Performance Pulleys

[anco2001]

Does anybody know where I can find lighter pulleys for an MSP?

 

[Captain KRM P5]

we sell the unorthodox racing underdrive pulley which a few people on this forum have been using for some time now

 

[anco2001]

we sell the unorthodox racing underdrive pulley which a few people on this forum have been using for some time now

What are the gains with this underdrive pulley?


EDIT - Nevermind it's on the website, thanks.

 

[Captain KRM P5]

What are the gains with this underdrive pulley?


EDIT - Nevermind it's on the website, thanks.

let me know whatever other questions you may have on this part!

 

[EvilMSP]

I'm not buying these anytime soon but I have a question. I asked about these a long time ago and a bunch of people were saying they were "bad" for our cars. Is that total BS?

Also just a clarification..so they are lighter than the stock pully's. But what exactly are underdrive pully's (I think I know but I want to make sure.) So everything attached to the crank is being driven less IE Alternator, A/C yada yada? Ill hold other questions until i understand exactly how they work.

 

[Captain KRM P5]

the unorthodox racing pulley is lighter and smaller in diameter than the stock pulley on the crank. there was the thought that installing one of these on the Protege would imbalance the engine. these engines are internally balanced at time of manufacture and do not have independent harmonic balancers like, say, a chevy v8. the official word from unorthodox racing's tech department (thanks topher for looking into that) is that this, even in combination with thier flywheel, will NOT harm the car or imbalance the engine.

 

[chrisjw85]

Oooh maybe that's what my friend with a wrx was talking about. He put in a lightened crank pulley and they said he couldn't get a lightened flywheel now. How is the flywheel involved though?

 

[Captain KRM P5]

Oooh maybe that's what my friend with a wrx was talking about. He put in a lightened crank pulley and they said he couldn't get a lightened flywheel now. How is the flywheel involved though?

you have a lighter pulley on one side of the engine, the flywheel on the other end - both pretty much mated to the respective ends of the crankshaft

 

[Tommy1005]

Wouldn't the pulley's be larger to underdrive? Being smaller would overdrive the accessories if I'm not mistaken. If it was smaller, everything would have to turn faster, than if the pulley was larger. I know about 85-90% of the gains are from the lighter weight, and the advantages of underdriving are minimal for a street car. Just thought I'd throw that out there.

 

[irr5302]

Im run UDP for 32,000milles and counting without any problem

 

[goldstar]

Wouldn't the pulley's be larger to underdrive? Being smaller would overdrive the accessories if I'm not mistaken. If it was smaller, everything would have to turn faster, than if the pulley was larger. I know about 85-90% of the gains are from the lighter weight, and the advantages of underdriving are minimal for a street car. Just thought I'd throw that out there.

Just the opposite. If the driving pulley's diameter is increased, the speed of the driven pulleys is increased. If the driving pulley's diameter is reduced, the speed of the driven pulleys is reduced. The crank pulley is the driving pulley.

 

[EvilMSP]

Hmmm this sounds like more of an option to me now. How long does it take to install this bad boy?

 

[b00sted]

thanks for clearin this up...i KNEW they weren't bad for us. mspeed101 swore up and down that underdrive pulleys were bad(butt)

 

[warrier04]

imma keep reading up, cause i really wanna know if theyre good or bad. this seems like a pretty good mod, especially to a turbo'd car.

drew.

 

[mspeed101]

thanks for clearin this up...i KNEW they weren't bad for us. mspeed101 swore up and down that underdrive pulleys were bad(butt)

(stfu)

 

[starflare21]

kinda late to respond to this thread but check this article out. valid points mentioned here do make sense. a friend of mine who is one of the top import engine builders here in the state (used to build domestics too) hinders any potential customer NOT to use these. the accessory ones are fine but just the crank he'd stray away from. read the article. be careful if it's not properly dampened.

http://www.overboost.com/story.asp?id=1283

 

[Nutari]

I also heard something bout it drops your alternator output..
so if you plan on running sounds.. DONT get aftermarket pulleys..

 

[JDM Sam]

do a search on the blown engines with the pulleys. i recall one girl had em on her msp b/c her bf said it wouldnt hurt and boom. oil pump failure. If you really wanna reduce rotating mass just get a lightweight flywheel next time you get a clutch. Does the same thing.

 

[Puckpimp71]

I'm with JDM Sam on this one... If the crank pulley's spinning faster (from size or weight) won't the oil pump be working harder than the engine can handle? Interesting read by the way...

 

[GreenPic]

i was just reading the protege faq and it had this to say about underdrive pulleys...

"Are there any underdrive pullies available?
Unorthodox Racing makes underdrive pullies however it is not recommended to
use any underdrive crank pullies from any company at all because it can cause
oil pump failures. All Protege engines are directly crank driven and if an under-
drive crank pulley is used, it can cause accelerated wear in it which will event-
ually lead to failure! Typical underdrive crank pullies do not have a harmonic
balancer and therefore all the oscillating forces from the crankshaft are
transmitted elsewhere. Even on the typically well balanced stock crankshafts,
there is always a very slight imbalance in them and as such the forces caused by
them results in the oscillations. Many turbo Miata engines have blown up from
oil pump failures due to the installation of underdrive crank pullies. Be warned!"

so can we mod our cars at all then? if the oem engineers already thought of everything to squeeze out all the power, then why do we show gains when we replace this stuff? also if you used the appropriate belts with the underdrive pulley and tensioned it right, would it not lead to a oil pump failure?