Quetions On The 1JZ Power

Gritz

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Aug 1, 2008
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10secdream;1204087 said:
A Custom Twin Turbo kit would be the way to go. Then again why not just go single and have a more reliable and cheaper solution.


Which is the reason i went with a 62-1 .70 a/r .68 a/r..
 

foreverpsycotic

Back in the game!
Jul 16, 2006
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Gritz;1203981 said:
Cool, are there any twins, that are a natural upgrade to the stock ones? New i might add..

There are a few sets floating around, not so much new. Single is a much easier road than twins.
 

SupraRacer

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Apr 10, 2005
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Wow alot of mis-information in this thread.

first of all if all you want is ~320whp just slap a full exhaust and intake on it, as most bpu 1j's will lay down between 300-310whp with just a full exhaust, i personally did 313whp with just those mods.

secondly, i ran 18psi with cams for 2.5 years with zero problems, the efficiency limit through the stock IC, is 23psi ,tuned on stock cams. THe stock IC is the largest OEM FMIC toyota has ever made, hell i made 395whp on 18psi, on stock fmic, ic pipes, 370ccinjectors, stock fuel pressure, with only cams, and a Sard ecu. when i removed the turbos to upgrade them they were/are in perfect condition, no shaft play, no smoking or leaking.

i do recommend that before you add a boost controller that you at the same time install a quality boost gauge, the stocker is a joke even at stock boost levels. Also if you are going to be pushing the turbos into 18+psi id also suggest an EGT and a/f gauges. AEM Uego is cheap and reliable, i use that. Never modify a turbo car without knowing exactly what the engine is doing otherwise you will detonate, or melt pistons, or blow turbos. you need to know how your doing on fuel, anything above 12.5 on a turbo car is dangerous, and anything prolonged above 12.0 is playing russian roulet, but on a stock ecu after you pass the stock fuel cut(~13.5psi) the ecu wont have a map for it and it will just throw fuel at it. which if you were like me is 9 and 10's air/fuel, very very safe. Its idiot proof, however if you tune it you can gather a bit more power.

guys have gotten 420whp out of the stock twins for years, and depending on the mileage and condition of your turbos will determine how much they can take as far as abuse.
 

ryangaudoin

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Dec 10, 2008
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so Ryan btw im Ryan to lolz umm yea if you check my first post #1 i really want around 320RWHP not to the crank with the stock turbo's and thats all with what trying to get at with #1 mods before i go upgrading , and then you see me posting in #2 is better surporting mods which helps more.

thanks Ryan

more info will help as well, as future mods im planning on around 400RWHP for a daily driver cause i got another car im trying to boost higher
 

Gritz

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SupraRacer;1204756 said:
Wow alot of mis-information in this thread.

first of all if all you want is ~320whp just slap a full exhaust and intake on it, as most bpu 1j's will lay down between 300-310whp with just a full exhaust, i personally did 313whp with just those mods.

secondly, i ran 18psi with cams for 2.5 years with zero problems, the efficiency limit through the stock IC, is 23psi ,tuned on stock cams. THe stock IC is the largest OEM FMIC toyota has ever made, hell i made 395whp on 18psi, on stock fmic, ic pipes, 370ccinjectors, stock fuel pressure, with only cams, and a Sard ecu. when i removed the turbos to upgrade them they were/are in perfect condition, no shaft play, no smoking or leaking.

i do recommend that before you add a boost controller that you at the same time install a quality boost gauge, the stocker is a joke even at stock boost levels. Also if you are going to be pushing the turbos into 18+psi id also suggest an EGT and a/f gauges. AEM Uego is cheap and reliable, i use that. Never modify a turbo car without knowing exactly what the engine is doing otherwise you will detonate, or melt pistons, or blow turbos. you need to know how your doing on fuel, anything above 12.5 on a turbo car is dangerous, and anything prolonged above 12.0 is playing russian roulet, but on a stock ecu after you pass the stock fuel cut(~13.5psi) the ecu wont have a map for it and it will just throw fuel at it. which if you were like me is 9 and 10's air/fuel, very very safe. Its idiot proof, however if you tune it you can gather a bit more power.

guys have gotten 420whp out of the stock twins for years, and depending on the mileage and condition of your turbos will determine how much they can take as far as abuse.

