No fuel cut without lex AFM

[87witmoreboost]

I hear a ton of talk about how to get above the stock fuel cut with the 440's and stock AFM. I have read about leaning out the AFR by turning a screw on the lex AFM in order to get some unmetered air in there. I want to jump right into a lex AFM and build up from there, but I continue to hear that it is possible to go far with the stock 440's.

I am aware that the 7M comes rich from the factory and there is more power to be grabbed by leaning it out a safe amount. I have a few mods in mind come spring time:

- K&N open intake
- 3" turbo elbow/downpipe (1 piece)
- MBC with custom EGR solenoid bypass (allowing high boost on the fly)
- AFPR (maybe)
- Proper gauges for mods (autometer boost, autometer AFR, autometer ___)

Wouldn't it be possible to create a controllable leak post stock AFM (pre-turbo) to allow some unmetered air so lean out the rather-rich stock AFR and raise boost cut? I imagine using some sort of bleeder as would be seen in a MBC.

Perhaps the HKS FCD would be a better option and thereafter allow the AFM to compensate for the extra air. I worry about completely eliminating the fuel cut. Are there any other good, safe, ways to raise boost cut (without lex AFM, requiring 550's)?

My overall question is this - How can I run 12psi on 440's and a stock AFM without catching fuel cut?

:1zhelp:

 

[hellraiser456]

A FCD will do the trick...though they are generally shunned upon simply because of the purpose of fuel cut.

That said...if you are going to remove fuel cut...do it properly. ethier get a FCD or use another air metering device. Creating a leak post afm will only cause more problems than solve. If you are removing fuel cut...it is a good idea to make sure to get a WBO2 to see what's going on. I would also get something to tune with.

Also the 440's are alright for what the ct 26 can throw at it. but in a turbo motor...running out of fuel is bad...so don't push those injectors too hard.

 

[bountykilla0118]

I hear a ton of talk about how to get above the stock fuel cut with the 440's and stock AFM. I have read about leaning out the AFR by turning a screw on the lex AFM in order to get some unmetered air in there. I want to jump right into a lex AFM and build up from there, but I continue to hear that it is possible to go far with the stock 440's.

I am aware that the 7M comes rich from the factory and there is more power to be grabbed by leaning it out a safe amount. I have a few mods in mind come spring time:

- K&N open intake
- 3" turbo elbow/downpipe (1 piece)
- MBC with custom EGR solenoid bypass (allowing high boost on the fly)
- AFPR (maybe)
- Proper gauges for mods (autometer boost, autometer AFR, autometer ___)

Wouldn't it be possible to create a controllable leak post stock AFM (pre-turbo) to allow some unmetered air so lean out the rather-rich stock AFR and raise boost cut? I imagine using some sort of bleeder as would be seen in a MBC.

Perhaps the HKS FCD would be a better option and thereafter allow the AFM to compensate for the extra air. I worry about completely eliminating the fuel cut. Are there any other good, safe, ways to raise boost cut (without lex AFM, requiring 550's)?

My overall question is this - How can I run 12psi on 440's and a stock AFM without catching fuel cut?

:1zhelp:

The leak will be post(after) AFM and pre(before) the turbo

Fuel cut is good thing leave sooooo leave it. But you can raise fuel cut a good bit I run 14-15psi with a holy accordian hose ....... sure u can use a fcd, maft, maft-pro, map ecu, safc, or any other tuning device to scale back. I didn't for almost a year and I was still pretty much at the stock A/F levels but I gained some good power once i got it tuned.

If you electronics are in good working order the stock fuel setup can support good power you wont run lean with the ct26. I will even say that it will support 400rwhp with a fuel pump and AFPR as many people have proven on this forum and www.clubna-t.com ..... Search the 2JZGE-T threads they even made a "sticky" about the lex afm and our stock 440's as an upgrade. But not everyone is ok with the blasphemy i speak LOL but oohhh well

for some reason i feel as if i had this conversation before

 

[dbsupra90]

afr i hope you mean wideband afr. otherwise, it wont help you.

back in the day, people use to use the port on the accordian hose where the stock bov used to reroute into. they would use a 3/4" heater hose to a small piece of hose fitting to a k&n breather filter. it would raise the fco a couple psi. there were variations to this, like using a vsv with a hobbs switch with a larger hose, making their own hole in the accordian hose, etc. but basically all the same thing.

either way, i wouldnt do anything without a wideband to know where you are, were, or going.

