Two different numbers. What is your guys idea of ideal idle A/F and WOT 6000 RPM's A/F?

 

idle should be around 14.7 +/- a few. At WOT seen that you are f/i I will be scare to see anything higher than 12. The reason it is leaner at idle/crusing is because you are not producing any load so the motor is in "relax mode". Sorry is the best way I can describe it.

 

For me, AF jumps all over at idle, cruise is a solid 14.4-14.8, WOT = 11.3ish. How do you have a 500+ HP car and don't know AF ratios??

 

Never said I didn't know what my ratios were, did I? Just got the V-Pro installed w/knock amp. It's visible all the time. I know what it is, I just wanted to get an idea of what others thought or are running. How does anyone ever know how they are doing or how they are set up relatively speaking without benchmarks of success and failure? I may be too rich/too lean. Just checking in with others.

Plus, I don't tune my own sheit due to V-Pro restrictions.

Thanks.

 

Boosted? NA? Pump gas? Race gas? Ideal for me...

cruising 14.7

WOT:

NA 12.8-13.3

FI stock block 10.8-11.3

FI built, pump gas 11.0-11.5

On race gas up to 12:1 "lean"

But what do I know?

 

Idle can be quite lean. I've seen cars with 18.0 idle.

 

The CATS need 14.7 +- 0.5 to function.........outside that narrow range they don't do much........they get washed wet during acceleration from the excess AF used to cool the combustion down [ 14>12>10].

 

I'd say around 15.5 for idle and 12.5 at wot for FI'd engines.

 

Alberto, in "A/F" air comes first meaning the higher the first number, the leaner it is. That doesn't seem to be what you are telling me above.

In my sig, boosted 12.5psi, built long block no cams. 93 octane.

 

I agree with Alberto

He is telling you what the ratio is. So basically dont go any higher than a ratio of 12.1 on race gas.

What is your A/F ratio right now Jokestrap?

Later
Todd

 

Okay, got it. I don't use race gas. Right now I am about 13.5 at idle and about 11.7 at WOT on 93 octane. Seems good to me based on all the threads I have read in the FI section. The reason for the thread is that I really wanted to get direct feedback on the subject instead of scattered comments.

 

that sounds very conversative, especially on pump gas.

 

Seem a little lean of FI but i dont know much I run the leanest 11.4 at WOT

 

Mark@SGP tunes conservatively. He will tune it as lean as you want within reason but if you leave it up to him, he will tune it on the conservative side.

Thanks for the responses guys.

 

With as many posts as you have you sure do make uneducated comments man. The comment above is not correct, not 1 tuner on this site would agree with you on that one...

11.7 A/F on pump gas is not on the conservative side IMO but----> one must also remember every tuner has a "method". Some prefer to pull more timing and run leaner A/F's while others wont pull as much timing and run richer low 11's, high 10's A/F's. Jokestrap - judging only by the A/F your idle is lean about 1 point and your IMO .5 point to lean for pump. But again this is all relative to the timing the engine is seeing so...Im sure SGP hooked you up with a good tune I wouldnt worry to much, just dont run leaner than what you are seeing, a 30 degree temp drop can push you into the 12's.

 

You probably won't pass a measured dyno emission with idle at 15.5 as the Nox goes higher either side of 14.62.

Even the finest $10,000 WIDE BAND O2 systems are not very accurate.
Manfacturers collect all exhaust and subject it to gas chromograph to get the EXACT 14.62

 

wow, what a total *****

any other peeps want to chime in?
what is a good range that's not too conservative. 15.5 is probably too lean, now I think about it, I'd suspect you can push 12s at wot with an aggressive tune?

 

I wasnt trying to be rude, posts like this should provide help, I read yours and think wtf?!?! I only corrected you because others might read your advice and think "hey my Turbo's A/F is right on!" When in fact its way lean. Dont be mad because you were wrong, we are all here to learn, as much as you are in the FI section Id figure you'd know by now. Most would agree 12:1 or so on race gas would be acceptable for FI-I wouldnt do that on a stock block though.

 

^ gotcha. I'm still NA and running 15.5 @ lower rpm and 14ish at wot. I know this sounds lean, even for NA, but I've talk to several shops in socal and they said it's still within reasonable range. I'd may want run abit lean (but within safe range) when I go FI, because I do a lot of highway driving.

 

Reasonable range? Yeah it is, NA it would be very hard to damage the motor from running lean. For a while with many bolt-ons I ran over 15:1 lean and still tracked the car with no immediate damage (who knows long term) I wouldnt recommend that though. Low 14's is ok, but for ideal/peak NA power you want it around 13:1 give or take some. For highway driving/part throttle cruising14.7 A/F is ideal. Im not sure if you have ever seen an A/F guage but its not "stable", it will fluctuate when cruising many times per second 14.3, 14.6, 15.2, 15.1, 14.7, 14.5, etc etc. I've never heard of anybody tuning slightly lean for cruising, as long as you dont have a super heavy foot and stay out of boost you will be fine