Mximus

does anyone happen to know if an overdrive pulley would increase the boost of a vortech supercharger kit? im assuming with the extra speed advantage that it would, i was just curious if anyone has ever tried it to see.

vortechpower

iTrader: (1)

No it will not increase/decrease boost. It will simply weigh less than stock and will give you an extra few hp. Kinda like a light fly wheel does. It will allow your rpm's to go alittle faster in the bottom end

Mximus

so would that mean that a underdrive and overdrive pulley would do the same thing? i guess i just cant picture it. I was under the assumption that an underdrive pulley would hurt boost cause its a smaller pulley and the mechanical advantage would be diff. the vortech is designed for the stock pulley i assume, so wouldnt it mean, a larger pulley at the crank would result in higher boost just like a smaller pulley at the blower would also increase the advantage and result in higher boost? if so, why did ur bother to make an overdrive pulley? just wondering cause i just dont see the physics in it i guess.

mjk

iTrader: (1)

yuh, I've read that the underdrive pulley hurst boos because it makes the s/c pulley turn slower... i think the best thing to do would be to get the light weight pulley, without underdriving...

vortechpower

iTrader: (1)

I was refering to the lighter pulley with the same diameter as stock. A different size pulley ohter than stock would not be good for the s/c

Nealoc187

iTrader: (23)

A LARGER than stock crank pulley would produce more boost if that is what you are asking. I've never heard of a larger crank pulley though, only smaller, and same size as stock. Putting a larger crank pulley on there has the same effect as putting a smaller SC pulley on there, spins the SC faster, producing more boost.

This might not be a bad idea for guys who experience alot of belt slippage with really small SC pullies actually, if a larger than stock crank pulley for our cars exists.

mjk

iTrader: (1)

yeah, but wouldnt low end suffer? bigger/heavier pulley = more inertia to overcome while basically no boost at low rpm. I guess its a trade off..

Nealoc187

iTrader: (23)

Probably wouldn't suffer any more than you gain with a smaller crank pulley... which is to say not much. You probably only gain like 4hp with a smaller one, so you'd probably lose something similar with a larger one. But since it'd be an aftermarket piece you could probably have one that is approximately the same weight while being a larger diameter to minimize those losses (same weight but larger diameter would still have more inertia and thus create a loss but you are probably talking about a difference which couldn't even be measured on a dyno).

mjk

iTrader: (1)

well i think is question is answered

Mximus

actually, unorthodox racing makes a overdrive pulley (it is called there Rc line) that is lighter and larger than stock for supercharging applications. the best part is...they make them for the max. i was thinking of doing that with a 3.135 pulley or something someday to increase boost and not worry about belt slippage or shredding possibly with a the really small 2.87 pulley. just a thought that ran across my mind.

SPiG

iTrader: (7)

According to Unorthodox's website:

S = normal underdrive pulley
Sc = stock diameter lightened pulley for those who are SCed (or need alternator to not be underdriven). A few SCed people have bought it with some gains.

*R = single belt conversion underdrive
*Rc = stock diameter single belt conversion

* not made for Maximas and would require loosing of power steering completely

Some Sc pulleys for other cars are overdriven, but the one for the Maxima is not. It is very close to stock diameter or maybe slightly underdriven.
http://forums.maxima.org/oldthread.php?t=304010
http://forums.maxima.org/oldthread.php?t=361142

Mximus

ahh i see that now, i was misinformed i guess, what i ended up looking at was not urs website. well thats dissapointing. somebody should make an overdrive pulley. it could have its uses.

SPiG

iTrader: (7)

It would be good for those with the smaller SCer pulleys so they can have less slippage issues and less tension. Maybe talk to Motostorm to see if they can't overdrive the Alt, AC, and SC pulley while underdriving the PS. I doubt UR would make another pulley especially since they already have one so similar unless they would change design.

I would want to underdrive the Power steering more if that would even make it less overbearing, or maybe I just need to change out my ball joints, etc.

cloudy

Will decrease boost, will underdrive your SC. Pulley is too small.

Nealoc187

iTrader: (23)

Did you bother to read any of the posts in this thread?

slimer

iTrader: (13)

looks like a bump to the post count to me.

MarcL

Old post I found by searching..

Just wondering if anyone makes an OVERDRIVE pulley for the VQ35?

Like the reasons stated here, I want to drive my blower faster without using a very small pulley and get belt slippage.