This is applicable for the sh5! We have the vdc as well. Hmm... I'll give this a thought when and if ever I do reach that 400 whp. Thanks for sharing! Might be applicable to another club member. I'll let him know
2006 - MPT to VTD conversion!
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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I no longer have a forester, but I stumbled upon this while researching how to make my 2.5RSTurbo with 4EAT 4WD for the snow coming up...
whats up with the FWD fuse in? does it disengage something like in my current stock 4EAT? or just keep the nagging AWD light away?
I'm not making crazy hp, just a bit over 210awhp, but it would be nice to be able to get the rear to slide around a little easier than the off throttle oversteer then punch it method.
whats up with the FWD fuse in? does it disengage something like in my current stock 4EAT? or just keep the nagging AWD light away?
I'm not making crazy hp, just a bit over 210awhp, but it would be nice to be able to get the rear to slide around a little easier than the off throttle oversteer then punch it method.
In the MPT transmission the signal that controls the MPT engaging the rear drive is interrupted by inserting the fuse. In the VTD transmission, that signal is used to control the clutch pack that changes the power distribution from 45/55 to 50/50. So with the fuse in, the torque distribution is entirely based on the gear configuration, and not the clutch pack, giving you a constant rear bias.whats up with the FWD fuse in? does it disengage something like in my current stock 4EAT? or just keep the nagging AWD light away?
At least this is my simplistic understanding of it. If someone knows more about how this works, feel free to chime in.
a6n6d6y, is your transmission still holing up well with this mod? Other than the AWD light flashing, are there any other downsides?
Other questions as I ponder conversion:
- Do you have to change the front or rear diff to work with the 45/55 center split? Or can I leave them both 4.44?
- Does the AWD light flashing mean that the TCU thinks the wheels are turning different speeds all the time? So is the transfer clutch trying to lock up all the time if the FWD fuse isn't in?
- I want this mod just for handling and voluntary power oversteer fun. With stock-ish power levels, should I even worry about taking the FWD fuse out at all? Have you driven in snow with/without the fuse? I want the handling improvement, but don't want to give up my snowboard roadtrip vehicle for it.
Other questions as I ponder conversion:
- Do you have to change the front or rear diff to work with the 45/55 center split? Or can I leave them both 4.44?
- Does the AWD light flashing mean that the TCU thinks the wheels are turning different speeds all the time? So is the transfer clutch trying to lock up all the time if the FWD fuse isn't in?
- I want this mod just for handling and voluntary power oversteer fun. With stock-ish power levels, should I even worry about taking the FWD fuse out at all? Have you driven in snow with/without the fuse? I want the handling improvement, but don't want to give up my snowboard roadtrip vehicle for it.
Has anyone else tried this?
I'm more interested in fixing the A/T light with the FWD fuse out, where might I find a speed sensor converter?
Think this might work??
Cyberdyne 9901 Cyberdyne Speedometer Calibration Box
or, I saw a "What is a microcontroller" kit at radioshack, looks like you can build one and maybe install rudimentary code to convert the signal to what I would need it to be
What's a Microcontroller BASIC Stamp Kit - RadioShack.com
on second thought, after reading the tech specs, this might not work
I have pretty much everything I need to do the swap, I'm also wondering if this makes the car a handful to drive in the wet, or snow
any thoughts?
Thanks
I'm more interested in fixing the A/T light with the FWD fuse out, where might I find a speed sensor converter?
Think this might work??
Cyberdyne 9901 Cyberdyne Speedometer Calibration Box
or, I saw a "What is a microcontroller" kit at radioshack, looks like you can build one and maybe install rudimentary code to convert the signal to what I would need it to be
What's a Microcontroller BASIC Stamp Kit - RadioShack.com
on second thought, after reading the tech specs, this might not work
I have pretty much everything I need to do the swap, I'm also wondering if this makes the car a handful to drive in the wet, or snow
any thoughts?
Thanks
It is better to leave it alone as there is a good chance of having erratic locking results by the TCU if you do not get it right.
Eventhough it is not really complicated it would require some experience to make the timing mod and the whole circuit correctly so I would not advice it to fresh microcontroller starters. If you do some mistake in the general design you could have bad TCU behavior at the wrong time when driving - too much to lose to learn trying to have it right.
