Feeler: Underdrive Pulley Kit Group Buy

[turboe30]

I've been doing some work on an underdrive pulley kit. The models have been completed and are ready for production.

The kit replaces the Alternator and Water pump pulleys with lightweight aluminum parts that meet the AC pulley on the crank. This gives a 20% reduction. The downside is that you can not use your AC, as due to the design of the m20 pulleys this is the only way it can be done.

I originally meant to make a crank pulley as well that slows down the power steering and lightens up the crank, but the problem comes with costs. It's going to cost a few grand to program the CNC machines so we can ever get started. I can afford to do the alternator and water pump pulleys, but it will be a couple months before I can make the crank pulleys.

So... who would be interested in buying one of these kits? The price is $249 for the two pulleys. A good price would be offered on the crank pulley when it is available.

I don't have the sheet here, but I believe it is a .7lb reduction in reciprocating mass, and considerably more with the crank pulley.

The parts are anodized. I havn't decided on a color. I was thinking purple because it doesn't seem common with other companies.

It is expected to gain 10-12hp with the power steering pulley reduction... so without that I'm not sure.

Maybe 5-8hp?

Thoughts?

[Jordan]

I would accept a demo set to install on my car and provide feedback on the product.

Do not anodize them some gay fucking color (no offense) Clear or black anodize.

[Skafrog]

if you can prove (dyno sheets, whatever) 10-12 hp, i will buy a set.

[turboe30]

I have a guy who runs DSP that is going to dyno the kit and provide feedback. It will be less than 10-12 hp because the power steering is not reduced.

I'm trying to find a company in china that can do this cheaper so I could do the whole thing at once.

[Jordan]

For the record... the "crank pulley" is part of the harmonic balancer. Changing this out in favor of a aluminum unit wouldn't be good for harmonics, nor would the CPS pick up shit on aluminum (as it is a non ferrous metal)

[turboe30]

Actually, the two front pulleys are NOT part of the harmonic balancer and can be replaced. This is why the kit moves the pulleys out to meet that pulley instead of the one on the harmonic balancer. The balancer is not affected or changed.

[Jordan]

I really think its a bad idea to reduce already low alternator output. P/S and water pump would be nice, with an optional alternator.

The alternator nut is a bitch to remove anyways, pretty much requires a impact gun or special tools.

[turboe30]

I had no problem removing the alternator pulley. Just use some WD40 and make sure the belt is still on and tight when you take it off.

There really isn't much choice with the alternator pulley... it is what gives the belt adjustment.

20% isn't really that big of a difference. ex: 1200rpm instead of 1000rpm for the same output.

[Jordan]

Alot of people have adjuster brackets with broken/worn out teeth. Also another thing to worry about.

You would need a new belt and bracket to fit such a kit.

[RCWells]

Well I don't know jack about the technicals here, but I will say that if your setup was functional with a measurable gain in HP, then I would def. consider the kit. I am not keen on losing my A/C as I live in South MS and summer temps here can reach 115 or higher even with the heat index. And our summers last a good long time.

Minor aside- I am in agreement with Jordan on the color thing, just plain aluminum, black, or a gunmetal/titanium color would look really good.

Keep us posted on the progress.

[UNHCLL]

I really think its a bad idea to reduce already low alternator output. P/S and water pump would be nice, with an optional alternator.

The alternator nut is a bitch to remove anyways, pretty much requires a impact gun or special tools.

m20 alt's are spun at a lower than normal speed. this is mainly an issue on s14's where they are under-driven.

[nando]

I really think its a bad idea to reduce already low alternator output.

90 amps is low?

[Mystikal]

I really think its a bad idea to reduce already low alternator output.

90 amps is low?

My lights have pulsed at idle since the car was brand new. Rebuilt alternator last year, still do.

[turboe30]

Really? I have a decent system in my e30 with no CAP and I don't have any pulse in the lights even when I have it turned up full blast.

If it was a real problem, you could use the throttle body screw to raise the idle.

Do you have a system? Perhaps you need a larger CAP?

[Mystikal]

Really? I have a decent system in my e30 with no CAP and I don't have any pulse in the lights even when I have it turned up full blast.

If it was a real problem, you could use the throttle body screw to raise the idle.

Do you have a system? Perhaps you need a larger CAP?

I'm talking with no accessories on at all. In fact, I've yet to see an M20 that doesn't do it to some degree.