I just got my guages installed and have a TBE and filter on my car. I went out driving to see what the stock boost was before installing a MBC. My car would boost to 24psi and then taper to 16 at redline. I didn't think 24psi was possible on 93 octane?
If higher boost is safe at lower revs, wouldn't running a MBC and keeping the boost at 21 psi actually decrese the torque at lower rpms?

 

The gauges you put in could be innacurate. Or something like your WGA could be sticking. I know I didn't boost over 20psi until after I put in my MBC. It was more like 18 or 19 actually.

Also, 24psi is possible. But probably not very safe. I'd put an MBC in there, for one to see if that clears up your high boost, and two to hold more boost to redline. I peak 21 and it doesn't drop below 19 at redline.

 

24.5 psi peak and 18 - 19 psi @ 7K is fine on my car....I can go 25.5 psi peak just fine if I want on 93 octane....Obviously if you want to be safer or plan on running at full boost for extended periods of time (e.g. road course events) then you may want to go down to 22/23 peak (IMHO)....or use race gas

 

I would say that's true on the 9, but not on an 8 like his. The only way to be sure though is to log some runs and see how it's doing.

 

The boost gauge is a Defi BF series.
Is the reason for the stock boost taper to run ahigh boost at lower rpm that would be unsafe at a redline? If so it seems to me that a MBC eliminates the ability to run high boost at lower rpms and safe boost levels at redline.
For example, most seem to set the MBC to run 19-21 psi throughout the revs, wouldn't it be better to run 24psi at 3500-4000 rpm and then taper to 21psi at redline?

 

Defi BF's are known to be innacurate from my understanding.

Better? Maybe for more torque, sure. But then wouldn't you rather run 24psi all the way to redline? The only problem is, is that it's not going to be as safe on a fairly stock 8.

Like I said, the only way to know for sure is if you log everything and see if you're experiencing any knock. Also see if you can log your boost with a MAP sensor, that way you'll know if your boost gauge is accurate or not.

 

running a TBE(catless)will raise the boost spike while using the stock boost control which is why you should put an mbc in to lower them back to safe levels. on an VIII, around 22. IX's can run a bit more boost on 93, around 24, safely.

 

Shouldn't the ECU prevent a harmful spike when using the stock BCS?
I'm starting to lean towards just leaving the stock BCS and having AMS eliminate as much boost taper as they can when they tune it.

 

Do as you wish. Although I ended up with almost no taper with a simple MBC. Of course I have ecuFlash as well, so I was able to avoid boost cut.

And yes, the ECU does protect you from overboost situations. So either your spike is too short (under 1000ms) or your boost gauge is wrong. I'm betting on your gauge, because I've heard many many times that the BF series are consistently off by at least 2psi.

 

with a tune, i ran 24psi for 2 years with no problem.

 

Your spiking that high because of the cold weather. Your in Milwaukee, its cold, that causes higher boost levels. Its normal IMO