The first product says about adjusting "through a knob" that means no exact results so, again, it may mess things up under the right circumstances.
You need exact conversion preferably done in assembly code to be sure what goes on in there. Vehicle applications require topmost reliability.
Eventhough it is not really complicated it would require some experience to make the timing mod and the whole circuit correctly so I would not advice it to fresh microcontroller starters. If you do some mistake in the general design you could have bad TCU behavior at the wrong time when driving - too much to lose to learn trying to have it right.
The first product says about adjusting "through a knob" that means no exact results so, again, it may mess things up under the right circumstances.
You need exact conversion preferably done in assembly code to be sure what goes on in there. Vehicle applications require topmost reliability.
I'm pretty sure that the VTD basically behaves as an open diff without the clutch packs activated with a rwd bias when the FWD fuse is in. It would be like having dccd in open mode.In the MPT transmission the signal that controls the MPT engaging the rear drive is interrupted by inserting the fuse. In the VTD transmission, that signal is used to control the clutch pack that changes the power distribution from 45/55 to 50/50. So with the fuse in, the torque distribution is entirely based on the gear configuration, and not the clutch pack, giving you a constant rear bias.
At least this is my simplistic understanding of it. If someone knows more about how this works, feel free to chime in.
I think the best bet for non-canbus foresters to use VTD would be to use the 03/04 Baja XT tcu. They had the same driveline as the forester, but with VTD and sportshift in the 4eat. Just have to see if the baja TCU and the forester TCU have the same pinouts.
Ok, great, as long as people are still watching this thread, I will post my findings.
I agree a microcontroller with the correct instructions would be the best choice, but since I have no background in assembly code, none, I think I may try the speedo calibration box and see how that goes. If I understand it right the rear wheel speed sensor produces a square wave pattern ON-OFF-ON-OFF-ON, and it uses the frequency of time of the pattern to obtain rear wheel speed, all I would need to do is modify that frequency so that it showed the correct wheel speed. From what I've seen, the front wheel to rear wheel speeds can be of by 1 MPH and not hurt anything, anything more and it might see that as slipping and use the transfer clutch to try to keep them the same wheel speed. I'll count the teeth on both the MPT and VTD and see if they are different or not. I have access to a select monitor so I can see the wheel speed difference after I get it in.
The 3rd-gen F-body crowd have been using the speedo calibrators to dial in larger wheels and trans swaps and the hot-rodders with digital dashes have been using the calibrators with great success
So it looks like some testing is in order, I'll hook up a pressure gauge to the transfer port and measure pressure and voltage going to the transfer solenoid with and without the FWD fuse is, with the MPT still in place, and then with the VTD installed- should happen later this week
To funkymonkey: I believe you are right about the VTD being like an open dccd with the FWD fuse in, as for the 03-4 Baja, I doubt the pinouts are the same, I'll look it up and see, I also wonder if I would also need the valve body for the sport shift to work, hmmm
I agree a microcontroller with the correct instructions would be the best choice, but since I have no background in assembly code, none, I think I may try the speedo calibration box and see how that goes. If I understand it right the rear wheel speed sensor produces a square wave pattern ON-OFF-ON-OFF-ON, and it uses the frequency of time of the pattern to obtain rear wheel speed, all I would need to do is modify that frequency so that it showed the correct wheel speed. From what I've seen, the front wheel to rear wheel speeds can be of by 1 MPH and not hurt anything, anything more and it might see that as slipping and use the transfer clutch to try to keep them the same wheel speed. I'll count the teeth on both the MPT and VTD and see if they are different or not. I have access to a select monitor so I can see the wheel speed difference after I get it in.
The 3rd-gen F-body crowd have been using the speedo calibrators to dial in larger wheels and trans swaps and the hot-rodders with digital dashes have been using the calibrators with great success
So it looks like some testing is in order, I'll hook up a pressure gauge to the transfer port and measure pressure and voltage going to the transfer solenoid with and without the FWD fuse is, with the MPT still in place, and then with the VTD installed- should happen later this week
To funkymonkey: I believe you are right about the VTD being like an open dccd with the FWD fuse in, as for the 03-4 Baja, I doubt the pinouts are the same, I'll look it up and see, I also wonder if I would also need the valve body for the sport shift to work, hmmm
Ok, it seems you know what you are doing.
