Will I need to run race gas with a JDM ECU?

lewis15498

Don't blame ebay cheapass
Sep 28, 2008
1,397
1
0
Raynham, Massachusetts, United States
Ok, so Japan uses the RON method. Its my understanding that 100 octane in RON is equivilent to 91 octane in (RON+MON)/2. This is secondhand info tho, so dont quote me on it. Assuming its correct, im assuming 98 Octane to them is like 87 Octane to us.

EDIT: Emilio beat me to it.... and did a better job.
 

Evilempire1.3JZ-GTE

SF what a waste of supras
Jun 22, 2006
1,382
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SoCal
www.myspace.com
The JDM ECU will be fine in US just use the best gas you can when boosting.

The only time you have to worry is when using remapped ECUs Blitz Sard Mines etc..
You never know what injectors mods fuel its designed for since you would have to use an AFC to retune you might as well save the money in those cases.
Get an OEM +Piggyback or standalone
 

MarkIII4Me

Project OVERKILL!!!
Apr 10, 2005
1,249
1
38
Charleston, SC
Be aware that many say there is a speed governor on JDM ECU's. Something like 105mph. Some claim they have surpassed this speed; other say they can't. HKS makes an SLD for this reason; however, it's pricey as hell.

I have a JDM auto ECU hooked up right now, but I haven't started the vehicle yet. I'm crossing my fingers that there is no speed governor.
 

Supraflymk3

Supraman
Dec 17, 2005
272
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37
Neenah, Wisconsin, United States
Is there a way to maintain the USDM ECU and use a piggyback while eliminating EGR with no problems?

---------- Post added at 09:37 PM ---------- Previous post was at 09:36 PM ----------

MarkIII4Me;1550070 said:
Be aware that many say there is a speed governor on JDM ECU's. Something like 105mph. Some claim they have surpassed this speed; other say they can't. HKS makes an SLD for this reason; however, it's pricey as hell.

I have a JDM auto ECU hooked up right now, but I haven't started the vehicle yet. I'm crossing my fingers that there is no speed governor.

Where did you find you're JDM ECU?
 

supra0022

New Member
Apr 6, 2010
44
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Suffolk, VA
I know that while I was stationed in japan, the highest octane rating for gas was 89. the lowest was 85 I believe and they base was using a japanese supplier for the fuel. dont know if that helps. I know on my 1j I owned in japan didn't cut out on me and I definitely pass that mark a couple of times.
 

VooDoo

Draggin ass on his build
Mar 20, 2008
342
0
0
Valdosta ,Ga
Supraflymk3;1550235 said:
Is there a way to maintain the USDM ECU and use a piggyback while eliminating EGR with no problems?

---------- Post added at 09:37 PM ---------- Previous post was at 09:36 PM ----------



Where did you find you're JDM ECU?

You will hear yes and no on controlling the motor free of issues. So don't be suprised if you don't even get a response to that one. Search on that one ::dead horse:: .

As for the JDM ECU. E-GAY. I have seen them there regularly.
 

MarkIII4Me

Project OVERKILL!!!
Apr 10, 2005
1,249
1
38
Charleston, SC
Yep, snached mine up off of e-gayness a year ago. The seller had 2 from an auto; which will work fine on a five-speed. Got it for around $100 shipped. However, like a month later a bunch of them started popping on SM for like $60 shipped. So they're not overly expensive. Many egay sellers don't even know what they have. So just do a search for supra ecu and look for the units with purple lettering.
 

Supraflymk3

Supraman
Dec 17, 2005
272
0
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Neenah, Wisconsin, United States
But think about this the JDM ECU's were going into Japanese cars. All the "JDM ECU's" I see on EBAY have English written on them. I'm pretty sure I seen a pic of an actual JDM one and where its supposed to say Engine Control it was all in Japanese characters. I think those people know what they got but they think someone will be stupid enough to buy them thinkin they're truly JDM ECU's.

That's just what I think but correct me if I'm wrong.
 

CassMori

Boost Addict
I have a JDM ecu, and it has no speed governor (I've been up to ~140 mph). It also seems to have no boost cut or rev limiter, likey due to what appears to be a TechTom chip installed, and this may have bypassed any speed limiter as well. :dunno:

It's been running fine on 92/93 octane for ~5 1/2 years.

I didn't get it for $60 shipped though :cry:


I found a pic of the label on mine, not the best but all I could find atm (please ignore the crazy wiring, it does not look like that now). It's an 89 grey plug ECU. "Engine control" is in English on it; it was shipped from Japan, so unless somebody bothered to take/ship a USDM ECU to Japan and have it modified and then used it there (a possibility, but not likely), it should be a real JDM unit.

sm_photo_missing.jpg


Hope this helps you out some.
 

CassMori

Boost Addict
They do use a lot of English, when it is easier/more convenient.

The only other Supra ECU I have personally seen (and I have it in my hands atm) is the N/A ECU that supposedly came from my car (it's a yellow plug unit though, so not sure). The only differences I see, besides the GE/GTE stuff, and the stickers related to the JES mods on my turbo ECU is:

The label on the turbo unit, that has Zイ and is separated from the main label (upside down, on the lower right portion of the ECU in the above pic), on the non-turbo unit has AE, and is not separated from the main label.

The main label on the JES/JDM unit is puple outline white letters (see above pic), the non-turbo USDM unit is light blue outline white letters. Basically everywhere on the main label that is purple on the JDM unit is light blue on the USDM unit.

I cannot say for sure if these differences are related to one being USDM the other JDM, or if there is some variation for being turbo/non-turbo, or a grey plug/yellow plug unit.
 

Poodles

I play with fire
Jul 22, 2006
16,757
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Fort Worth, TX
Supraflymk3;1550486 said:
Wouldn't that make sense though? Why would they put english on a part that is staying in Japan? Well if they truly do have english on them is the lettering color different than the USDM ones?

99% of the car is the same in Japan, and all of the writing is English on those parts...