I have heard that a 15% pulley is great for a simple upgrade. I was reading some info on the pulleys and came across an article that said that anything over 15% and it will overrevv the supercharger. Is this true? also will anything over 15% cause everyday driveability to greatly decrease?

 

no one??

 

Anything over 15% does over rev the supercharger.

 

Ah I see. So if I just run a lightened crank pulley instead of an underdrive crank pulley I should be fine correct?or will thelightened crank pulley make any noticeable difference on this car?I have purchased a 15% pulley and a 2% underdrive crank pulley, but I can return it I still have the receipt and whatnot.

 

There's a lot of debate about crank pulleys, the aftermarket ones don't have the harmonic damper that the stock ones do. Some people say who cares and some people think it's a very bad thing. As an engineer I say return it, you really don't want any chance of the crank vibrating. Plus, the amount of weight your saving on something with that small of a diameter is negledgable. My opinion is, just install the 15% and drive it (you'll really like it) and if you decide later that you want more just get a 16%, 17% or 19% pulley.

I have a 16% pulley on mine with the rev limit extended to 7,500 rpm and I can tell you that the supercharger does run out of breath right around 7,000 rpm. You can only spin it so fast before it physically won't go any faster. Heat becomes an issue too, the faster you rev the supercharger the hotter the intake charge is going to be. That means your car will start to pull timing and any gain you may have gotten is lost. You can get around that by adding a meth injection kit or running race fuel but those are both expensive with only a couple HP gain.

 

Cool stuff, thanks for the insight. Definately returning the crank pulley. I will probably just re-tune the computer after I put the pulley, plugs, injectors, and fuel pump on it. Hopefully I can do it this weekend, I don't think anyone is scheduled on the dyno so I may get to get paid to work on my own car... always a plus haha. What intercooler do you suggest? I've seen many, but can't decide which one too run. I've seen the ones w/ the nitrous sprayers on them, but I'm not a big fan of nitrous. I thought about just using CO2 instead of nitrous on the sprayer but I wasn't sure if the components would hold up the same. Any insight on this? Sorry I'm totally in the dark when it comes to this car. I work mostley with the Japanese stuff.

 

Well first, you won't need larger injectors and fuel pump until you're way over the power level you'll be at with a 15% pulley so you can probably send those back too.

Intercoolers are tricky, some claim that they make a huge difference others say not. My opinion is that they're one of the worst mods as far as hp:$ is concerned. I think the most popular aftermarket unit is the M7 direct flow intercooler though. Everyone I know that sprays anything on the intercooler just uses water.

Since you work at a shop you should look into a water/meth. injection system. The MINI/BMW computer is really advanced as far as timing is concerned and your power will be limited by knock/timing retard. No one is really doing it yet but a meth injection kit should cut down on knock and allow the computer to significantly advance the timing. I would bet this is one of the best ways to get a bunch of power cheap. Also, you won't have to tune for it, the MINI knock/timing algorithm will take care of it.

 

What is the average life span of a supercharger. Am contemplating purchase of a 2005
"S" hatchback with 32k miles. Thanks
Achilles (new member)

 

many are over 100K

 

I bought my 03 mini with 75k on it and it is still a beast. 32k on a 05 is great.