Got the wideband installed and started playing around yesterday (my father's day gift to me). The longtubes put the PE readings around 13.1:1....which is a bit lean so I dropped it down to 12.2-12.4 and then leaned it toward redline around 12.6:1. The car was MUCH happier!
The LC1 is a great unit, though a little quirky...once you learn to reboot the LC1 if it doesn't connect to your Pc, you'll be set.
I have some fine tuning to do but its amazing how much my car responded to a fairly small change in AFR. I don't know if this was because I was getting knock before (I don't have a way to measure it yet) or because the car was too lean. All I know is that the thing really wakes up above 4,000 rpm where it used to fall on its face.
whats the recommended afr at wot for a blower motor?
Max power and reliability will depend on the individual setup. I have mine set at 11.7 early in the RPMs and then fatten'er up to around 11.1 at the top end.
On my motor going richer than 11.0 early on, results in a loss of torque. I could probably squeeze a few more HPs out by leaning out the AFR some, but I don't want to risk detonation/KR in the event I get some bad gas or something else happens.
I have EFI Live on loan right now and I'm adjusting timing (finally!). I was seeing quite a bit of knock even at 12.6:1 ...I have pulled out quite a few degrees of timing above 3000 rpm and even more above 4400 rpm...I'm down to the low 20's and still seeing a little knock at 5200 now.
Now that I'm hearing that people seem to be liking closer to 13:1...I might lean it back out again. The car sure seemed to run much better at 12.6 than at 13....but I bet it was seeing so much knock that it was retarding timing all the time.
Factory tune was 27+ deg...I'm down to less than 25 already. Some areas are down to 24.
I have EFI Live on loan right now and I'm adjusting timing (finally!). I was seeing quite a bit of knock even at 12.6:1 ...I have pulled out quite a few degrees of timing above 3000 rpm and even more above 4400 rpm...I'm down to the low 20's and still seeing a little knock at 5200 now.
Now that I'm hearing that people seem to be liking closer to 13:1...I might lean it back out again. The car sure seemed to run much better at 12.6 than at 13....but I bet it was seeing so much knock that it was retarding timing all the time.
Factory tune was 27+ deg...I'm down to less than 25 already. Some areas are down to 24.
lean AFR is not the only thing that can cause knock-retard.
The car sure seemed to run much better at 12.6 than at 13.
in this case, richining the AFR may be only masking the real problem.
I'm down to 17 deg in the 4000-4800 range at WOT, but I'm fine everywhere else. I'd expect knock up high in the rpm (5200+) but I'm not seeing it. The knock is down from 10deg retard to 6 deg (max, not average)....average is down to 1-2 in some cells and still 5 in one of them.
When you say hiding the issue, I assume you mean false knock? Maybe slight piston slap causing false knock at that rpm range?
You do not want to go over 12:1 on pump gas... 12.5:1 is way too lean.
I set them up with a properly tuned VE table and the PE to command 11.84:1 on boost.
Hope that helps.
thanks bro.
im just learning the stuff...lots and lots of research....every little bit helps...
trying to get as much info crammed between the ears before i dive into it..
EDIT: "properly tuned VE".....with or without maf enabled?
i did the ve on my kids ride (h/c v6 camaro) and it really cleaned things up. but when i plugged the maf back in i had to "scale" it...thats my next research workload...hahahahaa
Sounds like I'll aim for 13.1 and then keep playing with knock. I am in the low 20's in every cell but a few that are right at 4800....which I have reduced to 17 deg. I'm only getting a few deg of knock retard now....wondering if I have carbon buildup or something causing that much knock.
go back to stock timing tables and see if you still get knock. If you do then you have other issues casuing knock or you could be seeing flase knock. Im pretty sure extreme throttle tip in will create a brief moment of timing retard but it will not sustain it past a second or two.
Corvette Store
Stock LS1 with longtubes, happy around 12.5:1
