AH-HA! Boost drop finally solved!
02-01-2006, 06:12 PM
#1
AH-HA! Boost drop finally solved!
since i replaced everything else on my APS ST kit that i thought might be contributing to my boost drop past 4500 rpms, i thought it only right to look deeper into my exhaust. i knew a single 3" exhaust was plenty enough to flow 500hp, i just knew it, despite others objections. so i called JIC and asked what the inside diameter of the resonator was, and they replied, "it has an ID of 3", just like the exhaust", and i believed them, since the resonator had quite a large bulge. but after dropping my downpipe and looking in there with a flashlight, i saw a terrible sight. the resonator tapered down very, very small. LESS THAN 2 INCHES
. i bought my JIC used, and i think its an older model. im thinking since some people have the exhaust and arent dropping boost, that JIC changed the resonator sometime, and went to a bigger ID one.
today my exhaust shop cut out the resonator and welded in a straight 3" ss pipe in its place. i thought it was gonna be loud, but it really isnt much louder. you can actually hear the turbine spooling from the exhuast, its pretty cool when standing behind the car.
its a totally different car now, boost builds faster and holds. finally, the car is running like it should be, with the new JWT clutch/flywheel setup and a free flowing exhaust. below are some pics of the resonator.
. i bought my JIC used, and i think its an older model. im thinking since some people have the exhaust and arent dropping boost, that JIC changed the resonator sometime, and went to a bigger ID one.today my exhaust shop cut out the resonator and welded in a straight 3" ss pipe in its place. i thought it was gonna be loud, but it really isnt much louder. you can actually hear the turbine spooling from the exhuast, its pretty cool when standing behind the car.
its a totally different car now, boost builds faster and holds. finally, the car is running like it should be, with the new JWT clutch/flywheel setup and a free flowing exhaust. below are some pics of the resonator.
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02-01-2006, 08:41 PM
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Originally Posted by Alberto
Ok cool, cuz I only see 5-6psi...but I was spinning a little so prolly less load on the motor than catching traction? I know we dont see full boost in 1st gear usually just wanted to see what the APS ST's were doing....
Tig - it's good to see your problems are hopefully coming to an end!
I'd like to see what's on the inside of my exhaust muffler in the same way. I'm pretty sure it's not very restrictive though, as I haven't seemed to have any issues with backpressure.
Last edited by taurran; 02-01-2006 at 08:43 PM.
02-01-2006, 09:20 PM
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Awesome then thats gotta be my problem too! I also have the JIC, good thing my new resonator-less exhaust will be here this week. Good job Tig I could friggin kiss you!!! <--- (not really)
Last edited by PhxBlue; 02-01-2006 at 09:24 PM.
02-01-2006, 10:09 PM
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Originally Posted by tig488
since i replaced everything else on my APS ST kit that i thought might be contributing to my boost drop past 4500 rpms, i thought it only right to look deeper into my exhaust. i knew a single 3" exhaust was plenty enough to flow 500hp, i just knew it, despite others objections. so i called JIC and asked what the inside diameter of the resonator was, and they replied, "it has an ID of 3", just like the exhaust", and i believed them, since the resonator had quite a large bulge. but after dropping my downpipe and looking in there with a flashlight, i saw a terrible sight. the resonator tapered down very, very small. LESS THAN 2 INCHES . i bought my JIC used, and i think its an older model. im thinking since some people have the exhaust and arent dropping boost, that JIC changed the resonator sometime, and went to a bigger ID one.
today my exhaust shop cut out the resonator and welded in a straight 3" ss pipe in its place. i thought it was gonna be loud, but it really isnt much louder. you can actually hear the turbine spooling from the exhuast, its pretty cool when standing behind the car.
its a totally different car now, boost builds faster and holds. finally, the car is running like it should be, with the new JWT clutch/flywheel setup and a free flowing exhaust. below are some pics of the resonator.
. i bought my JIC used, and i think its an older model. im thinking since some people have the exhaust and arent dropping boost, that JIC changed the resonator sometime, and went to a bigger ID one.today my exhaust shop cut out the resonator and welded in a straight 3" ss pipe in its place. i thought it was gonna be loud, but it really isnt much louder. you can actually hear the turbine spooling from the exhuast, its pretty cool when standing behind the car.
its a totally different car now, boost builds faster and holds. finally, the car is running like it should be, with the new JWT clutch/flywheel setup and a free flowing exhaust. below are some pics of the resonator.
peter was right
ARRRRGHHHH!
ahm
02-01-2006, 11:53 PM
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Originally Posted by amolaver
i can't even believe i'm going to say this........
peter was right
ARRRRGHHHH!
ahm
peter was right
ARRRRGHHHH!
ahm
APS has still changed their tune a few times, saying it is due to a safety feature programmed into the unichip, and then relating it to backpressure.
Am I right about this, or am I just crazy?
