[p.a.sti]

Hello everybody, My question is what is the average air/fuel ratio of your moded sti's . After dyno tuning what are your wideband readings? Full throttle and crusing. I understand that there are many variables in a/f depending on mods but there must be an average setpoint. Are we looking at 10.0 to 1 10.5 11.0 or what ? I do not have access to a dyno so all my tuning must be done by wideband and EGT . Your help is greatly appreciated.

[nhsilversti]

http://www.imprezawrxsti.com/postnuk...977&highlight=

[p.a.sti]

Thanks I already read the sticky and I appreaciate the reply. What I really want to know is what the currently modded cars are running. I am quite familular with the basics of tuning. What I am trying to do, with out the aid of a dyno, is tune my car. I currently have a godspeed down pipe, HKS header, AEM coldair intake, Blitz nerspec R catback, bov, catchcan, grnd sys. and a pilex wide band a/f sys. I want the info of cars that already put down the dyno time and what the a/f was at thier point of daily drivibility , and max lean, detination, bog and ect. Thank you all on the help I greatly need info on your cars.

[nhsilversti]

no matter what you have for mods on a turbo car, a/f needs to be tuned to 11.0:1. of course you can lean it out and risk having a motor that would work great as a boat anchor.

here is a post from my dyno tuning, this has a/f on it as well.
http://www.imprezawrxsti.com/postnuk...923&highlight=

[p.a.sti]

Thank you greatly

[Hummer]

Here is mine at 15 PSI.

[p.a.sti]

Ahh so your averaging about 11.2 after boost kicks in. Any idea what happens when you raise up the boost to about 17 with out fuel tuning?

[p.a.sti]

Ahh so your averaging about 11.2 after boost kicks in. Any idea what happens when you raise up the boost to about 17 with out fuel tuning?

[Invisiguard]

Originally Posted by p.a.sti

Ahh so your averaging about 11.2 after boost kicks in. Any idea what happens when you raise up the boost to about 17 with out fuel tuning?

you will not necisarily run lean just by turning up the boost to 17, at least not on the stock turbo, it cant even hold stock boost out to redline where it running lean would start becoing an issue anyhow. You will though be pushing it at 17 without tuning since we already run so much timing and also like to ping :-?

and heres my latest dyno chart with AF,
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[GameOver]

From my old r/c airplane days........isnt richer better ??? doesnt richer protect the engine alot better ?

thanks

[p.a.sti]

If you run too rich you can foul plugs,loose power, over heat cats ( if you still have them) wash down your cyl.walls and other such things. Way too rich you run into stalling, no start , and intake backfires. The key is to find out the sweetspot. Thats what I am trying to do. To lean and first nox emissions go up , then cyl. temps go up, Then !, oooh lets not speak of that.

[04STI_BLUE]

There are couple of things that you need to consider before you figure out what AFR works for you.

1. EGT - My preference is not to exceed 1800 F. Normally you would see 1400 - 1600 F cruising around.

2. Knock - You have to monitor knocks and adjust accordingly (Either take timing off or add fueling method).

With the pump gas 93 OCT here in PA, I ran around 11:0 to 1 in my 02 WRX. Car ran great with EGT of 1650 F WOT.

Again, collect data for EGT & Knock count and try to dial in the AFR.. If I were you I will start with 11.0 to 1 in Open Loop...

In closed loop, it's always near 14.7 (OBDII system).. No point for you to adjust anything..