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-   -   Cruise too lean? (https://www.miataturbo.net/megasquirt-18/cruise-too-lean-21847/)

wes65 06-02-2008 04:09 PM

Cruise too lean?
 
Okay, i have asked this question by threadjacking and not gotten a straight answer. Can a very lean (18:1) cruise cause you problems? i.e. burnt exhaust valves or pistions? I do not have an egt gauge

Braineack 06-02-2008 04:21 PM

Once i cruise at 16:1 the car gets pretty upset...I dont see how you can manage 18:1

wes65 06-02-2008 04:23 PM

no bucking whatsoever. my uego often goes - - - while cruising.

great mpg though, over 30

Saml01 06-02-2008 04:24 PM

^ downhill?

wes65 06-02-2008 04:24 PM

all the time.

wes65 06-02-2008 04:25 PM

goes back and forth from 17 to 18 to --- and back

hustler 06-02-2008 04:28 PM

there's a honda tuner advancing time way up and running like 19:1. Its not a gamble I'm going to take on my nice motor. I'm running at 15.3:1 now and noticed about 2mpg gain...getting me up to a whopping 25mpg now on highway.

wes65 06-02-2008 04:48 PM

so, what people are saying is i should get an egt gauge.

Splitime 06-02-2008 04:50 PM

Once I hit ~16 and crusing on highway I get lean bucking...

I wonder how retarded you have the ignition to get away with that. I'd concentrate on running more timing and ~15:1 AFRs and use an egt to check things.

IcantDo55 06-02-2008 05:29 PM

Mine ran off the gauge for while, no issues. Quizzed many people about it and the popular answer is when it get a lean "pop" in cruise fatten it up a bit. I'm 16 or so now.

Mach929 06-02-2008 05:33 PM

i can run mine pretty lean at cruise too, i'm in the 15-16:1 range right now but it's been 17-18:1 before and seemed ok but i wasn't sure if it would reduce my motors longevity or not. my gut feeling is it won't hurt anything at cruise but i really don't know.

The_Pipefather 06-02-2008 05:34 PM

lean "pop"? My car pretty much behaves like a huge hand was pushing/pulling it back and forth once I get past 16:1.

Aussie Driver 06-02-2008 08:16 PM

I'm running an AFR of 17.5:1 at cruise without any problems. I have run it as high as 19:1 at cruise without having any hassles either.

Mach929 06-02-2008 08:20 PM

interesting there's some that say they can't go past 16:1 and some say 17-18 no problem. i wonder how much has to do with timing

cardriverx 06-02-2008 08:55 PM

im running 16:1 at cruise no problem.

y8s 06-02-2008 09:25 PM

what kind of fuel pressures are you all running?

I dont think you're going to be EGT limited at cruise under 4500. just not enough load on the motor...

cardriverx 06-02-2008 10:05 PM

fuel pressure? stock FPR, nothing else.

Mach929 06-02-2008 10:27 PM

stock fuel pressure here too

y8s 06-02-2008 10:28 PM

i ask because I wonder if the guys running >16:1 are getting better atomization from higher rail pressures.

I do ok with 15.5 or so.

Mach929 06-02-2008 10:43 PM

heres a quick read. according to their rsx, 15.7:1 was the best
http://www.hondatuningmagazine.com/t...ing/index.html

wouldn't the best way to do this be to log duty cycle at 15:1, 16:1, and 17:1 for the same drive at the same speed?


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