Avoid any dash calibrators with sweep analog trimmers. Select digital controls if available. It would not be nice to have the TCU lock up the VTD while mid-cornering fast because the analog trimmer shifted a little due to vibrations...
If possible to have them checked in the same real world road situation it would be top!
Is the Baja direct control?
Avoid any dash calibrators with sweep analog trimmers. Select digital controls if available. It would not be nice to have the TCU lock up the VTD while mid-cornering fast because the analog trimmer shifted a little due to vibrations...
Very interesting - please do post readings.So it looks like some testing is in order, I'll hook up a pressure gauge to the transfer port and measure pressure and voltage going to the transfer solenoid with and without the FWD fuse is, with the MPT still in place, and then with the VTD installed- should happen later this week
If possible to have them checked in the same real world road situation it would be top!
Very interesting too....as for the 03-4 Baja, I doubt the pinouts are the same, I'll look it up and see...
Sport shift is implemented on direct control 4EATs only I think.... I also wonder if I would also need the valve body for the sport shift to work, hmmm
Is the Baja direct control?
I'm not sure about that, but thanks for the compliment!:icon_biggrin:Ok, it seems you know what you are doing.
Transfer duty pressure and voltage will always be changing due to driving conditions and what the tcm sees from inputs, I'll post what I find though
It does seem that the 04 Baja was able to have VDC and a direct control 4EAT, I printed out the TCM input/output, and a lot of the pinouts are the same, but there are the pins for the sport shift that are different for the baja compared to my car, maybe others too.Sport shift is implemented on direct control 4EATs only I think.
Is the Baja direct control?
So you would have to be sure you could get a TCM, all the sport shift stuff(i.e. switches, combination meter, possibly a BCM if it came with one), and most likely the ABS/VDC module, pretty sure only the VDC models came with the VTD, and most likely the wiring harness for the extra wires- all out of a VDC equipped Baja or Forester
I am pretty sure that the VTD only came with VDC because it would be easy to have uncontrollable oversteer cornering during slippery conditions if it would abruptly kick down along with turbo lag under conditions.
You know, D, 4th, slow slippery corner going up, more gas than needed, downshifts to 2nd, lag, bang, RWD biased tail goes lose, mediocre driver panics etc while with the MPT you just let off the gas pedal to control the usual understeer produced by such conditions.
So the VDC would keep the tail under control for the usual Joe.
Me thinking that is...
You know, D, 4th, slow slippery corner going up, more gas than needed, downshifts to 2nd, lag, bang, RWD biased tail goes lose, mediocre driver panics etc while with the MPT you just let off the gas pedal to control the usual understeer produced by such conditions.
So the VDC would keep the tail under control for the usual Joe.
Me thinking that is...
UPDATE:
Alright, so I've taken the plunge and have to say I can really feel the difference with the VTD center diff compared to the MPT one, I'm not running really high HP yet(250ish maybe), but the car just feels better
With the MPT, when taking off from a stop the front end used to lift up and most of the time get some front tire squeal before the rear axle would get any power- now with the VTD, the thing just gets up and goes- no more tire squeal from front tires even when turning- and with the FWD fuse it- it drives like normal- although I haven't gotten to try it in the rain/snow yet
Due to time restraints I wasn't able to do the testing that I had hoped to do, but I can at a later date- I also figure that pressure and voltage will be the same with either diff, because I would just be measuring the pressure and voltages coming from the valve body
Now the MPT rear wheel speed sensor uses the transfer clutch drum which has 30 teeth on it, and the VTD has a wheel with 22 teeth on it- and confirmed with a Select Monitor that the TCM does get a rear wheel speed signal from the sensor in the VTD housing, but runs slow- i.e. front wheel speed= 30MPH rear wheel speed=22MPH. That kinda surprised me a little, I thought it might run fast, but oh well, I think I'm going to try that speed calibrator box and see if that will allow me to get the wheel speeds close enough to take the FWD fuse out
I also installed a switch to lock the center diff that I received when I bought the VTD set-up, actually I think it might be the kit in the OP, because the shifter looks a lot like the OP's torque converter mod thread- I have a PM sent to him, but no response yet
Well, anyways, it can be done- I hope to get out to the track this week and see if it helps my 60ft times
