help to understand wideband

[laser05]

hey guys, so i recently purchased a sr20det and it came with a hksgt2540 turbo and ( possibly ) upgraded injectors and possibly mapped ecu. so i just got her running a few days ago set the timing and worked in the clutch a bit. its boosting 11psi stock and under full boost my wideband reads anywhere from 11.2-12.2 depending on what gear and rpm i'm in. so i hear these are good numbers because i'm not leaning out. around idle or crusiing its 14-16, also heard that was good. my question is can i crank up the boost a bit since its running rich or should i leave it be and could the stock ecu be able to handle all of this or is therea good chance that its been mapped, any input from anyone would be awesome, thanks!
my upgrades r the following
fmic
fuelpump
rad
clutch/flywheel
light weight pulleys

[msommers]

If you're looking to increase boost, I would strongly recommend taking it to the dyno for an hour and getting the ECU programed properly. Not only will you get performance upgrades, but your engine will be safer. Some in-car gauges are decently accurate but from experience, I have never found them to be as accurate as the dyno.

[laser05]

ya, i would like to do that. unforturnately theres not a whole lot of dynos/shops who are able to reprogram ecus in saskatoon hah. i only know of one dyno in the city, and i'm not sure of what they can all do for " reprogramming " if anything, thanks for you input. i'll probably play it safe right now and wait till i have more money so that i can get a few more upgrades then send the ecu away or get a safc.

[sr20s14zenki]

I dont see injectors in there.

get 550cc yellow top STI injectors, with modification to the connector, they are bolt ons, and a z32 maf, as the stock maf only has resolution to around 230 hp

pm xcye on here, he can chip your ecu for you and i believe he has a tune that will work well for your setup.

12:1 is ok...but i would be more aiming for 11.5:1, maybe 11:1 if im not mistaken. Does your wideband have datalogging capabilities? if so, i would log a few runs, and go over it, seeing if you are leaning out in any spots, it can lean out for 100 or 200 rpm and you may not see it in real time, but yet in that spot it can reak havoc on your internals.

[Toma]

Depends on what brand of wideband, and what RPM it is when its 11.5 and when its 12.2.

You could up the boost a bit, and watch the AF as you go....

What compression are you running? 8.3:1??

[laser05]

the compression is 8:5:1. and i haven't paid very close attention to the wideband but i know it always stays under 12.2. its a AEM UEGO wideband if that helps at all. i know someone who was running 11psi on the t25 turbo and his wideband was reading high 12's..the verge of leaning out i guess? like i said my computer " may " be mapped...no way for me to tell i guess. i might try cranking the boost up to 13 maybe 14 to see what the a/f mixture is.

[JRSC00LUDE]

Originally posted by laser05
ya, i would like to do that. unforturnately theres not a whole lot of dynos/shops who are able to reprogram ecus in saskatoon hah. i only know of one dyno in the city, and i'm not sure of what they can all do for " reprogramming " if anything, thanks for you input. i'll probably play it safe right now and wait till i have more money so that i can get a few more upgrades then send the ecu away or get a safc.

There are a couple dyno's here but yeah, there isn't anyone in town that I trust to tune anything other than a mustang or talon. I had my tune done in calgary and now we just tweak the fuel here and there ourselves as needed.

I would suggest you remove the word "possibly" from your sentence by finding out exactly what is in your car and go from there. Once you know you have everything you need under your hood I would suggest heading into Calgary and lining up some proper tuning.

In the meantime, it would be a pretty good idea to line up an hour of dyno time at Perf. + so you can have an accurate read of your A/F. I too run an AEM UEGO and it's good for basic monitoring but not dyno accurate for tuning beyond conservative. If you do that and post the chart up here, people can likely give you a much better opinion.

[sugoi240]

14.7 is Stoich, perfect ratio of 1:1 for gas and air
If the number is lower, ex 12,13, there's more gas than
air in the mixture and higher numbers means more air
than gas.

When you add more gas into the cylinders, the reactivity
of the detonation is less= less power, more gas consumption and also keeps temps down.

When tehre's less gas, there's more power, less gas usage
and temp goes up.

In cruising, you want the higher numbers for fuel economy,
and since you're about 100km, the air over the radiator will
keep temp at bay.

When going for 60mph rushes, lower numbers helps keep
temp down so your engine doesn't "detonate" and ignite
the fuel by accident causing knocking. This is where higher
octane in cars are useful.

[sugoi240]

Myself, I run 15.3 in cruise and 12.5-13 in 1/4mile
and ignition timing up.

[Annoyingrob]

Originally posted by sr20s14zenki
12:1 is ok...but i would be more aiming for 11.5:1, maybe 11:1 if im not mistaken.
It's all about the tune really.

The richer you go, the less power you'll be making, but the cooler your charge will be, and thus "safer".

Personally, I run 12.5:1 on high boost. I have a set of headphones hooked up to a microphone in my block, and notice no pinging.

Alternatively, I've seen cars blow ring-lands at that A/F. It's highly dependant on how precicely it's tuned, and how CONSISTANT your fuel system is.

[alloroc]

If you need help on the what's and whys of how to tune.

No better place to learn from than here.

http://sdsefi.com/tech.html