JDM driveline swap

[longassname]

I've put 300 something miles on the jdm driveline and everything is good so I went back to my US ECU so I can update the firmware without having to socket the JDM ECU. I installed the JDM version of stage1av1 into my US ECU. It's a huge performance improvement over the stock jdm tuning which had some areas of noticeably weak acceleration. There aren't any trouble codes so far. It's looking good so far; I'll drive on it a while and then I'll dig into the TCU.

[longassname]

I'm up close to 500 miles on the jdm driveline and still no trouble codes or issues. I think it's safe to say now that the jdm firmware can be used in the US ECU with a jdm engine. That means anyone who wants to get a jdm engine doesn't have to find a jdm ECU they just need to get the jdm version of Stage1av1.

[92 SVX]

If they want the jdm trans though they still need the jdm tcu?

[longassname]

Yes, that is correct.

Originally Posted by 92 SVX

If they want the jdm trans though they still need the jdm tcu?

[92 SVX]

Originally Posted by longassname

I'm up close to 500 miles on the jdm driveline and still no trouble codes or issues. I think it's safe to say now that the jdm firmware can be used in the US ECU with a jdm engine. That means anyone who wants to get a jdm engine doesn't have to find a jdm ECU they just need to get the jdm version of Stage1av1.

What are the differences in the jdm firmware, and the usdm? other then no egr?
I removed my egr on my 92 with no ill effects could I run with jdm firmware?

[longassname]

I haven't tried to go through cataloging differences between jdm and us firmware. The tuning is different in the stock versions but I use the same tuning in both the JDM and US versions of stage1av1. There may be some benefit to using it in a US car that has the egr removed but I haven't searched it out.

I don't know how the stock JDM tuning performs with Japanese gasoline but it performs poorly with US gasoline. The dreaded hessitation US cars experience with stock firmware is the same or possibly worse with stock JDM firmware. It's very nice to be driving on stage1av1 now. The stage1av1 is a huge improvement over the stock tuning. Acceleration is instantaneous and smooth and you can hear the growl of an engine that has all the ignition timing it wants.

Originally Posted by 92 SVX

What are the differences in the jdm firmware, and the usdm? other then no egr?
I removed my egr on my 92 with no ill effects could I run with jdm firmware?

[92 SVX]

Ok I have one of your chips bought it in Feb 2011 it's that the same then?

[longassname]

Yes, you would presumably have a stage1av1

Originally Posted by 92 SVX

Ok I have one of your chips bought it in Feb 2011 it's that the same then?

[longassname]

actually it looks like I'm not active enough on nasioc to be granted the priviledge of posting in their for sale forums....either of you want to try to get rid of the 3.45 rear end with the wrx lsd for me?

[longassname]

As a follow up: I'm still enjoying the jdm driveline. It's a nice set up. I like the 3.7 gear ratio and the vtd. I also like not having egr.

I now have ECUtune firmware in the TCU as well. As I mentioned when covering my going through the transmision, I left the valve body stock in this one so I could use it to work on line pressure maps. I've been doing that.

to summarize:
1)with stock TCUs I like the JDM transmision better than the US. If you have a bad transmission by all means find yourself a JDM TCU and get yourself a JDM transmission.

2)The shift maps in the ECUtune version of JDM firmware really made a nice difference. I had ported the shift maps from the US ECUtune firmware over to the JDM firmware and been told by customers that they were very happy with the results but now I'm driving on them myself. I'm very happy with the results. I don't think you can install the ECUtune version of JDM firmware into a US TCU and haven't tried but it may be possible you can install it into a European TCU. The supply of JDM TCUs seems to be annoying locked up thus far by someone less than sharing; however, there are a good handfull of European SVX owners who may be able to get us EU TCUs.

3)I've made further modifications to line pressure maps which only I and a handfull of people around the globe have been trialing. Things are going well and improvements are very nice. They aren't really specific to the JDM driveline though so I will cover them in more detail elsewhere.

[92 SVX]

Very nice update, I love manual trans but if I could find jdm trans and tcu I might be tempted to keep it auto, with the rear bias it would be nice.

['E']

Can you convert a usd box to vtd and if so what part of the vtd box do you need? I'm assuming it's mainly the centre diff.

[longassname]

Here E,

I put pictures when I covered the actual work in the begining of the thread. The mpt, extension housing, and mounts on a US transmission could be replaced with the VTD parts with the transmission still in the car. I don't remember for sure if the harness and speed sensor are different or not. I think they are in which case you would probably have to cut off the us speed sensor and connect up the jdm sensor or get a jdm harness.

Originally Posted by longassname

So..... into the vtd transmission.

The transmission itself is the same as the US part. All of the differences are in the extension housing. The exception to this is the Japanese seem to put more loving care into the assembly of their own stuff than they do ours. There are paint marks from gear matching and hand assembly checks all over this thing.

Here's a picture of the vtd extension housing.
http://www.ecutune.com/posts/jdm/DSC_9012.JPG

open it up and you find the vtd:
http://www.ecutune.com/posts/jdm/DSC_9015.JPG

pull it out and you have a 4eat just like any us model
http://www.ecutune.com/posts/jdm/DSC_9037.JPG

skipping forward to when i put it back together and we have a vtd again
http://www.ecutune.com/posts/jdm/DSC_9039.JPG

transfer clutch frictions going back in
http://www.ecutune.com/posts/jdm/DSC_9046.JPG

output shaft put on
http://www.ecutune.com/posts/jdm/DSC_9051.JPG

rebuilt jdm transmission closed back
http://www.ecutune.com/posts/jdm/DSC_9060.JPG

['E']

Ok, I have 7 of these gearboxes lying around

[longassname]

What about TCUs?

Originally Posted by 'E'

Ok, I have 7 of these gearboxes lying around