Boost Again???

[b11dragone]

Ok when my 97 GSX was completely stock I ran at 14psi. Which from what I read is fairly high but ok. So since then I have installed my thermal r&d exhaust, K&N Intake, Greddy Upper&Lower Intercooler Piping, and Type S Bov. So after installing all these parts my boost went up to around 16psi at wide open throttle....which i expected. However if i keep the car at wide open throttle untill about 4500 rpms the psi shoots up to 19psi. Then it stays there untill about 6000rpms and then slowly drops down to 16 again. I think this is a major sign of boost creep? Is this normal? Why would this happen after I installed these parts on my car? Thanks.

 

[FASTSPOOLINGST]

how did u run that high of psi's without a boost controller? You said you did it with a stock set up? I could be wrong, but I beleive you should have been 10-11 max on stock set up, and that is with the solenoid restrictor removed. 8-10 without.

Get a bigger turbo and O2 housing, port both and your manifold and get a flapper mod on the turbo. The bigger turbo will hold the boost to redline and not drop off from whatever you have it set at. The O2 housing will decrease the creep. (ported evo is nice, requires modification to your dp flange though-slowboy is coming out with a nice ss one now, and punishment racings are pretty nice O2 housings at decent prices).

It is normal for your car as soon as u hit it to wot for it the boost to go higher than you have it set, then settle to what you have it set at. I don't know why, but it does. I guess it's due to the initial suction of the turbo, when it first begins to spin, it spins so fast that it increases the boost, until the blades can settle down at the set boost level.

 

[b11dragone]

I didn't put my boost contoller in yet. So I don't know how the boost got that high. I assume it is still running on stock boost settings, just with an intake,exhuast,intercoller piping, and bov.Don't really know what's going on.

 

[FASTSPOOLINGST]

are u sure it's not just spiking out at 14 then settling to around 11? Anyways, I guess anything is possible.

 

[b11dragone]

No when I was completely stock it was at 14psi. I thought this was unusually high but when I started a thread asking if everything was ok I got replies from alot of people saying it was normal and they were reading 14 psi stock. But I just find it funny how now it went up to 16psi which I guess isn't that bad, but why doesn it jump up to 19psi if i keep it to the floor long enough then drop down again, it just seems really strange.

 

[FASTSPOOLINGST]

do a good look in your engine bay, manual boost controllers are very small and maybe one is in there hidden somewhere.

If not, who cares, squeeze all the boost out of it that you can till u hit fuel cut.

 

[FASTSPOOLINGST]

it spikes then drops off because you have a stock T-25 turbo, which is a piece of crap. It is too small to hold your desired boost all the way to redline and shift points. Once you upgrade your turbo, you will have your boost set at whatever psi and your new turbo will hold it at that boost until you shift. My Evo III turbo is awesome. A world of difference from the T-25. Also either port your O2 housing or get an aftermarket. I have the ported EVO III O2 housing and it is sweet, bigger than a 2g ported, but you have to modify your flange on your downpipe to fit the different angle and the bolt pattern.

 

[FASTSPOOLINGST]

BTW, my stock set up was only boosting 10-12 psi max and that is with the restrictor removed from the solenoid. I have a DSMBC and i have one boost setting at 15 psi and the other is the stock setting for when it rains and stuff, and even with my new engine set up, i still do not boost over 12 psi on the stock setting. Maybe cuz u have gsx or something, i don't know, i guess it's true what they say.....all cars are different.

 

[b11dragone]

Thanks for all your help. I am going to try and upgrade my turbo soon. But thank you for your input.

 

[2GeNTSi]

Originally posted by b11dragone
Ok when my 97 GSX was completely stock I ran at 14psi. Which from what I read is fairly high but ok. So since then I have installed my thermal r&d exhaust, K&N Intake, Greddy Upper&Lower Intercooler Piping, and Type S Bov. So after installing all these parts my boost went up to around 16psi at wide open throttle....which i expected. However if i keep the car at wide open throttle untill about 4500 rpms the psi shoots up to 19psi. Then it stays there untill about 6000rpms and then slowly drops down to 16 again. I think this is a major sign of boost creep? Is this normal? Why would this happen after I installed these parts on my car? Thanks.

Yeah I believe it is boost creep as well, one day I went WOT in 3rd gear was staying at 15psi up until about the same RPMs as you said and it crept up to about 17-18. I just got my boost gauge about two weeks ago so I don't know what I was running without the IC piping, 1g bov, catback, and intake. But I'm sure that if I didn't replace my IC piping and bov, that I wouldn't be boosting that much, it's the only mod that actually made a noticeable difference in response and power.