Boost creep problem maybe? VIDEO

[DriftS14]

OK. The 1820 turbo's "stock" boost setting is supposed to be 8 PSI. The problem is that it will hit 8, then starting at about 5000 RPM the boost slowly rises till it hits 11 PSI at 7000 RPM. Now I've heard plenty about boost falling off at higher RPM, but rising? What's up with that? What can I do to remedy this?

Below is a short vid so you could see what I'm talking about. It is in quicktime format.

http://rap.midco.net/jprosper/boostcreep1.MOV

[SpeedRacer1]

Which turbo? Where do you get your vacuum signal from?

[DriftS14]

Power Enterprise 1820 turbo. The hot-pipe for the wastegate signal.

[SpeedRacer1]

The stock turbo falls off because its not the greatest turbo. Upgraded turbos usually do not drop off and actually keep building boost until redline.

Heres a pic of a some tomei arms turbos vs a stock S14 turbo. Granted the tomei engines had more done, you can see how the efficiency of a stock turbo goes down after 6000 RPM's.

[DriftS14]

So boost rising at higher RPM is most likely expected and not necessarily bad? I find myself hitting the rev limiter consantly becuase at max RPM is when the car pulls the hardest. When I had the MBC on there I had 12 PSI dialed in and it would hit and hold 12 with no other side effects. Now it seems to be doing this. But I guess it's not that bad. Just wondering if something else had something to do with it.

[ItzGenX]

Manual boost controller? An electronic boost controller might be able to control it a tad better.

[DriftS14]

I thought that too. I got rid of the MBC in hopes of convincing the wife into me getting an electronic one. That situation is still to be resolved. Perhaps I should not have been so hasty in selling it. lol

[compression]

Nice video, definitly looks like boost creep.It sounds like your wastegate is not able to relieve enough exhaust gas to keep you at the 8psi level. Make sure it is working properly, inlcuding the boost controller, check for leaks in all the vacuum lines going to the wastegate. Remember, the lower the boost level, the more exhuast the wastegate has to release.

[DriftS14]

Nice video, definitly looks like boost creep.It sounds like your wastegate is not able to relieve enough exhaust gas to keep you at the 8psi level. Make sure it is working properly, inlcuding the boost controller, check for leaks in all the vacuum lines going to the wastegate. Remember, the lower the boost level, the more exhuast the wastegate has to release.

Remember, the lower the boost level, the more exhuast the wastegate has to release

That makes so much sense. I didn't even think about that. Lately it has been unusually cold here at night (30 F) and the boost creep problem is even worse. It can hit 14PSI with ease. The car is extremely fast too I don't know if you have ever seen the Power Enterprise wastegate actuator, but it is a 2 piece design, with allen screws and a gasket sealing the canister. I have the feeling that this might be the culprit.

[Nismo_Freak]

I'd check the signal line... it might be bleeding somewhere as it's subjected to higher pressure. Other than that I think Compression is on to something.

[nismostate]

my joe p mbc works really good. no creep at all. ebc are overrated. do you still have the stock actuator? if you do, try putting that back on to see if it helps any.

[DriftS14]

I don't have the stock actuator anymore. The MBC I had was the turbo xs standard. I've heard many great things about joe's mbc. I wouldn't mind trying it.

[nismostate]

can't beat 45 shipped. i know 2 other guys that has it and it works good for them too. 1 gsx and 1 sr.

[Nismo_Freak]

ebc are overrated.

Incorrect.

[nismostate]

Sorry, let me reword what i mean. I meant that you don't HAVE to have a ebc for a swap. especially with a stock setup. Of course ebc's are going to be more precise and easier to adjust but it works the same imo. just without the luxiury.

[DriftS14]

I think I may try one of those Hallman or Joe P. MBC's. They are relatively cheap and apparently effective. I was going to get a profec b, but I just might hold off on that. Thanks for the help guys. I'm only injectors away from seriously cranking the boost on this turbo, so maybe I should get those first.

[nismostate]

yup. i agree. injectors would be a good upgrade before ebc. mine is very accurate. im reading off of a autometer so im not sure if it's exact.

[GTS4-R]

was that 2nd or 3rd gear?

[DriftS14]

That was second gear.

[Nismo_Freak]

Sorry, let me reword what i mean. I meant that you don't HAVE to have a ebc for a swap. especially with a stock setup. Of course ebc's are going to be more precise and easier to adjust but it works the same imo. just without the luxiury.

Depending on the controller there are many more aspects you can tune on the controller that will affect the way the car drives.