powermalex

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If you installed an underdrive main pully what benefits did you really get.
More HP 3~5 HP or is it just fiction.
I'm going to install one on my 93FD.

Bridgeported

On a near stock engine, you will gain little with underdrive pullies (maybe 3-5 hp like you said) but on a high performance engine like a 400+ hp 13B the gain will be larger by installing the pullies (i'd guess around 5-12 oooooh so much lol)

How about removing the crap you don't need:
- power steering
- air conditioning system
- air pump
- cooling fan

That just leaves the alternator, which you obviously need to keep (well, depends how hardcore you are...). With those gone, you will gain some HP (probably about 20 total with all removed), but the best part is your engine will rev noticably much faster and smoother. Plus you'll save yourself 50 pounds about.

WackyRotary

I have the RB underdrive pulley on my 12a bridgeport. I got it mainly for the fact the stock pulley will cavitate at high rpm otherwise. Any horsepower gain is minimal.

gamble302

12a bp, im sooo jealous
well ive got a sp12a so im not far off, but im goin turo
anyplace else have ud pulleys?

powermalex

I have 285rwhp on my 93FD with M2 Stage 3 upgrades and I just ordered under drive main pully. New cat converter will come in spring the guy at the shop said he would dyno after I install pully because he was just as curious.

SPZ510

Damn, I love this guy. It's not out of his realm just out of his practicality. He could actually justify someone running a total loss ignition. Ahhhhhhhh! I Love it! Everything you got just to run a short sprint race! Sacrificing everything just to run a fast lap time. That's what I'm all about! All about the record book.

Rx7carl

Yea, ditch the alt and get a 16v battery

riffraff

there are some hard core drag guys that do that.. if you are only running a short time, then there is no reason to have one..

fstrnyou

I have an 88 TII and all my pullies are rusted. can i get a pully kit to raplace more than just the main pulley?? i'd like to get as many as possible and get the remaining from a junk yard or ebay or if all else fails...i'll go to mazda.

Craig

BDoty311

3-5 hp is probably right. But the main thing is that it allows you to rev faster and those 3-5 hp are gained throughout the entire powerband unlike most mods that just add power to the top end.

von

I have both pullies on my FC n/a making 160rwp and I feel no difference. 3-5 I dought on my car mabey 1-2 but ever bit counts and also reduces cavitation above 4krpm like previously stated.

93redFD

I have a greddy pulley set and I want a main drive, and a power steering. the only place that i know sells them is unorthadox or whatever is call, sell them in a kit. Is there anywhere I can buy the pullies seperate?? Also, is removing power steering pointless for drag racing(horsepower wise).?? I was told that it only uses power while turning..

peejay

Try this as a test.... dyno your car with normal pullies, then remove all belts and quickly make another pass (quickly so you don't overheat), then put the belts back on and dyno it again.

Most engines only gain 1-2hp by running with no belt whatsoever!

However that's not so say underdrive pullies are worthless. Stock water pumps start cavitating near the stock redline. I know on 12A cars cavitation starts at about 6000rpm. I also know that if you drive said 12A around above 6000 continuously for more than 20 minutes, the engine will start to overheat due to insufficient cooling. Underdrive pullies would slow down the water pump so that it doesn't get up to the RPM where it starts cavitating, and thus you get better coolant flow and therefore no overheating due to your water pump spinning so fast it just sits there making vacuum bubbles instead of moving coolant!

Cavitation also costs power, which MAY be why some people report as much as 5hp from underdrive pullies. But the main advantage is for engines that see constant high RPM use (and trust me you will NOT be driving your car like that on the street by any stretch of the imagination) to ensure that the accessories work properly.

Ryde _Or_Die

I believe pulleys will help you out some, but are only worth it once you have everything else done and gotten rid of all the accessories you want/can.