Help me with my pull (boost creep)

[UndergroundR32]

So I did a pull today in 3rd gear today.. I'm not having the sputtering problem that I was having before I swapped the flywheel, so I don't know what was causing that. Anyway, the pull is at 16 psi but around 6000-6500 I start creeping up to almost 20 psi. As you can see from my setup, I shoudn't be having problems, unless it's from the Joe P. E-MBC or something. Anyway, this is the tuning forum so...

RPM Timing

4093 18
4500 19
5281 20
5468 21
6031 22
6281 20
6406 19
6812 17
7062 16
7593 17


I had 0 knock through the whole pull acept one count of knock at 7593 rpm

I didn't log the o2's because from what I've read on this forum and others it's pretty useless. As long as my EGT's didn't go really high because I was running too lean and as long as I wasn't knocking I would think that I'm safe. ANY input is much appreciated on this, as well as any critisizm towards what I'm being clueless about.

 

[kpt4321]

You should log knock too, and O2 isn't that bad because the curve within one particular log can show you if you have major enrichment problems.

With no knock, you look good.

I'm not exactly sure what else you wanted to know.:

 

[UndergroundR32]

I guess I'm just not really sure where to take it from here. It pulls a lot harder once I get around 5500rpm. I hit full boost long before that, but for some reason it feels like I have more power at that range up to 8k. Should I just lean it out all across the board a little bit and do another pull?

 

[talon1979]

From your mod list it appears you have an internally gated 50 trim. It is really difficult to get a big turbo like that to not suffer from boost creep unless you have an external wastegate. It seems to me that electronic boost controllers do a much better job at not suffering at boost creep, but that is an expensive fix. If the boost controller isn't your problem people will try and port the hole the flapper door dovers on the turbine side of the turbo. I am trying to think of some much easier things to try.

 

[UndergroundR32]

I have an EXTERNALLY gated 50 trim t3/t4. The AGP kit, and I'm still creeping. I actually have a Profec "A" at my house right now but I've heard bad things about it and was going to try to sell it and buy a Profec B.

 

[talon1979]

I would *GUESS* the problem is your mbc.

 

[UndergroundR32]

Originally posted by talon1979
I would *GUESS* the problem is your mbc.

How does an MBC cause boost creep? I was under the impression that all it does is tell the wastegate when to open. It's an on/off type of thing, right? Either the wastegate is open or closed.

 

[JiveMasterT]

you revv your car to 8k? wtf? redline is at 7!

as for the creep... id try another boost controller, and try adjusting your external wastegate.

 

[UndergroundR32]

Originally posted by JiveMasterT
you revv your car to 8k? wtf? redline is at 7!

Look at my mods in my profile. If I stopped at 7k I wouldn't be getting the most potential out of the car.

Originally posted by JiveMasterT

as for the creep... id try another boost controller, and try adjusting your external wastegate.

Again, how does the Boost controller affect boost creep?

 

[GiRtHyTaLonTsI]

you could have a small hole in one of the vaccum line that causing you to creep

 

[JiveMasterT]

Originally posted by UndergroundR32
Again, how does the Boost controller affect boost creep?

a poorly designed boost controller will not function properly at higher boost levels and allow the boost to creep up. think about it... there is a spring in there, and if the spring isnt firm enough, then it will "slip" and allow more boost through than what you set it to. try a halman, they are what people agree are the best boost controllers. turbo xs is good, and i belive dejon tool just released a few boost controllers, and all are worth looking into.

 

[alex027]

Originally posted by UndergroundR32
How does an MBC cause boost creep? I was under the impression that all it does is tell the wastegate when to open. It's an on/off type of thing, right? Either the wastegate is open or closed.

The boost controller can cause boost spike by not opening the wastegate quick enough, but as soon as the wastegate is opened the boost level should go back down.The boost controller has nothing to do with creep. I had this problem with the softer spring in my mbc. Once I got all of my fuel mods, and put in the stiffer spring to run more boost the problem went away.

 

[UndergroundR32]

Originally posted by alex027
I had this problem with the softer spring in my mbc.

Softer spring in your Wastegate you mean.