downside to a "JDM" ECU?

[Tire Shredder]

I need an ECU for my 7mge engine I'll be putting in my mk2...

my engine came out of a US car but all EGR equipment was removed, instead of tracking down the EGR parts, i'm going to throw some EGR blockoff plates on it.

since my car is an 84, I'll have no emissions testing...but plan to keep the cat on as i'm not interested in destroying the environment and want to keep it some what legal.

I got thinking that a US ecu may dislike having the EGR removed since it's timing and fuel maps expect it to be there. perhaps I should pursue a "JDM" ecu since it would assume it wouldn't have one. I realize the EGR is great to have, reducing detonation...lower EGTs but am hoping in conjunction with a japanese ECU, I would be in less danger of detonation. Did japanese cars have cats? can anybody think of a downside to using a japanese ecu on my car (such as damaging the catalytic converter etc.)?

 

[Tire Shredder]

well, I ended up buying one. As far as I can tell, this is the safest way of removing the EGR. The ECU will be aware there isn't one, thus less aggressive timing maps under high load, part throttle conditions, hopefully reducing the chances of detonation (compared to a US ECU with no egr).

JetJock, have you done any research/testing that can confirm the japanese ECU is indeed different than a US spec? I'd love to have some reassurance.

comments welcome from all.

thanks, Steve

 

[amichie]

Australian versions didn't have EGR but did have cats.

 

[Tire Shredder]

Australian versions didn't have EGR but did have cats.

excellent. thank you.

 

[AJ'S 88NA]

Yeah I got a JDM motor one time that didn't have the EGR. And I believe the ECU is not affected by it.

 

[cuel]

Block off plates might make the back of the head a little hotter than normal. The egr system on this motor only works on cyl.6, and works through the head. The exhaust gases are going to collect in the egr cooler, and not go anywhere, being constantly heated by the next pulse on cyl. 6. The best way to block it off would be to tap the hole in the head from the ex. port to the egr cooler, and screw a plug into it. Then you only need the plat for the intake, and can remove the egr and cooler plate from the head. I need to check on my other head to make sure, but I think that would do what you want, and not leave a hot spot on the back of the head.

 

[Tire Shredder]

Block off plates might make the back of the head a little hotter than normal. The egr system on this motor only works on cyl.6, and works through the head. The exhaust gases are going to collect in the egr cooler, and not go anywhere, being constantly heated by the next pulse on cyl. 6. The best way to block it off would be to tap the hole in the head from the ex. port to the egr cooler, and screw a plug into it. Then you only need the plat for the intake, and can remove the egr and cooler plate from the head. I need to check on my other head to make sure, but I think that would do what you want, and not leave a hot spot on the back of the head.

The cooler will be removed, I'm aware how the EGR works. The EGR actually works on all cylinders, but it only draws exhaust gasses from one. The exhaust gasses reach every cylinder. It's not about re-burning exhaust....it's about displacing/supplementing for oxygen on the intake side.

There are plenty of threads talking about EGR systems and the effects it has on the motor (99% good things)...

lets keep the talk about the ECU differences...

 

[Sawbladz]

I saw that edit

 

[Tire Shredder]

heh I can't remember what I changed but I posted and had to go the bathroom, then remembered something

 

[87nasupra]

as far as i can rememeber..........JDM supras didn't come with a n/a ever. Getting a ecu from a n/a jdm supra is not possible? the cressida's had themin the US but i don't know if they will work for our body harness, the same from overseas. I got my jdm engine from japan but i had to swap all my egr stuff and oil pan and new oil pump and etc. stuff over. You might just want to frind the egr stuff and put them on just in case. Then again......i have been wrong before. I'm basing this off what i was told from SF 4 years ago. Good luck though

 

[Tire Shredder]

your motor likely came from a cressida, which is a front sump engine. Thus, you had to put your supras mid sump pan and pump in. Because it's japanese, it didn't have EGR stuff and you had to swap that aswell.

N/A supras did exist in japan. it's my understanding that the connector for the ecu is either an 89+ or a pre 89..

for anybody that searches for this thread in the future, I got work back from jetjock (not quoting directly):

N/A motors are under considerable less stress than a turbo motor and should be just fine. The JDM ecu is indeed different than the US spec ECu and takes into account the lack of an EGR, however no testing has been done to determine the actual differences.

Steve

 

[87nasupra]

Yeah, thats exactly what i did. I sent you PM back, i love the way the jdm n/a runs w/o the egr stuff but i can tell the difference if you run it hard in the temp gauge. With the egr stuff installed it does stay about 30 degs. cooler from my gauge on #6 cyl.......im using an old digitron racing go-kart gauge designed to go under the spark plug on a 5hp briggs and stratton engine so it registers the metal temp. Yeah it sounds stupid but i can really tell a difference.

 

[Tire Shredder]

Yeah, thats exactly what i did. I sent you PM back, i love the way the jdm n/a runs w/o the egr stuff but i can tell the difference if you run it hard in the temp gauge. With the egr stuff installed it does stay about 30 degs. cooler from my gauge on #6 cyl.......im using an old digitron racing go-kart gauge designed to go under the spark plug on a 5hp briggs and stratton engine so it registers the metal temp. Yeah it sounds stupid but i can really tell a difference.

sounds like it works well to me! cool! thanks for the info. Jdub posted up some very eye opening results when he measured EGTs with the EGR installed aswell.