NoTears316

I thought you had the SR kit. I know mine came with belts.

zaglo6204

im a wee bit confused. from wat i understand, or thought i understood, the weight savings would simply allow the engine to rev more quickly, which would thus allow for quicker acceleration because of the celerity with which you would reach the 'powerband'. but under load, ie the engine making the tires turn on the ground (with traction), that would set a far lower limit on rev speed than the mass of the pulleys.....im so unbelievably confused.....AAAAAAAAAAAAAAHHHHHHHHHHH i just gave myself a headache

carbonRX8

iTrader: (1)

if you were talking about a lightweight flywheel, that would be measurably true. It is also true with the pulleys, but the difference is so minisule, it is unmeasurable by any practical means. Now, I contend (and this is somewhat disagreed upon) that you could measure, on a dyno, a hp increase with underdriven pulleys with an underdrive ratio greater than 20% over stock (about 2-8hp, big range for flame safety).

AlexCisneros

...get the UR pullies. They're good, mkay...

zaglo6204

yeah, thats wat i thought. i just confused myself for a moment there......happens way too often. i think my parents dropped me on my head when i was little, but thats okay. i still love them for helping with car funding....hehehehehehehe. thanks for clearin it up carbon.

Fanman

I had to adjust my belts as well, still won't justify substantial increases. In the beginning of the post, the difference is only a few % of underdrive.

rotarygod

I've had underdrive pullies for RX-7s for years. I can't feel a thing different. It's not saying there isn't a difference. It's just not big enough for the human body to feel with any degree of accuracy. A dyno might see it though. The weight differences between pullies is a nothing more than advertising as people believe it makes a difference. As has been stated earlier, it's the location of the weight to the rotational centerline that makes the big difference. The pullies concentrate this weight close in. I could care less what a big V8 has as far as pullies go. We aren't talking about a V8 and their harmonic balancers weigh more than all the pullies combined anyways. The power gain comes from being under driven. Period. If and that's a big if, there is a power gain from weight loss on this car, it would be miniscule and probably smaller than the variation between 2 dyno runs so you'd never even prove it was there. I always find it funny that people swear by pullies and it's gains. A gain is a gain yes but don't expect to noticably feel it. That would be a placebo effect. If you combine this with several other small gains, they could add up to something you would actually notice though so they aren't worthless.

KJ238

I'm using a pair of Trust (GReddy in states) pulleys for the SE3P... I'll take a couple of pics later...

Jaguar_MBA

I have the SR Motorsports pullies on my RX-8. If you must get Pullies, I would suggest UR ones and save yourself a couple of hundred dollars.

On a regular piston car these work just fine because they have a heavy harmonic balancer. The RX-8 does not. Reducing weight on the crank shaft increases HP to the rear wheels...or reduces inefficiencies that reduce HP from the Rear Wheels. A standard harmonic balance on my 1992 300zx must have weighed ~ 20lbs and I replaced that with an aluminum unit that weighed ~ 4-5lbs or so. That is where the performance gain is to be had. RX8's underdrive crank pulley must weight ~ 1.25lb stock.

BoosTED

iTrader: (2)

Anyone factor in RPM's?

The majority of gains, if not all, are after 4,000 RPM's. It is there for me and even if you barely pay attention to how your car feels you will notice a difference.

Since we have a higher revving engine the weight being less will make more of a difference with even small underdrive since it is spinning that many more revolutions per minute.

Jaguar_MBA

Right..all the gain is due to less parasitic drag....very limited gain from weight reduction....jump for joy +1HP

Riogrande

Anybody knows how to unscrew the main harmonic bolt? Is it clockwise or normal counterclock???

Riogrande

Trying to remove the crankshaft main bolt harmonic balancer. Is it counter or clockwise?

StealthTL

iTrader: (1)

It's a 'normal' lefty-loosey bolt.
Try using an extension and letting it lay on the ground, and use the starter to break the torque.

Riogrande

Trying to change the main oil seal. I will try using the engine itself to loosen it up with a 1/2 inch ratchet against the ground with the Computer fuse off.