Diff - The Hard Or Easy Way?

[Melmac]

Hi guys,

 

First of all, please excuse me for my bad english.

 

I have read all postings about the rear of the small Triumph's but I still don't know what to do.

 

I have a 2.7 litre GT6 Mk2. Don't know exact how much power because the car sat on the exhaust pipe at the dyno test so we couldn't get full friction. The guy behind the computer guessed at around 200 bhp.

 

The gearbox (T9 by Frontline Developments) feels reliable but when it comes to the rear I'm really scared and it's not fun having to think about that all the time. So what do you experts out there recommend; the Subaru diff with all that comes with it or the easier way, Quife transplant together with the Canley drive shafts?

 

I don't aim at a late racing career, just to embarrass friends and others with really expensive cars

 

 

[Gunner1]

Hi Melmac,

 

Very nice Gt6. What engine do you have in it? What was the reading on the torque?

 

I would not mess around with anything other than the Subaru alternative.

 

I did a Datsun 240Z (same as Subaru) diff swap 35 years ago that has survived a 160 hp Tr6 transplant, and now a 3500 Rover V8

For details on how to do it, check out my thread on  Member's cars and threads. It is headed with "Gt6 Rover V8".

 

Gunner1

[zetecspit]

I have fitted a subaru diff to my zetec powered spitfire, and although only a few months ago, it has been seriously abused.With no signs of any issues. So dropping the clutch at 5000rpm is not a worry, and indeed being careless and locking the back wheels by changing down a gear at the wrong moment on trackdays has all been taken in its stride. Any of those things would cause a triumph diff to destruct.

 

The problem may be sourcing the parts, as it requires nicks CV conversion which uses the subaru inner CV's. Not to mention mounting the diff, though all the bits are available if you look carefully and are patient.

[Melmac]

Thanks guys!
I envy you!

The engine in my car was a TR6 (PI I think).

Since the dyno test was a complete waste of time I din’t get any diagrams. The dyno guy said that there was a nice curve going straight up but then it got a severe attack of Parkinsons. Not enough friction thanks to the exhaust against the floor. They tried to spray some glue but it didn’t help much.

I have to rebuild the exhaust system, maybe not 2.5†this time.

The biggest problem for me is to find the right bits for the diff conversion. I can get a diff (and drive shafts) from a 2002 Subaru Impreza WRX STi (43.400 miles). STi means R180, yes?

Concerning the MG parts it’s nearly impossible to find them in this country. Rover parts totally impossible. So with that in mind and that it’s kind of stupid trying to invent the wheel again I was thinking of getting in contact with someone in GB who have already done this. First to help me find the bits and then with the fabrication/machining as well. I don’t want to destroy my existing uprights because I want to drive the car until it’s time for tranplantation, so I got to find those too. New or used.

I also have to make the infamous back plate. Or there have been new ones made somewhere?
Gunner1, I love your solution! It’s really clever, but I don’t think I want to take the modification that far. Or will I …?

[Kusanagi]

Another diff to look at is the ford Granada ( sierra ) diff as this can be fitted with very little modification to the chassis.

 

 This is the diff I have used in my injected v8 spit which is in the area of 200bhp and have had no problems so far, I have made my own uprights and drive shafts ( see my thread 8pot spit in members cars for more details ) but it can be made to fit with the rotoflex uprights with a little work.

[Melmac]

I wouldn't have guessed that such a big diff could fit in there. Is it a 7" with LSD?

The first 3 of your pages show no pictures anymore, that's frustrating because I'm very interested in this alernative. Ford parts are common here.

Do you think it's possible to get the pictures in again?

[Kusanagi]

It is a ford 7" diff but it is not a LSD but it has a very good ratio ( 3.38 to 1 ) but a 7" LSD would fit the same. The missing photo's only show an early design of the diff mountings which I discarded as they required modifying the bodywork of the car where as the current set up does not.

 

  The only down side of the current set up is the spring mount is moved up about 1.5 inches so the cars ride height at the back is dropped by the same amount and you also lose some tension there as well, the only way to fix this is to replace the shock absorber with a coil over shock absorber.

 

  It is also worth stating that you can only use the ford diff with a suspension setup which uses a lower suspension arm ( like a rotoflex setup ) as the diff will not take any side loadings ( like a standard swing axle setup ).

 

  I will try to get under the car to get a couple of up to date photo's of the setup but this may not be for a few days. 

[Melmac]

Yes, I was just wondering how the height would affect the spring. I have seen how some guys use aluminum arms instead and then coil overs with that. Looks nice and I think it works well too. I have to look in to that a little bit more.