Recomended WOT WB AFR...

[krunchss]

I hear WOT WB AFR numbers thrown around all the time, "Shoot for 11.5 to 11.7 WOT AFR", etc.

Where do these target WOT WB AFRs come from? Are they just a general concensus on where your WOT AFR should be, or somewhat mod related?

If so, what should I be attempting to achieve with my mods? ie, L36 with a liquid intercooled turbo?

Krunch

[passingpower]

Have a look around www.turbobuick.com/forums/ think forcefed 3800 GNs.
Those guys have more years and broken parts behind them than almost anybody else.
I'd sooner learn from their mistakes than my own. Dependant on mods, most or their AFRs are in the "mid 11s". Browse their forum for specifics.

[krunchss]

Thanx for the link. Mid 11's? Really? Sounds richer than a lot of the L67 SC guys are running no? I will check out that link for sure, but is comparing (and tuning) the technology in a GN that's on average 15 years older than my car, is that a good idea?

Thanx,
Krunch

[Perforator]

I think you will find most L67 SC guys think they are running in the 12's but when they put the wideband on find out different.

[krunchss]

Running ALOT richer? high 10's low 11's?

Go to clubgp and answer the question I have over there now

Krunch

I think you will find most L67 SC guys think they are running in the 12's but when they put the wideband on find out different.

[mourat]

Depends on what octane you run, if you run Meth you can run 12.5 with 8lb boost I'd say safely just because Meth is 116 octane and cold, but regular gas say 94 octane I'd stick to 11.7 with 8lb-10lb boost, higher boost ofcoarse warrants a richer mixture for safety

[KShef]

lean on it until it knocks, then take it back up a little for safety
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Video Review

[5_Liter_Eater]

On any FI application I personally shoot for 11.5:1. Then on the dyno I'll lean it out a half point and then richen it op a half point. Then look at all three runs against the same chart. If it made more power leaner at a particular RPM range then leave the PE at that leaner AFR if it's not knocking (which it won't be if it's making more power. If it made more power with the fatter AFR then I leave the fatter commanded AFR in that range. Then set the commanded back to 11.5 where it didn't make more power to lean out or fatten up. For the areas that it makes more power by leaning or fattening you could even try another 1/2 point and see if it makes more power.

I think you'll find that leaning it out is not going to give you much more power and it's safer to leave it at a fat (~11.5:1) target AFR.

[krunchss]

Thanx man,

I should have posted boost / octane I guess.

91 octane is readily available, so, I am going to tune it for that. While 94 is available at a few stations, I am not guaranteed to get it depending where I am driving to, so, 91 octane it is.

Boost level? Well, basically as high as I can safely get it I guess. I hear I might be able to hit 12-13 psi on my current setup. Engine is virtually a stock L36, ZZP HVTB and 42.5 lb injectors came with my turbo kit. Also, just a reminder (it's in my sig) liquid intercooled too.

Does that help to make a better guess for a starting WOT AFR?

Thanx,
Krunch

Depends on what octane you run, if you run Meth you can run 12.5 with 8lb boost I'd say safely just because Meth is 116 octane and cold, but regular gas say 94 octane I'd stick to 11.7 with 8lb-10lb boost, higher boost ofcoarse warrants a richer mixture for safety

[krunchss]

11.5:1 wow, I figured I might be able to run a little leaner than that with my liquid intercooler setup.

WRT a dyno, not really in the cards right now. The closest one is about 120 miles away. While I will get it on the dyno at some point, I wouldn't mind bing in teh "Ballpark" with the tuning before I hit it. Smaller changes once I hit the dyno would be good instead of making drastic changes in an afternoon since I am a noobie tuner and learning each tuning step as I go. Guess I'll just use the butt-o-meter for now.

WRT "lean it out until you get KR then richen it up again."

I never really understood this as how do I know I am running an appropriate spark level right now?

Example, lets for numbers sake, I am running 9 degrees WOT with no KR and I manage to lean my WPT AFR to 11.8:1 Then I get a tiny bit of KR, so I go back to 11.7:1. Now, can I start advancing spark, or would I expect to get KR again at 10 degrees of spark for example. Or would it advance to 15 for example. I mean, I always hear "A little extra fuel to stop the KR" so wouldn't I just add spark, then KR, then richen AFR to combat KR, then advance spark, and repeat. I'm mostly trying to understand teh process here.

Hope to have my WB installed in the next week or so and I'm trying to do my homework on how to use it

Thanx,
Krunch

On any FI application I personally shoot for 11.5:1. Then on the dyno I'll lean it out a half point and then richen it op a half point. Then look at all three runs against the same chart. If it made more power leaner at a particular RPM range then leave the PE at that leaner AFR if it's not knocking (which it won't be if it's making more power. If it made more power with the fatter AFR then I leave the fatter commanded AFR in that range. Then set the commanded back to 11.5 where it didn't make more power to lean out or fatten up. For the areas that it makes more power by leaning or fattening you could even try another 1/2 point and see if it makes more power.

I think you'll find that leaning it out is not going to give you much more power and it's safer to leave it at a fat (~11.5:1) target AFR.

[KShef]

WRT "lean it out until you get KR then richen it up again."

I never really understood this as how do I know I am running an appropriate spark level right now?

Example, lets for numbers sake, I am running 9 degrees WOT with no KR and I manage to lean my WPT AFR to 11.8:1 Then I get a tiny bit of KR, so I go back to 11.7:1. Now, can I start advancing spark, or would I expect to get KR again at 10 degrees of spark for example. Or would it advance to 15 for example. I mean, I always hear "A little extra fuel to stop the KR" so wouldn't I just add spark, then KR, then richen AFR to combat KR, then advance spark, and repeat. I'm mostly trying to understand teh process here.

Hope to have my WB installed in the next week or so and I'm trying to do my homework on how to use it

Thanx,
Krunch

There is a point when throwing more fuel at it won't suppress the detonation.
I would get the timing to something reasonable first(not sure if the 9* was hypothetical), then play with the boost and AFR. See what the car likes best...
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LovelyWendie