JDM vs. USDM Heads

[MKiiiturbodrift]

Is there an differences between a JDM and USDM head? Could I bolt a JDM head right to a USDM block?

 

[shaeff]

They are interchangeable. Take the proper precautions, though.

 

[IJ.]

Practice safe head jobs

 

[mirage83]

Practice safe head jobs

That's why they invented tilt steering wheels wasn't it? And seats that slide back? :biglaugh:

 

[adampecush]

From what I understand, the o2 sensor is different on JDM Supra's. It senses different hydrocarbons and chemicals in the exhaust to the ( JDM EECU )..

I didn't realize oxygen in Japan was different from the rest of the world.



(oxygen sensor senses OXYGEN, nothing else...why would it be different?)

 

[jdub]

Well depends? Do you have a JDM ecu? Do you have a Egr and egr cooler?

From what I understand, the o2 sensor is different on JDM Supra's. It senses different hydrocarbons and chemicals in the exhaust to the ( JDM EECU ). This is because it has no EGR. if you have a USDM ECU you need a EGR and EGR cooler, and you can place the head on a USDM block.

I didn't realize oxygen in Japan was different from the rest of the world.

(oxygen sensor senses OXYGEN, nothing else...why would it be different?)

That's because it's not different. The O2 sensor has nothing to do with the EGR.

JDM heads do not have the EGR cooler installed. There is a block-off plate on the passenger (US) rear of the head...the intake manifold has an EGR block-off plate in the usual place. Otherwise, the heads will interchange and have the same casting numbers as the years progress. One exception is the Group A heads that have a different combustion chamber configuration.

Teal - This is the Tech Section...this is getting old...you are not helping. You post "I heard" far too much here...if you are not 100% sure, do not post.

 

[lewis15498]

USDM head is equipped with an egr system, the JDM head is not. If you choose to run with no EGR system, you should get a JDM ECU that is calibrated to do so. Running NO EGR with a USDM ECU will result in a lean condition in certain situations (cruising). Some argue that No EGR removal can increase performance, but the general concencus is no. If you have a working EGR you might as well use it, and if you have to replace a component of it, its probably still cheaper than the JDM ECU.

 

[figgie]

The Hammer falls starting today.

Folks, If you are coming into the tech section. Be prepared to post facts!

If your sentence begins with the following

"I believe...."

pause and think about what you are about to post as more than likely, it will get torn apart.

Others that might lead you to pause before pressing the Enter button...

"I heard...."
"I have a friend...."
"I read on another forum...."
"But so and so did it...."


We are looking for science, facts. Not speculation, Heresay, BELIEFS, rumors etc.

 

[lewis15498]

Also make sure the gasket is good and the bolts are tight on the EGR cooler BEFORE you put the head on. Its located on the back of the head, and i can tell you first hand, its a fucking bitch to do when its on the car!

 

[Poodles]

Do NOT use a fel-pro EGR cooler gasket, it's made out of the same paper stuff that the intake gaskets are made out of instead of the metal material that exhaust gaskets are made out of like OEM.

Also, the Group-A heads look like they are heavily modified stock castings.

 

[Nick M]

There is no such thing as USDM head. Or any other for that matter. There are different casting numbers, but those are casting numbers, not part numbers. Excluding the homogolation head mentioned.