Lexus afm

[cre]

Originally Posted by realdeal

Ya I've junked that narrow band meter and gt an aem one. As or the afc. Don't I need a "base" setting when I first install new injectors and afc?

Which make and model fuel controller did you get? Yes, you have to set it up for your type of system but there are no base "tunes" for you to use, the fuel trims you'll start out with all zeroed out.

The 7M-GTE uses a KVAFM or Karman Vortex Air Flow Meter. It's a frequency signal and not a graduated voltage signal such as the Vane AFM used in the GE. Most AFCs have either certain wire you use for a certain type of meter or you set it up in the digital menu or both. The instructions should cover it for you though.

[cre]

I posted this in the wrong thread earlier:



Honestly you don't even really need the Lex AFM if you've got 550 injectors and an AFC. It's not bad, allows things to move more freely pre-turbo. But not needed. Keeping things on the cheap there are two scenarios (sorry for not covering this *again* sooner... I've covered this many times):


1) 550cc/min injectors + Lex AFM + tuning via stock or extended trim screw (if needed). I dislike this as the trim screw blindly adjust the entire range and you may only need to tweak fueling for idle and end up having to sacrifice elsewhere (for better or perhaps for worse).


2) 550cc/min injectors + AFC + tuning (-15% "main scale" and then tuning to improve over stock tune).


3) Would be a combination of all of the above. On the AFM you'd keep the stock screw in place or open it as much as you can for easier breathing and then you'd just have to adjust the fueling with the AFC (but no "main scale" adjustment).

As cheap as you can acquire a first generation Apex'i SAFC I see no reason for tuning with the AFM's bypass calibration screw.... It's not precise, too broad and well, old school crap.

[realdeal]

Yes I have my hands on an apexi safc 1. Don't have a pinout drawing for my ecu tho. I found one diagram online but it turned out to be wrong. I looked on apexi website and all they have are wiring diagrams of their afc. Not specific ecu diagrams. Also googled pinout diagrams and came up empty. Any good place to look???

[realdeal]

Ok so I found the correct pinout diagram, but the rpm signal isn't listed here. Anyone know which pin that is? I have the yellow connectors that are 10p, 18p, 24p.

[cre]

Well, my wiring diagrams for the MAFT-PRO show the pre89 GTE pinout and the online TSRM has the 89+ pinout. Which year do you have? (Put your car's specs in your signature so people don't have to keep asking.)

[cre]

Originally Posted by realdeal

Ok so I found the correct pinout diagram, but the rpm signal isn't listed here. Anyone know which pin that is? I have the yellow connectors that are 10p, 18p, 24p.

http://www.fadingworld.com/CRE/Autom...gDiagrams.html

My diagrams hosted here are for the MAFT Pro, but if you look at the diagram under Step 1, Turbo, 1a you'll find it shows the locations you need for just about any air fuel controller: VTA, Ks and IGt.

I recommend you power the SAFC with a relay as documented in some of the other diagrams I've put up there.

[Piggy808]

This is a very informative thread

Question: Lets say I got the Lexus AFM mod with 550cc injectors. I can eventually upgrade from 550cc to something bigger, lets say 750+ (this is after getting a larger turbo like maybe one with T04 housing), I can keep the Lexus AFM and use the SAFC to "tune" my fuel?

I am asking this question because it seemed to me that if you go for larger turbo, you have to go stand alone, with MAP sensor, instead of using the MAF since the inlet would have to be larger and the MAF housing becomes a bottle neck???

I apologize in advance if this question is apparently dumb and all I had to do to figure this stuff out was to search for it in the forums.

[cre]

Yes, this has all been covered before.

No model of the MKIII had a MAF. 7M-GE had a VAF and 7M-GTE had a KVAF meter.

While anything other than a MAP (or speed/density) setup will always impose some degree of restriction the KVAFM isn't much worse than a medium size GM MAF. Between the Supra and Lex KVAFM housing yes, the Lex would be preferable.

Yes, you could use an SAFC or other fuel control piggyback but there are some serious concerns which accompany such a setup such as the significant offset in ignition timing maps. As you'll probably be wanting some different cams too a more advanced ignition timing control would be a good idea anyway.

Standalone is your best solution. Second is a solution such as the MAFT Pro or a combination of piggyback devices which offer fuel, spark and boost control. Something with closed loop and open loop A/F tracking/correction is a good idea. Something which supports speed/density would be nice but the piggyback solutions are quite temperamental whereas a massive GM MAF has very little restriction, is easy to find and requires a little less initial tuning to get it to play nice with the stock ECU. Read up on any system you consider, they've all got their little caveats here and there... For example the MAFT-Pro cannot be used as a boost controller is you are using any type of air flow metering other than speed density; The developer has spoken periodically about hybridizing the system so MAF users could also run a MAP sensor for boost control... but I haven't checked in to see if that ever made it beyond the suggestion box.