Joes is the only table here I don't hate with furious vengeance.

Try taking someone's logs after they've had a good multi-load dyno tune, and build an AFR table from there.

 

whatever you love mine too:

vs.

Pretty similar if you ask me. The 5000+ vacuum rows hardly matter, and I kept my 100kPa the way I did because I found that if I was cruise on the highway and little low vacuum, it would go rich too early. I have no problems going from 14.5 to 12.6:1 between 1-3psi.

 

I'm surprised to see how lean everyone runs at 200kpa. I put mine at 11.5 because the car spends so much time up there at the track.

 

Peak torque for gasoline is somewhere between 13:1 and 12.5:1, so we're already a tad richer than is optimal.

Unless somebody can show me dyno proof that running at 11:1 allows them to put in so much more timing that it's significantly more powerful, I'm unconvinced of the utility of running much richer than I do now.

 

Why do you run so lean around the 100Kpa range? You don't get knock or misfire doing that?

 

I've been looking for a definitive answer on what's "safe" in terms of AFR for track cars at 250whp / 14psi. No one agrees on anything. Some shops say 11.5, some say 12.5, and the rest fall somewhere in between. There is zero consistency.

 

No. :-) It seems to run great there. SOMEDAY (when I get a willing passenger) I'll tune those rows: Look for the lowest pulse widths to maintain a cruise at those cells. But it runs great, so why throw more fuel at it? Possibly I could get more power, but the truth is I pretty much find everything under 3-5 psi boost is "cruise" anyway.

Actually, that raises an interesting point - only at high RPM. In fact, only in high gear. If I had a gear selector, I would only have it that lean in the top gear. Also, below 4,000 rpm, I couldn't "cruise" there, even uphill, in top gear, so I should richen it up.

Perhaps an AFR target the leans out anytime you maintain "constant rpm" ( (delta)rpm/s < 100) since you're cruising anyway.

Yeah - "safe" is up to interpretation. Personally, I'd look at the leanest someone you trust is running with success, and copy it. :-) There's no reason to go higher than 12.5 as joe said. Really, peak power is close to the number you want, after that it's all safety. Water injection, or monitor EGT's, and you should be free and clear. I wonder if you can add a point to AFR if EGT's raise over some amount and stay there for more than some time.

 

Why do I have a feeling that by the time this Free EMS thing is done, the compiled code is going to be bigger than a Windows Vista distribution?

 

I remember Ben saying he made more power at 11.4:1 than he did any richer, and my car detonates if I go any leaner than about 12.2:1.

 

Thankfully, they have the option of ignoring me. :-)

Besides, it's decently modular, so you can leave out as much as you want. The serial code, for instance, might be bigger, but it sure is inclusive, and runs much, much faster than MS-II, over the same connection. I'd like to think of it as an improvement. Leaves more time for sillyness.

 

Says the man that's blown up how many engines?

 

I get 20-22 city, 30-35 highway. Just got 30 on the highway today and I had ~350 pounds of cargo jamed in the car and made 50+ boosted pulls on that trip. FYI.

 

My thoughts in bold.

 

I may change my boosted cells to be similar to yours.

EDIT: FWIW, there's a reason ALL my boosted cells are the same too. If I'm boosting, I can look at my AFR gauge and no matter what, it should read 11.5 as I have all my boosted cells tuned for that number.

 

Might as well take all the air out of the tires so when you walk up to the car, all you have to check for is the rims touching the ground. And, stop using unpredictable gasoline in the car, who KNOWS what "92 octane" really means, let alone if it's reliable. I'd say run nice, pure, predictable water.

Remove all uncertain images from your life by stabbing out your eyes.

Sorry, 11:1 everywhere is a joke, beyond wasteful, hurts everything, etc.

Heh. Touche. :-) Though to be fair, every problem I had was when running an open loop, untuned, no wideband, piggyback system which fought the stock computer, and had an injector rail which was basically designed to fall off, leaning out the motor. Since the MS, where I can actually CHOOSE how much fuel or timing I get, things have held together just fine.

 

I run a map very similar to Joe's, and unless somebody tells me that's wrong I'm going to keep trying to get MS to run that.

 

This I can vouch for. Abe is the only man I know who has bathed his whole engine compartment in gasoline several times (while driving) and yet still does not carry a fire extinguisher. Hell, I started carrying one because of him, and I don't even have a piggyback rail.

 

Oh, no, I got one... It's just that gasoline has never prompted me to go digging for it the way oil leaks have.

Actually, I'm quite happy with my "midsized" extinguisher, and carry it all the time - no only worry is that sometimes in the trunk it'll get burried, not good for fast access. But there's not a lot of room in the cab, even though it's slender.

 

Calm down abe, I leaned it all the way out too 11.5:1.

FWIW, I have a small fire extinguisher infront of the passengers seat, velcro'd to the floor. Fits fine, isn't in the way of anything, and is very handy.

 

Think of all the space you'll clear up when you take out the sportscar pedal. :-)