Ok I just got back from Iraq and I just started driving the car around again after it has sat for a few months.

Hit the gas in 3rd and look down and I hit 13.4psi. So I turn the boost controller off and do it again. This time I hit 11.4, which is ok to me but I look up at my wideband display and it read 12.8 AFR I stop the car and and turn the fuel up to +25-+30 from 4500 RPM and up. Do it again and the AFR's are still high 11's and low 12's. I'm running 550's, 720's Rtek 1.5, rewired walbro, BNR stage 1, HKS Super-AFR.

Can temps in the teens cause me to run this lean and with almost no boost control? In the summer I don't have this problem at all. No creep, boost stays around 10 and the AFR's around 10.5-11.0 in the summer with the boost controller on.

With the temps below freezing. Is it safer to run a slighty higher AFR than you would in the summer?

Still new to tuning. So help me out a little, don't flame me to bad now.

 

The added benifit of the very cold ambient temperatures, is a drastic reduction of the intake charge.

The whole point of running richer AFR is to reduce combustion temperatures. You are achieving the same with the much lower intake temperatures. This will certainly help in preventing detonation.

Are you as safe as you would be in the summer. I can't say for sure

 

I'm just worried about my AFR's. Some people say to stay around 10.5-11.00 for safe AFR's in hot weather. But I can't seem to get my AFR's down to the mid to low 11's in this extreme cold.


The injectors are a year old. RC 550's and Greddy 720's.

Walbro is a year and half and the fuel filter is about 2 1/2 years old.

Could the fuel filter clog that fast. Probably could.

I could check the fuel pump voltage and fuel filter first to see if thats it.

I think I'm going to run some Xylol to try and richen it up a little for the time being. Maybe try and bring the octane up to around 97. Could that help?

 

IMHO unless you are running wicked intake temps, or you are running more than 15psi, your afr's should be in the 11's. But Then again each to his own.
But eViLRotor has it right.
Yes, I change my Fuel filter every 4 oil changes.

 

Colder air is more dense with oxygen so you will leaner with the same fuel controller settings than you did in the summer. Winter = need more fuel, summer = need less.

 

Yeah I want to be atleast in the low low 11's also. I'm going to change my fuel filter as soon as poosible. Well as soon as the damn snow stops and I can get to the shop and tinker around the engine bay.