SilverSmoke

I have an old Jantzer ported/polished TB been using for years with no issues. Now that I have had a cam for a while, and still trying to tune this bucking out of the car, I noticed that most peoples cars the RAF table increases with a larger cam.

On my car the RAF has decresed by around 2-3g's. Is this normal?

SSpdDmon

iTrader: (10)

I'd say it's because air is getting around the tb blade. Yes, you may have had the tb before you had the cam. But, the air slipping around the sides of the blade may not have been enough to cause a problem with your stock tune. Now that you're digging around in the PCM trying to tune your cam, you're finding out what's going on.

The only other thing I can think of would be a vacuum leak somewhere in the intake stream allowing unmetered air in.

nikon1999

iTrader: (22)

i have a similiar cam and mine increased quite a bit, so i would say no yours is not the norm

SilverSmoke

Hmmm, is there anything I can do per say, for self elimination on what can and cannot be causing the bucking? Or in other words, a sure way to narrow down the culprit of the issue.

Maybe lower the RAF by another 2g's and see if that works to calm the bucking?

I don't know of any vacuum leaks that would exist, and I also would have no idea how to even look for one...

nikon1999

iTrader: (22)

well i know one way to test for vaccum leaks would be to spray some carb/brake clean around the intake/tb seal areas and if the idle rises that means theres a leak... In terms of bucking its either fueling or timing...i dont think you need to be taking air out, probably adding. imo