Yesterday I was driving home from the store with my girl and she was wondering why my boost gauge stays under 0 psi on cruise.So I explain to her and show her when I make go above 0 psi and I was in fourth gear and must have been like 40 mph.I floored it and showed her when it boosts and my boost went past what I have
it at which is 23 psi.It went to about 25 to 26 psi.I let go of the gas quickly and was just stunned.I have never went past 23 psi.Was it cuz I was at a very low rpm and thats why boost went so high.I floored it before on fourth gear and it went to like 23 and a half then started dropping off as rpm climbed. Can anyone explain to me why this happened.I'm at work right now and this just won't leave my mind.It's slow right now so I'm on the net.Oh yeah I have a greddy exhaust,aem intake,defi boost gauge,and dejon mbc.Later today after work I'm going to adjust the manual boost controller and see whats up.I would really apperiate anybody's input about what happened to me last night.

 

Well if you lived up north where it's cold now I would say boost spike for sure, but either way you look at it i guess its a boost spike. It might have been from it being a little colder since it was nighttime, but possibly just the fact the factory wastegate fails at holding boost, so it probably just crept up on you, nothing to worry about if it doesn't do it again i would say.

 

I have constant spiking issues, not sure what causes it. Nothing realy to worry about, the knocking system is good on the X's. I have boosted to 27.5 before and worried but my tuner assures me there is noting to worry about...

 

yeah same here. i spike to even 30psi some times! mostly when its cold.

 

Do you think that not having a tune might be bad with a boost spike.I want a tune but I'm going to wait a little bit.I want to get most of my bolt ons before I get a tune.

 

yeah i spike up to 27psi (before FMIC 25-26psi spike) a couple of times since it got colder and installed new FMIC

 

since where talking about high boost.i finally hooked up mbc.i dont know if it was boost cut or from hitting the limiter,the car let off acouple shot gun blast from the stock exhaust.was awesome.my car boost spiked before i even touched anything,it would spike to 25-26psi.now i spike to 27-28psi.the egts get really hot quick running 19-20psi to redline,afr are fine.

 

Its because u were in a low gear. Mine did that as well espically when i was in 5th gear lol. get a tune and it should fix it. Mine is set to 23psi but high gears ill spike to like 25 at low gears. With out a tune **** the car wanted to spike to like 29 lol

 

SpeedI2acerX What is your boost level set to?

 

I have a Works tune and it's set to 21psi, no mbc.

 

Good lord. Did your tuner remember to turn boost correction back on after he tuned the car? Many tuners turn it off during tuning so as to see exactly what the boost is doing without any ecu intervention, and then when they have dialed it in, it is turned back on for the final flash to prevent overboosting in cold weather and/or low rpm+high load scenarios. Check with your tuner, because on ecu controlled boost you should only get spikes of a couple psi in cold weather and usually only for a quick second.

 

my friends X was spiking to 25-26 psi just after the AEM intake. Got the perrin mbc and set it down to 20 psi... boost does sometimes go to 21-22 depending on the temp...

 

yeah ive been trying to get some answer about it from Works but "their engineers are working on it". im not saying that the ecu is not limiting boost. it does its job most of the time and i like mention before it happens when i get on it from a good acceleration or when its cold.