Here are my A/F #s from my dyno:

RPM A/F
3600 12.6
4000 12.6
4400 12.5
4800 12.5
5200 12.3

Are these #s too lean for a truck without a chip? Is it correct to assume that since the timing is not advanced by means of a chip that you can safely run slightly leaner?

Thanks for the input guys!

 

I think the tuner consensus is that 11.5 is a safe place ...

 

You are not running a chip and your AF's are 12.5?


12.5 is or at least was considered safe for forced induction. Personally 11.5-12.0 sounds better, but IF your truck is stock w/NO chip.......and NEVER been chipped (and more importantly - under warranty)....I wouldn't change a thing.

 

I think with no timing advance you are just fine.

--Joe

 

Thanks for the input. It means a lot coming from you experienced L owners!
Redneck, are you surprised that it is so lean? I forgot to mention in this post (although it is in my sig) that I am also running a 4#.

 

Sorry rookie mistake not reading the sig first:o

 

Get a chip.

 

I have an 01 with similar mods except stock lower pulley. My A/F was 12 on the dyno. I find it intresting yours was 12.5 with a 4lb pulley.

 

Does anyone know what the A/F of the factory tune is at WOT?

 

My experience is that 99-00 are very rich around 11.0 stock and some in the high 10's. 2001's and up are leaner and usually in the mid 11's. I bet Sal or JL would know for sure. I think 12.5 is a bit high, you could get a bad batch of gas then ping-ping. My truck always liked around 11.7 best.

 

The most aggresive I would run is mid to high 11's

Anywhere in the 12's is too much for me.
12.5 and more is outright Dangerous IMO (no room for error)
Like Calightnin just said, all you need is the wrong tank of gas and next thing you know, -->"BOOM"

 

He guys, check out my Numbers, first two are stock and 3rd is with the filter removed (ran a bit richer cuz it saw all the new air).

Let me know what you think, looks like stock is pretty lean allready?? When you say your ratio, are you taking an average or near redline??

First Run (Bone Stock)

0.00,3400,116.9,14.7,,,,
0.42,3500,242.8,14.7,,,,
0.64,3600,297.1,14.6,,,,
0.85,3700,303.9,14.8,,,,
1.06,3800,311.4,14.4,,,,
1.28,3900,320.7,13.8,,,,
1.49,4000,325.9,13.3,,,,
1.71,4100,331.3,12.9,,,,
1.93,4200,334.7,12.8,,,,
2.15,4300,339.5,12.8,,,,
2.37,4400,347.1,12.8,,,,
2.59,4500,352.1,12.7,,,,
2.82,4600,353.7,12.7,,,,
3.05,4700,356.4,12.6,,,,
3.28,4800,358.9,12.5,,,,
3.52,4900,362.4,12.5,,,,
3.76,5000,361.8,12.4,,,,
4.01,5100,362.3,12.4,,,,
4.26,5200,360.9,12.3,,,,
4.51,5300,359.9,12.2,,,,



Second Run (Bone Stock)

0.00,3500,280.5,14.7,,,,
0.21,3600,293.8,14.8,,,,
0.43,3700,303.5,14.4,,,,
0.64,3800,310.1,13.9,,,,
0.86,3900,318.1,13.5,,,,
1.07,4000,324.9,13.1,,,,
1.29,4100,331.7,12.8,,,,
1.51,4200,337.2,12.7,,,,
1.73,4300,343.6,12.6,,,,
1.95,4400,348.6,12.6,,,,
2.17,4500,352.4,12.6,,,,
2.40,4600,354.6,12.6,,,,
2.63,4700,358.7,12.5,,,,
2.86,4800,361.7,12.4,,,,
3.09,4900,361.4,12.4,,,,
3.33,5000,363.6,12.2,,,,
3.58,5100,361.6,12.2,,,,
3.83,5200,360.5,12.0,,,,
4.09,5300,359.3,11.9,,,,
4.35,5400,355.3,11.9,,,,
4.63,5500,357.1,12.0,,,,

Third Run (Filter Removed)

0.00,3500,257.2,14.7,,,,
0.22,3600,288.6,14.7,,,,
0.44,3700,297.3,14.5,,,,
0.66,3800,304.5,13.9,,,,
0.88,3900,315.0,13.4,,,,
1.09,4000,321.1,12.9,,,,
1.31,4100,326.7,12.5,,,,
1.54,4200,330.3,12.3,,,,
1.76,4300,334.5,12.1,,,,
1.99,4400,340.2,12.1,,,,
2.22,4500,344.4,12.0,,,,
2.45,4600,348.2,12.0,,,,
2.68,4700,350.6,11.9,,,,
2.92,4800,351.4,11.9,,,,
3.17,4900,354.7,11.8,,,,
3.41,5000,355.9,11.7,,,,
3.66,5100,354.9,11.7,,,,
3.92,5200,356.4,11.6,,,,
4.18,5300,353.7,11.6,,,,
4.45,5400,353.7,11.6,,,,
4.73,5500,281.7,11.6,,,,
4.94,5500,0.0,11.6,,,,
5.49,5400,0.0,10.0,,,,

Sean

 

My truck for some reason hates to run any richer than high 11's.
I've had my programs re-tuned several times to get right around a 12.0 Its a BIG difference!!!

 

Hmm that's weird how the removal of the filter richened it. Maybe the loss of restriction made the computer dump more fuel?

 

Yeah, I think the computer saw a bunch of air and dumped fuel until it had a chance to adjust. I just got my chip yesterday and based on my stock numbers, I'm worried I'm going to be too lean..

What do you think?