I think most people in this thread is giving safe advice...I see nothing wrong with that..I heard of people running 20+psi with the twins but i wouldn't tell someone..."sure you can run 20psi safely"...
 

Evilempire1.3JZ-GTE

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Jun 22, 2006
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SupraRacer;1204756 said:
hell i made 395whp, 370ccinjectors, stock fuel
:bsflag:

Do not run 395HP on 370 injectors thats beyond 100% duty cycle and running lean.

Steel blade upgrades for our supra is not the solution 12Bs add lag more then the 2JZ-GTE just go single if you cant take 330-340hp.

More boost then 14-15psi will hit fuel cut and no AFC can adjust an oem map sensor once it just pegs at 5vdc max psi you need a scalable 2bar map like GM to register your boost for your afc input.
 
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BlackMKIII;1202442 said:
With a full 3" exhaust, if I take the silencer out I bang on fuel cut all damn day, even with the boost controller off. It's a farking pain in the arse. I installed a fuel cut defender and had it "tuned" for about 1.3 bar.

Well about 6 months later I melted the pistons. Never even heard it detonate. Even though my wideband showed a nice healthy mixture, the cylinders were too hot and I got to spend more money on another 1JZ.

The moral of the story? FCDs ARE BAD, MMMMMKKKAAAAAAAAYYYYYYY????

Thanks for the input.
I am dealing with the same damn fuel cut issue and i have had a hks fcd sitting around. I have been tempted to wire it in. My megasquirt build is going so damn slow! Well, i will be patient. Thanks again!
 

ryangaudoin

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Dec 10, 2008
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and what is the max psi I can put down the turbo's for the safest running every day, basically for me running hard all day

is it 12-15 psi
 
ryangaudoin;1205901 said:
and what is the max psi I can put down the turbo's for the safest running every day, basically for me running hard all day

is it 12-15 psi
That is what i drive daily. But my aftermarket ecu died, and so it fuel cuts after 12 lbs now. But with a fuel computer 15 daily was safe for me. Make sure your a/f ratio is always safe. Get a wideband!
 

SupraRacer

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Apr 10, 2005
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Evilempire1.3JZ-GTE;1205526 said:
Do not rune 395HP on 370 injectors thats beyond 100% duty cycle and running lean.

Steel blade upgrades for our supra is not the solution 12Bs add lag more then the 2JZ-GTE just go single if you cant take 330-340hp.

More boost then 14-15psi will hit fuel cut and no AFC can adjust an oem map sensor once it just pegs at 5vdc max psi you need a scalable 2bar map like GM to register your boost for your afc input.

I dont see why not, i ran it just fine, in fact i did so untuned dipping into the 9's a/f, mostly tho it was low 10's, also its not true what you are saying as far as not being able to tune a car because the oem map is pegged. once you go beyond what the stock fuel maps are programmed to)in this case 13.5psi when the car would hit fuel cut) the car doesnt just stop running, it simply give the car everything its got. I.E it max's out the injectors. perfect example, when my brother installed his 57-trim ct26 on his 7m, he was running into the 13's a/f when he would run 10psi, i told him to turn up the boost to fix it..he was reluctant but found out that when he turned it up to 15psi that the car started running 10's a/f because the ecu didnt have a map for it and just gave it everything. You can tune for this with a more advanced tuning software such as megasquirt, or emanage blue. anything that has an excel bar type mapping system.