Alright, so I've taken the plunge and have to say I can really feel the difference with the VTD center diff compared to the MPT one, I'm not running really high HP yet(250ish maybe), but the car just feels better
With the MPT, when taking off from a stop the front end used to lift up and most of the time get some front tire squeal before the rear axle would get any power- now with the VTD, the thing just gets up and goes- no more tire squeal from front tires even when turning- and with the FWD fuse it- it drives like normal- although I haven't gotten to try it in the rain/snow yet
Due to time restraints I wasn't able to do the testing that I had hoped to do, but I can at a later date- I also figure that pressure and voltage will be the same with either diff, because I would just be measuring the pressure and voltages coming from the valve body
Now the MPT rear wheel speed sensor uses the transfer clutch drum which has 30 teeth on it, and the VTD has a wheel with 22 teeth on it- and confirmed with a Select Monitor that the TCM does get a rear wheel speed signal from the sensor in the VTD housing, but runs slow- i.e. front wheel speed= 30MPH rear wheel speed=22MPH. That kinda surprised me a little, I thought it might run fast, but oh well, I think I'm going to try that speed calibrator box and see if that will allow me to get the wheel speeds close enough to take the FWD fuse out
I also installed a switch to lock the center diff that I received when I bought the VTD set-up, actually I think it might be the kit in the OP, because the shifter looks a lot like the OP's torque converter mod thread- I have a PM sent to him, but no response yet
Well, anyways, it can be done- I hope to get out to the track this week and see if it helps my 60ft times
^I can not comment on actual 60' times but when comparing 2 different FXT's, one with VDT(275whp/270tq) MPT(27xwhp/3xxtq) The vdt car pulled times nearly a half second quicker. This was with different drivers, different tracks so take it with a grain of salt.
If I am correct, you should be able to launch it better and at least get into the 1.7's
If I am correct, you should be able to launch it better and at least get into the 1.7's
1.7's would be great, I would be happy with consistent low 1.9's as I'm not putting gobs of power down yet^I can not comment on actual 60' times but when comparing 2 different FXT's, one with VDT(275whp/270tq) MPT(27xwhp/3xxtq) The vdt car pulled times nearly a half second quicker. This was with different drivers, different tracks so take it with a grain of salt.
If I am correct, you should be able to launch it better and at least get into the 1.7's
doesn't look like I'll get to the track this week, but last time I was there, I could get 1.98 a couple of times, but mostly in the low to mid 2's for 60ft times with the MPT
I did end up getting that speedometer calibration box, I hope it will allow me to get the rear wheel speed closer to front wheel speed so I can take the FWD fuse out- I'll take some pics of the install
subarutech77, you the same one at RR right?
Know of anyone doing this for the 09/10 fxt?
Know of anyone doing this for the 09/10 fxt?
Don't you SH guys already have VTD from the factory?Know of anyone doing this for the 09/10 fxt?
Hey MFB, yep same guysubarutech77, you the same one at RR right?
Know of anyone doing this for the 09/10 fxt?
It looks like all 09-10 models of foresters have vdc according to subaru.com, so its most likely that you have a vtd center diff, I would try to get a look at the rear part of your trans, if it's kind of cone shaped it's a MPT- if it's more of a square shape it's a VTD.
Take a look at the pic in the first post of this thread- see the difference in the housings?
EDIT: just looking through an 09 and 10 FXT service manual and it only shows the MPT type center diff- I wonder how the VDC would react with this swap
Did you do the swap yourself? Did you have to remove the whole trans or just unbolted the tail housing? Do you think the VTD differential would fit in a MPT housing?
This is way more cost effective for me than buying the LSD for the front differential I think.
This is way more cost effective for me than buying the LSD for the front differential I think.
Hey MFB, yep same guy
It looks like all 09-10 models of foresters have vdc according to subaru.com, so its most likely that you have a vtd center diff, I would try to get a look at the rear part of your trans, if it's kind of cone shaped it's a MPT- if it's more of a square shape it's a VTD.
Take a look at the pic in the first post of this thread- see the difference in the housings?
EDIT: just looking through an 09 and 10 FXT service manual and it only shows the MPT type center diff- I wonder how the VDC would react with this swap
Is there any front LSD for the 4EAT?This is way more cost effective for me than buying the LSD for the front differential I think.
I though they are only available for the MT, not enough room in the front diff housing. Am I wrong?
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