Trying to up the MPG of the SRT. So im thinking of changing the slope on my Lm-1 analog output to the ecu to offset the closed-loop switch point from 14.7:1 to somewhere between 15-17:1. I run 15:1 during closed loop on my Duster(Commander 950 MPI) and it works fine but i think closer to 16:1 is doable. Just trying to get more aplication specific idea.
Wondering how lean of A/F you guys are run at cruise.
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Last edited by duster360 : 05-22-2007 at 03:12 PM.
im at 15.5:1 in cruise and it works great. i could lean it out a bit more, but i just havent had time yet.
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how do you do so w/o a standalone? im assuming its not possible?
Once again you are mistaken
Quote: Originally Posted by duster360
So im thinking of changing the slope on my Lm-1 analog output to the ecu to offset the closed-loop switch point from 14.7:1 to somewhere between 15-17:1.
With my stock exhaust I was comfortable running anywhere from 15-15.5. EGT's get a little high for my taste after that. Power starts to noticeably decline once you get past 15.5, too. Not majorly, but you can feel it and see it on the boost gauge if you change back and forth between 15 and 16 afr. It changes about 3 inHg between the two.
With my stock exhaust I was comfortable running anywhere from 15-15.5. EGT's get a little high for my taste after that. Power starts to noticeably decline once you get past 15.5, too. Not majorly, but you can feel it and see it on the boost gauge if you change back and forth between 15 and 16 afr. It changes about 3 inHg between the two.
Chris
Interesting,,3"Hg? thats more than i'd expect. I guess I can tune on the fly to get the leanest A/F that deosn't adversely affect the vaccum. Or better yet I'll just do a back to back mpg test between ~15.5 and slightly leaner than ~15.5(16-16.5) and see what the results are at the pump.
As long as operating temp is in check, elevated low load cruise EGT shouldn't be of much concern.
You know, I never did see much over 30mpg, even running the 15.5 afr. Of course, I wasn't in vacuum the whole time, either... EGT's were usually around 1450 cruising at about 75 (probe 2-3" from head), hitting mid to high 1600's if I was going uphill a lot (2" vac to 2-5psi PTB). The uphill part is what made me uncomfortable, I was imagining a cherry-hot area behind my motor...
i bet with a port/polish and some valve work you could lean it out in cruise and keep the egts lower at the same time. Most of all improvements to cars are for emissions not economy. There is always some left on the table for performance and MPGs. Who knows how much NOX comes out with those raised egts. From cali nazi standpoint, theyd rather have you pump out a black cloud of HCs with no nox than burn a tank of gas to go 30 more miles with higher nox. I however don't work for them and want 30 mpg too. I cant wait to get my complete setup going.
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how do you do so w/o a standalone? im assuming its not possible?
Once again you are mistaken
Quote: Originally Posted by duster360
So im thinking of changing the slope on my Lm-1 analog output to the ecu to offset the closed-loop switch point from 14.7:1 to somewhere between 15-17:1.
no need to be a F'n prick. i asked a question. not doubted. and since this is in the EMS section, i pondered if it were possible to do on a stock pcm.
theyd rather have you pump out a black cloud of HCs with no nox than burn a tank of gas to go 30 more miles with higher nox.
Enviro-Nazi, tree-huggen, Castro-lovin, Liberals!!! I'm going to make it a point to stick my ever growing Carbon footprint in thier ass.
Seriously though, NOx is a major contributor to Acid rain. NOx is a non-issue here in ass-flat IL. Don't get me wrong, I'm all for sensible enviromental regulations for the bennefit of nation's personal health but the Enviro-Nazis can take their "C02 = pollution" , "Global warming" BS and go live in France.
I am having problems with my closed loop, it keeps going from 17+ for a few seconds, then drops to 12.5-13, then hits ~15.4 for about 5 secs then goes lean again, continuous loop. Any ideas?
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How Lean is your closed loop A/F??
EGT's were usually around 1450 cruising at about 75 (probe 2-3" from head), hitting mid to high 1600's if I was going uphill a lot (2" vac to 2-5psi PTB). The uphill part is what made me uncomfortable, I was imagining a cherry-hot area behind my motor... 
I'm going to make it a point to stick my ever growing Carbon footprint in thier ass.
when I said the stock motor could handle 400whp now look.
that you could run anything above a dry 35 shot on the motor, and then they went all the way to pushing 75.
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