Lex Afm+57 trim+440's=bad????

[Ozz89supra]

So I just got my turbo back from driftmotion. I got the ct-26 57 trim, I have a 3 inch downpipe and stock fueling system, but I did install an SAFCII and a wideband. I am now hitting fuel cut at 9 PSI and I was wondering if its possible to install my Lex afm and just richen up the car with the safc so I dont run lean and blow my engine, or should I just wait and buy some 550's and install the lex afm with bigger injectors and a walbro? Any information is appreciated Thanks!

Mods are: 3 inch downpipe, ssqv, knn intake, rsr cat-back, SAFCII, aem wideband, stock intercooler, 57 trim ct26

 

[WhtMa71]

It has been done and can be pretty safe as long as you have a very good tune.

At the very least I would install a Walbro and adjustable fuel pressure regulator and remove or drill out the J tube if you plan to run the Lex with 440's.

 

[Ozz89supra]

It has been done and can be pretty safe as long as you have a very good tune.

At the very least I would install a Walbro and adjustable fuel pressure regulator and remove or drill out the J tube if you plan to run the Lex with 440's.

Yeah thats what I was kinnda thinking. I will definitely buy a walbro within a week than 550's as soon as I get some cash but I just really hate hitting fuel-cut all the time. ohh and as far as the afpr I thought they came with a kit that bypassed the j tube???

 

[CajunKenny]

Yes. The Aeromotive AFPR Kit from Driftmotion allows you to bypass the J-Tube Completely.

 

[Ozz89supra]

Yes. The Aeromotive AFPR Kit from Driftmotion allows you to bypass the J-Tube Completely.

OK I might go with that then.

 

[CajunKenny]

And my .02 regarding the lexus AFM is to wait until you have your 550's. You'll have to richen up your mixture quite a bit to keep it from running lean. Plus, you're already hitting fuel cut!

Not to mention the stress you'd put on your stock pump trying to richen it up.

Good luck!

 

[Ozz89supra]

And my .02 regarding the lexus AFM is to wait until you have your 550's. You'll have to richen up your mixture quite a bit to keep it from running lean. Plus, you're already hitting fuel cut!

Not to mention the stress you'd put on your stock pump trying to richen it up.

Good luck!

well I'll get a walbro soon. But Im just having mixed feelings about putting in the Lex afm. I guess it dosent hurt to just wait a bit a do it right....

 

[CajunKenny]

Nope, it doesn't hurt to wait.

But, it could hurt if you don't.

 

[SUPERIUM]

What kind of afr's are you getting (wot, idle)? I would first double check if you dont have any boost leaks. If you have a healthy motor and fuel delivery, running just the lex afm can and has been done plenty of times though you are running a 57 trim you should be more cautious and limited to only 10psi or so.
Right now I been running with just the lex afm on my stock setup @14psi with just a full 3" exhaust and ic pipes and heres the differences:
Stock - Lex AFM
WOT 10.0 11.9
Idle 14.7 15.6
Coast 15.6 16.0
Still safe afr's, Im going to get readings off 2 other 7ms with similar mods to mine but one with 550s and 255 pump and another with 440s, 225 but with the j-tube drilled out.

 

[Ozz89supra]

What kind of afr's are you getting (wot, idle)? I would first double check if you dont have any boost leaks. If you have a healthy motor and fuel delivery, running just the lex afm can and has been done plenty of times though you are running a 57 trim you should be more cautious and limited to only 10psi or so.
Right now I been running with just the lex afm on my stock setup @14psi with just a full 3" exhaust and ic pipes and heres the differences:
Stock - Lex AFM
WOT 10.0 11.9
Idle 14.7 15.6
Coast 15.6 16.0
Still safe afr's, Im going to get readings off 2 other 7ms with similar mods to mine but one with 550s and 255 pump and another with 440s, 225 but with the j-tube drilled out.

Wot is like 11.5 than it leans out to 12.5 right before fuel cut
Idle is like 13.5-14

 

[CajunKenny]

What kind of afr's are you getting (wot, idle)? I would first double check if you dont have any boost leaks. If you have a healthy motor and fuel delivery, running just the lex afm can and has been done plenty of times though you are running a 57 trim you should be more cautious and limited to only 10psi or so.
Right now I been running with just the lex afm on my stock setup @14psi with just a full 3" exhaust and ic pipes and heres the differences:
Stock - Lex AFM
WOT 10.0 11.9
Idle 14.7 15.6
Coast 15.6 16.0
Still safe afr's, Im going to get readings off 2 other 7ms with similar mods to mine but one with 550s and 255 pump and another with 440s, 225 but with the j-tube drilled out.

That's all well and good; but, NOT advisable. Just because your afr's are ok doesn't mean that your 20+ year old pump is going to hold up.

However, what I would fear most if I were you is the fact that you're pushing your 20+ year old 440 injectors well beyond the 80% duty cycle safety zone. One failure in that area will leave you with a blown motor.

To ozz89supra: I'm not tooting my own horn here; but, the best statement in this thread so far is this:

Nope, it doesn't hurt to wait.

But, it could hurt if you don't.

 

[Ozz89supra]

That's all well and good; but, NOT advisable. Just because your afr's are ok doesn't mean that your 20+ year old pump is going to hold up.

