I just installed a 1/4" smaller pulley on my whipple. It is supposed to give me 8psi. Well, it does, but only when i'm going about 80mph or so. Otherwise, it feels weak while accelorating and I'm getting knock retard of up to 6. I also am now getting 02 sensor codes again which I haven't since I got my most recent tune from Allen. What is causing these problems and is there a way to remedy them or should I just put the stock pulley back on?

 

You are probably running lean running that much boost if your still running stock injectors and the 2 whipple ones. What is you fuel pressure on a WOT run?? Without having it tuned for that much boost your going to get detonation and KR. It probably feels so weak because of all the timing its having to pull not to detonate. I think you should put the other pulley back on for now, plan to upgrade to a set of bigger injectors and get rid of the 2 auxillary whipple injectors. After that, put the pully back on then try and have it tuned. When I had my truck dyno tuned I saw a max of 10 pounds boost with no KR and no detonation.

 

I sometimes have spark knock with my 6# pulley on. I had my 8# pulley on for a short time and took it off because of the knock. I was gonna try some racing fuel at the track but thats not for about 2 months. I have no tune at all on my truck other than the stock whipple programmer. What size injectors should I run to get rid of the whipple xtras? If I call allen at Nelson can he make me a custom tune with the whipple?