Unorthodox Racing underdrive pulley remarks

[jefferson]

Just got the pulley installed last night and drove the car for the first time today. I am very happy with the improvement in the car.

First off the UR pulley is 3.81 lbs lighter than the stock piece. It was 4.76 lbs. and the UR is .95 lbs. Pretty significant.

The car pulls smoother and better down low and I was able to climb the steep hill leaving my area without the car protesting the way it always does. Never got that harmonic going that starts everything in the car vibrating. It just pulled up cleanly and quietly. Major improvement right off the bat. I am expecting an improvement in the mileage I get, but that will take a while to find out.

The car is for sure putting more of the horsepower it makes to moving the car down the road rather than driving the accessories.
I didn't notice any difference in the feel of the power steering. I say money well spent. I will post again when I see how the mileage is affected.

Jeff

[DLC]

I'm one of the many who think that the main benefit of the pulley comes from the weight decrease. I also think there's a bit of help in having a solid pulley as well.

I had a UOR underdrive on my car, but replaced it with a Cobb lightweight. Because of the other stuff I did to the car at the time, it would be impossible to gauge the difference.

[Kelly]

I think its placebo.

No way a couple pounds off the crank pulley, at such a small diameter, could make a difference when theres a 27 POUND FLYWHEEL THATS A FRIGGIN FOOT IN DIAMETER ON THE OTHER END!!!!!!!!

Only thing Ive seen lightweight pullys do is eat up belts due to their pourus aluminum build.

Ever seen a stock pully made in Aluminum, from ANY manufacturer?

[jefferson]

It' s not the pounds that makes the difference in my opinion, it's the gearing the accessories down and it is definately not a placebo, it's call physics.

The lighter weight may help the engine accelerate a little quicker, but I see no way that more hp will result.

The gearing of the pulleys would be like putting 4.11 in your car versus 3.90. It is now easier for the engine to move the mass of the car. Same thing with the engine and the accessories. The engines hp can now be used for moveing the car rather than turning them faster.

Jeff

[Adam West]

I got +2-3 mpg on installing my Perrin lightweight pully...

[jefferson]

I'm guessing that the perrin is an underdriven pulley then. With that much of an increase it would almost have to be.

I have never had any belt problems on my other vehicle with an underdrive pulley on it and it has been on for years. I don't know where that is coming from. Aluminum pulleys work fine and the only reason the factorys don't use them is the cost factor.

Jeff

[DLC]

The factory pulley on my 93 was a cast piece that was in two parts with a rubber buffer inbetween. Eventually that rubber began to let the outside part slip over it and it made a lot of noise when that happened. I replaced the stock part with an UOR from Cobb (in 2001) and never looked back. As far as I know, biggreen still has that same setup on the car.

http://legacycentral.org/library/underdrive.htm

[jefferson]

I really only had one problem with getting everything up and running and that was the instructions with the pulley listed Gates belt numbers to use since the diameter of the pulley is smaller. They gave 2 different numbers for the alt/ps belt and neither of them worked. One was too short to go on and the other was too long to get tight enough and I ended up breaking the adj. bolt trying to get it tight enough when it bottomed out, or actually I guess it topped out. There was a belt size in between and it worked fine. Got her going again this morning after running to pic and pull for a bolt. I got the only one they had.

Jeff

[dzx]

If you have the same perrin pulley that i have it's not underdriven.

[Adam West]

Perrin pully is not underdriven. I swear it gave me better gas mileage...Not super noticable mod tho...Still cheap an easy checklist item. The underdriven with the belts seems like a major PITA...I would like to get the full set of GFB lightened but not underdriven pulleys - but that more like engine bay jewelery - when I win the lotto kind of thing...Good luck with all that!

[jefferson]

I haven't heard of this GFB. Who are they and where can I find their stuff?

The belt stuff wasn't any more than a hassle and it would have been real easy if the correct belts were listed. I bought all the belts listed so I had everything on hand when I did the work and wouldn't have to run back to the store to get another one. Good plan gone awry.

Jeff

[Adam West]

http://www.gofastbits.com/index.php?par ... ption=2002

[wrxzzz]

I've heard they can damage your oil pump. I'm not sure how though? I'll stick with stock and just lighten my internals with forged pistons and rods. Lightened flywheel will make a big difference too.

[jefferson]

The only way I can see would be through some sort of harmonic doing some damage as the stock harmonic damper is removed. Other than that I have no clue. Really don't know what type of damage could result either. Hope I don't find out the hard way.

Jeff

[NICO]

stock one is best, didnt we cover this like 5years ago on this board?

[skid542]

The harmonic balancer is not needed near as much as it is on a tradition inline or V. There is a little bit of secondary vibrations, as I understand it, but it's pretty minimal. The old engines, particularly the 22T, are pretty stout and will readily take this without a peep.

And I don't understand how's upset your oil pump either. That sounds like rumor to me. If you drive in the powerband then you'll have plenty of RPM's to drive the pump.

That's my .02 on the matter.