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Boost is my drug!
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Discussion Starter #1
I did a search but didnt find what I was looking for ..


I was wondering if its OK to install the walbro and cartech afpr with lex afm ON A 440cc injectors..

how much fuel pressure should I set it at to be "safe" and how much boost is "safe" for the lex and 440cc's

dont tell me stuff about "thats bad, cant, you will fry pistons. etx etx. " I already know the story about lex and 440cc's I am in the progress of getting 550's very very soon and I have apexi safc. I just want to know the SAFE limit to run them on 440cc's its not like im going to max it out or blow up my motor I just want to keep it low like 10-15 psi at least!!!


back to the question.. how much fuel pressure should I set it at using the setup I mentioned. and how much boost is allowable before I start to denonate.

I see some people use 38 psi. is that good?
 
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ok... my question to you is why?? why risk your engine on trying that... im sure if you had some good fuel management then it might work but why? why risk an expensive rebuld to do it.. i say fork out the extra $$ for some used 550's or something so you know your safe and your motor is safe...
 

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Boost is my drug!
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Discussion Starter #3
im not trying to risk my engine. I just dont push it to the limit. I only want to drive normally before Im able to push it to the max.

I refuse to boost any more than 12 psi bec of the fuel.

I constantly watch my egt and boost all the time to avoid damage

Im only asking for safe limits so I can know how much to push because I am getting the 550cc's in couple of weeks!!!!

$390 for new set of 6 :)
 
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ahh i see... i tjought that you were gonna run the 440's for a while... honestly i dont know what psi you should set it at.. i know with my old setup, walbro, 550's, afpr, lex, i set them at 38... im pretty sure it will be higher than that for the 440's... someone on here should know
 
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I have been told by SEVERAL knowledgeable people that it is totally safe to run 440's with the Lex...Assuming you have other supporting mods, and a good bit of knowledge.

We all know that these cars run rich all the time, and even thought 550's arent a bad idea, I wouldnt think youd need injectors that size until you were pushing the 450hp envelope.

If you have an AFC intake, full exhaust, maybe a turbo/ic upgrade you should be fine on 440's as long as you dont push it to the limit.

You could install the lex, and the afc, and have it dyno tuned. It would be totally safe as long as you didnt try to run 20+psi which you probably wouldnt be able to do anyhow unless you got an FCD.

I myself havent done this yet but once I have my AFC (going with the HKS S-AFC) Im going to have it dyno tuned with 440's and see what happens.

The car is known to be over enigineered, the same goes for the injectors.

I know im going to start a whole debate here, but most of it is in that sticky about 3 threads above this one that you couldnt find.
 
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dude... i would rather be safe than sorry.. and i dont want to find out.. im sure alot of people will agree with me on this one
 
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it really depends on your goals...

safe then sorry or stupid then sorry

if you are only looking to gain a few extra psi of boost and dont have really high HP goals in mind, why bother dumping all that extra fuel in the car.

i know people that run a lex and 440s and the car still tends to run rich.

if you have it dyno tuned for your preset hi-lo boost settings, and the dyno tells you that you af ratio is perfectly fine...and you know you arent going to change anything...

What isnt safe about that?

Now if youre a punk ass and you cant keep your fingers off that boost knob, and you think you might be tempted to try to run 24psi without enough fuel, then yes, youd be sorry.
 
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man i need to know... who's cars are you talking about running rich???? i know mine sure as hell didnt... are you hanging out with a bunch of supra owners who have boost leaks??
 

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Boost is my drug!
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Discussion Starter #11
Now if youre a punk ass and you cant keep your fingers off that boost knob, and you think you might be tempted to try to run 24psi without enough fuel, then yes, youd be sorry.
LOL yeah thats very true!!

I only plan to run at least 13-15 psi. BTW my a/f reads very very rich when I boost at 13 psi.

when I get 550's I plan to boost it up to 20-22 depends on my afm if it hits FCO.
 

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Moderator, megalos ntabatzis!!
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uhhh problem is not so much the lex afm, its ppl putting it in with stock fuel and no tuning esp with crappy 15 year old fuel pumps and injectors.

440s will flow to 450 hp if tuned properly.
 

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Even at 85% duty cycle you should be able to support 375 hp with 440 cc injectors. Look at Will N. pushing 730 rwhp with 720 cc injectors. Your spray pattern might get alittle messed up and your inj. might not last 200,000 miles, but as long as you got the fuel psi behind it and have a way to tune it you should be okay. I would start at a base psi on the fuel at 35 with the vacuum line off and tune from there. You might need alittle more base psi to be safe.
 

