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JZA70 448 rwhp everyday
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Discussion Starter #1
Hey just got a 2jz map sensor, i think its a JDM one. I assume that since it was only designed to run 440s, that using 550s isnt a good idea? What are people that are using 550s using for a mapsensor, ect. I want to keep stock electronics, and only use my SAFCII to WOT tuning.

~scott
 

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JDM 2JZGTE map sensor is a direct replacement for the 1JZGTE one. Injector size has nothing to do with map sensor. It has to do with air pressure.
 

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JZA70 448 rwhp everyday
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Discussion Starter #3
interesting, so i could run 550s with a 2jz jdm map?

~scott
 

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Yes. But you still must compensate for the extra fuel.
 

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Dr. Jeff Lange
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I thought the 2JZ MAP sensor allowed larger injectors to be used, can't remember if it was 440's or 550's.

(It is scaled differently than the 1JZ sensor).
 

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JZA70 448 rwhp everyday
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Discussion Starter #6
that was also my understanding, but i assume i can only use JDM 440s since my map sensor is JDM 2j?

~scott
 

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scottiedawg66 said:
that was also my understanding, but i assume i can only use JDM 440s since my map sensor is JDM 2j?

~scott
Scott,
What's the part number of that Map?
I think you can use them for both.
You'd still have to have that SAFC give/take fuel as needed due to the bigger injectors.
 

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Engine Geek
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2jz map is a supposedly a scaled upgrade that matches the jdm 440cc injectors... like the lex afm/550 combo for 7ms
 

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GT40 1.5JZ
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any 2JZ map sensor will work, as long as they're not broken

the JDM one should be matched up to 440's, and I'm guessing that the USDM one matches up to 550's, because of different part numbers.

I'm running the USDM 2JZ map sensor, and I'm still compensating for fuel. Hey moe, when are you going to stopby so I can tune your emanage??? Still got my map sensor???
 

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We decided long ago that the US and JDM numbers superceded to the same number. So they are the same item and will be a perfect match to the 440s but will be off slightly for the 550s do to different maps in the ECU for the 550s in the US ECU. The 1j and JDM 2J use a similar set of maps I would guess.
Cary
 

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Dr. Jeff Lange
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Yeah, the JDM and USDM MAP sensors have identical part numbers and are 100% interchangable.
 

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JZA70 448 rwhp everyday
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Discussion Starter #12
can anyone with the mkIV map sensor and 550s comment on how their wide band reads at idle, cruize, gas mileage, WOT? I think 550s are waht im gonna want for my power goal 425 rwhp, thas do able with 440s but i dont like the idea of running injectors at over 80% duty cycle.

~scott
 

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MAP sensor has nothing to do with injector size. It just measures the manifold absolute pressure and sends that signal to the ECU. Its just a diaphram with some eletrical contacts. If you add anything bigger then the stock 380cc injectors on your stock turbo 1JZ,
#1 you'll be overfueling in most of the powerband, and we all know the car ALEADY does it anyways.
#2 youll need a fuel ECU to lean them out on the bottom end. SAFC is a bandaid that never works. Ive seen single turbo 1JZ's @ 20psi with SAFCII's make under 300rwhp.

If you do not have cams, 440's will just drownd your engine out and you'll make less hp and kill your MPG.

My 1JZ on 10psi boost on stock turbos is faster then others on 1 bar. I make over 300whp on 10psi on stock degreed in cams. I never tested 15psi, i like making it fast on lower boost because it can.
 

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Dr. Jeff Lange
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MAP sensor has a lot to do with injector size the same way the AFM has to do with injector size on the 7M. Because of the scaled signal.

MAP sensors are 5v sensors, but on 1 sensor, 4v = 10psi and on another one 4v = 30psi, obviously that makes a pretty big difference.

With the 2JZ MAP sensor, when you're at 15psi of boost, the ECU only thinks you are at 10psi of boost, so it's injecting the amount of fuel needed for 10psi of boost, obviously that's not enough if you have 15psi of boost, which is why you use larger injectors to get the correct amount of fuel at a lower pulse.

Those are just numbers I made up, I don't know the scaling of either the 1JZ or 2JZ MAP sensors, but I do know they are different, and the 2JZ is a higher pressure MAP sensor, meaning if you use one on your 1JZ, you'll either be running lean, or you'll need larger injectors, though if the 1JZ runs as pig rich as the 7M does from the factory, a 2JZ MAP sensor might just make you run at a nicer A/F instead of actually LEAN, but it really doesn't change the facts.
 

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JZA70 448 rwhp everyday
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Discussion Starter #15 (Edited)
so why / what is there a difference in the 1j and 2j map sensors. I assume it lies in teh Mapping of the ECU? BTW im gonna read my EFI book again to confirm what you are saying about the MAP, as far as i know the scailing of the MAP does affect the injector size.

EDIT i agree with Jeff here, seems like what i can remember from the EFI books i have read. As for 1jz running rich my car is a constant 14.7 range everywhere but WOT, then its all 11.5 no tuning, seems pretty decent to me. Im just getting ready to go single, and need more fuel.

~scott
 

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VJ RC51, I dont know about the AFC sucking that bad. Maybe it was user error, but my single turbo 1JZ is making 560rwhp with a greddy bcc, cams, and afc. Just with good tuning out of it. It's a good unit, but far from what stand alone computers can get. You should maybe try pushing your twins a little harder man. 10 psi is nothing, I was running my twins at 15 daily and never broke and the power felt incredible. Remember, our stock twins run out of efficiency around 23psi. But it's the reliability factor that kills them.
 

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Engine Geek
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jeff is right. if you want to run the stock ecu and 550cc injectors i would recommend using the 2jz map sensor to get closer to normal and then tuning it with a piggyback of some sort. even if you do the 2jzmap/440cc it isnt perfect and still should be fine tuned with a piggyback.
 

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Maybe that would explain why my friends stock 1JZ on stock boost and stock injectors on a 2JZ map is so slow? We've been trying to figure it out.
 

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JZA70 448 rwhp everyday
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Discussion Starter #19
its probably lean better chek it out on a wideband.

~scott
 

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Doesnt smell lean, but i can get it on a wideband this weekend. It has 3in dp, exhaust, stock boost and smic and it feels like a 1jz car on OEM exhaust with restrictive mufflers. Basically it feels like its hitting a brick wall power wise.
 
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