Lexus AFM and 550's

[hvfracingwilly]

I tried to search but with every other post mentioning the Lexus AFM its hard to weed through everything.

When converting to the Lexus AFM do you need the Lexus sensor also? Or do you use the stock Toyota sensor in the Lexus housing.

 

[zoppii]

You can use the stock sensor that was in the Supra housing. Just remove the screws and it will fit right in. DO NOT try and clean the post that goes in the hole.

 

[hvfracingwilly]

Sounds good to me, so the housing is simply larger for better flow and the injectors are for compensating for that increase of flow?

What if a guy was to run the Lexus AFM with stock injectors but run a SAFC? Is it possible to tune to a safe O2 with this setup?

A little background, I have a very well rebuilt motor. h beam rods, .020 over pistons, metal HG, ARP Studs, and the list goes on. The outside of the motor is pretty much stock. Tt has a stock CT 26 on it running at 9 pounds of boost. Cone filter, and a 3" turbo back exhaust with a DDP.

When I hooked up my wide-band I am running pig snot rich! Is it possible that I could run the AFM to get more air in and fine tune my fueling with an SAFC? Or am I barking up the wrong tree here.

 

[reckless916]

I believe I asked that question once...and ARZ from Arizona Performance ran the stock injectors with the Lexus AFM and he tuned it, in his Z. He did tell me to run a wideband which you already have so...I don't see why not.

 

[isnms]

Question is; Why would you want to chance your "very well rebuilt motor" to only half of a balanced upgrade?

Can it be done? Has it been done?... maybe, but why chance it.

 

[zoppii]

A lot of controversy over that same question (440's or 550's). Generally you'll have to take fuel out if you switch to 550's and 440's you'll have to add but I've done this to more than one 7M and the amount of adjustment will vary based on the engine. The safe route is the 550's (what isnms said) with an AFPR for your coarse adjustments and SAFC to dial it in. Plus this way you will be comfortable for future upgrades like Turbo or Cams.

I wouldn't do any of it before you get a wideband or at least save up for some dyno time.

 

[mkIIIman089]

The controversy typically comes from people who have never actually tried it. When I bolted on just the AFM (no other changes) to see what happens, the ECU essentially compensated for it and A:F ratios hardly changed at all. It also cancelled out the benefit of the AFM as well.

It it 'splodes by just bolting on the AFM, something else was wrong.

 

[zoppii]

I also wouldn't do it without the Reimer screw or similar devise to limit the amount of un-metered air and to keep VF in check for a similar reason to what mkIIIman pointed out . Here again some people claim no difference.

 

[hvyman]

the screw is in the afm body on both. teh stock one you ahve to srill out the plug and the lex you can already see it.

 

[isnms]

^lex screws are sealed off, stock, too. you have to drill out the plug on if not already done.

 

[hvyman]

ah thanks for clarifying.

 

[ft413]

i wouldnt run the lex afm without the 550s. i did for a couple days and it would start bog around 4k. just do the mod the whole way threw 550s and fpr included. youll be thanking yourslef when your done.

 

[GOT BOOST]

I tried to search but with every other post mentioning the Lexus AFM its hard to weed through everything.

When converting to the Lexus AFM do you need the Lexus sensor also? Or do you use the stock Toyota sensor in the Lexus housing.

The Lexus sensor and the Toyota sensor are the same part number.

My 91Turbo was running rich before I installed the new AFM, and it ran much richer after.

Keep in mind I am running the Walbro fuel pump, an aftermarket fuel pressure regulator and also the stock injectors.

After drilling out the screw cover, I adjusted backed the screw out and made it leaner. The car picked up a few ponies and sounded more agressive. Granted, I need to install my wideband 02 sensor to make sure I am not running too lean. I do not jump on the loud pedal often, so I am not too concerned.

 

[mkIIIman089]

The Lexus sensor and the Toyota sensor are the same part number.

My 91Turbo was running rich before I installed the new AFM, and it ran much richer after.

Keep in mind I am running the Walbro fuel pump, an aftermarket fuel pressure regulator and also the stock injectors.

