how to lean mixture wo/piggy back.

scottiedawg66

New Member
Apr 1, 2005
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Bay Area Ca
Hey, i'm running real rich, black smoke when letting off throttle, and smelly! I Have 550s and lexus. I wanna lean her out with out using a piggyback. I need to pass smawg! Will my lexus screw help me achieve this or is messing with the screw a bad call?

~scott
 

silver88turbo

Former Owner
Mar 30, 2005
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Illinois
That is exactly what the screw will do. Be careful though if you are not monitoring the A/Fs. You could also drop the fuel pressure.
 

87_7MGTE

SOLD :(
Mar 30, 2005
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Bellingham, WA
what do you guys set your FP at with lex/550s? do you do around stock (~38 psi w/o vac), or is it higher or lower? what do you set the stock lex screw at (mine is all the way out now) thanks
 

supralover2000

12.8 and dropping..
Apr 4, 2005
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Long Island, NY
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38-42 psi without vac line, then it drops to about 35 psi with the line on. I run venom 580's and with lexus (Stock screw) I actually have to pull the screw out as far as it can go without falling out. I then had to pull fuel out with the HKS S-AFR. But I guess how much is pulled or added will also depend on the Turbo and the Boost that you run. I was using an upgraded Ct-26 (60-trim / no clip) and 15-20 psi boost.
 
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flubyux2

Madd Tyte JDM yo ®
Apr 2, 2005
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if you put the longer screw in, it causes the AFM to count more air. this makes the ecu add more fuel. the longer screw is counterproductive in this case. dont do it. back the screw out more. you need to get more air in w/o the ecu knowing it.

if you have an AFPR, try to back down the fuel pressure, that could help too.

you may have to put a breather filter on one of the nipples on the according thing. that way it can pull in unmetered air
 

supralover2000

12.8 and dropping..
Apr 4, 2005
132
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Long Island, NY
www.mk3.us
Also if you end up turning down the fuel pressure, try to watch the fuel pressure (assuming you have a gauge) as the perform the test. This will give you an Idea of where the pressure sits while its being driven on the rollers. Make sure you didn't go too low in pressure!
 

87_7MGTE

SOLD :(
Mar 30, 2005
278
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Bellingham, WA
ok i will try that tonight, im putting the afpr on. and yeah the stock screw is all the way out on the lex, but i have no fuel comp right now because i have to save money for one now (doh)! hopefully in about a month or 2's time i will have one. thanks for the replies

also flubyux2: is a breather recomended until i get a fuel comp? or should i be ok without it (just have surging/crap idle)?
 
B

Boostaddctn

Guest
supralover2000 said:
38-42 psi without vac line, then it drops to about 35 psi with the line on. I run venom 580's and with lexus (Stock screw) I actually have to pull the screw out as far as it can go without falling out. I then had to pull fuel out with the HKS S-AFR. But I guess how much is pulled or added will also depend on the Turbo and the Boost that you run. I was using an upgraded Ct-26 (60-trim / no clip) and 15-20 psi boost.

Damn thats high, I usually do 32psi without vac line and then leave the stock screw in its place and no problems then use a SAFC to tune or a Emanage... aight peace