It seemed to be the general concensus around supraforums, and here that the stock twins would grenade after 14psi because the rear fins were weak. This just isnt true, and has been proved over and over again not to be. I ran 20-22psi on my twins daily before my cams, and 18psi daily aterwards, and trust me i was very hard on my car, damn near everytime id go out id boost it. You push the limit of any turbo and it will greatly shorten the life of it. but the stock turbos wont run of out breath until 23psi on stock twins if tuned, if you add cams the limit is ~18psi. If you want to be safe and try not to blow the turbos up id say with stock cams 18psi is perfectly safe and will yield a good amount of power, but check the play in your turbos, if they have play than they will most likely blow soon even at 12-14psi.

The stock injectors will, AND HAVE, supported over 400whp on stock fuel pressure. i cant find the guys SN anymore but its a grey 1j in cali, who put down 420whp and 370tq on stock fuel, the jdm 440's have done 550whp, ive seen it do it, a local shop here in st louis(and also one of the first guys doing 1j swaps) dyno tested the 1j trying to find their weakness. Not only did he find that the stock twins limit were 23psi, but that it would also rap out to 10,500rpm with no valve float. My car ran 7.68@95mph in the 1/8th on stock twins, put it ~11.9-12.0 @115mph. i did this untuned, now i may have been clost to 100% cycle duty, but really there isnt much risk with saturation injectors, 100% for them just means they stay open as wide as they can , they dont go static like peak and hold injectors.

And Ryangaudoin i know you wanted 320hp to the rear wheels, and im telling you that on average depending on elevation that a Full exhaust, 1jz does 300-310 hp to the rear wheels. I did 313rwhp with only a full exhaust and intake. IMHO id say get yourself a good 3" full exhaust, good intake, a good boost controller run 16psi and tune it with an emanage blue, and youll be well over your goal. id say 330-345rwhp.
 

ryangaudoin

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Dec 10, 2008
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so a full 3'' y-pipe and 3''downpipe,and the whole cat back with a im thinking 3'' or 3 & half inch & high flo cat converter and a HKS EVC boost controller you'd saying i'll be fine with getting around what i want 320RWHP and maybe more and can i run this hard all day?? if so then 13-16 psi would be my safe range if i beat on it hard all day ??

greddy fuel cut defencer & HKS Speed cut Limit later on with 550cc injectors, and a fuel pressure regulator,cam gears with the O2 wideband, will be my big suporting mod's and i might get even more power but im not sure if i would need a fuel cut defencer or a speed cut limiter or would both just keep me doing good on the safe side ??


thanks for everyone's help and more help would always be good cause i only plane to hit 400 with the easiest way but not the most expensive but not the cheap stuff
 

SupraRacer

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id say yes. from what ive seen on my friends bpu 1j's that even through the stock y-pipe with no boost controller they all have pulled over 300whp

also id try to find an upgraded ecu. it either removes or raises your revlimiter, boost limit, speed limiter, not to mentionhas a more aggressive fuel and timing maps. the only downfall is some of them are tuned for certain parts. like my ecu is tuned for 104octane, so it has timing and fuel maps set for that. I still ran 93oct through the car, but it just pulled alot of timing out. But not only is it a cheaper alt than buying a FCD, and a speed cut defencer, but it also is partially tuned for power already.
 

apexi287

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Jul 24, 2005
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Hey man got your PM look below in my sig those are the mods that gave me 370rwhp and 380trq. Also yes it's on stock twins, I've had it that way since around march or whenever tx2k8 was. Since then I turned the boost up to 18psi and installed 2jz 440cc injectors with a wally 255 and tuned to around 10.5 a/f making just above 400rwhp.

It's all gonna depend on the health of your 1jz, I was lucky with mine and got a great front clip from Jose that runs extremely strong with perfect compression. The stockers aren't going to last long though as they have been slightly blowing smoke since I received the engine, if you want to stay with the stock ct12's and have a good 300+ for a while reliably I'd suggest a rebuild of yours because they will give on you relatively quickly.
 

