smpd357sig

For the last 8 months or so my car has been running on a tune that my buddy made using my sct II tuner. Today i got my brenspeed tune and before i loaded it on, iset the carback to stock and drove it around. When i drove it in stock form, at hard exceleration at around 4500 rpms, there is a pinging or sound like something is rolling aroundin a tin can. It still does it with the brenspeed tune.Im using 91 octane fuel, which is also what the tune is.When igoslowlyup to the same rpm range, it doesnt make the sound. Any ideas? should i be concerned?

MusiccityGT

Sounds like to much timing if it is pinging. BAD THING!! Get with Brent and he will make the needed adjustment, or try 93.

ETx06gt

Do you have an aftermarket CAI? You can't run the stock tune with an aftermarket CAI setup. Sucks too much air and runs lean.

smpd357sig

i set it back to stock but with the exeption of the cai and 91 octane fuel.

acstone7

ya not good, if you set it back to stock,put your stock CAI back on as well.

modular81

Unless you have a cai that doesn't require a tune, you should never run the stock tune with a cai that is designed to run with a special tune. Not even for a couple minutes and especially not in open loop "WOT". There are only a couple intakes that don't require K&N, and Granatelli are ones i can think of. The sound you heard was more than likely detonation which sounds like marbles in a can. A very lean WOT a/f mixture is likely what caused this. At part throttle our cars are designed run at 14.7 a/f ratio give or take .2-.3, but at WOT this a/f ratio is way to lean. 12.8-13.2 WOT a/f are ideal for n/a cars. This is why you heard the detonation only under heavy load and not so much under light exceleration.