parish8

iTrader: (6)

i put this in the FI section but though it should go here too.

check it out.

2 weeks ago it was 10deg, best i could run was 9psi before i started seeing knock and i actualy heard knock at 10psi once. with some good gas(98octane) i was able to turn it up to about 13psi before is showed KR.

today it is 50deg out, at 9psi i am running the same ET as before. i just turned it up to 13psi and still got no KR. this is on pump gas only. then to top it off i am running the same ET's at when it was 10deg. 50deg is what i might see on a good night at the track so i feel real good about the gtech numbers i am seeing.

best run of 10.91@128 on the gtech, add .3 for my std gtech corection and then drop about .3 for the extra 400lb's i had on board so that sugest i can pull some 10's on pump gas!!

so, is 10deg just too cold to run right? can it be that 50deg is better? is their an ideal temp?

unredeemed

iTrader: (2)

cold air is denser. Which would explain why you may have seen KR. Add fuel, rinse and repeat findings.

parish8

iTrader: (6)

wtf did you just say?

my a/f ratio is dead on at 11.8-1 and timing is the same as before.

the maf is reporting less air with the warmer temps. i under stand the more dense air but it is cooler air too so who knows. what i dont get is running aprox the same ET with the same boost even though it is 40deg warmer and being able to run more boost on pump gas than before.

whitt1

The cold air was causing you to run lean.You are supposed to tune your fuel mixture rich for cold temps so if the mixture is tuned rich enough you should at least in theory run faster in colder temps.Tuning that rich is'nt practical,because you would be belching black swoke from the tailpipes at 50 degrees and undrivable at 75 degrees and above.

James B.

iTrader: (1)

What's your coolant temperature like?

Also, you might consider putting a temperature sensor somewhere in the manifold to keep tabs on things.

Something like this perhaps...
http://www.mototron.com/prod_delphiairtemp.htm

I'm not sure where your intake temp sensor is now, but with speed/density as you are running it's the temperature of air in the manifold that is important, not the intake air like it would be metering Mass-Air. (I'm sure you know this, but just in case....)

parish8

iTrader: (6)

i am running speed density aftermarket pcm with WOT closed loop. my a/f ratio is 11.8-1 dead on at any temp so it isn't the fuel ratio.

parish8

iTrader: (6)

coolant? 176-178. my iat's(i have 2 of them) are both after the turbo and after the intercooler. i get actual readings.

i was seeing 10 up to 70 or so in the cold and 50 up to 110 today for iat's

James B.

iTrader: (1)

I guess what I was thinking is that you could have some sort of retard table based on manifold air temperature. Stock programming uses IAT for this but you could get spot-on accuracy with a sensor actually in the manifold.....

Where you have the sensors now really should be fine.

whitt1

You are reading 11.8-1 air/fuel ratio,but the air is almost twice as dense.Your effective air /fuel ratio is closer to 15-1 at 10 degrees.

moregrip

iTrader: (8)

Is he using wideband? If so, it is what it is.