You wont typically get any knock on a base pressure SC kit as long as the After cooler is functioning normally. Its safe to run up to 13afr on the street in my experience but 12-12.5 is better and will lower the combustion temp a bit. Consider that your making 1psi at 4k rpm and 5-6psi at redline. Its not a lot. The kit doesn't even require any timing retarding.

 

13's AFR's at WOT??? Thats NA air fuels, id personally never risk running a boosted setup leaner than 12.5. On my car i stay 12.0 to keep safe

 

I've seen first hand truth to this on a members kit for several seasons, also zero knock.

 

Yep, it is leaner then what you would ideally like to run, but the motor doesn't seem to mind, was the point. Keep in mind the kit calls for one step colder plugs as well, this is important. The problem lays with how rich it runs under vtec, so its a compromise with balancing that with the upper rpms. On a typical base kit on an ap1 with recommended base fuel pressure, the afr will run 11.5ish up to vtec, spike momentarily to mid/upper 13's, settle to 12.8-13 and tapper off to low 12's redline. Its how the stock ecu fuel curve is with the comptech rising rate curve. If you never want to see a 13 on the gauge you will be borderline fuel washing your motor under vtec running mid 10.'s. Adding the vafc is a big benefit in better shaping the fuel curve. However many have put 100,000+ on a base comptech at recommended settings.

 

see to me that is not a good tune, going from 11.5 under vtec to 13.0 after is a big jump in afr and does not sound smooth at all. Car can be leaner in low end and get a little richer toward redline. like my car will go low 13's high 12's as it starting to get into boost will get lower 12's and at full boost stay 12.0 range to redline.

IMO pump gas and high 12 to low 13 afr is a time bomb waiting for a issue

 

see to me that is not a good tune, going from 11.5 under vtec to 13.0 after is a big jump in afr and does not sound smooth at all. Car can be leaner in low end and get a little richer toward redline. like my car will go low 13's high 12's as it starting to get into boost will get lower 12's and at full boost stay 12.0 range to redline.

IMO pump gas and high 12 to low 13 afr is a time bomb waiting for a issue
[/quote]

I totally agree, but thats how these older comptech kits run out of the box. And these are an improvement over what Vortech offered at the time. The vafc is an integral part in shaping that fuel curve on these kits as mentioned. The current CT-Engineering and SOS kits have incorporated a additional plug in box that does what the vafc does IE change fuel duty for better curve and lower vtec. Its a lot better, but you cant tune it, still just the RRFPR adjustment is it.

 

You're right, its not a good tune, and I don't think anyone will disagree with you. The only thing you have to tune the base kit with is fiddling with your RRFPR, and that's never going to get you a good tune. Like Junky said, it works for these kits due to the low amount of boost they run. I don't think that high 12's is a time bomb for your engine, and the way that Junky had his set up he only tapped 13 at the VTEC transition point and went back down into the 12's after. I used his advice when initially setting up my RRFPR and VAFC, screwing with the RRFPR to get the VTEC spike right at 13, no higher, then use the VAFC to lean out the upper RPM range. It worked great and I saw no problems. But, you know there's always the exception to the rule.

But its easy to see when looking at my AFR curve from that setup that it is NOT a good tune. The AFR graph is like a roller coaster. Any good tuning option (AEM, Haltech, Flashpro, even GEMU) can keep the AFR line flat and adjust timing, etc to get a good tune. But the base kit doesn't have that capability. I mean, you're at maybe 3.5 PSI boost pressure when you dip into 13 AFR, and only there for about 0.5 seconds. Its not going to grenade your engine.

 

Bumping this because ive noticed that while I'm driving along the freeway cruisin at 70 or so my A/F usually jumps between 14.3- 15.5 but occasionally it will suddenly lean out to 17-18 for about 3-4 seconds then go back to the normal range. is this normal? seems alittle weird and you can kinda feel it in the car when it happens

 

Mine does it too with the same setup, I think it's the stock ECU trying to lean itself out because when mine does it , it's when I'm running stupid high fuel pressures. I've now recently acquired emanage ultimate and hoping to get rid of the FMU and this problem all together