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ike84 · 05-17-2021, 05:44 PM

So today I got to test my AFR guage. Its actually a solenoid controller from innovate motorsports that integrates a Bosch wide band afr sensor. What I saw was rather interesting (and a bit concerning).

On startup at idle, AFR was running 15.1-15.3! Too lean! Under light loads this would fluctuate back down 14.5-14.9. At higher loads this would go lean again, 14.5-15.3. At WOT it dropped way rich, down to 10.5-11.3.

Interestingly, with foot off gas, it would peg lean (over 22).

Numbers in the drive home were a little less lean but Instill saw 15+ a fair bit of time.

I can explain the WOT richness - switching into open loop, the computer is fueling a 3.4L engine. Even with the biggest air intake in the world that ****************s just not gonna match up on a 2.7

The closed loop operation afr bothers me though. I would assume that with as sophisticated as our computers are (combined with what I perceive to be a general cover-your-ass approach from Porsche in regards to performance aspects of this car) that the computer would shoot for 14.7 or less at all times. I was really quite shocked to see 15+ so much.

With that being said, if the computer is gearing the fueling to hit a target above 14.7, I think that may be just one more piece of the puzzle as to why we see issues like bore scoring, overheating, etc.

I did have my battery disconnected this weekend so maybe it just needs a few days to relearn short term trims again.

Anyway, I'll keep things updated over the next few days to see if things change much.

Sent from my POCOPHONE F1 using Tapatalk

05-17-2021, 05:44 PM	#33
ike84 Registered User Join Date: Oct 2020 Location: KY Posts: 1,216	So today I got to test my AFR guage. Its actually a solenoid controller from innovate motorsports that integrates a Bosch wide band afr sensor. What I saw was rather interesting (and a bit concerning). On startup at idle, AFR was running 15.1-15.3! Too lean! Under light loads this would fluctuate back down 14.5-14.9. At higher loads this would go lean again, 14.5-15.3. At WOT it dropped way rich, down to 10.5-11.3. Interestingly, with foot off gas, it would peg lean (over 22). Numbers in the drive home were a little less lean but Instill saw 15+ a fair bit of time. I can explain the WOT richness - switching into open loop, the computer is fueling a 3.4L engine. Even with the biggest air intake in the world that ****************s just not gonna match up on a 2.7 The closed loop operation afr bothers me though. I would assume that with as sophisticated as our computers are (combined with what I perceive to be a general cover-your-ass approach from Porsche in regards to performance aspects of this car) that the computer would shoot for 14.7 or less at all times. I was really quite shocked to see 15+ so much. With that being said, if the computer is gearing the fueling to hit a target above 14.7, I think that may be just one more piece of the puzzle as to why we see issues like bore scoring, overheating, etc. I did have my battery disconnected this weekend so maybe it just needs a few days to relearn short term trims again. Anyway, I'll keep things updated over the next few days to see if things change much. Sent from my POCOPHONE F1 using Tapatalk __________________ 2000 Box Base, Renegade Stage 1 performance mods complete, more to come When the owners manual says that the laws of physics can't be broken by this car, I took it as a challenge...