2006 - MPT to VTD conversion!

114022 Views 238 Replies 50 Participants Last post by nutville, 2 mo ago

a6n6d6y

Discussion Starter · Jul 19, 2008 (Edited)

7

this mod is intended for US vehicles without VDC as all others (AFAIK) allready have this type of differential

edit: looks like 2007+ XTs have this as an option as per http://www.subaruforester.org/vbulletin/f63/usdm-forester-specs-options-prices-all-years-34187/#post435339

this mod will do little for your vehicle unless your making A LOT of power

as you can see the diagram has the first half of the part numbers (for the most part)..I have a wad of papers that finished them by Year Motor etc

Edit by admin: parts list and diagram attached and downloadable below.

if you copy and paste the part numbers into one of the OEM parts sites you can get a total cost..(note the quantities on some of them)...and they will put them in a box and ship them to you..then you (or your favorite transmission shop :icon_wink

must assemble and install, however, this project will require the use of a shop press and some specialty tools (or their home made equivalent :icon_idea: )

This article explains this diff well: see downloadable 4eat.pdf attachment below

once this is assembeled installing it to the transmission is fairly straight forward...if you have never opened an automatic transmission this may not be a job for you :evilatyou:

here they are side by side left MPT right VTD

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1 - 20 of 239 Posts

g00fy

· #2 · Jul 19, 2008

So you need the center diff, and a different tail housing?

a6n6d6y

Discussion Starter · #3 · Jul 19, 2008

g00fy said:
So you need the center diff, and a different tail housing?

yes, if you are curious save the diagram and parts list and you can match up most of the stuff ...some of the numbers don't line up well ..the "G" parts start with "806" on the list then the number on the diagram, a little confusing but doable

g00fy

· #4 · Jul 19, 2008 (Edited)

a6n6d6y said:
yes, if you are curious save the diagram and parts list and you can match up most of the stuff ...some of the numbers don't line up well ..the "G" parts start with "806" on the list then the number on the diagram, a little confusing but doable

Well odds are i'm gonna let IPT figure it out because the 4eat is far beyond my and many of my friends technical know-how. Glad to hear it just bolted right in with no issues, that should make it a quick job for IPT.

I also had 1 more question andy, how's it feel to wake up in the morning and piss excellence?

Reactions: 1

a6n6d6y

Discussion Starter · #5 · Jul 20, 2008 (Edited)

g00fy said:
Well odds are i'm gonna let IPT figure it out because the 4eat is far beyond my and many of my friends technical know-how. Glad to hear it just bolted right in with no issues, that should make it a quick job IPT.

I also had 1 more question andy, how's it feel to wake up in the morning and piss excellence?

it's temperd by the hangover from drinking it away the night before :biggrin:

also let me run it for a while to see how the TCU responds

Andy_PHA

· #6 · Jul 20, 2008

nice I'll be keeping an eye on your progress.

thefoos

· #7 · Jul 21, 2008

I don't have an auto, so this doesn't apply to me. But I'm curious none-the-less. What are you up to here?

a6n6d6y

Discussion Starter · #8 · Jul 21, 2008

thefoos said:
I don't have an auto, so this doesn't apply to me. But I'm curious none-the-less. What are you up to here?

getting rid of the "not high horsepower friendly" MPT center diff and replacing it with one that is high HP friendly plus it just feels better driving with it..more balanced accelerating in turns

a6n6d6y

Discussion Starter · #9 · Jul 21, 2008

OK so the TCU responds well, the p0700 mil request went away as I expected.

I removed the FWD fuse and the car drove fine, a little tightness with the steering wheel hard over but no more than I would expect

I am going to leave the FWD fuse in so as to preserve the clutch pack as there is very little benefit to having the TCU control the AWD at this point ...maybe winter will change that , but for now I will let the diff do its thing

at this point I have to say this modification is a resounding success and I am extremely happy with it :woohoo::woohoo::woohoo:

guroove

· #10 · Jul 21, 2008

Andy, this is awesome. AFAIK, this is uncharted territory as far as 4eat mods. Does the VTD diff change the torque split or is it static? Are you able to bring on power induced oversteer?

a6n6d6y

Discussion Starter · #11 · Jul 21, 2008

static 45/55 with a clutch to lock the f/r together

yes :biggrin:

Andy_PHA

· #12 · Jul 22, 2008

I don't understand what you are doing with the FWD fuse. Is it just that this center dif doesn't need the TCU to tell it what to do? With the fuse in are you still AWD? I must say when it comes to the trans I'm lost and even more so when it comes to the diffs

a6n6d6y

Discussion Starter · #13 · Jul 24, 2008

Is it just that this center dif doesn't need the TCU to tell it what to do?

that is correct, however it can be controlled by removing the fuse..plus I still have the manual lock :biggrin: but I am not finding any need for it anymore

With the fuse in are you still AWD?

yes, there is no way to disable the AWD with this diff.

g00fy

· #14 · Jul 24, 2008

I'm gonna need this mod ASAP this 20G is outragouse, I'm gonna end up toasting this center diff very quickly.

a6n6d6y

Discussion Starter · #15 · Jul 24, 2008

g00fy said:
I'm gonna need this mod ASAP this 20G is outragouse, I'm gonna end up toasting this center diff very quickly.

I made Ty aware of this mod and where to find it...they may be able to take the Diff off another trans instead of buying the parts new..???

g00fy

· #16 · Jul 24, 2008

a6n6d6y said:
I made Ty aware of this mod and where to find it...they may be able to take the Diff off another trans instead of buying the parts new..???

Yea i'm assuming they'll be able to source me the used parts for alot less money, now the question is if they want to give it a shot.

funkymonkey1002

· #17 · Jul 24, 2008

Nice job! If the tcu were switched would full vdc be available?

a6n6d6y

Discussion Starter · #18 · Jul 24, 2008 (Edited)

funkymonkey1002 said:
Nice job! If the tcu were switched would full vdc be available?

AFAIK the VDC replaces the ABS computer and pump

but I don't see how that conversion would be economically feasible as there is a lot of other stuff involved with VDC

Mi_ka

· #19 · Jul 24, 2008

Nice mod!

The MPT can move power abruptly rear-to-front on the wrong time.
Going too fast on a gravel road I lifted my foot too fast while attacking a corner, the MPT released transfer to the rear ( to help braking as supposed too) and I found that the car over-oversteered and I started a fish-tailing sequence as the back of the car felt too light as the front wheels had more grip than the rear that have been realeased by the MPT. I regained control only when I floored it and the MPT moved power to the rear again.
All this beside a 200ft cliff.
I suppose that with this mod I would have a more consistent behaviour by the car with the constant 45/55 split. But again, I was pushing the envelope...

a6n6d6y

Discussion Starter · #20 · Jul 28, 2008

well I got around to launching the car today....holy crap What A Difference, felt like my seat back was going to break :woohoo:

no tire squeal or any of other BS the thing used to do it just jumped up and WENT

hopefully I will be at the track Wednesday and I'll see how much the 60' improves :rock:

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