-Boosty-
10+ Year Contributor
- 135
- 0
- Dec 4, 2011
-
Kalamazoo,
Michigan
Hello, I'm new to the turbo scene and by that I mean I have never had a turbo car, but have done a lot of reading and researching not only on this site but all over the google search bar.
Ill cut to the chase and save you the time of looking up my mods as well. I have a 98 gst with and injen intake, big 16g turbo, greddy 3" full exhaust with a high flow cat, OBX tubular header, fresh stage 1 head with injen valves (friend blew a valve in the 3rd cylinder thats why i got the car for 1200$), greddy type s bov, apexi safc, apexi avcr, boost gauge, a/f gauge (wired to the ecu), rc 550cc injectors, Fresh timing belt, new plugs (gapped correctly), tre trans with act 2100 clutch, pressure plate and an act lightweight flywheel. I believe that is all i have in this car the only thing i havnt checked is the fuel pump, which i was told was a stock pump.
Im using the stock waste gate (unported) and i have it set up to run directly from the waste gate to the hardpipe leading to the stock intercooler (new hose and clamps) right below the intake, as my j-pipe does not have a nipple, so my avcr is not doing anything for controlling boost, its only monitering from my ecu, my safc is tuned to all zeros, because im not sure how to tune it properly because i dont have a wideband yet. With my bigger injectors i would think its running rich at stock boost.
My down pipe leaks at the flex pipe. Ordered a new one from Megan Racing today.
THE PROBLEMS: My major problem i am having sounds like boost creep to me, based on what i have read. It seems i can go wot in first gear, and my boost only hits roughly 10-15 psi, but when i go wot in any other gear, once my boost climbs up to 10psi it proceeds to climb very very quickly to up words of 20+lbs where it hit fuel cut. I can hold it at around half throttle, and basically control my boost with throttle input to keep it at around 10psi. I have only hit fuel cut once, because i only held it that long to see if it would keep climbing or if it would stop. I've read a lot about boost creep but cant seem to find people having 10+ lbs of creep. Ive checked my waste gate actuator and it moves, and opens with a pair of pliers, but i have no way of knowing if it opens under boost. But i have pushed air into the tube to the wastegate and it actuates very easily. I have had the o2 housing off the turbo to make sure the flap moves with the actuator.
I havnt done a boost leak test yet, because it seems to hold boost just fine, although that is on my to do list. I havnt replaced the fuel pump yet as im currently researching which to use for my application (300 hp/20lbs boost max) a 190, 210, or 255. The wideband and or egt gauge are both top priorities.
I do not currently drive this car, as its winter in Michigan so no need for the dont drive it comments. I am wondering if it would boost creep that much with the modifications i have on it, a few of my friends have no problem with their dsm's creeping. I am also wondering if i upgrade my fuel pump would that take care of the problem and just deal with the boost creep, or buy an aftermarket o2 housing or external wastegate and go that route. Im looking for a cheaper but effective alternative, ill doll out the cash to do it the way it needs to be done either way, but if there are some legitimate corners i could cut i wouldnt mind going that route either.
Sorry for a huge post i just dont want to miss anything.
Ill cut to the chase and save you the time of looking up my mods as well. I have a 98 gst with and injen intake, big 16g turbo, greddy 3" full exhaust with a high flow cat, OBX tubular header, fresh stage 1 head with injen valves (friend blew a valve in the 3rd cylinder thats why i got the car for 1200$), greddy type s bov, apexi safc, apexi avcr, boost gauge, a/f gauge (wired to the ecu), rc 550cc injectors, Fresh timing belt, new plugs (gapped correctly), tre trans with act 2100 clutch, pressure plate and an act lightweight flywheel. I believe that is all i have in this car the only thing i havnt checked is the fuel pump, which i was told was a stock pump.
Im using the stock waste gate (unported) and i have it set up to run directly from the waste gate to the hardpipe leading to the stock intercooler (new hose and clamps) right below the intake, as my j-pipe does not have a nipple, so my avcr is not doing anything for controlling boost, its only monitering from my ecu, my safc is tuned to all zeros, because im not sure how to tune it properly because i dont have a wideband yet. With my bigger injectors i would think its running rich at stock boost.
My down pipe leaks at the flex pipe. Ordered a new one from Megan Racing today.
THE PROBLEMS: My major problem i am having sounds like boost creep to me, based on what i have read. It seems i can go wot in first gear, and my boost only hits roughly 10-15 psi, but when i go wot in any other gear, once my boost climbs up to 10psi it proceeds to climb very very quickly to up words of 20+lbs where it hit fuel cut. I can hold it at around half throttle, and basically control my boost with throttle input to keep it at around 10psi. I have only hit fuel cut once, because i only held it that long to see if it would keep climbing or if it would stop. I've read a lot about boost creep but cant seem to find people having 10+ lbs of creep. Ive checked my waste gate actuator and it moves, and opens with a pair of pliers, but i have no way of knowing if it opens under boost. But i have pushed air into the tube to the wastegate and it actuates very easily. I have had the o2 housing off the turbo to make sure the flap moves with the actuator.
I havnt done a boost leak test yet, because it seems to hold boost just fine, although that is on my to do list. I havnt replaced the fuel pump yet as im currently researching which to use for my application (300 hp/20lbs boost max) a 190, 210, or 255. The wideband and or egt gauge are both top priorities.
I do not currently drive this car, as its winter in Michigan so no need for the dont drive it comments. I am wondering if it would boost creep that much with the modifications i have on it, a few of my friends have no problem with their dsm's creeping. I am also wondering if i upgrade my fuel pump would that take care of the problem and just deal with the boost creep, or buy an aftermarket o2 housing or external wastegate and go that route. Im looking for a cheaper but effective alternative, ill doll out the cash to do it the way it needs to be done either way, but if there are some legitimate corners i could cut i wouldnt mind going that route either.
Sorry for a huge post i just dont want to miss anything.
