ok so I've been having this problem for a while but it seems to be getting worse. everyone tells me a little boost spike when shifting is normal but on my 3-4 shift I'm spiking from like 7.5psi to over 10 psi occassionally hitting the utec fuel cut. This can't be normal can it? What kind of spikes do other 5at guys experience?

 

This is still a problem with the APEX'I unit?

 

no i don't think so. I've had the problem since i was using a manual boost controller. I also didn't mention that I'm using the SGP VB upgrade which they told me would help the problem

 

ttt

 

ok if anyone else is wondering about this issue I found this article that was extremely helpful

http://www.supras.com/06/techcenter/...c85bfcd7536fac

I'll post later to see if this information was useful to me

 

Hey Daniel with my greddy setup and forged perf vb i have never had a boost spike.I am getting ready to retune to 9psi with the hks evc6 so ill let you know.

 

I've not had this issue consistently as you describe.

 

are you currently using the evc? or are you going to be using it when you retune?

 

Not yet gonna wait for the retune.

 

let me know how that goes... I think that the EBC lets you spool faster (especially with a ST) but with the trade off of not being able to keep the boost spikes down between shifts as efficiently. What I found is that I have to sacrifice some of the aggressiveness of the spool up to keep the boost spike in check by turning down the duty cycle just a bit. I think I've got it at a reasonable range now where I'm not hitting fuel cut off on the 3-4 shift.

 

Daniel i dont know how fast yours shifts but the forged piece i have is real fast.One example is if i shift at 6-6200 rpms its in the next gear by 6500 rpms and the back end breaks loose pretty bad.But i am on my stock wheels with my blizzacks and not my much wider summer tires so thats a big factor too.

 

yeah the sgp is about the same. breaks them loose pretty good on 1-2 shift and chirps in 2-3. Its way faster than stock but it didn't really seem to help the boost spike issue like i thought