Tcm

97 SVX · #1 09-11-2007, 10:09 AM

Hello from the frozen north
(well not at this time of year

)

I have a JDM trans (97).

Anyone know if the Oz - Kiwi SVX's are the same

and would anyone have a TCM (trans control modual)

or any info that may be pertinent.
Thanks Ian

b3lha · #2 09-11-2007, 02:26 PM

Quote:

Originally Posted by 97 SVX

Hello from the frozen north
(well not at this time of year

)

I have a JDM trans (97).

Anyone know if the Oz - Kiwi SVX's are the same

and would anyone have a TCM (trans control modual)

or any info that may be pertinent.
Thanks Ian

No. We know for sure that the Aussie/Euro TCU is different to the JDM version. It is possible to make a JDM box work with a Aussie TCU, by swapping in an Aussie speed sensor. It has been done. There's a long thread about it.

http://www.subaru-svx.net/forum/showthread.php?t=31506

If you know a computer/electronics uber-geek, it should be possible to download the JDM TCU ROM from my website, copy it to an EPROM chip and insert that chip into the upgrade socket on your USDM TCU. But nobody has ever tried this. It will be a voyage of discovery, so think of it as a very last resort if you can't get a JDM TCU.

Phil.

svxistentialist · #3 09-12-2007, 05:44 PM

Hi guys.

Phil, as the US market utilizes the same speedsensor that is in the diff housing like the Japanese use, what's to say the US TCU won't plug and play with the Japanese box?

Do you think there is some fundamental differences in the software? Or are you basing your remarks on the fact that the JDM box is the fulltime AWD, and that the software to control it will be different from the US rear-assist?

I expect you are correct, they are probably different.

Joe

b3lha · #4 09-13-2007, 05:12 AM

Quote:

Originally Posted by svxistentialist

Hi guys.

Phil, as the US market utilizes the same speedsensor that is in the diff housing like the Japanese use, what's to say the US TCU won't plug and play with the Japanese box?

Do you think there is some fundamental differences in the software? Or are you basing your remarks on the fact that the JDM box is the fulltime AWD, and that the software to control it will be different from the US rear-assist?

I expect you are correct, they are probably different.

Joe

It's quite possible that the US and JDM TCU are actually the same. The unconnected power-mode pin that Nomake discovered is a clue to that. But I've made many assumptions like that in the past and later been found wrong. It doesn't seem intuitive that they would be the same given the different AWD system and the different final drive ratio. Who knows.

There are a few US guys with interface boxes now and I'm hoping that someone will download their ECU and TCU for me to look at. Maybe one day you could download one of your UK cars for me and then we'd have a complete set?

Phil.

Trevor · #5 09-13-2007, 06:31 AM

Quote:

Originally Posted by b3lha

It's quite possible that the US and JDM TCU are actually the same. The unconnected power-mode pin that Nomake discovered is a clue to that. But I've made many assumptions like that in the past and later been found wrong. It doesn't seem intuitive that they would be the same given the different AWD system and the different final drive ratio. Who knows.

There are a few US guys with interface boxes now and I'm hoping that someone will download their ECU and TCU for me to look at. Maybe one day you could download one of your UK cars for me and then we'd have a complete set?

Phil.

Phil,

I established that the C solenoid in the US cars is normally closed, whereas that in the JDM is normally open. This would take care of the alternatives of centre clutch and center differential arrangements, without hardware alterations being required in respect of the required control signal.

One would expect different control parameters to be required and delivered via specific modulation. However it is possible that the variables could be adjusted by other means, leaving the signals identical.

Regards, Trevor.

97 SVX · #6 09-13-2007, 11:40 AM

you are all amazing..
Thanks for the info..

About the dif ratios..different?
Ian

svxistentialist · #7 09-13-2007, 12:17 PM

Quote:

Originally Posted by 97 SVX

you are all amazing..
Thanks for the info..

About the dif ratios..different?
Ian

They are actually different Ian.

So far as I know US cars [and Canada too I expect] run a really high final drive of 3.54. This is no doubt because of the driving experience on the American continent, long straight highways, big miles between towns.

The rest of the world for the SVX got the 3.70 final drive. Still fairly high, but lower than the US.

If you look in my locker here you will see where I made a spreadsheet comparing three ratios.

The high ratio is 3.7, which is the UK autobox I had figures for. The other two are commonly used conversions. The 4.11 was the ratio I had in my Legacy Twin Turbo. The 4.44 is pretty low, and is normally found in the Forester over here.

Most people looking for more power on the road and better acceleration go for the 4.44.

Now that I think of it I must update this spreadsheet, and add in a column for the 3.54 ratio. It is just a matter of doing the sums.

Joe

SURTEESS · #8 09-17-2007, 01:33 PM

I may have one at home - will check tonight or you could try this link, Peter is the guys name, I have bought from him in the past - I see he has 3 SVXs that he is parting out -

http://www.trademe.co.nz/Members/Lis...?member=439082

regards

Steve in Auckland (red 95 - plate number "1 OF 1")