Frankenstien

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Mar 2, 2008
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JDM 440s, full 3" turbo-back exhaust.

That and either a "tuned" ECU; Mine's, Sard, etc. or a boost controller will easily get you a safe 320rwhp at maybe 14psi that you can run hard all day with your current mods IF your motor and twins are in good condition.
 

Frankenstien

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Mar 2, 2008
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Yup, that works as well.
IMO I would just go with what pretty much everyone else is saying. A y-pipe, full 3" exhaust, an air intake and a better front mount intercooler(with hardpipes if you want) will easily get you to 320whp, probably even a little more.

Rebuilding the twins isn't really cost effective unless you plan on keeping the car on the twins for quite awhile. I would highly recommend the JDM 2JZ 440cc injectors as they are a drop in upgrade along with a wideband O2 sensor and some sort of AFC just to keep things safe and running properly. And if you decide to go with more boost in the future, you already have the supporting mods for it.

Mind you, the stock twins are famous for failing after turning up the boost past about 14psi. Stock boost is 11.8psi. With the mods I mentioned first, you shouldn't have a problem with the twins failing unless they are already on their way out. The main killer of twins at higher than stock boost levels is the restriction of the stock exhaust, specifically the y-pipe. If you're really set on keeping the twins, I would say just run them until they die, then rebuild them with better internals.

HTH
 

drewgo

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Dec 1, 2006
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Fellas:
1) 373cc injectors are good for appox 330rwhp to remain in the 80% duty. Yes people have done way over that however, if they stick you have no clue what you are spraying. Your AFR can dip into the 9 but that can well be the other 5 compensating for the 1 going lean.
So stay safe and keep within safe margins and 440cc starts to sound like the way to.
2)Second an FCD works just fine. Once your ECU sees 4.7v from your map, it will stop fuel delivery. Which mean around 14psi. Your map with 440 will read at most 17psi. But since you are clamping the singal at 4.7 or around 14psi you'll need an AFC to tuned beyond that point and ensure proper fuel management. So there is more then just an FCD for this to work like it should.

My car is Daily driven at 470rwhp on a single GT4082 @23psi. I got Stock ECU, fuel cut and speed cut with a SAFC and 550cc MKIV injector. I also get 22-25mpg.
I attest that this set up works.
 

aphxero

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Jul 4, 2006
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Hey drewgo I wanna see your graph. I run the exact management setup you do and make 400whp@14psi and that's with 3.0l block!

Maybe I'm too conservative.

But seriously thread guy. Just get a stock motor and bpu it. BPU lol that term always makes me laugh. To me all that bpu crap is stuff you do to any car no matter what. Who'd ever run stock intake/exhaust/intercooler? "hard pipes" is a funny one too. I mean who the hell runs a stock intercooler/piping on anything? Supra people are the only ones ho use these terms so I LOL@them.

"Dude 1j BPU+ you'll get that 320whp" ROFL
 

drewgo

Akuna MaTata...!
Dec 1, 2006
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South florida
aphxero;1209805 said:
Hey drewgo I wanna see your graph. I run the exact management setup you do and make 400whp@14psi and that's with 3.0l block!

Maybe I'm too conservative.

But seriously thread guy. Just get a stock motor and bpu it. BPU lol that term always makes me laugh. To me all that bpu crap is stuff you do to any car no matter what. Who'd ever run stock intake/exhaust/intercooler? "hard pipes" is a funny one too. I mean who the hell runs a stock intercooler/piping on anything? Supra people are the only ones ho use these terms so I LOL@them.

"Dude 1j BPU+ you'll get that 320whp" ROFL
Here you go:
sm_photo_missing.jpg
 

aphxero

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Jul 4, 2006
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Wow your powerband is pretty high up there. Spool makes it look kinda laggy but once you're in boost how's the response?

Are you holding tq with boost duty or do you have cams?