I have a 2000 supercharged s-281. It is basically stock besides a 12lb. pulley. Heres the problem. When ever i give it boost in high rpm's it looses power and stops pulling around 4000. Then whenever i shift into another gear it hesitates a couple of times before it takes off. Does anyone know what this could be? Do you y=think i should put the stock pulley back on just to be safe or what?

If it only happened after you put the pulley on then yeah, but i dotn know why that would make all this stuff happen. sorry man im still in the N/A department

is it detonating? do you hear pinging? if so I would STOP until you get a smaller pulley back on or a better tune.

...Make sure the car is tuned right. I had similar problems with an o1, until i put a MAF tuner on it (pro M). That allowed me to get an exact dynotune on the air-fuel ratio, which in turn improved the smoothness during acceleration. (and i picked up 40 rwhp)

it is more than likey ur belt is sliping that is while the boost falls at a certain RPM try it in multible gears and see if the problem persist. mostly like it is belt slippage u may need a new one simple fix

because of the smaller pully diameter there may be less belt tension causeing the slip

Did you upgrade your fuel pump when you put the pulley on? From what I have read from various forums, a 255 lph pump is a must.

On a 2000 stage 3 saleen, the problems you described were similar in that it the engine would hesitate in higher rpms and surge when shifting gears. When read with an OBD2 scanner it was discovered that two cylinders were misfiring. After changing the plugs in those cylinders that problem no longer arose.

this is true.
ORIGINAL: Saleen644

Did you upgrade your fuel pump when you put the pulley on? From what I have read from various forums, a 255 lph pump is a must.