Quick AFR question. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

EnthusiastMan · 08-20-2007, 10:54 PM

Hey guys, sorry if this has been covered before but I can't seem to find my answer.

I just finished my SR swap and have been driving it and raising the boost pressure till I start to run lean, then adjust it down a lil bit. The car has an S15 T28, Z32 MAF, Sard 550's, and an RS Enthalpy tuned ECU. Now, I've set my boost pressure at around 15psi. Pulls hard and strong and getting between 10.5-12.5 AFR's. A little rich, I know, but I'm cool with it for now till I can get an AFC. Anyway, when I'm in 3rd or 4th gear and in boost, it seems like I can hear some pinging/detonation. While this is going on, I am monitoring my AFR's and they are in the 10.5-12.5 region. It should not be pinging.

Is it possible to get a little pinging yet be running good AFR's? I have my timing set to 15 degrees and am wondering if I should lower it to about 13 degree's. The noise I'm hearing might in fact not be pinging but maybe an exhaust leak or something, but I just wanted to make sure that the engine cannot ping/detonate while running good AFR's.

Thanks for any advice.

steve shadows · 08-21-2007, 10:28 AM

pinging under knock conditions sounds like sand being rattled around inside a tin can.

en exaust leak sounds like a crisp fart.

hope that helps

double check your fuel pressure under load.

08-20-2007, 10:54 PM	#1
EnthusiastMan Join Date: Mar 2007 Location: Stockbridge, GA Age: 41 Posts: 21 Trader Rating: (0) Feedback Score: 0 reviews	Quick AFR question. Hey guys, sorry if this has been covered before but I can't seem to find my answer. I just finished my SR swap and have been driving it and raising the boost pressure till I start to run lean, then adjust it down a lil bit. The car has an S15 T28, Z32 MAF, Sard 550's, and an RS Enthalpy tuned ECU. Now, I've set my boost pressure at around 15psi. Pulls hard and strong and getting between 10.5-12.5 AFR's. A little rich, I know, but I'm cool with it for now till I can get an AFC. Anyway, when I'm in 3rd or 4th gear and in boost, it seems like I can hear some pinging/detonation. While this is going on, I am monitoring my AFR's and they are in the 10.5-12.5 region. It should not be pinging. Is it possible to get a little pinging yet be running good AFR's? I have my timing set to 15 degrees and am wondering if I should lower it to about 13 degree's. The noise I'm hearing might in fact not be pinging but maybe an exhaust leak or something, but I just wanted to make sure that the engine cannot ping/detonate while running good AFR's. Thanks for any advice.

08-21-2007, 10:28 AM	#2
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	pinging under knock conditions sounds like sand being rattled around inside a tin can. en exaust leak sounds like a crisp fart. hope that helps double check your fuel pressure under load. __________________ Like Me on FaceBook !