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Discussion Starter · #21 · (Edited)
NegativeGeForce said:
umm not exacly

taking 35% of fuel out with an afc sets back the afm 35%...so your timing from the ecu could be anywhere.

if your just letting unmetered air in through a lex afm, and setting fuel back 10% then your setting the afm only 10% backwards so the timing is more close to stock....
I hear what youre saying and thats what ive always thought, but ive managed to confuse myself.

But think about it. lets say the signal for the afm has 10 points (since hz doesnt tell the whole story) before fuel cut. Our operating conditions (boost/incoming air remain the same)... So when my afm reads xx airflow the ecu sees 10 and i hit fco. lets say its sending 10 to the ecu, so i pull 30% fuel, now the ecu is seeing 7. Now apply this to a lex afm. Same thing, the lex afm will "pull" 25% of the signal away, so now your ecu is seeing 7.5... take away another 5% from the safr and youre in the same boat.

Am i wrong?

suprafly1986 said:
my advice would be not to poke holes in the intake pipe with little filters, since the system can't effectively meter air that enters the system AFTER the AFM. If you have some sort of tuning, go ahead and use Lex AFM. All you need is the housing, the brains stay the same.
I dont mind picking one up, but i dont want to get one for no reason.

Ang
 

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NegativeGeForce said:
umm not exacly

taking 35% of fuel out with an afc sets back the afm 35%...so your timing from the ecu could be anywhere.

if your just letting unmetered air in through a lex afm, and setting fuel back 10% then your setting the afm only 10% backwards so the timing is more close to stock....
What your saying is exactly the same thing. The afm is scaled down the whole map ~ 25%

25+10 = 35%

edit: suprang is spot on..

The main advantage of the lexus afm mod is there really isn't a need to have an afc to run the lex afm 550 injectors to increase fuel cut. The afm is actually bigger so will flow more as well another bonus of the afm over stock
 

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desufnoC
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tissimo said:
What your saying is exactly the same thing. The afm is scaled down the whole map ~ 25%

25+10 = 35%
Is this a fact? Isnt there a difference (as far as timing goes) between taking 35% with a fuel computer and using a lex and then taking an additional 10% with the fuel comp?
 

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Not so boring anymore
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its about the same +- a few % but yea you are reducing the engines apperant load ~35%
 

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Discussion Starter · #25 ·
thanks for verifying what i thought. So should i pull my base timing back a little bit or something?
 

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Moderator, l337 M0d3r4t0r
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naw... i ran -27-28% and jacked my base timing to 15... thats why I always had very nice torque curves and a little low HP numbers....

Gain some downlow but give up some up top.

I can live with that.. I'm all about everything under the curve.. ;) makes the car fun to drive ;D
 

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i always thought there was a difference...because a lex afm doesnt directly scale the afm frequency....

edit: ok..yah im retarded :bigthumb: I wasnt thinking at all when i said that...afm and afc both do alter the afm frequency as a combined total.
 

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desufnoC
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NegativeGeForce said:
i always thought there was a difference...because a lex afm doesnt directly scale the afm...the afc does
Im waiting for some other comments as well
 

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1JZ BLING!
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hate to tell you this, but if you bypass air on the accordian with the stock AFM you are doing the same thing a lexus would..

it's the same principle, so you are going against your own belief...

the original idea behind lexus is, 25% less air reading, 25% more fuel (550s), so it evens out

if you were running 680s you would either want a lexus and some correction, or a stock afm and MORE correction

either way you end up with lots of timing so you just have to be careful... considering 550s is fine for 400+ i'd be surprised if you NEEDED more fuel then that...
 

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Discussion Starter · #31 ·
^ oh i know that. I was just saying that whne people kept saying you need a lex afm.

I didnt want to push the 550s to their limit, so i got the next step, at least this way theres less strain on the pump too.

I think i should be fine seeing as how in boost im not pulling out 37%, but much less (well see when i get the car tuned). And people have been running the lex 550 combo for years with no probs. I may though have a little extra timing off boost. Just gotta make sure to run good gas and tune it well.

Anything im missing?

Ang
 

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Moderator, l337 M0d3r4t0r
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yeah a working car.. ^^
;) welcome to my ever lasting club.
 

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Discussion Starter · #34 ·
bump

so how much extra timing am i running pulling out so much signal? How can i detect this? Will i run lean, will it show in my afr's or egt's?

I was thinking of buying a maft so the car could idle and run a bit leaner, but i cant see how it would do anything different than my safr pulling signal?

Ang
 

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boost freak
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SuprAng said:
bump

so how much extra timing am i running pulling out so much signal? How can i detect this?
heh. that's the million dollar question. no one has quantified the amount of timing advance based on % pulled from AFM sig.

SuprAng said:
Will i run lean, will it show in my afr's or egt's?
nope. advanced timing really won't show up anywhere....other than knock.

SuprAng said:
I was thinking of buying a maft so the car could idle and run a bit leaner, but i cant see how it would do anything different than my safr pulling signal?
yeeeep, it's no diff than the SAFR, just another AFM scaling device.
 

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Discussion Starter · #36 ·
thanks dude, youve been a lot of help.

I guess the best i can aim for is to try and run low fuel pressure and try to pull a lesser amount of fuel in the top end/high boost area to keep the timing relatively low.

Ang
 

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I don't want an MK4!
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Why are you so deadset against getting the larger AFM?

I feel it can only help in this situation.

How much power are looking to run anyway (sorry, didn't reread the whole thread if you mentioned it).

From all I've read and researched, making the corrections that you are is not making the TCCS happy at all.

I am sure you have read all the technical articals by Reg Reimer. I don't know if he is right, but he does seem to extensive knowledge regarding the 7M-GTE and how the TCCS works.

Shoot him a mail and see what he thinks of the setup.

Not trying to flame or anything, just not understanding why you want to go down this path.

At the very least, get a WB asap that includes datalogging.

Dan
 

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Discussion Starter · #38 ·
i have a wideband setup.

I dont really care about the power i just want to run the most i can on pump gas (with good afrs) to be honest. It should be around 500

Ide go with a larger afm if the only advantage to it were not the bigger housing. It will not help my situation. Ive tried talking to reg on the increasing rev limit thread and he never got back to me.

Ill buy a lex afm or a maft right now if it solved anything, but all it will do is scale my afm signal.

thanks for the comments.

Ang
 

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I don't want an MK4!
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Bottom line is you need to introduce additional air into the system. The TCCS thinks you're flowing 440 levels of fuel when you're flowing roughly 1/3 more. The more extra air you can flow the less correction you need to make.
Though I could be wrong, I feel the less correction in closed loop is better.

Good luck!

Dan
 
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