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Forum nameTurbo/Nitrous Tech
Topic subjectRunning Lean after my headgasket is done
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i8&topic_id=56478
56478, Running Lean after my headgasket is done
Posted by MmmDeion, Sep-17-03 05:37 AM
Ok so after a grulin battle with my engine I replaced my own headgasket and timing belt, WOO HOO!!
But now when I boost and have it at WOT my turbo timer reads that my air/fuel is only 10psi (or whatever the hell the measurment is)... I remeber before I did all this it would stay around 12.5 at WOT and now it has no problem just droppin right below 10 at WOT...
Any suggestions or am I gonna have to guy and buy a SAFC now, cause I dont have one...
:thumbsup
56490, RE: Running Lean after my headgasket is done
Posted by turbo8u, Sep-17-03 07:05 AM
ok im thoroughly confused as to what you mean....

try to explain what you mean better


_________
96 talon esi-t
san clemente, ca

Uberingram> I bow down to the Geo
56500, RE: Running Lean after my headgasket is done
Posted by lickscissors, Sep-17-03 08:17 AM
are you sure you had your timming correct?... does it idle properly?

screw flanders
56517, RE: Running Lean after my headgasket is done
Posted by MmmDeion, Sep-17-03 11:35 AM
ok here we go...
i boosted my car 2 months ago and installed an Apexi TT at the time... The TT read my air/fuel ratio and at WOT it read my air/fuel as 12.4... Now after i put my new t-belt and headgasket on my air/fuel ratio on my TT reads 10 at WOT...
I was wonderin if i messed somethin up along the way, or if I need like an SAFC to adjust my air/fuel curves...
understand now?
:thumbsup
56519, RE: Running Lean after my headgasket is done
Posted by siueclipse, Sep-17-03 11:49 AM
if it reads like a wideband then the lower number would be better..

i run 10.7 at wot on the wideband.

James
56526, RE: Running Lean after my headgasket is done
Posted by XtremeRS, Sep-17-03 12:23 PM
>if it reads like a wideband then the lower number would be
>better..
>
>i run 10.7 at wot on the wideband.
>
>James

Holy fuk that rich! Did you get best HP and TQ with that tuning?? Just curious...Most shoot for 11.5:1
56529, RE: Running Lean after my headgasket is done
Posted by siueclipse, Sep-17-03 12:29 PM
i hi 329 on the dyno with that. oh but im sorry.. i screwed that up.. im at 10.7 at idle and 11.2 at wot.. my bad

James
56595, RE: Running Lean after my headgasket is done
Posted by MmmDeion, Sep-18-03 05:29 AM
>im at 10.7 at idle and 11.2 at wot.. my bad

Jesus... At idle im at 14.6
I think I have some really messed up fuel curves, and sure as hell dont have the money for a SAFC
56597, RE: Running Lean after my headgasket is done
Posted by ner947, Sep-18-03 06:33 AM
if i were you, i wouldn't trust your piston ring landings to the apexi turbo timer for accurate readings of your a/f ratio. remember, it just runs off of the stock 4 wire lambda sensor. stock type oxygen sensors aren't THAT accurate, but they'll give you a very decent ballpark of what your mixture really is.

here's a hint: i dyno'ed my car in june. (from memory) my a/f curve looked kind of like this (man, i wish i had the dyno printout):

i remember running lean down low. dangeriousally lean. also, there were some weird ups and downs in the midband which affected my torque curve. as i got closer to redline the mixture got closer to where i wanted it to be but it was still lean. (the big thick red line would have been ideal) the whole time, my air/fuel gauge was reading in the green, and corbin's air/fuel gauge said .94. cheers, for the stock oxygen sensor.

personaly, i'm gathering parts for the DIY-WB setup. much more accurate IMO.

as for now, i "tune" for .96-.98 for my oxygen sensor voltage. that way it can be off by 4 to 6 hundredths of a volt from what it should really be and in theory i'd still be running "safely".

so, it boils down to this:
unless you've used a wideband oxygen sensor of some sort to tune your car, tune it to what you would think is almost too rich. that's just my opinion though, i don't trust my OEM oxygen sensor very much.

EDIT: BTW, i made 235 WHP and 245 WT at about 12-14 psi of boost.