The ECU is adaptive, but does not "learn". Consequently it takes about ... that long to adapt to new parameters and conditions. Humans, especially those full of expectations, and the reality of spending hard earned money on mods, take significantly longer to "adapt" to changes. Most humans also learn, even though as a college professor I have met some exceptions.
I'd say your reaction to the reduction pulley is well within the norms of human experience. Don't worry, be happy.

cheers,

 

thanks for all the reply, mine is a regular cooper S, has like 44000 km on it.
he said my belt is ok, everything seems ok. may be i didn't clean my fuel injector?

 

What RPM range do you run the car in?

If you're not revving the engine above 3000 rpm..... you may not feel much. Run her up into the 5000-6000 range through the gears, then evaluate the power.

 

or is there a boost leak from my car?
how do i take the BPV out and check it? anyone know where is the BPV located?
thanks

 

^^Is everything else on your car completely stock?

Of course getting a boost gauge would be the easiest way to check everything, but the biggest difference I could tell when I added a 15% pulley was the increase in s/c whine (hence more boost).

 

i have a promini intake as well
how do i take out the bpv and where is it?

 

What are good boost readings with the stock pully and the other reduction pullies?

 

you might consider taking it to a mechanic with experience and ask him to check it out your work...... no offense... maybe something is not quite right..... you should feel a dif

 

I've heard stock boost should be 10(ish) psi, didn't have a gauge back then. 15% reduction pulley on my car is just a bit over 15 psi.

 

Thanks for the reply..that is what we have seen also, just wanted to make sure it was in the ball park. The best I have seen so far was 12 psi.

15psi! Nice Now I really want one.

We are going to get the reduction pully also....one of these days.

I would say having an extra 5psi would be noticeable. But if you are looking for the extra air at normal cruise power (3,000 +/- RPMs) you will not see it.

 

would you recommend a pulley switch from to 15 17 or 19?