My engine mods are:

1) straight pipe from catylytic converter
2) HKS downpipe
3) silicon hose job on rats nest (pills are in)
4) stock sequential twins

That's it. Unfortunately, with just those two performance mods, I've been seeing a boost spike to 11 psi on my boost gauge. My question is, is this immediately critical? I should state that knowing what I know, I never push it WOT to avoid going above 10. I drive pretty moderately to tell the truth.

If this needs to be corrected, what would be your choice and why? I'm not too concerned with spending some cash, I'd rather make my car run safe and still pass smog in CA...

1) Power FC
2) Electronic boost controller (Blitz SBCID, Apex AVCR, Profec B, Greddy E-01)
3) Relief or popoff valve

 

11 psi is not really an issue. 12 psi is tolerable, but anything beyond that is beyond the range of the stock ecu and fuel system.

If you do want to fix it though, i'd say just get a home depot boost controller, which basically consists of a valve that you set manually. It's the cheapest easiest route to solve that.

But feel free to go WOT as much as you want with 11 psi, it'll be fine as long as you don't see 12 regularly.

 

Describe in more detail what's happening. A spike is a very fast peak, not a constant value. A spike of 11 psi is not harmful at the transition. Mazda designed the stock ecu to allow more boost there and to add fuel at that point. The real question is what is your constant boost level at high rpm (above 5.5k)? If that is still around 10, you are perfectly fine.

If it would make you feel more comfortable, just pick up a Profec B for $300.

 

so with my boost controller, Apexi intake and downpipe, I have my boost set to 10 pounds. Can I take it up to 11 saftely and run 11-10-11? I thought stock fuel cut past 6krpms was 10.7 ??

 

It's a fast spike. It's most noticeable in 3rd gear if I start to get on the throttle. Around 3500 rpms or so, the boost builds up, continuing until it hits 11 psi. I believe this may be at the transition. My boost pattern before the installation of the downpipe was I believe 10-6-6. My secondary turbo doesn't appear to be generating boost up to 10 psi, which is why I got the hose job done and solenoids checked. I don't recall the current pattern right now. Once I saw the primary hit 11, I've been holding off WOT tests since.

 

Running 11 on the primary is perfectly fine, the stock ecu doesn't even fuel cut until 12 or so on the primary.

I'm still confused about your boost pattern, don't use terms like spike. People frequently mis-use the terms spike, creep, etc. Simply describe what value it goes to at what rpm and what it does once it gets there.

 

Hmmm... I wonder if it's a prob for my stock ECU that I dole out a consistent 12 and spike at 13-14??

Of course, it is... but I get no fuel cut. Home Depot, here I come