Air Fuel Ratio at WOT

[rchops33]

Guys,

If there is a such thing...what do you think the "danger zone" for the air fuel ratio is for running too lean at WOT?

[Firebirdjones]

For a naturally aspirated engine???

For a safe tune I shoot for 12.6-12.8 You can squeak out a few more HP with 12.9-13.0 but if you get much higher than that it's a bit risky. I prefer to give up a few HP and stay on the safe side, especially if running pump gas.
Every engine is a bit different in where they make the best power. I use the track and MPH along with the wideband to see what the engine likes on a given day.

[5abivt]

12.8 is a good afr. Any higher and it really isnt worth the risk especially for any car that is driven any more than at the track.

[farmtruc]

Next time you have a completely stock truck/car slap the wideband on it and notice how long GM keeps the a/f ratio at 14.7:1.
On the trucks it's worse!
When we dyno trucks here, the entire dyno pull is at 14.7:1.

With GM's fuel delays based on RPM, time and torque, you'd think these engines would break more often than they do, but you'd be surprised.

I'm sure they have their reasons.

Like the guys said above, 12.5 to 13.0 is optimal. If you use a dyno to dial in your a/f ratio, be sure to check it at the track in real world driving conditions.

good luck,
allen

[mark21742]

Next time you have a completely stock truck/car slap the wideband on it and notice how long GM keeps the a/f ratio at 14.7:1.
On the trucks it's worse!
When we dyno trucks here, the entire dyno pull is at 14.7:1.

With GM's fuel delays based on RPM, time and torque, you'd think these engines would break more often than they do, but you'd be surprised.

I'm sure they have their reasons.

Like the guys said above, 12.5 to 13.0 is optimal. If you use a dyno to dial in your a/f ratio, be sure to check it at the track in real world driving conditions.

good luck,
allen

look at the timing tables on those trucks and they dip down into retarded timing in the the main tables......think that's how they hold together running so lean? or do they run that low timing for emissions?

[Frost]

They delay PE fueling for highway/towing economy. As you guessed, the timing they run is very low by comparison to the cars.

[V8MUSCLE]

i thought you wanted 14.7ish?

[mark21742]

i thought you wanted 14.7ish?

part throttle cruising = 14.7:1
wide open throttle you want to be richer 12.5-13:1

[V8MUSCLE]

i see said the blind man...

[mark21742]

i see said the blind man...

lol hey man don't feel bad, we're all still learning

[lovedrvr]

how do you read the a/f mixture
i have a predator hand held can i read it with this ?
if not what all do i need,ill get it.

never mind did some reading going to get this
http://www.lethalperformance.com/98-...t-blue-p-18823

[mark21742]

how do you read the a/f mixture
i have a predator hand held can i read it with this ?
if not what all do i need,ill get it.

never mind did some reading going to get this
http://www.lethalperformance.com/98-...t-blue-p-18823

a bunch of us are running the LC-1 with a gauge. itcomes with a manual on CD ROM and pretty good instrutions to hook it up, also it if you have a laptop you can log your wideband readings with it.

[Firebirdjones]

I use the LM-1 so I can move it from car to car.

[mark21742]

I use the LM-1 so I can move it from car to car.

don't be so tight old man and just buy one for each car lol
j/k

[Firebirdjones]

don't be so tight old man and just buy one for each car lol
j/k

Ya I'll get right on that one

[mark21742]

Ya I'll get right on that one

if you have more than one toy the LM-1 is the way to go

[Firebirdjones]

if you have more than one toy the LM-1 is the way to go

Ya I use it on other peoples cars as well as my own.

[346ci]

I use the LM-1 so I can move it from car to car.

I have my AFX set up to easily use on multiple vehicles, granted I had to add a little extra wiring to make it easily mobile

[Wreckless WS6]

I feel anything over 13.50 is pushing your luck....

[Dr.Crash]

i see said the blind man...

to the deff guy