jdm vs usdm
 

what are the differences in HP in both jdm and usdm turboII engines?
I know usdm are S4-180 S5-200
are the jdm engines the same?

If I remember correctly JDM engines have no cat or emissions, therefore more power.

what are you plans? t2 jspec is a fairly common swap..

I'm sure the basic question is is there an advantage of going with a JDM motor instead of a USDM motor. I've been wondering the same thing.

well i know they have zero emmissions, and a bit more hrs power than usdm. but there pretty much the same thing..

I've got a S5 JDM swapped into my vert. One difference is that the JDM UIM and BAC valve are different. The JDM BAC has no adjustment screw and the UIM has no hole to allow for adjustment with a USDM BAC.

JDM's also have a reputation for coming to your doorstep blown.

What's with all this bad information? Seriously, if you've never seen a Jspec motor, don't guess.

I have a S4 Jspec motor right now, and it HAS EMISSIONS. The ACV is identical except for the lack of a split air solenoid, which just means air is pumped to the cat more often. The airpump is smaller, but has a smaller pulley so it pumps faster.

Internally, US and JDM motors are the SAME. Any published power differences would come from the lack of a precat. The main cat is still there, so the gain would be minimal. The engines themselves DO NOT produce more hp.

^^+1. jdm motors are nothing special unless you like saying that you have JDM or jspec motor. VIRTUALLY THE SAME. as rotaryrocket said, there are a few accessory diff's, but who cares. the jdm cars are rated like 5 hp more, but again, like rotaryrocket said, that not because the motor different or anything.

Jdm fc has cat converter but no precat...
If you gonna remove the emission system (block off plates) then i think it will yield the same hp.

Ah, memory did not serve me correct then.

hahaha
You know nothing so dont talk like you do and mislead more people in the process.:wallbash:

Don't take that as an insult because that is a fairly common myth.

The only thing the JDM cars dont have is the EGR and they only have on cat instead of 2 or 3 like the USDM cars.

The usdm cars have a pre-cat and a cat and thats it correct? If so make that basically two cats.

The power output of the two cars is different partially due to the lack of a pre cat on the jdm cars and the higher octane used in Japan. I am about 95% certain the USDM and JDM ecu's are the same aside from JDM ecu having a speed limiter.

If you are trying to make a decision on which motor is better I suggest making your decision based on compression numbers, price, and if you have a chance to peak inside the motor through the exhst ports then you can also judge the internal components condition.

If I lived in the states and both engines were for sale at the same price and roughly the same compression I would opt for the USDM engine.

the general idea thought behind any jdm motor was the that people drive less in japan then they do in the US, so hence the idea that all jdm motors would have lower miles.. it varies.. but with the age of these cars now.. its whatever

does a jdm clip use a different ecu compared to the usdm?

yes, the jdm is N374, but you can use an N370 if you have it. Many have had issues with the jspec ecu and having it not run the fuel injectors on the rear rotor (think it was fuel, that or spark, can't remember). I have an N374, but I haven't tried it yet as the car isn't up 100% and not drivable so I'm still using my N370 N/A computer.

My JDM clip had emissions.

I had a hell of an injector problem with my n374 ecu.

That's strange that some guys have problems running an N374. I am running a RDOM chipped N374 in my 90 turbo right now as a temp. ECU while my N370 is getting chipped by Rtek. But my car runs fine. The only problem i have is being that i did not swap the 5 wires needed to make the N374 work 100% with the USDM engine harness, is that the ECU is running in limp mode. All injectors run fine, and spark plugs fire, it's just that i'm burning very fat. I run 1000 degrees exhaust temp on the freeway cruising. I mean it really burns rich. but better rich then lean as i say. once i get the N370 back from Rtek, i'll be back in business.

Power ratings...

J-spec Zenki FC - 185PS
US-spec Zenki FC - 182HP

J-spec Kouki FC - 205PS
US-spec Kouki FC - 200HP

Convert from PS to HP, there is NO difference.


-Ted

there is a difference... european is 200 PS ^^

I bought a Jspec S5 T2 motor. I had a 30 day guarantee. I found out 4 months later the JDM junkyard sold me a motor with no apex seals in the 2nd rotor. I got screwed 1300$ CDN. I then bought a rebuilt S4 T2 HBP USDM for 1500$ CDN from a fellow rx7club forum member and to be honest it was worth the extra 200$, the 4 weeks waiting to get it shipped, and the scar it left on my left hand from reinstalling everything. I still have a little oil leak but nothing dramatic.

Also, if you do get a package deal on motor/tranny/turbo/ecu/wireing harness, the whole kit. Keep in mind the wireing harness is made for a RHD car and if you plan to install it in a LHD car, the ECU wont be in the stock location. Have fun with that. My humble opinion, stay away from JDM engines.

jdm motors of anysort (ESPECIALLY ROTORIES) should be bought with the pretense that they are gonna need replacement parts (in a rotaries case, there gonna need a rebuild). with that said, if you live in north america, it will almost always be cheaper to get a US (or canadian) spec motor, whether its blown and you rebuild it yourself, or you buy a low miles/rebuilt motor. seriously, there is no reason to buy a j-spec motor, then pay another grand in parts (assuming you can rebuild it your self) to rebuild it. unless your a jspec fanboy and wanna write in your sig, "88 TII= JDM motor, greddy cat back.....etc etc"

JDM wiring harness setup
The harness is longer than the US one an I ran mine over the tranny an hole sawed it so it would then reach an plugged in with no problems in the ecu it came with. Have to mod ecu kick plate but mounts the same. Wrapped harness with heat reflective tape an rigged a grommet were harness came through tranny tunnel. All the hook-ups running from harness to engine fell into place.

Us/jdm
 

[QUOTE=SubZero7;12201972]JDM wiring harness setup
The harness is longer than the US one an I ran mine over the tranny an hole sawed it so it would then reach an plugged in with no problems in the ecu it came with. Have to mod ecu kick plate but mounts the same. Wrapped harness with heat reflective tape an rigged a grommet were harness came through tranny tunnel. All the hook-ups running from harness to engine fell into place. Blew the motor in a 89 gtu N/A and converted to JDM T2. Running over tranny an to ecu after hole sawing made it problem free. JDM has a much longer harness. The wiper motor is a different story. Running it directly from wiper switch to motor with a fuse as JDM harness doesn't have separate clip for wiper motor.