 

[7MGTEsup]

I have been experimenting with this sort of setup. I run my stock AFM with the screw as far out as it will go and 13psi boost, I have a wide band so know exactly what is going on. I even turned my base fuel pressure down to 34psi (no vac) and was still seeing 10:1 at WOT. The stock fuel system is overly safe from the factory.

 

[hajemesito]

You can drill out the port where the screw is on the stock mass air and back the screw out. I had a lot of problems with fuel cut. I backed the screw out opening the unmetered air port. I also added an adjustable fuel pressure regulator and leaned it out and i still would hit fuel cut at 13 psi. I upgraded my fuel system to Lexus, 550s, walbro and stopped hitting fuel cut. I then got an safc2 and turned the boost to 15 psi on stock turbo intercooler and piping it hit fuel cut again. My afrs are 10.8 wide open. So good luck hopefully you can get out of it.

 

[MmmBoost]

ive got my car running 14psi right now, and no fuel cut on the stock afm and injectors.

the trick: big t4 turbo that doesnt spool till 4k rpm. i guess that the fuel cut tables have a certain max amount of air that can pass thru at certain rpms, and my old turbo @ 12 psi was exceeding that. new one isnt though...

 

[87witmoreboost]

A big T4 would cost as much as the lex, 550's, SAFC, and a good wideband - right?

 

[bountykilla0118]

ive got my car running 14psi right now, and no fuel cut on the stock afm and injectors.

the trick: big t4 turbo that doesnt spool till 4k rpm. i guess that the fuel cut tables have a certain max amount of air that can pass thru at certain rpms, and my old turbo @ 12 psi was exceeding that. new one isnt though...

Fuel cut should happen earlier with a bigger turbo. The karman vortex afm that we have reads frequency signals and when it reaches a certain number you hit fuel cut and I believe the number is 1600(+/-)hz I think. That’s why the lex afm is a good alternative/upgrade on the stock ecu because you pull in 25% more air at the same frequency and in theory all you would need to do is increase the flow of fuel with 550’s but you can tune it to run well with the 440’s but that’s something different.

 

[MmmBoost]

yeah, but each rpm has its airflow limits for fuel cut to go into effect. i think that the slow spool doesnt let the airflow hit the limit low in the rpm range like the old turbo did.

and btw, trust me you dont want a big t4. it sucks.

 

[87witmoreboost]

so how can 440's be ran with the lex? SAFC?

 

[7MGTEsup]

so how can 440's be ran with the lex? SAFC?

All you need is an adjustable fuel pressure regulator, and a wide band. sock fuel pressure for a turbo according to the TSRM is between 33 - 40 psi with no vac. With a lex afm just bump it up to about 43 psi. The car is so rich from the factory you don't need the 550's. 440's at 85% duty will flow enough fuel for around 380 (crank)hp which is well beyond the limit of the stock ct26.

 

[bountykilla0118]

So you are saying that the 440's can only support the low 300rwhp range????

Ummm no there are plenty of people putting down 400rwhp on a good running set up stock 440's. Get then serviced and sure they are in good running order first.

The general rule of thumb for injectors is that every 1 CC you can support 1 HP.

There are plenty of people with 2JZGE-T who are running are our stock 440's along with the LEX AFM as a basic upgrade.

 

[7MGTEsup]

So you are saying that the 440's can only support the low 300rwhp range????

Ummm no there are plenty of people putting down 400rwhp on a good running set up stock 440's. Get then serviced and sure they are in good running order first.

The general rule of thumb for injectors is that every 1 CC you can support 1 HP.

There are plenty of people with 2JZGE-T who are running are our stock 440's along with the LEX AFM as a basic upgrade.

Yes you can get more out of them but note I said at 43psi and 85% duty. More fuel pressure and 95% duty would probably allow you to run 450 (crank)hp

 

[87witmoreboost]

I apologize for not taking the time to search forums for the answer to this question but figure someone here knows a good answer - who makes a good aftermarket FPR? (I've hear aeromotive more than once) Is there a way to control the factory FPR? What would I be looking at for cost to change the fuel system to support the AFPR?

 

[bountykilla0118]

Aromotive