Odd boost spike

[Puckpimp71]

Need some input here... I have a boost sciences dual stage controller on my car right now, along with all the mods in my sig. In the past couple weeks, I've been getting really a really bad spike in boost (from about 8psi on "stock" setting to 12 and from 10psi on the second setting to 15) basically, an extra 4-5 psi above what I've tuned it for. Now the most obvious problem would be the wastegate, but I think it's something else for a few reasons, 1) if it was the wastegate, when I blow into the hose for it, it doesn't seem to leak, 2) I'm not getting the idling problems I was when the wastegate failed the first time, 3) Vacuum is right about 20in/hg, when the wastegate went the first time it held at 10, and perhaps oddest of all, 4) I only get the spiking when my car has been driven for more than a 20 minutes. It doens't spike at all when it's still cold.
I think it might have something to do with the silicone hoses I'm using, but I'm pretty sure I'd see that in the form of a vacuum leak. Any ideas would be appreciated as I'm about to hire a priest to exorcise my car.
Thanks,
Chris

[jestermsp]

i have the exact same problem with the same boost controller. i'll be putting the atp wategate actuator on today. i'll let ya know if it helps. i have silicone vac lines to n i read 25in/hg but i can also blow right through my wastegate line. explain that!

[hoindawall]

subbing. i have a similar problem except i do notice a drop in vacuum when the a/c fan goes on.

[jestermsp]

subbing. i have a similar problem except i do notice a drop in vacuum when the a/c fan goes on.

thats normal. ac raises ur rpms so ur vac would drop 3-5in/hg

[hoindawall]

thats normal. ac raises ur rpms so ur vac would drop 3-5in/hg

i meant lower than normal, lately i've been boosting about 15-16 psi. i have no boost controller

[jestermsp]

holy hell! is your motor forged? ur wastegate actuator is fried. get a new one and dont boost until you do. my 1st motor blew up at 6psi. 10psi is concidered the absolute max for the stock engine. and thats with alot o supporting mods.

[Puckpimp71]

How's the ATP actuator install going?

[jestermsp]

oh yea i finished that yesterday morning. my stock boost spike is fixed. it hits 6psi and holds. and my 10 psi setting is good during the day but at night when its real cold i still get a 4psi spike n i hit fuel cut. kinda sucks i think ima look into the aem tru boost n see if its any better.

[Puckpimp71]

hmmm bump for some more input since my wastegate seems to be holding okay.... Maybe tomorrow I'll take the MBC off and see if it still spikes badly.

[jeffmsp]

well if you have your wastegate signal coming from the intake manifold you will getting slightly better responce, but more spike. This is amplified in the cold. Try giving it a signal from the hot pipe, it should stay where you want it but sacrifice a very small bit of responce. hot pipe for teh win since you cant afford to mess around on 91-93 octane. we just did this on my buddies sr20DET with MBC and i will be doing shortly on my msp. this info is also in maximum boost by corky bell btw

[Drumfreak]

well if you have your wastegate signal coming from the intake manifold you will getting slightly better responce, but more spike. This is amplified in the cold. Try giving it a signal from the hot pipe, it should stay where you want it but sacrifice a very small bit of responce. hot pipe for teh win since you cant afford to mess around on 91-93 octane. we just did this on my buddies sr20DET with MBC and i will be doing shortly on my msp. this info is also in maximum boost by corky bell btw
How would one hook a hose up to the hot pipe? Please explain and let us know hot it works on your car. This sounds like a great idea because no matter what I have a -bigger than it should be- boost spike.

[Puckpimp71]

Going by process of elmination, I disconnected the solenoid for the boost controller and that's where a tiny leak would cause the boost spike. Time for a different set-up.