So whats the deal with this? Does it work on the 2.0l or not? If I get it do I have to "grind" away some of the engine to install it properly? And why only one pulley, why not a whole set? -- Give it a shot 'http://www.alladvantage.com/go.asp?refid=FCQ-517' Why Not?

In a nutshell, the gains in installing one of these are there "theoretically" but I haven't seen anyone see any "actual" gains. I suggest you spend your money on upgrading other components. -Lino Sacman

"thereoretical"? So how does that differenciate it from every other performance part out there. Header gains, thereoretical. Exhaust gains, theoretical. Intake gains, theoretical. I have not seen anyone verify any gains on any PSE performance parts except for the Bosal system, which was by Bosal themselves, and I always question the manufacturers because there results can be biased. If you want to make it a financial desision, well you could spend $399 (MFSR, I think) for a PSE exhaust system that gives you 2-3 ponies, or you could try the UR Pulley at $150, plus another $10-$20 for belts, and probably free up just as many ponies. Even if you only get 1-2 horses, you are still ahead of the exhaust system. I am aware that you can certainly get better prices than these too, but that was just for reference. The fact is we have no clue what the pulley's will do for our cars, we could free up 5-8 ponies, or maybe its the 1-2 I mentioned earlier, or somewhere inbetween, or maybe 50 horses, but the point is we don't know. I tried to find out, but as I am sure most have heard the story, I did the before dyno, then installed the pulley, then the car would start. Well I found out the hard way that the 1996-97 PSE will not run without the cam position sensor working. I wasted alot of time, and $60 on a "near" useless dyno session. I am sorry for affending anyone, I just get dissappointed when everyone blows the pulley off, particularly since I feel most make their descision on the results of the PGT pulley. If you have a 93-95 PSE the pulley will bolt right up. 1996-97 have a cam position sensor sprocket ring on the back of the OE pulley, so the UR pulley will not work, at least not if they havn't updated it for the 96-97. The PGT is the same way, but they made one with the ring for the GT's The grinding you are referring to is PGT cars only, so you don't have to worry about that. I have photos of the pulley and a final installation photo, as well as belt sizes and other info on my website: probenet.tripod.com Look under PRODUCTS -> Engine Enjoy, Bryan Pendleton >

Where can you buy the GC springs at?

I don't have an under drive pulley so I don't claim to know all the numbers on it. My only basis for not recommending one over any other mod comes from the comments from other Probe owners who have and underdrive pulley and from what I know about simple physics. The "theoretical gain" from an underdrive pulley is simply based on a diversion of available power. The idea is that some of the power created at the engine is used up by the accessories. The power is transferred from engine to accessories via that one pulley. By replacing that one pulley with another that has a smaller diameter (this is what an underdrive pulley is) LESS engine power is used by the accessories therefore leaving MORE power available for use in moving the car. But how much power are we really saving? You can reach down, grab the accessory belt and turn the whole accessories assembly by hand so it really could not be "robbing" that much power to begin with. I would probably guess it really takes 5hp (at most) to run all those accessories. Now by installing the underdrive pulley, the pulley is 2/3 the diameter of the original so only about (2/3 x 5hp = 3.3hp) is used. You only really saved 1.7hp. My numbers are by no ways very accurate and maybe oversimplified but I'm pretty confident that they are good "ball park" values. The point I want to illustrate is that the 1.7hp (1 to 2hp "theoretically") is really all you should expect to see (at best) in power gains from an underdrive pulley. Now let's talk about experiences from other Probe owners who have underdrive pulleys installed. A real good one to pull up is one of our SCPOC members Jin Kim. We dubbed him "dyno king" because of his peculiar interest in dyno results. Jin claimed no substantial gain after installing his underdrive pulley. Claims from other people I've talked to (some who race) are similar. -Lino Sacman SCPOC, '93 Rio-Red PSE, 2-spd

An underdrive pulley is two-fold. First, as you had mention is the reduction in "drive speed" of the accessories. Second is the reduction in rotating mass. I am guessing, but the OE pulley probably weighed in excess of 10 lbs, while the UR pulley was weight at just a "hair" over 1 lb. Please don't take this offensively. While your "number" exercise was fine, I will argue were you came up with 5 hp to drive the accessories. Again, here is a number that seems to be pulled from the air. I have not tried rotating our accessories, but just because you can rotate them by hand means nothing. My car will run the 1/4 mile, and so will a Dodge Viper, the difference is the time it takes to do the 1/4 mile. Try accelerating the accessories to 10,000 rpm, then maintaining that speed. The accessories are turning at some pretty fast speeds, just at idle. They then have to be accelerated to high rpm's which will be were most of you power is lost, because your motor is fighting the inertia of the 10 lb OE pulley plus the others. The engine must then maintain the rpm of these accessories when the engine is turning 6000 rpm too. The other Probe owners you refer to are PGT owners, I believe. Of all the pulley dynos I have seen on PGT's they were never before and after pulls, they were always taken weeks, or months apart. Those indicated mixed results though. They only "true" valid dyno results I have heard of are from SCC magazine, but heck those are probably biased too, just coming from then. 8-) They claim 5 horses at the wheels though. Anyway, enough on that. Enjoy, Hopefully one day the debate will end. 8-) Bryan Pendleton probenet.tripod.com >