I posted in general but figured i would throw this here as well....

I have my car tuned for 26lbs of boost. When full throttle every now and then i get knock.(rapid flash of check engine light) And air fuels read 10's(10.2-10.5) right in that area. Now the tuner said it was from heat soak. And he cant get rid of it, he told me to get a bigger intercooler and pipes and it will fix it. Or to turn the boost down.

Now with 26psi im blowing the intercooler pipe off more than i want to.(with hairspray, t-bolt clamps)

Now my question is can i turn my boost down say to 24psi and not have to retune?

Also my air fuels bounce at idle from 14.2-15.6 constantly. Also bounces during cruising, around 14.8-15.2 in that area.

http://www.youtube.com/watch?v=eHeUxoemYTY

Is that normal for idle(Cosworth m2 cams, springs retainers, walbro 255, cobbsf intake, invidia g200 turbo back catless, ebay o2 housing)

Main concern is whats in bold

 

Yes, you can turn down your boost to 24lbs and be fine. I was tuned but could only run 20lbs that day cause on my mbc spring. I put in a stiffer spring and turned it up to 26lbs and it runs great (I asked the tuner about it before hand and he said it was fine to do).

I have the same afr gauge as you and mine goes between 14.6 to about 15.2 at idle. I have stock cams tho.

 

Your tuner is right. I mean he could log and try backing the timing off a little bit where you're getting knock. What octane fuel are you running? 26psi is going to be right on the edge for ****ty pump gas. Your car probably wouldn't lose any power and pull smoother if backing off the boost gets rid of the knock. When you knock the ecu is going to pull timing back. So running 2 more psi and losing the timing advance is probably going to rob you of more power than making clean pulls at 2psi less boost with full timing imo.