AFR help - SRT Forums

BrettsSRT4 · 01-25-2005, 10:29 PM

I just wondered if my air/fuel is ok at WOT, it goes from about 11.3-11.5 then near redline it jumps up to 12.1:1, would that be alright, Im running the AGP 50 trim, with walbro 255lph pump at about 14psi on stage 1 injectors.

SpecJ · 01-25-2005, 11:15 PM

The numbers are safe numbers. From what i hear, its not safe to be running anything over 12psi, but the 255 seems to be helping with some extra fuel. Just keep your eye on the A/F. Just make sure you really dont see anything higher than 12.5:1 or your gonna run into problems.

NIVO88T · 01-26-2005, 08:39 AM

12:1 is right where you want it if you are running 93 octane. that's fine.

hydrohopper · 01-26-2005, 09:49 AM

Nivo can you give a quick lesson on how to read A/F readings? Example: What the numbers actually mean, where is the "perfect" AFR that you want to be at, where your danger points are, etc. Thanks.

BrettsSRT4 · 01-26-2005, 02:10 PM

yeah, Im running 94 octane, so I should be alright

mohillmopar · 01-26-2005, 11:50 PM

Is the perfect A/F ratio the same for all of are cars, or does it change with your modifications?
Stock Turbo vs. Big Turbo have the same sweet spot?

SpecJ · 01-27-2005, 01:33 AM

the perfect A/F ratio is different for all cars. Turbo cars, more alike, have a perfect A/F around 12:1 - 12.5:1 where as naturally aspirated cars tend to run much leaner towards stoich in the high 13's even 14's. It really can depend on your setup and what your motor is made out of. A built block would be able to run leaner than a stock block before melting a piston.

mohillmopar · 01-27-2005, 11:28 AM

12:1 - 12.5:1 is near perfect for any srt-4 right.....Thats what ill shoot for then
P.S. ALWAYS on 91 oct.

Turbolag87 · 01-27-2005, 12:10 PM

Quote: Originally Posted by mohillmopar

12:1 - 12.5:1 is near perfect for any srt-4 right.....Thats what ill shoot for then
P.S. ALWAYS on 91 oct.

those AFR are not safe for 91, i can see timing/knock being pulled for sure.

mohillmopar · 01-27-2005, 02:17 PM

How about 11:1 on 91oct?

SpecJ · 01-27-2005, 10:11 PM

11.5:1 should be ok on 91. I would invest in water injection kit if you are running 91 octane. This way you can run more boost safer and keep your knock under controll under higher A/F