Hey guys
Was wondering what you guys have your air/fuel set at when under boost on the 2.2L ecotec motors?
How much boost and what air/fuel are you at?
11.8 is a nice stable AFR on the eco
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
1-3 psi = 13.5
3-6 psi = 13.2
6-7 psi = 12.8
7-14 psi = 12.5
14-18 psi = 12.2
18-21 psi = 12.0
I also richen it up a bit at higher rpms in each range. This is just what I run and I can in no way garentee that it is safe, but from what I've seen the ecotec is very detonation resistant, and with 94 octane I have no detectable misfires.
anything above 12.2 creates knock, if you run 12.5 on 7 psi your going to blow it up or have full 8 degrees of knock retard
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
Rodimus Prime wrote:anything above 12.2 creates knock, if you run 12.5 on 7 psi your going to blow it up or have full 8 degrees of knock retard
That may be the case, as I said I can not detect the knock but I don't have a good means for knock detection yet. I run 94 octane and never see intake temps (at the TB) above 36*c. I don't throw codes but thats not saying much, I killed a ring land on two seperate occasions without throwing codes .... LOL and before you say it it had nothing to do with the tune, both times were on a totally different set up and I knew it was going to happen..... well once I didn't think it would but I wasn't surprised.
Ive worked with several ecos on HP tuners and 12.2 is the threshold in which when you go above your getting knock retard, and I dont have to tell you thats bad. Intake temps really have effect on it, unless your throwing in above 111 IAT, at that temp the computer will pull timing, if your IAT is above 111, you have other issues than fuel to deal with.
You dont get codes from knock retard, the only thing you might see if the situation is bad enough is a blinking cell which of course is a misfire
If your blowing ring lands, your either running too much boost or not properly, nobody blows ring lands on an NA car or low boost, the only folks that have busted ring lands on here were in excess of 12psi which is past the safe line
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
My ecu never sees over 95*F IAT's. The stock AIT is located inside my fender in the end of my intake. The actual charge temps never go above 102*F even under hard sustained boosting.
LOL I know you don't get codes from knock retard. I was illistrating that the uce doen't appear to use the knock sensor for it's misfire detection, but actually seems to use the crank sensor. This would also explain why I used to get misfore codes at idle when i had a lump idle. The only codes I get now is a p0135 and once in a while a p0172. I should get off may ass and see what the scan tool says the timing is under boost though. I'm still trying to find a knock module that works with the stock Ecotec knock sensor.
The first time I blew a ring land I was running 12psi non intercooled with #30 injectors and a fmu. It was pinging very loud at 10psi and above, but i didn't care I wanted to race that weekend. It actually took a few weeks to kill the piston to my surprise.
The second time I was on the way back from the dyno running 8psi intercooled and tuned with a megasquirt. I knew the injectors weren't keeping up at 6500rpm but I was running a 12.2 at 6500 rpm. I wound it out to 6800 and midfired badly. Only took once and another piston needed replacing. LOL I should have known better but it was too much fun.
Rigt now I am running the above set up with a few tweaks including #42 injectors although they are maxed out at 12psi. So far I havn't had any problems with detonation, and normally my egt's are in the 1350-1450*F range under boost, although with hard sustained boosting I can hit 1600*F. I'm not totally happy with those tempts but my egt probe is mounted preturbo into the the header and I run a decent amount of advance on my exhaust cam which accounts for some of it. I idle at 1000*f.
I've looked over that dyno report and there was a noticable dip in power when the a/f's went below 12.5, so where as I agree that your findings might reflect that an 11.8 is ideal for you and cars in your area, I'm not sold that I can't safly run a 12.5 with my set up. Each set up is different and each set up will have different tolerances. I put alot of effort into keeping my system as efficient as possible, which includes a 3" intake routed to the fender. Under average driving I have seen a 68* difference in the temps in the engine bay versus the fender.
All the power in the world means nothing if it doesnt last
Id have to disagree on the power though I was running stock injectors and getting 168hp , with nothing more than a change to 310cc i went to 185hp, even my 310s were not strong enough to keep me under 12.4AFR at redline and I had knock all over
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
ok mr i have life easy port fueler man
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
11.5 Wide Open Throttle @ 5psi
Quote:
ok mr i have life easy port fueler man
hehe. it was tuned for stock injectors in the head.. not 370s with the gm flash. so it needs a lil work.. not much though
http://www.myspace.com/15102113
with the gm reflash i see 11.7-11.9 at low boost levels and 10.6-10.9 at WOT
