Lexus LS400 AFM Capacity and Limits on 7m

[teamslow]

Lots of Questions. I did a search. Didn't find anything.

What is the highest amount of boost that can be reached on the Lexus LS400 AFM?

I am sure it also depends on the size of the turbo. So what is the largest size trim turbo that can be used and what is the maximum boost that can be used for maximum efficiency without hitting fuel cut on pump gas (93 octane)?

Are there any advances having the LS400 AFM over MAF Translator?

I know that if you back the adjuster screw out, the higher the fuel cut will be but the leaner the car will run because there is more unmetered air passing through the AFM. 550ccc injector are suppose to compensate for this.

What is the best setting for the adjusting screw? I read that the best setting is screwing it all the way in then backing out the screw 2 and a half turns for the best setting.

Is this true or will the ECU compensate under normal driving conditions no matter how far in or out the screw is? Because I read that the the ECU will compensate for the AFM at normal driving condition without 550cc injectors?

thanks

 

[aljordan]

Eric Varah did mid 600s on a lexus afm and afc. I think his dyno vid is on youtube.

 

[gofastgeorge]

The ECU will not compensate for large changes,
so don't rely on it to self tune a Lexus MAF install.

And if you go to a S-AFC to dial in your fuel curve,
then you don't need to jack with the screw.
And ditto on the 600 HP (720 injectors) range.

Run a MAF Pro, and loose the AFM altogether, and it's restriction.
But it's a lot more $$.......

 

[WhtMa71]

I believe the screw can allow more air in so isnt it suppossed to raise the fuel cut a bit?

 

[teamslow]

I believe the screw can allow more air in so isnt it suppossed to raise the fuel cut a bit?

There is 2 air passages. The top passage is where the honeycomb is. This is where air is measured. The bottom passage is where air bypass screw is located. Air is not measure there because there is not a honeycomb in that area. Someonone correct me if that is wrong.

 

[teamslow]

Eric Varah did mid 600s on a lexus afm and afc. I think his dyno vid is on youtube.

What size trim turbo was he using? and at what psi?

 

[Nick M]

Are there any advantages having the LS400 AFM over MAF Translator?

Cost.

I know that if you back the adjuster screw out, the higher the fuel cut will be but the leaner the car will run because there is more unmetered air passing through the AFM. 550ccc injector are suppose to compensate for this.

You should not need any tuning, unless you are using a bigger turbocharger. It can be done with tuning, but why? Get the better device.

 

[turbonator]

The ECU will not compensate for large changes,
so don't rely on it to self tune a Lexus MAF install.

And if you go to a S-AFC to dial in your fuel curve,
then you don't need to jack with the screw.
And ditto on the 600 HP (720 injectors) range.

Run a MAF Pro, and loose the AFM altogether, and it's restriction.
But it's a lot more $$.......

how much approx $ I just opened up my stock afm after incorrectly cleaning it .It is fine now.but maf pro sounds like the way to go

 

[turbonator]

There is 2 air passages. The top passage is where the honeycomb is. This is where air is measured. The bottom passage is where air bypass screw is located. Air is not measure there because there is not a honeycomb in that area. Someonone correct me if that is wrong.

I beleive your right.I just talked to a guy in San Antonio from ebay about the whole set screw idea.BS the guy who invented it is from Calgary and ya its snake oil he says

 

[bountykilla0118]

LOL snake oil … Actually the screw does affect the amount of air that enters un-metered… I will check 2morrow to see if what happens to my A/F ratio at idle when I adjust the screw.

The Lex AFM and 550's is the most cost effective and user friendly setup there is. You could basically put both of them on and your car would run pretty well with 1 or 2 minor changes. You could get a Lex AFM and a used SAFC for less than $350 shipped to your door.

 

[NashMan]

from what i sean in my life the lex afm can yeild you about 500 to 550 can 600 be done sure it can but it is all about the tune and teh smarts you ahve on building your set up

 

[gofastgeorge]

how much approx $ (MAF PRO)

They are around $500 if I remember correctly.......
There was one in the 4-sale section yesterday.

 

[Nick M]

And MAFT-Pro is better.

 

[TheNewRed]

Will someone please explain the adjusting screw a little more!!!

 

[jdub]

Bounty is correct...the screw affects the amount of unmetered air entering the system. More unmetered air means you can attain higher boost before you hit fuel cut. Keep in mind the AFM looks at air intake volume and fuel cut is based on that volume. It also will affect AFR to an extent, more unmetered air will push AFR more lean.

 

[shaeff]

For those who enjoy being spoon fed:

http://rob.carlile.home.mchsi.com/lexus/lexus1.htm

Read it. UNDERSTAND IT. Then ask questions.

 

[isnms]

^I forgot about that one, though I've read it many times.
That should have the second post in this thread :bigthumb:
edit: also this one - http://suprasonic.org/lexusriemer/lexusnotes.html

 

[aljordan]

What size trim turbo was he using? and at what psi?

It was a 66mm turbo I beleive. I don't know the boost. I'm sure it was upper 20s though.