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I'm planning on running the Lex with 440s and an AFC. I have spent hours upon hours reading Reg's article and the arguments portrayed in the Lex/440 sticky on this board. I plan on installing the Lex, setting my AFC 20% richer across the board to compensate for the Lex's larger body and drive it straight to the dyno and tune at 10 psi and up to about 14 psi.

At 14 psi tuned, my car will just as safe as the same setup with 550s. The only thing the 550s do for you is allow you to safely run more boost. 14 psi is not pushing the 440s to the ragged edge. That said, 14 psi will be as high as I go.
 
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I have a totally upgraded fuel system, sans injectors...Im looking for 400-450 hp and I refuse to upgrade them until I absolutely need to.

I am the #1 advocate of preventive maintenance, and reliablility. But I honestly see no reason to upgrade them. YET.

As with every supra owner im sure my HP goals will increase as my HP does, but for now, Im going to get an AFC and have it properly tuned.


Heres another question tho, not to steal the thread.

How come on a supra 16psi sounds like a lot, but on other cars, not naming specifics stock boost is 17psi and they can easily hit mid 20 psi range on a very limited set of upgrades (mostly 4 bangers)
 

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A Happy Dad
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I did it for quite some time and when I pulled it all apart for my turbo upgrade and mhg I was pleasantly suprised at the guts, comb.chambers had a good amount of carbon, not too much but NO signs of lean, valves nice colors too. I ran 15 on stock turbo with s-afr, Walpro uprade, I hadn't planned on going above 12 but I did with no ill effect but imo those two upgrades are MINIMUM. I think pople run into trouble when they think they can just slap a lex on a stock fuel system and go with it.
 
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agreed.

you need at least the fuel pump, and afr...itd be good to have intake and full exhaust too so that the turbo flows a lot more freely to keep the egt's low.

afpr isnt a must, but a fuel pressure gauge is a good idea. theres a couple ways to raise fuel pressure on stock fpr
 

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A Happy Dad
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werkkrew said:
agreed.

you need at least the fuel pump, and afr...itd be good to have intake and full exhaust too so that the turbo flows a lot more freely to keep the egt's low.
Right, I had that stuff too
 

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One big point I see a lot of you are missing is that Dust is not on a stock turbo. With what you guys have said thus far, yes I believe that with GOOD 440's and a good pump, you can do things safely with a Lexus. I STRONGLY don't advise it, but it has been proven to work.

Dust has a 60-1 from T'netics therefore he will pushing a lot more air. Doing what you guys have said might not work too well for him. On a stock CT or maybe a small upgrade it might be ok. But I really think he should use the Lexus as a paperweight until the 550's are in.
 
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ok, i usually don't post much on the supraforums because i'm lazy but here's what happening to my supra. I dyno'd 309.8RWHP and 319.9 RWTQ @ 14psi of boost and my car ran so rich that the air/fuel ratio went off the chart. It had a chart that went down to 10.0:1 and my air/fuel ratio dipped under that into the 9.x:1 ratio. This was with 110k on my car with STOCK fuel pump, STOCK injectors, STOCK FPR, and a FRAM fuel filter with about 10k on it. Basically a completely stock fuel system with no fuel computers. They way i bypassed the fuel cut was by using the bov inlet hose on the accordian intake tube. I just left it open to let in unmetered air to trick the ecu into raising the fuel cut to 14psi. I thought i'd be running really lean but the wideband 02 sensor proved that i was running extremely rich.

Major mods at the time were:
Apex'i Intake
HKS Down Pipe
Ported Turbo Elbow
Apex'i Cat Back
CT26/T04E .54 trim

Minor mods at the time were:
Autolite 3923 plugs @ .029 gap
NGK Spark Plug WiresRemoved AC Compressor Belt
Intercooler Hard Pipes
HKS SSQBOV
Ball/Spring Boost Controller
STOCK Intercooler / STOCK Fuel System

I think you guys should just slap the car onto a dyno with a wideband 02 sensor and see for yourself. If my fuel cut had not been only increased to 14psi, I would've definately ran up to 16psi on the .54 trim seeing how rich it was. Or if i had a super afc, that would've netted an easy 15-20RWHP by leaning out the mixture.

Kenny
89T /w 1JZ-GTE
87T /w 7M-GTE
 
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