I started an "official" flywheel thread, thought I would start a pulley thread also that would have all the info in one spot.



SR Motorsports
0% lighter (2 pounds)
0 % underdriven
3 pulleys
$0

SR Motorsports
45% lighter
? % underdriven
3 pulleys
$430 includes belts
http://www.shaneracing.com/RX8_Power_Pulleys.html

unorthodox
? % lighter
11 % underdriven
3 pulleys
$280
http://www.rx7store.net/product_p/unorthodoxrx8.htm
Video with flywheel already- http://videos.streetfire.net/video/e...71cee4ae60.htm video with no flywheel comming soon.

Agency Power
75 % lighter (1/2 pound!)
20 % underdriven
1 pulley (crank)
$145 includes belts
http://www.rx7store.net/product_p/ag...r%20pulley.htm
Video - http://www.youtube.com/watch?v=LwCdf5WzP3k

Rotary Expert
30 % lighter
? % underdriven
3 pulleys
$ ?
(there is no link from what I am told)

Speedsource
80 % lighter
40 % underdriven
2 pulleys (crank, Alt) (eliminates A/C)
$ ?
(need a link)

Gredy/TRUST Is this differant the the TRUST pulleys?
? % lighter
0 % underdriven
2 pulleys (alt, and water pump)
$ 135
http://www.vividracing.com/catalog/p...ducts_id/23066


this is all the info I have found please post somehting if you have it.

 

TRUST Pulleys for Alternator and Water Pump : Supposedly 20% lighter and not underdriven. Waste of money, show off.

Rotary Expert Pulleys: 30% lighter, suppose a little underdriven, very efficient for revving and 3-4 hp, nothing more than completion of a tune up. High quality, no check engine lights, unknown metal process. Number of pulleys: 3

These two I have tried myself.

 

Speedsource pulleys. Two machined black anodized aluminum pulleys; main and alternator. Eliminates A/C drive pulley (no way to attach it due to the main drive pulley design). I'd guesstimate that the water pump is approx. 40% underdriven and the alternator is close to 80% underdriven. Intended for high rpm racing and only available through the Mazdaspeed Motorsport racer program for around $350. They are lighter maybe 1 or 2 lbs less (OE are steel) plus the weight of the A/C drive pulley that was eliminated (entire engine bay A/C system with pulleys, belt, hoses, condensor, etc. is 18 lbs).

Mazdaspeed claims 10 hp and frankly I'm inclined to believe it, but I have no dyno proof, just an overall seat of the pants.

 

Rotary Expert Pulleys, where I could get them?? Cause I haven't seen them in any net shops.

 

info has been added, I will try and get pricing on all of these when I get a chance.
thanks guys!

 

wish there was a little more info.

 

Unorthodox (info taken from web)

Our Underdrive Series of pulley sets provide power gains through weight loss and through the underdriving of all the accessories (which accounts for about 15% additional gain).

In most applications all of our underdriving is done with the crank pulley, not the accessory pulleys. This is done so maximum weight loss can be achieved at the crank where most of the horsepower gains are found.

 

I have the Agency Power pulley with before and after dyno's done. Not a whole lot of peak hp gains but as you can see the power is under the curve. Plus it is about 1-2lbs lighter than the original crank pulley.

 

in the pulleys thread can someone explain more about what they do and how they work and pros and conns, as Im not too clear on what undrerdriven etc means

 

I'll post photos and the price for RXpert Pulley Set is 400 euros. For the TRUST set the price is 150 euros.

From summer time and so on the RXpert pulleys will be available in USA, I think, not sure though.

Look, as Team explained his pulley set is racing oriented for higher rpm's. So you see the cons(and no AC) but I am pretty sure that they are razor sharp and indeed produce the hp claimed. I knew this guy that had a similar setup, when he hit 7000 to 9500 rpm, all hell broke loose! But in lower rpm's a graveyard...

So I went with street version pulley set and what you notice instantly is the free revving, nothing more. And of course due to faster revving the sound changes(if you have aftermarket exhaust).

 

Basically what an underdrive pulley does it slow down all the accessories on the car (Water pump, alternator, AC etc). Usually most are lightened by a decent chunk, which also give some gains (Sort of like a flywheel on the other end of the crankshaft). The lighter and more underdriven it is, the better the gains.

The only bad thing about it is that it slows down your accessories (if it is underdriven). If you have a big stereo system, then your lights may dim at idle. I had underdrive pulleys on my ZX2, and the AC didn't seem as cold after that, but who knows, that could have just been me.

 

Can underdrive pulleys do any damage ?

 

I've never really heard of an underdrive pulley doing damage. Of course, if it's poorly machine or installed, it can give you issues, but mostly it's a drivability issue. With an underdrive pulley, you are getting less alternator action, power steering pressure, and AC output. With the loss in inertia, especially coupled with a light weight fly wheel, can make the car rev really fast. Conversely, it'll drop revs quickly and be easier to stall. On the extreme, it is possible that your headlights will flicker when your bass hits. This is more likely an issue with you not using a capacitor than the pulley. Few underdriving effects are noticeable when driving. It is usually at idle when your car is running slowest.

 

Personally, I wouldn't underdrive the AC on the 8 (unless you are racing, then why have it at all) as it is already not the best performing pump. Of course if I lived in the great white north, I might feel differently.

 

lol @ crankshaft

 

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/agency-power-underdrive-pulley-review-pics-90310/

Has pics, install notes, and recommendations.

 

Heh, I didn't even think about it... I know it's an eccentric shaft... But they perform the same function.

 

'sall good

 

posted some links,, can some of you find me some link to the ones I am missing. having a hard time finding them on the net.... thanks!

 

Greddy has a pulley kit too.
http://www.vividracing.com/catalog/p...ducts_id/23066
Greddy web site has no info on underdrive or weight. It is a 3 piece set.

 

added thanks!

wow 135 for a 3 peice???

 

Geez, just what we need, another Greddy product to f**k up the car. Hope their pulley system, isn't as half assed as their turbo kit is.

 

Fanman, how did you choose your pulley setup? I know you purchased a lot of your products ealry on, and there weren't that many to choose from...but are you still happy with your setup? Got any pics that you can add to this thread?

 

I'm pretty sure thats only a 2 piece lightened alternator and water pump pulley set, no underdrive, no crank pulley.

 

At the time the SR unit was the only one out. I was one of the earliest adopters of a whole bunch of parts for this car. To be honest I have gone through my share of parts, and if I had to do it all over again, there are several parts (& several thousands of $) that I would not have gotten, but me being an idiot, I had to be the first one to get this stuff.