After drilling out the screw cover, I adjusted backed the screw out and made it leaner. The car picked up a few ponies and sounded more agressive. Granted, I need to install my wideband 02 sensor to make sure I am not running too lean. I do not jump on the loud pedal often, so I am not too concerned.

:bsflag: (All of it)

 

[GOT BOOST]

:bsflag: (All of it)

Care to clarify Colin?

 

[supraboymk3]

yeah in my case i installed the lexus AFM and the car started to idle funny... so in some cases it has to be tuned... but i if your tuned then go for it

 

[MA70_Powa]

I had the same thing happen - Lex afm istalled with my 550s but it ran mega-lean at low rpm and idle, while other people see it work just fine when they do they double swap. Have an SAFC now and that fixed the problem (although its now running mega-rich but meh, I'll fix it when I get my wideband).

As people have said, every set-up is different.

 

[mkIIIman089]

Care to clarify Colin?

Sure.

The Lexus sensor and the Toyota sensor are the same part number.

In many cases, the Lex electronics cause problems, PNs on Toyota electronics don't always tell the whole story.

My 91Turbo was running rich before I installed the new AFM, and it ran much richer after.

'Should have been no change in closed loop, and only a marginal change (if any) in open loop.

Keep in mind I am running the Walbro fuel pump, an aftermarket fuel pressure regulator and also the stock injectors.

This will not cause you to run rich unless you REALLY messed up something along the way. You'd have to be like 30+% out of spec on fuel pressure...

After drilling out the screw cover, I adjusted backed the screw out and made it leaner. The car picked up a few ponies and sounded more agressive. Granted, I need to install my wideband 02 sensor to make sure I am not running too lean. I do not jump on the loud pedal often, so I am not too concerned.

The change (if any) you got from doing this and changing nothing else would have been minimal and temporary.

Then again, you don't even have a wideband. So these attributes you're describing are... complete speculation?

Oh, and whoever rated my post as "not helpful" is obviously as ignorant as got boost here to not see what I mentioned above...

 

[GOT BOOST]

Sure.


In many cases, the Lex electronics cause problems, PNs on Toyota electronics don't always tell the whole story.

'Should have been no change in closed loop, and only a marginal change (if any) in open loop.
This will not cause you to run rich unless you REALLY messed up something along the way. You'd have to be like 30+% out of spec on fuel pressure...

The change (if any) you got from doing this and changing nothing else would have been minimal and temporary.

Then again, you don't even have a wideband. So these attributes you're describing are... complete speculation?

Oh, and whoever rated my post as "not helpful" is obviously as ignorant as got boost here to not see what I mentioned above...

Thank you for putting some substance behind your post. Yet with out asking a few simple questions you make inaccurate assumptions.

To clarify.

When I cross reference the part numbers Toyota and the Lexus number they are identical. From part to part, year to year. Even comparing several electronics side by side, they appear to be identical. I would speculate this is pretty solid evidence that the part numbers are the same.

My car has always run very rich when I am in boost. I did not say all the time, did I? I will have to check the A/F ratios that were provided when I had it dyno’d about 3 years ago. The only change in the last 2 years was a ported and polished the head with some valve work. The car ran fine at idle and was fine in boost.

After I installed the FPR and the Walbro fuel pump my car my car still ran fine with out issues, except for the rich issue. After installing the Lexus AFM, the car was stumbling more and dumping fuel into the cylinders. During higher RPM and boost, the car would stumble (due to spark blow out) and there would be fuel dumped into the exhaust. There was a substantial amount of backfiring. Other drivers, and supra drivers behind me were able to verify that I was having more fuel into due to clouds of burning rich and the stench of unburned fuel stinging their eyes as they drive behind me.

After I backed out the Lexus AFM screw all my issues went away. I do have a wideband, it is just not wired up 100% in my car.
Anything else you want to add?

 

[Koenigturbo]

Just so you know, there's sticky on the Supraforums titled "Lexus and 440's= bad idea?? which by the way is my original thread.