I'm assuming calling this a boost spike would be the appropriate term here.... but if not you'll have to forgive me.

I've notice this mainly since the installation of the dezod black box that I just got, not that it is causing it in anyway, it just makes it easier to brake boost/"pre-spool" the turbo. Anyways, if I brake boost giving it just enough throttle to make it out of vacuum, maybe making 1-2psi of boost, at 50% throttle (is this bad for any reason?) as soon as i release the brake and stomp the gas, besides the sudden rush of power, I'll jump to about 8-9psi for a second before settling back down to the normal 5-6psi. (defi electronic boost gauge, not a cheapy, and you can DEFINITELY hear the difference when the WG opens)

So when this happens, the AFR spikes a bit too, not real bad, just to about 13ish but not a lot higher, and only for a second. This isnt a HUGE deal at 6psi... but it could be when i turn up the boost after i get this clutch and flywheel in. Shiz... particurally with the flywheel if it decreases spool time. Ahh!!

Basically i have a few question though, now that I have explained the situatiod First, is what I'm doing "bad" in any way? Second, if I get away from the MAF and switch to a MAP/Greddy pressure sensor is it possible to tune for this so the AFRs don't lean out? And lastly, is there anything (besides "don't do that" :p) I can do to prevent the boost from spiking like that.

(38mm GT concepts WG w/ 6psi spring on a zpi stage 1 setup btw)

Sorry for the obscenely long post, just trying to be thorough

 

Whats your AFR under normal 6 PSI of Boost?

 

Normally it is between 10.5-12 but generally in the 11s I only see 10s at low RPMs
edit - i also only see 12 when its fairly cool. 11s is the norm

 

i also left out that im running open dump

 

That shouldnt make a difference. I would call kenny and ask him, but if it only 1-2 pounds over normal than it should be fine. I Would be a little scared of the 13 AFR, but as long as its there for only a second, then you shouldnt worry other than getting it tuned for a little richer.

 

cool. thanks whocares.... anyone else have anything to offer on this one?

 

Bad waste gate ... that is exactly how I blew mine up... 100% garantee

 

These are external wastgates...

Did you by chance have a Greddy kit?

 

will a higher quality WG (like a tial) be less likely to do this?

 

I told you not to worry. its only spiking 1-2 pounds? your fine. almost all turbo cars will spike slightly, then drop back down. look at the SRT-4 for example. Its not like the greddy kit were its boosting 25 pounds. then you have an issue.

 

my bad didn't realize the external WG thing your right all turbos spike a little

 

OK cool, i never cared for internal wastegates anyways... not that that has anything to do with anything.... but yeah, thanks guysi suppose i wont worry.

i wasnt doubting your answer btw whocares... more hoping i could get a response to the other things like whether or not with a boost pressure sensor that you could account for spikes in the tune, to an extent? when you arent relying solely on throttle position and RPM to determine how much fuel to add.... what i mean is, could you set the WG or MBC to like 9 psi, but tell the emanage add X amt of fuel at 12 psi.... does that make sense? anyways, more of a curiousity thing than anything else

 

Not with the emanage blue, but you can add some fuel in the upper RPM's, or have some timing pulled up top to be a little safer at those AF levels.

 

Sorry, I forgot to mention I am running the ultimate, I know it cannot be done with the blue

 

Ah, in that case you should ask kenny. you may be able to. ive only tuned on the blue. Ive personally made adjustments to mine so im only able to speak from a "ametuer " tuning perspective

 

Haha, thanks man. Thats way more tuning than I have done , so I do appreciate the input! It sounds simple enough, and seems like it would be a rather good idea to be safe, but I suppose I may be oversimplifying things.