are "jspec" and "usdm" t2 motors the same?
 

other than EGR, and other small bits, arent Jspec motors generally the same?

are the internals the same?

trying to settle a dispute :git:

yep...

the differences are all exterior engine shit.

The shortblock is the same...

manifolds, emmisions and intercoolers are different pretty much what funkspectrum said.

Other than not having fittings for the EGR, AWS and sub-zero start injector, and being short one vac nipple, the manifolds are basically the same (i.e. everthing is exactly the same size). And other than what's written on them, the intercoolers are identical.

Here a full list of the engine differences:

No non-turbo engine
No EGR (S4)
No AWS
No sub-zero starting assist system
No pre-cat
Different ACV with no split air solenoid
FPR and PD in opposite locations
Twin-scroll actuator on opposite end of exhaust manifold (S4)
No thermovalve on TB

i'm pretty sure that the s5 engines from japan also do not have egr (i was under the impression you were saying that s5 jdm engines do have egr) can someone confirm that none of the jspec engines have egr valves? it ain't really important anyway since you just get a block-off plate right?

No S5 engines had EGR no matter where in the world they were sold.

No thermovalve on TB? So....that could be the one of the issues contributing to my cold start and idle problems....

No, the thermovalve has nothing to do with cold start or idle. I think you're getting confused with the thermowax. The thermovalve is attached to the thermowax and is responsible for holding the #2 secondary throttles shut until the engine warms up, to stop idiots romping on a cold engine. J-spec engines have the same thermowax, just without the thermovalve attached. Mazda obviously trusted Japanese drivers more... ;)

I was under the impression that the J-spec have a sharper bend in them. and about the intercooler thats what I meant, from 13b turbo or w/e to rotary turbo with intercooler

I had heard that some of the J-spec IC's had bigger core tubes, but side by side I can't see any difference.

Nope. Why?

So we agree that the intercooler isn't different then, just what's written on it. ;)

S5 intercoolers have bigger internal tubes than S4 ones. J-spec intercoolers are internally identical to US ones of the same series.