here is a link we somewhat used for info about GM fuel systems:
[URL=www.customefis.com/GMEFI.html ]www.customefis.com/GMEFI.html [/URL]
Some of you have dynoed your ecotec and come up with the 14.4 to 1 mixture as we did before we developed the ecotec turbo kit. The factory setting is suppossed to be at 14.7 to 1. A 14.4 to 1 is not that lean for this GM system. The only reason I can see that GM sets it that low is either for performance upgrades (ECU responds kindly to performance upgrades) or maybe to easier pass emission standards. The question has not yet been answered by GM. However, when we developed the turbo kit we started with keeping the fuel system running as close to stock ratio as possible. Even at our lowest fuel setting with no major upgrades other than 6 psi we were showing 14.7 exactly on the dyno. We carried the boost all the way up to 9 psi slighty changing the air/fuel ratio as we went. With few fuel modifications we able to retain the 14.7 air/fuel mixture. The only time it will run slightly rich is at full throttle. Talk about tuning, that is the best tuning job I believe we have ever done after more than 200 tuning jobs in the past 12 years. The ecotec is very simple to tune. Good job GM for a great design!
David Seaton
www.haasperformance.com
I forgot to include that this was all done on our proto -type car. Kits we sell for customer cars tend to run slightly richer. You may want to tune your cars on a dyno to get best results.
A/F ratio should not be 14.7 under boost. NOT EVEN CLOSE TO THAT. It should be around 12:0 under load. Use a WideBAND (lambda) 02 to verify that. If it was 14.7 it would BLOW UP, melt a piston. It should only be 14.7 not under load
My eco ran 14.4:1 all the way to redline, at WOT on the dyno, with only cams, and an intake. Well, stock was the exact same also.. That was with a wideband O2..
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2004 Sunfire, 5 speed, billet aluminum short shifter
AEM CAI, experimental cams
FRD 68 Anthracite 17",215/45/17Y Ventus K104
Progress Springs, KYB AGX
Hawk HP/slotted rotors
148.8hp@5300, 155lb-ft@3800(@ the wheels)
As i said: "We carried the boost all the way up to 9 psi ***slighty changing the air/fuel ratio as we went***. With few fuel modifications we able to retain the 14.4 - 14.7 air/fuel mixture. The only time it will run slightly rich is at full throttle." The 14.7 ratio is an idle retainment. Most aftermarket systems increase even the idle air/fuel mixture. (Most of those idle rich as well). We were able to retain the stock air/fuel mixture at idle, while building the air/fuel mixture at boost.
We cant give away how we did it because we dont want our competition to take our hard spent time and research to use them for their benefits.
A/F ration under boost should not be in the 14's at all when under load. Are you sure that you calibrated the WB 02 before running the tests. I have never heard of a boosted car running in the 14's because it is to lean under load.
What about a bone stock eco? Mine runs 14.4 at WOT on the dyno, with or without my cams installed..
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2004 Sunfire, 5 speed, billet aluminum short shifter
AEM CAI, experimental cams
FRD 68 Anthracite 17",215/45/17Y Ventus K104
Progress Springs, KYB AGX
Hawk HP/slotted rotors
148.8hp@5300, 155lb-ft@3800(@ the wheels)
because there is no boost. Boosted cars should be in the 12's MAYBE 13's
Ok, let me say this again and brake it down for you more.
At idle, we were able to retain the stock ratio. It is very difficult for most turbo kit companies to retain this ratio at idle with the fuel upgrades they use. We were able to upgrade our fuel system so it would run a richer ratio under boost and and full throttle. While at the same time, with the same fuel setup, we had a stock ratio at idle. I dont know if I can possibly brake it down anymroe than that.
ummm....congrats i guess, but its not that hard.
when my car was running super rich w/ 36lb injectors and the blazer fuel pump it would still idle at 14.7, as soon as the 02 warms up the computer will adjust by shortening the injector pulse. the a/f was between 10-11 at 10psi.
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<img src="http://www.j-body.org/registry/vegacavy9396/personal_pic.jpg">
NACHOTEC wrote:ummm....congrats i guess, but its not that hard.
when my car was running super rich w/ 36lb injectors and the blazer fuel pump it would still idle at 14.7, as soon as the 02 warms up the computer will adjust by shortening the injector pulse. the a/f was between 10-11 at 10psi.
But how well did it idle with those injectors? It should be idling very rough with no controller to lower the fuel rate at idle and even in normal driving conditions. 36 lb injectors are extremely large.
And yes, it is that hard to change a system that refuses to see change. If you are running a true Ecotec motor in a newer Cavalier it will be difficult to insure it is running correctly.
it would idle just fine, i had a CEL for running rich, actaully i still have that with the FPR.
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<img src="http://www.j-body.org/registry/vegacavy9396/personal_pic.jpg">
I appollagize for being a tad off topic but it contains a question for fuel deliverly on a turbo ecotec. Im about to intsall my turbo kit and i wnat to know what upgrades to make for running 9 psi. What fuel upgrades should i make and where can i find these upgrades? What are your opinions on the vortech fmu or obx fmu? What size injector should i go for and what type who makes them and so forth? any info would be much appreciated in my quest for boost.
*2012 mazdaspeed3*
IMHO, fmu's are a poor way of managing fuel, and wouldn't recommend either of them. Cars these days are all computer controlled and that computer expects the engine to behave in certain ways. Simply increasing fuel injector size and/or messing with with fuel pressure could allow it to run, but not well and the ECU will know something is wrong.
It is better to tweak the injector pulse to supply the correct amount of fuel with either the stock or larger injectors. The best way to do this is to modify the fuel maps on the stock ECU. Don't know where or even if you could get this done. The next best way is to get a piggy back fuel controller. A couple companies make them, and usually market them to them for Civics and what not. I know A'pexi has one that wouldn't be too hard to get to work on the Eco, so take a look on their site. You can probably get a used one on eBay for around $200.
Also, get yourself a wideband O2 sensor and controller. They are usually pretty expensive, but there are DIY kits available on the internet that make it a little more affordable. Or better yet, have someone else tune it for you.
<img src = "http://registry.gmenthusiast.com/images/limaxray/thumbnail_personal_pic.jpg" width = "149" height = "143.5">
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mmmm.... Disco Potato goodness
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why did you bother putting the website up if your company has closed its doors?????????????
