JDM vs USM SVXs
 

Has anyone ever noticed that acceleration and mileage figures are better for the SVX in other countries? And people say that the they use different trannies and computers between the different countries. So I was wondering, what are the exact differences between the US and foreign SVXs, and how many different versions are there? And can we put the foreign ECUs that rev to and shift at 7,100 RPMs and give high 6 sec 0-62 times in our SVXs?

I wonder if the US SVXs were just detuned to deal with our "inferior" (compared to the JDM version) trannies and emissions regulations. Oh, and what are the differences betwen the JDM trannies and ours?

And I wonder if the shutting down of the cylinder banks was also a feature left out for US SVXs, because weather i'm driving the car hard and in the city (17 MPG) or on the highway at about 60-80 MPH (19 MPG), I get basically the same mileage as you can see. Hmm..

Any thoughts?

Your post is, for the most part, pure nonsese. No offense. :)

Yes, JDM (and therefore European and Australian market) SVXs use a different tranny. But other than that the differences are pretty superficial. I've never heard anything about SVXs 'shutting down' a cylinder bank. But I have heard reports of wildly different mileage from members on this board. Hell, my own SVX has gotten as little as 15mpg and as much as 31.

US SVXs were not 'detuned.'

I don't know about the ECUs, but I would bet that differences would only go so far as the different fuel used in parts of the world, different communication standards, etc.

If I'm wrong on any of this, somebody feel free to correct me.

if you could swap out a JDM TCU for a 7,100 rpm rev limiter, i'd do it in a heartbeat..

i HAVE heard that the ECU will pull fuel from the right cylinder bank during the 1-2 shift to make it a little less "harsh" on the flexplate and torque converter.. i forget where i read that , and i don't know if it's even true, but i've heard of it..

-adam

Do you have the R&T guide to the SVX? I can dig it out if you don't and point out where it talks about shutting down one of the cylinder banks during the 1, 2, and 3 shifts, but not the 4th, among other tranny info. I *BELIEVE* it said it had a sort of displacement on demand system that when the TC locked up, one of the cylinder banks shut down, just like when it shifts.

The original reviews of the SVX had 0-60 in 7 seconds, and in the Automobile mag review, it said that shifts were creamy smooth right up to the 7,000 RPM redline. I can dig that out too if you want.

No offense taken lol...i'm not intending for people to take what I say as gospel, but I guess I just have an inquiring mind.

Oh yeah...and this Australlian magazine I bought on eBay had a big article about why the SVX and 300ZX failed, called "The X Fails". It was on a 1996 yellow SVX, stock, and it did 0-60 in 6.8 secs. Hmm...

Wow...with me throwing all these claims around I better pull these mags out and check :D

P.S. - It was here in these forums that someone told me that he US and JDM trannies were "completely different beasts"

My seat of the pants impression is that during shifts, the ecu does not shut down any cylinders or pull fuel from any cylinders. The car feels too smooth for that. I've read elsewhere that the ecu retards the timing by about 10 deg when the tranny shifts. That feels more like what's happening to me.

The trannys have different center diffs and a different final drive ratio. I would guess there are some other internal differences owing to the different center diff designs.

I have said it before, take the R&T and such mags for what they are worth. They truely are not SVX technical manuals regardless who pay whome to do it.

L

Would final drive diferences cause different performance numbers?

And do the JDM trannies have the problems ours have, like cooking the clutches?

Well, most of the stuff is true, but I think it's probably 100% true for the japanese versions. And it's not R&T's fault, because Subaru provided them with the answers to their questions. Thats where my curiosity lies...why would the tranny and other things, except emissions stuff, be changed for the US market?

If we wanna know the diffrences then lets ask our forign SVX members about thier SVX's... Lets ask them about the 7100rpm thingie... And the shutting down of the cylinder banks... And thier fuel economy and Performance... And if they have an english written SVX Work manual to look stuff up for us that would PROOVE things that people have been claiming here for years!!! Lets take this route...

Okay well, then maybe you could guide me in the direction of those members???

Oh, that's what you're talking about. Yes, I do have the R&T Guide, and I do remember that the car supposedly cuts fuel when the tranny shifts. But the shifts are so long, I don't know when this is supposed to happen.

But I've never heard a claim that the engine is capable of 'displacement on demand.' I think you misinterpreted the book.

And they are, which is what I said in my first post. I'm still waiting to see a picture or a diagram of one. If anybody has such information, I'd appreciate you sharing. :D

OAB_AU (Australia), Jam SVX (Sydney, Australia) , Trevor (New Zeland)


Try looking in the regional forums.... DUH!!! There are people from those REGIONS that post in there... It isn't that hard man... :rolleyes: :p :cool: :cool:

I just looked at the R&T Guide, and here's the quote I found concerning the fuel cut:

"To make first to second gearshifts of the electronically controlled automatic transmission buttery smooth, fuel delivery is momentarily cut to three of the cylinders as a torque abatement method."

See, there's no claim of shutting down a 'bank' of cylinders - it just cuts fuel to whichever three cylinders it needs to in order to make the first shift smooth.

I'll buy that - the 1-2 shift on my SVX has always been quicker than the 2-3 or 3-4.

But I see no mention of displacement on demand.

The difference in final drive would cause the non-USDM SVXes to be a little quicker. The non-USDM trannys seem to be more failure resistant than the UDSM ones. There are few things to break and at least one less source of heat generation.