Is 10.8 a safe afr to be going down to, i was told this was quite a conservative afr on my tune?

and would it be safe for it to go down to 10.2 ?

 

actually it's very safe. matter fact it's rich. the lower the number the richer it gets. the higher the number the leaner.

 

thanks man,

my afr's from 2k to 7k are 12.7 going down to 10.8, what could i do to optimize my performance and still keep it within safety?

it put down 325atw, usual mods on stock MR cams tho, tbe, mbc, fmic, fuel pump etc

 

could some one please explain briefly what should be done to optimize ie what should it be

heres my graph including afr graph

http://www.lancerregister.com/showth...hreadid=153368

 

Based on those images, you do not have a conservative fuel tune. You are around 11.7:1 at peak torque, which is actually a little leaner than some would run on pump . The best thing you could do it flatten the AFR curve a bit. But, your original question was about the taper at redline ... yes, it is normal and quite alright. The added fuel slows the burn and help reduce knock at higher RPM.

 

Thats not extreemly rich, here is what rich looks like:




That was before tuning W/M at 24 psi

 

hold on I thought low 12's were pretty conservative...

 

c6, that is brutal rich, that is bill gates rich.

to the original poster, if you are not knocking that afr looks good .
think I'd throw a little fuel at 3500 rpm to get away from 12.

more in line with 11.5 or so if you can get away with it. knock rules all.
the point is low elevens have worked, but its a mix of timing and afr. if you can get 12 to work on your set up so much the better. you don't want to drop a bunch of timing to save .5 afr.
so check knock and go from there.

 

Low 12s are the upper edge of safe for a stock ish car on pump.

MB

 

Hell no. 12 is race fuel safe. 10.2 on pump is safe but you get no kinda power running that rich. Depending on the car 11.0-11.5 is cool for AFR.

 

12.5
is about the most you can get from fuel burn but leaves no margin of safety, esp under boost.

12.0
is slightly less productive, but with more room for error (timing, miss, spikes, whatever) however tune will need to be perfect, water inj or racegas is suggested, and 93 oct would be pushing it

11.5 - 12.0
a good target, with optimal timing however

10.0 - 10.5
- this here are bubba tune, just turn that distributor all the way ( run 10* - 23*) and let the ECU adjust timing for you from the knock. Very simple and very safe if too with proper octane and intact WGA hose. This mode of operation was inbred into the ECU by engineers to accomidate "hillbilly gas" or 89 octane. In fact the factory USDM tune off the dealer lot is indeed a bubba tune, just with less timing.
Back in the days of SAFC (2005 and earlier) people would run leaner and more timing on stock tunes and racegas just by dicking up the MAF signal. One guy was 0.01 seconds shy of 11s with this setup and just a MBC

Thanks

 

LOL at Bubba Tune description. That is right on.

 

good info thanks!

 

I wouldn't get anywhere near 12.0 on pump gas after 3000 RPM or so unless you have alky/meth/race gas

 

You need to flatten that AFR more. The taper you have going on is a little out of hand. The AFR @ peak torque(3000-4000rpm) can be as lean as 11.5:1 on pump gas, then slowly taper to 11.1:1 after 6800rpm or so. Continue that AFR until rev-limiter. THis is actually very safe and is a good proven AFR. It's a good trade off between safety and power.

But, your question was asking if it was safe, YES your current tune is safe....very safe. If you are asking to tune even richer, i would not do that. You can actually cause a knock condition if you are running too rich. If you do anything, do what i recommend.

Good luck!

CJ