Eric in Chicago

While looking at my new Performance Products cat.
I came across a Weltmeister 993 RS/RSR Pulley Hub.
The ad states "it replaces the dual pulley set up with our Weltmeister RS/RSR hub so the fan and alternator spins at the same speed" I wonder if this could take the place of the pulley update or if there is any positive gains from having the alt and fan spin at the same speed??? at 178.00 I would hope it does something good! comments please

993RS

I do not believe there are any tangiable benefits. It is just the philosophy of the RS to simplify and eliminate parts. This setup allows the elimination of the electrical pulley monitoring electronics.

Eric in Chicago

Thanks Phil,
Just looking for winter projects to go along with my monoball installation...

Greg Fishman

The benefit is that it keeps the alternator from spining as fast as it would with two belts and therefore increasing its life (possibly) and it may make a little more hp.
Another benefit is that you only have one belt to change but if that belt breaks you MUST pit.

Most of the race cars had only one pulley if they turned over ~7500 rpms. EDIT ( Make that one much larger belt)

I ordered one also to see what it consists of. My mechanic is also pricing me a pulley from PMNA$$.

tom_993

I think the benefit of this is that the alternator spins a little slower, which decreases the drag on the engine. This results in a few more HP. The downside, though, is that it may spin too slow if you’re stuck in traffic, meaning you’re living on battery power. This can discharge your battery pretty quick, especially at night when you have your lights on. Another downside is that all the stress is put on one belt and pulley, rather than two. Yet another downside is that if the one belt breaks, you’re hosed! All in all, it might be a good thing for a track only car, but probably not recommended for a street car.

Tom
’95 993

Eric in Chicago

[quote]Originally posted by Greg Fishman:
<strong>The benefit is that it keeps the alternator from spining as fast as it would with two belts and therefore increasing its life (possibly) and it may make a little more hp.
Another benefit is that you only have one belt to change but if that belt breaks you MUST pit.

Most of the race cars had only one pulley if they turned over ~7500 rpms.

I ordered one also to see what it consists of. My mechanic is also pricing me a pulley from PMNA$$.</strong><hr></blockquote>

Thanks Greg, thats all I need, the promise of a little more hp...
Changing one belt vs. 2 also sound attractive. Hell, if ANY belt broke I would pit as one would take out the rest... As for belts, my guess is that this device replaces the upper pulley set thus letting the AC belt (when used) to stay functional??
By the way Greg, Anir and Family came by Sun. night. A good time was had by all. Going to take his kids out trick or treating Thurs.

David in LA

Most of the rice-boys install anodized "underdrive" crank pulleys as one of their first engine mods (cost is $75 or so). The pulleys causes the alternator and other accessories to turn slower and supposedly results in a few extra hp as the drag on the engine is less.

A few hp is a big difference for these guys when they are starting off with only 115-125 or so.

Greg Fishman

[quote]Originally posted by Eric in Chicago:
<strong>
Changing one belt vs. 2 also sound attractive. Hell, if ANY belt broke I would pit as one would take out the rest... As for belts, my guess is that this device replaces the upper pulley set thus letting the AC belt (when used) to stay functional??
</strong><hr></blockquote>

Ask Hank about that! You definetly are risking your engine if your belt light comes on and you stay out on the track. You got a 50/50 chance...

I wouldn't be surpised if this kit assumes you have removed your A/C. Not too many dedicated track cars that pump cool air into the cabin. Sometimes I wish mine did though.

I hope Anir was on his best behavior, sometimes you can't take him anywhere...

KINGSRULE

I've had the pully setup on my street car for months.
No problems at all including running air in stop and go traffic. Getting rid of parts, IMHO, is a good thing, especially the foolish belt sensor! Plus the bearing on the double pully gets noisy and fails.

Flying Finn

[quote]Originally posted by GJ:
<strong>I've had the pully setup on my street car for months.
No problems at all including running air in stop and go traffic. Getting rid of parts, IMHO, is a good thing, especially the foolish belt sensor! Plus the bearing on the double pully gets noisy and fails.</strong><hr></blockquote>

And A/C works too?

If yes, again another thin I 'need'...

P.S. Gert doesn't seem to have this? Gert?

Eric in Chicago

GJ,
Which belt do you keep, I would guess the large inner belt

leslie

I have this single belt setup and I run my a/c daily in stop start traffic. There are no obvious side effects of having only one belt on the a/c system or the car itself but I do agree that you do tax the battery. My battery recently died and the replacement was brand new. Despite that, my idle was still at 1100 rpm with the new battery. This higher idle is only suppose to happen when the battery charge is low but despite my car being a daily driver, my idle rpm is typically in the 1050rpm range. It only gets to 950 rpm (the RS norm) about 20% of the time, typically after some extended period of driving.

KINGSRULE

Eric,

Correct, the inner belt.
BTW you can still keep the belt sensor if you like.