However, what I would fear most if I were you is the fact that you're pushing your 20+ year old 440 injectors well beyond the 80% duty cycle safety zone. One failure in that area will leave you with a blown motor.

To ozz89supra: I'm not tooting my own horn here; but, the best statement in this thread so far is this:

OK it sounds like I will have to wait than. But at-least once I install my Lex/550's I'll know my car will not blow :biglaugh: . Thanks for all the good information guys!!!

 

[Ozz89supra]

I just ordered a Walbro, and had them overnight it......than I found out that tomorrow is Sunday :kickinthenuts: ....... Epic Rage! hahaha O well

 

[GC89]

14psi shouldnt be over 80% on the 440s, they have more in them that a lot of people think. However 14psi on a stock system is all around bad. At that your pushing the stock pump pretty hard. Afpr and a new pump are a must and 440s should only be pushed if they have been cleaned and flowed. Your stock turbo probably isnt liking 14 either and is pushing some hot air.

Also leaning out to 12.5 before fc isnt a good thing either, thats getting lean and creating a lot of heat.

 

[Ozz89supra]

14psi shouldnt be over 80% on the 440s, they have more in them that a lot of people think. However 14psi on a stock system is all around bad. At that your pushing the stock pump pretty hard. Afpr and a new pump are a must and 440s should only be pushed if they have been cleaned and flowed. Your stock turbo probably isnt liking 14 either and is pushing some hot air.

Also leaning out to 12.5 before fc isnt a good thing either, thats getting lean and creating a lot of heat.

Yeah its a 57 trim thought not stock

 

[CajunKenny]

I dyno'd 294 hp @ 13psi on a stock fuel system. That's around 320 hp at the crank. I got a little concerned about my injector duty cycle so I went to RC Engineering's Injector Duty Cycle Calculator and put in my numbers.

According to the calculator, 277 crank HP is 80% on the 440's. At 14psi he should be well over that. Just as I was at 13 psi.

I don't mean to argue with anyone (especially Ryan ). But, if I have my thinking all messed up, PLEASE someone correct me!!!

Here's my reference:

 

[Ozz89supra]

I dyno'd 294 hp @ 13psi on a stock fuel system. That's around 320 hp at the crank. I got a little concerned about my injector duty cycle so I went to RC Engineering's Injector Duty Cycle Calculator and put in my numbers.

According to the calculator, 277 crank HP is 80% on the 440's. At 14psi he should be well over that. Just as I was at 13 psi.

I don't mean to argue with anyone (especially Ryan ). But, if I have my thinking all messed up, PLEASE someone correct me!!!

Here's my reference:

So you are saying that its possible to put down good power on stock 440's just good tunning???? Ohhh BTW did you have an SAFC or anything like that??? thanks!

 

[CajunKenny]

I am saying that you can make good power with the stock fuel system if you're comfortable pushing them passed their safety. I wasn't. Once I got my dyno numbers and calculated the duty cycle of 294 hp, I turned my boost back down to 10 psi to be 'safer'. The car dyno'd 258 hp at 10 psi. Still pushing the stock system; but, not as hard.

I did not have any tuning device installed at the time of the dyno run.

After turning the boost back down to 10 psi, I obviously didn't like the decrease in power so I upgraded the fuel system and installed the Maft.

Are there people making good power on the stock fuel system...? Sure! Have there been people that have lost their engine by trying to make good power on a stock fuel system...? Absolutely!

Every car is different. Your stock fuel system may handle the extra stress or it may not. Tuning makes a HUGE difference!!

You do what ever you're comfortable with.

 

[GC89]

Yeah its a 57 trim thought not stock

Oops missed that, everything else still applies

Ken, not arguing with you one bit. I agree the fuel system should be upgraded first, I just believe there is a bit of a false mentality that you have to upgrade to 550s for any real power increase. Upgraded pump and fpr are a must and either have your 440s cleaned and flowed or go to 550s (which should be cleaned and flowed if not new anyways). Also IIRC the stock fuel pressure is 40psi plus 1:1 rising rate, so that would adjust your duty cycle a bit but still getting up there. And a good tune is the most important thing!

 

[Ozz89supra]

I am saying that you can make good power with the stock fuel system if you're comfortable pushing them passed their safety. I wasn't. Once I got my dyno numbers and calculated the duty cycle of 294 hp, I turned my boost back down to 10 psi to be 'safer'. The car dyno'd 258 hp at 10 psi. Still pushing the stock system; but, not as hard.

I did not have any tuning device installed at the time of the dyno run.

After turning the boost back down to 10 psi, I obviously didn't like the decrease in power so I upgraded the fuel system and installed the Maft.

Are there people making good power on the stock fuel system...? Sure! Have there been people that have lost their engine by trying to make good power on a stock fuel system...? Absolutely!

Every car is different. Your stock fuel system may handle the extra stress or it may not. Tuning makes a HUGE difference!!

You do what ever you're comfortable with.

Yeah its definetly possible but I would feel soooooo much more confortable with 550's installed. I really dont trust my 20 year old injectors. :3d_frown: and My walbro will be here on wednesday :icon_razz now just need money for 550s