Downpipe + catback. Boost spike under heavy load. ECU or boost controller?
 

I have a downpipe and a catback but I still experience boost spike (14-15psi) every now and then. Usually at WOT going up a hill in a high gear. Aside from the occasionally spike my boost pattern is pretty solid 10-8-10.

I strongly suspect that these boost spikes may be the reason for the internal damage to my housings, so I'd like to have a plan to eliminate the problem for my new engine. I've read that installing a powerfc is the best option, but I really don't have the money to buy one. Would a boost controller solve the problem? Or, is there something cheaper that I can do to prevent this from happening?

I was under the impression that the stock ECU has fuel cut to prevent overboosting, but I've never had this happen - could my boost gauge be wrong?

Thanks,
-Charlie

The stock ECU will cut fuel at certain boost levels (it varies by rpm) but cutting fuel is not the right way to tackle spikes. A PFC is probably not going to give you better control over boost either. You need a boost controller - a simple Home Depot MBC or pills will do the trick. You can search for more information on these.

Here are the stock fuel cut numbers:

rpm max boost
1000 11.8
1500 11.8
2000 11.8
2500 11.8
3000 12.2
3500 12.4
4000 12.8
4500 13.3
5000 12.2
5500 11.3
6000 11.1
6500 10.7
7000 10.7


Do we really need to see an ad for a casino in every one of your posts?

A powerfc may fix it, but the real solution (esp if you intend to modify anything else in the future) is to install a boost controller. In a nutshell, the PFC is a boost control upgrade over stock, but not as good as a separate manual or electronic boost controller.

Dave

try a bc because i have the same mods as you and every once in a while i get those 14psi spikes with my pfc

Don't drive the car like that. If you're having to gas it that much going up a hill downshift. These cars don't exactly make alot of torque. I noticed the same thing years ago.

get a profec b boost controller. pfc wasn't enough for me and others.

so u guys r saying boost controllers can fix spike?

Boost controllers cannot lower boost...If it is spiking to 15-16, he can't get a boost controller to hold it at 10, 11, whatever. He has to port the wastegate, remove mods, or let off the gas.

Boost controllers fix spike.

Wastegate porting fixes creep.

Get it straight.

Where do these guys post all day?? :MissileSm

Fixed the same problem as your having with an Apexi AVCR boost controler.

I can hear the boost being lowerd when it gets anything above what i put on the avcr.

I had boost of 10-8-10 and the ocasinal spike to 15, the only thing i did was fit the avcr and not i only ever get 10-8-10.

I 2 have downpipe and cat bypass.