View Full Version : Should my boost be lower???

02-23-2005, 07:29 PM
I had magnaflow cats and resonator installed today. I had been running gutted cats and no resonator. I've got flowmaster 40s. The first thing I noticed was no more ricey sound. :D The second thing I noticed was my boost seemed to be lower by a pound or two. I would have thought it would go up a little. I've got a 5% od pulley on it now and I have a 10% to put on it, but thought I'd ask about the lower boost before installing the 10% pulley.

I know the magnaflow parts flow good, but thought there would be a little more back pressure than the gutted cats and resonator delete, causing the boost to go up a little. Maybe I misunderstood the whole concept.

Anyway, any ideas about why the boost would be lower?


02-23-2005, 10:01 PM
Thats the way it is supposed to be. Boost is created by backpressure from the motor. When you open up the exhaust you have less backpressure on the supercharger and it lower boost, making it more efficient. Thats about it.

Everybody who has a supercoupe that put exhaust on their cars experiences this.

02-24-2005, 02:47 AM
the diffrence is in the cats. your gutted cats where like air baffles causing turbulances where as the highflow cats still flow air in one constant direction . probably freed up some air flow