guys any1 with any inmput/experience plz share

 

well, sence no one is really giving you the answer your looking for, I read a artical a while back. Euro Turner the magazine put a light/underdive pully on the alt. and power str. of a 1.8T jetta and they saw a 5 hp-ish gain the whole way through the power band. It's not going to make a huge difference, but it does reduce the parasitic draw from the engine, which in turn alows more power to go to the wheels.

 

that's cool... any side effects they mention in the article??
what abt crank pulleys?? they should accnt for the same increase i guess...

i agree there is no power increase on flywheel, the power increase will be at the wheels, bcs loss through the whole system was decreased...

if alt & power steering pulleys gave 5hp & same goes to the crank pulley, that will make 10 bhp... not bad once u fined tuned your car and got all the power it can give...

 

Lookup what many of the well known tuners prefer - stock. I had mine replaced and Ivey suggested stock - this was last summer.

 

ok, tuners prefer stock, most of the people prefer stock, every1 prefers stock,
but WHY?????

 

oh

 

Because they don't help to slowly kill your engine.

 

There is a lot of "be afraid, be very afraid!" stuff on the boards regarding the use of an undamped crank pulley. The only aftermarket damped pulley that I'm aware of is Fluiddampr, and it weighs more than stock (no performance gain), so most people say to keep it stock. This may be a meme, or it may be based on actual user experiences (I don't know).

I have not seen any engine failures first hand that resulted from an undamped crank pulley, but I also have no personal experience with using one on an Evo. Interestingly, this general attitude towards undamped crank pulleys seems to be much more prominent in the 4G63T community than other platforms I've worked with (mostly Toyota engines). I've used an undamped crank pulley on a 2zz engine for many years of hard track use with zero problems, but this may have been due to larger engineering margins in the Toyota/Yamaha engine vs. the mitsu 4G63T. There are some JDM companies that offer light-weight / undamped crank pulleys, if that gives you any reassurance.

If you don't mind the possible reduction in longevity, a lightened / undamped crank pulley is a worthwhile mod. It will improve engine responsiveness, and gain some hp (3-10 depending on other mods) throughout the power band. The main benefit is really throttle response though, much more so than peak power - just like a lightened fly-wheel, CF drive shaft, or light weight wheels.

If you want to play it safe, you can still replace the water-pump and accessory pulleys with light-weight aluminum units for a little performance improvement, and leave the crank pulley stock.

Underdriving pulleys won't hurt your engine at all, assuming you continue to use a damped crank pulley (either OEM or Fluiddampr), and underdrive the accessory pulley. They just impact the electrical system performance. I personally don't like underdriving, because it reduces power delivered to your ignition system, which is pretty heavily loaded on a turbo car to begin with, leaving very little margin.

Making more power by modding the stock engine almost always implies loosing some margin, and thus reducing reliability and total life. I'd bet that using a MBC to crank up the wick has a bigger impact on engine life-time than using an undamped crank pulley, but for some reason most people are more comfortable with one than the other.

as always, ymmv

 

@voidhawk: Thank you

 

welcome . One thing I forgot to mention, because of the "fear-factor" associated with lightened crank pulleys on the Evo, they don't sell well and many vendors give them away dirt cheap ... I got mine from Gruppe-S for $50. I haven't gotten around to installing it yet though, so I can't tell you how it performs (yet). Lastly, if you get an underdrive pulley, you'll need a new (shorter) belt, non-underdrive you can use the stock belt.

 

So any company that makes lightweight accessory pulleys???
I only found Unorthodox, but they're aslo underdriven...

 

If you go on unorthodox website you have a waterpump pulley and a accessory pulley.

http://www.unorthodoxracing.com/

 

Also Perrin and Gruppe-S. http://www.gruppe-s.com/Evo/evoeng.htm bottom of page