slimsdizz

I don't want to get into wether lightweight crank pullies are a good idea or not in this thread I've run one on several cars and never had an issue.

That being said I need assistance I have a jackson supercharged GSR integra. I am using the motorvations pulley on the alternator boost pressure is right at 9-10psi

I have been looking at lightweight crank pullies and I cannot find a lightweight crank pulley that is not an underdrive pulley. I have looked everywhere

So my question is how do I run an underdrive pulley and still maintain my exact current level of boost. Or does anyone know of a pulley that will work on my crank that is the exact same size as the stock GSR pulley. I was told a civic type R single belt pulley might work but nobody can give me an exact answer so far.

I'm looking for a solution to this problem someone please help I respect the heck out of you guys and would really appreciate your help. I did contact pulley boys they said they could make some for me but it's 500 dollars just to have them do the cad and make the initial pulley so I guess I'd have to find some other people who wanted one to make it worth my while.

I am still holding out hope that someone can offer a solution.

TheShodan

iTrader: (14)

Had you considered the ATI and Hollwy Dampner Crank Pulley?

turtleman321

If you can't find one. Why not run an oem one? There are no advantages that make a lightweight aluminum pulley worth it. Get an oem or a good dampened pulley

slimsdizz

Every car I have ever had a lightweight crank pulley on it feels like a night and day diffrence driving it. It feels like the acceleration is faster. Granted I've run them both ways and track time never more than a second but it does feel like the car accelerates faster. At least the cars I've run them on.

Is the JDM Civic type R pulley part 13811-PCT-000 The exact same size as the stock GSR pulley the reason I ask is because it is an oem pulley and has a damper in it but was built by honda for racing only. No I have not looked at those two brands of pulley but I will in about ten minutes.

slimsdizz

ok I looked at the two companies you suggested one of them makes a pulley but it's the same weight as stock. Not really the way I want to go.

I just need an answer on the JDM civic type R pulley
I talked with several machine shops in my area nobody has the ability to cut the factory one down and balance it dynamically so it doesn't look like thats going to happen either.

If I ran an underdrive pulley how much boost pressure would I loose roughly.
I think the civic type R might be the solution someone out there has to know wether it's the same size as the GSR.

sc34dc4

iTrader: (1)

Are you meaning outside diameter? If so I wouldn't see why it wouldn't be. If it was smaller it would require a different belt. I've never heard of anyone having to run a different belt with the ctr pulley. I'd say it's the same.

TheShodan

iTrader: (14)

[QUOTE=slimsdizz;45346099]ok I looked at the two companies you suggested one of them makes a pulley but it's the same weight as stock. Not really the way I want to go.
[QUOTE]

won't change a lot with the underdrive pulley, but better acceleration can work quite well with the lighter weight flywheels.

Otherwise, prepare for the custom. Chance the CTR crank pulley if you'd like, but.... make way for custom application

[Ennis_D]

iTrader: (1)

To the OP: I have a OEM pulley that has had the PS and A/C pulleys removed and rebalanced. It came from dunkd here on the boards. If you are interested, PM me and we can talk about it further.

Raw

I ran the basic 6psi JRSC kit on my '95 GSR with an Unortadox Underdrive crankshaft pulley.

My car made a solid 2psi at WOT all throughout the power band.

I changed back to an OEM gsr crankshaft pulley and the gauge instantly pegged at 6psi again.


Go with OEM.

slimsdizz

Ennis I'd be interested in the stock pulley if and only if it's been dynamically balanced
if it hasn't I'm playing with fire. I called every machinist in our area and nobody had the capability to dynamically balance the stock pulley. My laser cutter can cut it thats not the issue it's balancing it back perfect like honda intended.

I called a friend in japan today who sells the CTR pulley they are smaller then the GSR not by much but enough to affect my boost pressure. Unorthodox racing made some pulleys that were not underdrive back in the day where they are now I have no idea I keep checking ebay and nobody has any. I don't know the science behind why a lightweight crank pulley helps the car all I know is when I run one the car accelerates like a scalded dog. My scion. So I am assuming I'll get the same effect on my integra.

I think my best solution is to have pulley boys custom make some. If I could find a couple people who also want one I'm sure the price would come down allot.

Common sense tells me that a stock pulley is heavy so there is allot of weight the crank has to rotate if you remove the heavy weight by installing a lightweight stock size pulley of course the engines going to accelerate allot faster because it's less work to turn the pulley because it weighs less. which should also help reduce some of the parasitic drag the roots blower puts on the engine. We went round and round and round on the scion forums about the little rubber damper on the stock crank pulleys. What we found was the stock crank pulleys were not in perfect balance from the factory so the rubber damper was needed. When you install a laser precision cut perfectly in balance pulley you no longer need the little rubber damper but like I said I don't want to get into that argument here. I've spoken with several top engineers regarding the pulley issue on the scion when it was in discussion and that was the general consensus.

slimsdizz

we used to have people who opposed lightweight crank pulleys because some guy somewhere told them at some point that they cause engine problems or bearing problems. The bottom line is nobody has ever proven that nor produced any evidence to back up that claim one could argue that a factory crank pulley that is not perfectly in balance would cause far more damage then a laser cut perfectly balanced pulley.

Given a choice between a stock pulley and a lightweight laser cut perfectly balanced pulley I'll take the laser cut one any day of the week.

slimsdizz

I do not like underdrive pulleys the aftermarket people should have just made lightweight stock size pulleys and called it a day. People would be allot more apt to purchase them

TheShodan

iTrader: (14)

It was attemped by a company called Industrial Concepts back in 2002, but it went nowhere. There has to be a desire and a demand to warrant lightweight pulleys like that for supercharged individuals.. Not enough people stayed supercharger (or wanted to grow with it) long enough to warrant the demand to make such a product, in addition, even though they came decently balanced, it had to be made more precise by a machine shop with the entire rotating assembly separated from the block, and it became very expensive. By the time they started making them a bit more available to the public, custom turbos kit were more readily available, there were fewer people with superchargers, and the idea went underwater

slimsdizz

be nice to see if they still had any pulleys and thanks for the insight. If I can't find one my best bet is to have one made. The only underdrive pulley I thought might work if anyone even makes one would be the CRV pulley because people use it to cut up boost I wonder if with it being underdriven it would be the size of a stock gsr pulley.

I'm exploring all options. I might just have to have one made. I plan on keeping my blower so it is worth my while to have one made.

slimsdizz

be nice if I could find some metal pulleys to replace the plastic jackson pullies as well.

TheShodan

iTrader: (14)

Again, lack of demand. You're going to need to get this stuff custom made.

slimsdizz

Thanks a bundle I'll have pulley boys make me one custom in about a month.