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Discussion Starter · #1 · (Edited)
Im a real non believer in the lexus afm, and since i always ran an fcd, i decided to stick to what works for me. I installed my rebuilt 680s (which i got rediculously cheap from tlfsupra89 from here) and got the intake back together. At first the car started and as expected was being flooded with fuel. It wouldnt idle, wouldnt rev... basically it ran like shit.

So i started fidgiting with my safr, took away a wopping 45% at idle, and then inputted -37% across the board until spool up which i then ghetto tuned randomly for now.

*Note dont overlap the idle and the safr maps, or else the car wont run properly. I actually did this and flooded my engine wiht fuel and had to pull the plugs and let it evaporate so it could start.

Anyways i drove the car around the block, my o2 sensor is reading a pretty consistent 14.7 on the turbo timer (it fluctuates a little more than ide like, but i attribute this to the ecu not having learned the curves yet).

Another thing i was considering doing is opening up some of the ports on my accordian hose and putting little filters, i wonder if they would flow the same volume as a lex afm?

Either way, im surprised i was able to run such a big injector on a stock afm.

Ang
 

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Discussion Starter · #4 ·
myMUSICveins said:
Reasoning?

Whatever it works, i just never liked the idea of it since i was always running 440s and correcting it to run safely would only yeild me the same fco. It was too much of a bandaid. It does what its inteded too, i just never got one.

Ang
 

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Discussion Starter · #6 ·
drjonez said:
i've run 720s on the stock AFM w/the eman.....

howde you set it up? Run well? I was thinking of switching to an eman so i can have more flexibilty. Did you touch the timing/fuel pressure? I cant drive my car right now so im just gathering info.

Ang
 

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Discussion Starter · #13 · (Edited)
drjonez said:
i guess? i stay away from total corrections over 30%.....too much is happening w/timing to make it remotely safe....

so i should stay away from pulling more than -30% from the maps wiht the safr? Will this advance my timing to the point where it is unhealthy?

Im only gonna run the car for one month this summer so im not looking to get a lex afm or maft unless i absolutely have to.

Rajunz said:
Not to bag on you dude, but this is sort of a contradiction!

I can fully understand that costs may be an issue but to say you're a "non-believer" in the Lexus is probably worded wrong. Just to make it fair to newbies reading this thread, the Lexus performs very well to cure fuel cut when used with the 550's.
yes.

Like i said though, i just didnt want to get 550s when i was on stock turbo. It seemed pointless to me for just 300hp. But its probably the safest and easiest way to get over stock fco especially with a bigger turbo.

Ang
 

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Discussion Starter · #16 · (Edited)
^^ well i need the fuel for the boost im running. So i dont pull that much signal when im in boost.

Anyone have any idea how much volume i can pull through two ports on the accordian hose?

Even with a lex afm im looking at ~ -20% correction. I guess it wouldnt be a bad idea.

Thanks for the comments/replys so far.

Ang

EDIT: i can monitor my vf with a voltmeter i guess, ill do that next time. Ive only driven the car on closed loop since this setup, i have a turbo timer that monitors the o2 signal and displays in real numbers, its reading 14.7 most of the time, but fluctuates a lot. Also where can i get a lex housing for 80 bucks?
 

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Discussion Starter · #18 ·
^^^ thats what the lex afm does, its just that you know exactly how much extra air youre pulling (25%)

i know i have extensive tuning to do regardless, i got a wideband ready to street tune it as soon as i get the car on the road.

And hold on, whats the difference between pulling 35% fuel with my safr and stock afm vs pulling 10% fuel with the safr and the lex afm... The ecu sees the same signal does it not? Meaning that timing will be just as messed up either way?

Ang
 

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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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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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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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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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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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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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Discussion Starter · #41 ·
90Legend said:
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
Actually the ECU does not think im flowing 440 levels of fuel (well it always does, but for all intents and purposes in this conversation it doesnt) it thinks im flowing 37% more since thats the signal being pulled. If i were to pull 25% it would be identical to a lex afm as far as what the ecu sees at least. The correction with the safr vs a stock lex afm is the same thing as far as signal is concerned.

Ang
 

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Discussion Starter · #43 ·
how low can i go? ive got it at 35 base, i hear anything less than 30 will make poor spray patterns on the injectors?

Ang
 
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