Overboost
 

I have been getting overboost with my car so i have been watching the boost guage and kepping it under 12psi.. I have an apexi AVCR contoller and checked out the settings. The boost was set at .75 which i think is around 12psi correct me if im wrong. When i monitor the boost on the conroller the most i see is 1.03 bar.. Is my problem with my controller or the car... The car has an exhaust leak that im fixing this weekend. Could that be the reason why im getting so much boost?

does your boost spike or does it creep? do you have strait tubro back? catback? little more info would help...

I have a high flow cat back on the car... whats the difference between ceep and spike?I notice the boost get to 10-12 and stay there for a bit and then when i get to higher rpms it gradually gets to 15psi+ I turned the controller to the off setting to run the factory psi but it still goes past 12. Could the waste gate be the issue?

Per the FAQ's:

Boost Creep - A steady increase in maximum boost, usually at higher rpm. Creep is caused by the exhaust flowing more than the wastegate and turbo can control. The (only) solution is to either restrict overall flow or enlarge the wastegate opening. Installation of a cat-less midpipe often cause boost creep.

Boost Spike - A sudden surge in boost, usually appearing between 4500 and 5000 rpm. This is dangerous on stock ECU systems, which sometimes do not detect and compensate for this extra boost before detonation occurs. Boost spikes often begin to occur after installing a modification that increases flow, and can be resolved in most cases by installing a better boost controller.

From your description (still too much boost at higher RPM's, even trying to limit to the WG spring 7 psi), you are getting creep, which means your WG cannot handle the intake/exh upgrades. This is not too surprising, since it's cold out, and cool temps often make creep worse.

Dave

I have an exhaust leak right before the muffler do you think this could be the cause or not? If not what do you think I should do replace whole exhaust system? Ill run through the FAQ in the mean time thanks alot Dave

It'd have to be a pretty large leak to cause creep. I think you're on the edge with your exhaust modifications, and the cold weather is making the creep worse. In warm weather, you probably wouldn't have creep.

Dave

What are all of your intake and exhaust specs? Do you have a DP, MP, etc.? Aftermarket intake? If you don't have much in the way of flow improvements, then maybe the controller is installed wrong. Do you know exactly how it is plumbed?

Dave

It has a downpipe,K&N intake not sure how the controller is hooked up though...

If you do not have a midpipe or at least a high-flow main cat, the probability of creep is much less. Just an upgraded intake, DP & catback shouldn't cause creep. That's why you need to know how your controller is hooked up.

Dave

alright thanks alot i appreciate it

You may have to get deeper into this to diagnose the problem. If it's not creep, something is not working correctly. There are several links to boost troubleshooting in the stickies.

Good luck. Be careful until you solve this issue. Don't join the ranks of "I just blew my motor" threads.

Dave

Do you have the stock ecu on the car? Or do you have a aftermarket ecu?

its a Power FC ecu

When I had my PFC it would cut fuel above 12psi, is yours tuned? You should check how the solenoid is hooked up. There is a diagram showing how it can be hooked up. If you could, take the lines off the ebc solenoid and see how it works without it. If you only have a intake downpipe and catback. You should be holding boost fine.

The guy i bought the car off said it was tuned... I recently bought the car just a month ago and im trying to sort out the bugs.. do you know where i can get the diagram is there a link you can post

https://www.rx7club.com/attachment.p...1&d=1201152694

Theres a diagram for the HKS EVC, should give you a idea of how it works. In could be a vacuum line (off the UIM for example) Out goes to the wastegates. You AVCR also should have a pressure sensor which can be hooked up to a vacuum source as well. I will include a link to the AVCR manual for you. Go to page 41, that's where it starts talking about the installation process!

http://www.apexi-usa.com/pdfInstallation/45.pdf

Edit: Go to page 50, there's the diagram for you!

FIXED!! there was a hose coming off the wastegate that was supposed to be blocked off and it wasnt...blocked it off car boost is stable.

Super! Glad to hear it! :)

Dave

Which hose was it that needed to be capped?