A/F Ratio?

abhattan · 06-07-2007, 09:09 PM

What's a good air fuel ratio to be at with 580cc injectors on 12 lbs?

cre · 06-08-2007, 06:14 AM

AFR for what? WOT, idle, cruise, PT?

Supra2NR · 06-08-2007, 09:27 PM

shouldnt it be still at the 14.7 to 14.9 range
no matter how much boost your running?

IHateHacks · 06-08-2007, 11:14 PM

I think he means WOT like on a dyno run.

It should be around 11:1.

abhattan · 06-12-2007, 11:44 PM

So while cruising it should be closer to 14.7 and WOT should be lower? 11 is kind of low, isn't it. I'll be dumping mad gas! I have the HKS Super AFR, it will do both cruise and WOT? I plan on doing this myself on a DYNO with a 5 gas analyser at my school.

cre · 06-13-2007, 02:21 AM

Most of the people I see tuning these are aiming for the low 12's at WOT (12.3 and up is considered rather aggressive though). There are a number of reasons for the high fuel level, the biggest is probably temperature. The leaner you run the hotter it gets, this doesn't magically change once the AFR hits stoich (14.7).

You can lean out on cruise, I don't really know too much about tuning for that though. I've seen lean cruise AFRs from 15.1 to 16.1 (seems like pushing it to me, but I guess if it's a low load setting it'd be fine).

abhattan · 06-13-2007, 11:33 PM

thanks for your help.

06-07-2007, 09:09 PM	#1
abhattan 3" Exhaust Join Date: Oct 2006 Location: Brentwood, New York Posts: 162	A/F Ratio? What's a good air fuel ratio to be at with 580cc injectors on 12 lbs? __________________ '91 Turbo Targa 5 Spd. '87 Corolla GT-S 5 Spd '91 Accord Daily Driver 5 Spd Soon to be rebuilt (All to some extent)

06-08-2007, 09:27 PM	#3
Supra2NR 1000whp postwhore Join Date: Apr 2006 Location: Chi-Town Posts: 1,643	shouldnt it be still at the 14.7 to 14.9 range no matter how much boost your running? __________________ http://www.myspace.com/supra_2nr Into Bikes now,, apparently the supra couldnt kill me, so my zx6 might lol

06-12-2007, 11:44 PM	#5
abhattan 3" Exhaust Join Date: Oct 2006 Location: Brentwood, New York Posts: 162	So while cruising it should be closer to 14.7 and WOT should be lower? 11 is kind of low, isn't it. I'll be dumping mad gas! I have the HKS Super AFR, it will do both cruise and WOT? I plan on doing this myself on a DYNO with a 5 gas analyser at my school. __________________ '91 Turbo Targa 5 Spd. '87 Corolla GT-S 5 Spd '91 Accord Daily Driver 5 Spd Soon to be rebuilt (All to some extent)

06-13-2007, 11:33 PM	#7
abhattan 3" Exhaust Join Date: Oct 2006 Location: Brentwood, New York Posts: 162	thanks for your help. __________________ '91 Turbo Targa 5 Spd. '87 Corolla GT-S 5 Spd '91 Accord Daily Driver 5 Spd Soon to be rebuilt (All to some extent)

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06-08-2007, 06:14 AM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	AFR for what? WOT, idle, cruise, PT?

06-08-2007, 11:14 PM	#4
IHateHacks 20psi boost Join Date: May 2006 Location: New Haven/Hamden Posts: 793	I think he means WOT like on a dyno run. It should be around 11:1.

06-13-2007, 02:21 AM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Most of the people I see tuning these are aiming for the low 12's at WOT (12.3 and up is considered rather aggressive though). There are a number of reasons for the high fuel level, the biggest is probably temperature. The leaner you run the hotter it gets, this doesn't magically change once the AFR hits stoich (14.7). You can lean out on cruise, I don't really know too much about tuning for that though. I've seen lean cruise AFRs from 15.1 to 16.1 (seems like pushing it to me, but I guess if it's a low load setting it'd be fine).