New super charger from the dealer was just put on my car today however they had to put on the stock pulley for warranty on the work reasons.

Q's:
When I had the 15% on there i was making 13-13.7psi load dependent but now with the stocker im making right at 10psi. Im sea level and also I heard that 10psi with a full exhaust and alta intake sounds right. but i always thought that my 13- 14ish psi was about 2 psi low. The car feels great mid and low but it seems its lost top end but not a whole lot via the but dyno. Also i was finding metalic crap getting caught by the intercooler.

So asuming i put on my 15% pulley how much farther would that bump me up PSI wise from 10psi? and why would the new super with a stock pulley feel better more responsive than the 15% (What sounds wrong with the old charger?) they replaced gaskets as well.

more varibles: im about to go out in the garage and install my DT bypass and new alta intercooler boots as my old ones seemed worn so ill see if some PSI was missing there. **EDIT** I never had the DTbypass installed so stock Bypass is still there. Bout to go wrenchin!

15% pulley is smaller than the stocker, it seems from your post that you have it backwards. Anyways, I have hit 15 psi with the 15% pulley consistently since the install and I am at sea level. I have to assume you either had a leak somewhere or your supercharger was on its way out. I figure they put the 05' and later supercharger on there if its new, so that might have something to do with the better performance (coating on vanes) but it really shouldn't be noticeable by butt dyno standards.

What happened to your old s/c?

Just for another data point, I have an '02 with just an intake and hit 10 psi at redline.

15pulley = 14.5psi

i second this... this is exactly i'm reading with my 06 and 15%

Ok im back not much diff in peak psi mabye .5 psi 3rd gear. However much better response as expected. During my little highway test drive I noticed sightly less top end but again low to mid felt great plus the response.

I wish i got to see the old Supercharger mabye ill try and sneak a conversation witht he tech. This i will tell you i have better bottom end with the larger stock pulley and new supercharger than I did with smaller pulley 15% and old supercharger. Also my check engine light for in efficent cat has not come back yet and i put on about 30 miles since the SC swap. Im starting to think that while the old one was spining faster and allowing more flow for high end it was chewed up causing poor low end boost. This mabye was also messing with the AFR i dunno time will tell on that. my AFR always looked more rich than others out there.

Oh and that little o ring on the bypass was totally flattened compared to the new one i just put in so mabye some leakage there.

My gas milage before the new SC would always level off on the computer to 30.5 - 31.5. Now even before the DT BPV it was more like high 20's so im all confused now and this is with the stock pulley. Butt dyno likes the response so im guessing i need to get on the dyno and check it out.

Ill be getting with a local tuner to check out the car and runa dyno to see whats up with my AFR and how much power i lost or gained at x rpm. He will probably be the guy to tune my ECU too.

Today i got to put a lil over 100 miles ion the car and the service engine light came back on for the same p420 inefficient cat. Had a feeling.

My mileage is back up to 30.9 but the car feels great still but a little anemic at the top compared to before but very nice to drive as its more responsive and just feels better down low. Ill probably spend a few weeks with the stock pulley on at least and get my cat situation repaired. then get a good belt and probably a new 15% as mine has some nicks in the grooves and one of the hex bolts look stripped. (safe than sorry). once thats on ill probably have a good base to do my tune considering my other parts on the car. It will actually be the car I bought with the parts it had except without the problems.

I also asked about head work and stuff to my tuner and he pointed to the window where he had a full machine shop.

Also a nice little heart attack mode i watched my temperature gage rise like a tachometer but it would go down real quick too. I get out after letting the engine cool a bit and I can see the bottom of my coolant reservoir so i remember from reading about it on nam that they most likely needed to disconnect coolant lines so i call to verify as I'm looking for distilled water in a near by publix they said yes and i fill what it will take up to the line and it ends up being half a gallon after that no temp issues.

So my next step is to fix the cat issue and will probably hand over the car to him to look at it see what issues he finds I believe he will have it on the dyno too so ill see how the power band has changed. Does feel slower up top though :(

Since im going to be having to change my SC soon. (its on its way out) If you dont mind how much did it cost to have it replaced. Oh and for those who are interested. im running 19% with +2 .. Just hit the 60k mark. When first switched the pulleys was running +1.19 pressure.. 30k mark +.79. at 50k +.34 and at 60k. +.09.

And yes i've check for pressure leaks and replaced couplers.

Wow that's killer pressure drop off. Post some pictures of the rotors and inner casing please!

Jeremy

At the BMW dealer I ended up paying $1300 half of what the original parts and labor was. So basicly dont expect to pay that at a BMW dealer or Mini id imagine. I would search out some refurbished ones on here some even have port and polish options. Car still feels great but need to fix this nagging bad cat situation and see about getting a 15% pulley back on.

Oh also have you checked out your BPV i replaced mine with a DT BPV and noticed the old ones rubber o ring was completely smooshed.

Sounds like belt slipping, ck how much adjustment room is left for the belt