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Ideal EGT and A/F?

Posted: Fri Mar 02, 2007 6:04 pm
by shemoves
Just installing some gauges and wondering where I want them to be. Car is a '92 SS with a Walbro, FCD, WRX IC and a 16g.

Posted: Sat Mar 03, 2007 12:43 am
by Innovative Tuning
No such thing. If you do a search you'll find some good info on both though.

Posted: Sat Mar 03, 2007 11:25 am
by rallysam
Yeah, you can search here and on nasioc. I've posted charts before.

Did you get a wide band AFR system? If you just got a standard AFR gauge, it's not going to tell you much. It'll tell you whether you're running stoich at idle, but as soon as you accelerate it will go off the chart.

Posted: Sun Mar 04, 2007 7:07 pm
by shemoves
I got a WB02. (AEM EUGO).

Well, I know where the values should be for the STi, but was not sure if they were different for the older leggys. (AFR optimum ~11:1, max egt 1650 +/-).

I did try some searching, but only found 'this is where I am at' type stuff, not ideals and maximums.

I'll look for charts sam

Posted: Mon Mar 05, 2007 6:22 pm
by shemoves
I searched rallysam...could not find anything. I read about people running 12:1 AFRs in the Legacies (which would not be good on an STi), and I also don't think the Legs can handle 1600+ degree EGTs.

So, any help is appreciated.

Posted: Mon Mar 05, 2007 9:27 pm
by rallysam
All my image links were broken because Thawa's server is down. I fixed em. Here's the thread:

http://bbs.legacycentral.org/viewtopic. ... highlight=

Of course, no guarantee that what you see there is optimal. That's just the AFR's the stock computer, sensors, and fuel system decided to do on my particular car. Mind you, they may be creating different AFRs than stock due to higher boost and mass airflow. For that matter, no guarantees that any of them were working properly to start with :lol:

I get EGT's up to around 1400's or so, but that's because I put my EGT pretty far back in the exhaust system (where the 4 pipes come together). Everyone gets pretty different readings, most people higher than mine.

You're not going to find much of a consensus for AFR or EGT. It's different for every person's car, and you can't know what's "good" without a dyno. On this board, most people's setups are a total hack that just got tuned by butt (and shoot fireballs) Most tuning rules of thumb on this board come from the WRX guys on nasioc anyway, so you'd probably do better to believe what you find there. For example, the "keep EGT below 1600" rule (very rough rule of thumb and different depending on setup)

What you want is a good tune, anyway, which is usually pretty custom to that particular car. If you just want rough stuff, then you can definitely find more of that on here and Nasioc. That'll tell you if something is completely broken. But, you'll also be able to tell some of that based on the backfiring and shuddering and plugs. A dyno is the finer test - that'll tell you whether 12:1 or 10:1 is "right for you".

Posted: Tue Mar 06, 2007 3:23 am
by shemoves
lol...looks like I'll just have to keep an eye on it.

Thanks for the update.