94touring

Well i've searched around and didn't exactly find the info I was looking for. I was thinking about going with the unorthodox pulley kits, since the forum store claims 16-20hp, but found that you can damage your motor if you don't install them properly. So, not wanting to take that risk, how good are the other kits.....greddy? I can't find any hp claims with the greddy or any others for that matter and would like to see some data. Thanks for any informative info on the subject

purepsi

pm me i have a friend that is selling a pulley kit, alt waterpump and main for 235 shipped with belts.

purepsi

sorry forgot to tell you that the pulley kit is new

Lost Time

The UR pulley is dangerous because of removal of the eccentric shaft bolt. The others that don't require removal of the bolt won't show quite the same gains because it won't be as light. Don't believe everything you hear. The 16-20hp on the site is what Unorthodox Racing claims, not Jason and the RX7 Store. You're probably looking at more like 5hp than 16-20. Here's an interesting write-up if you are considering the UR kit. It shows what can happen. And just so you know, I'm pretty hamfisted, but I installed the UR pulley with no problems.
http://www.mazdatrix.com/faq/pulley.htm

94touring

What brand kit is it?

Lost time, So basically your saying that you don't really notice a difference in power....at least none that is worth a few hundred $$. Cause if there are only small power gains for the money the unorthodox kit cost, I would rather buy 4.33 gears. I saw on srmotorsports website they noticed 8hp with a kit they sell put on their project car.

Lost Time

To each their own but I wouldn't spend the money again on a pulley. Not unless I had done everything else and I was looking for those last few hp.

maxcooper

That is my engine after my install (oops!). Whether the thrust bearing slips out of place is largely luck (though you can take some precautionary measures to reduce the chances), but the smarts comes in on recognizing when it happens and fixing things before you bolt it down. I drove the car for 8000 miles with the botched install, including a few track events. You can see the pulley wobbling if something is wrong after the install, but at that point you will already have a lot of fix-it work to do.

The UR main pulley is really nice, but I don't think the power gains are much different (the stock pulley is only a pound or two heavier that the UR, and it is all close to the shaft) and you can save yourself a lot of installation hassles with a pulley that bolts to the stock hub from Pettit, Rotary Performance, or SR. The main pulley will give the most gains, because it underdrives everything. The GReddy kit just underdrives the WP and alternator, but you also get more belt contact if you have removed the air pump. SR also sells a similar kit with underdrive pulleys for the WP and alternator. The UR pulleys for the accessories are the same size as stock, just the main pulley is a different size.

I think the UR main pulley gives you an extra 10 RWHP (roughly), which may not be butt-dyno perceptible if you already have a lot of power, but it is still 10 RWHP.

The stock pulleys are pretty light (e.g. the plastic PS pulley is lighter than any aftermarket unit), so I don't think you get much HP from the weight. UR says that 85% of the power increases from their pulley kits come from the weight difference. Of course, the exact amount will differ from car to car. Since the RX-7 pulleys are so light in the first place, I would guess that the majority of the power increase comes from the underdriving. That does not conflict with UR's claim about the average increase from weight for their entire line of pulleys, it just means that the RX-7 application deviates substantially from the average.

-Max

94touring

Thanks for the good info guys. One more question...the power pully sold on the forum store (by pettit), I am assuming that it is just the main pully. Correct me if I am wrong. I'm thinking I can go with the greddy kit and get the pettit main pully.

Lost Time

Most say it's ok to run that setup but you will have a very limited contact patch on your water pump pulley. I haven't heard of anyone having overheating problems, but I'd keep an eye on the temp guage.

Bucrx7

Isn't the dyno results for the rx7 Jason's car? If Jason can chime in on this I am very sure that it was his car.

Jason

iTrader: (5)

Yea that was my car that was on the unorthodox website. We dynoed the car before and after the pulley and it was about a 13-16 RWHP gain, I forget, it was a while ago. I think it was worth the money, but I wouldnt try installing it on your own.

Jason