water no antrifreeze and a terrible looking radiator, since this it
s been flushed 3 times. The new radiator definetly made a huge difference, damn thing barely ever gets in closed loop (hate these low temp things but, i plan to reprogram the prom for it properly some day).

 

If your planing a pretty decent stereo system, I would avoid the pullies.

 

well i plan to run infiniti kappas in the frnt and boston acoustix rears.

2 12 inch audiobah flamebucket woofers in a custom well box. A mid sized amp pumping around 125 rms

is that considered to big for pulleys with the addition of an aftermarket 140 amp alternator?

 

You might might want to post up in the audio section, it's been a long time since I've competed in IASCA. So I can't remember specifics, but I do remember that nobody uses smaller pullies with a decent stereo system.

 

i had 2 amps wired togther off of a 8gauge amp kit with a distribution block, then ran individual turn on signal switches to each amp so i could turn each amp on or off or both on or both off depending on what iwanted. i used 200 watt kenwood system and then both maps totalling 920watts and since i mono bridged them to roughly 340watts rms each. to each sub. i made a custom fiberglass sub box for both 12" subs and a 1 farade capacitor with digital voltometer, this thing kicked i mean it was sick.

even with the underdrives and stock 100amp altinator thats roughly 4 yrs old i only got low voltage with the lights on sitting at a light at idle. the capacitor helped ALOT!

ive installed many systems in many diff cars and u can run the stock altinator with a 1000 watt setup. thats my experience, just dont run too many accessories with the system on at a light etc.

125rms is very minimal. i shouldnt have a prob, anything over 500watts non rms amp i would get a 1/2 farade capacitor, 1 farade for 1000 watts. ill be going with a 140watt alt with my 383 thats goin in the spring.

 

I used March p/n #4010 on my 1988 Form 350 and never had a problem what so ever. I did not have any high end stereo euipment though. I just bought this set for my 1992 Form 350.