Supra Diff Conversion (2WD Cosworth)

[Cochyn]

Here's some info about the new kit to fit a 3.73.1 ratio differential from a MK3 Toyota Supra. A 3.9 ratio is also available, both diffs have an LSD as standard and are very strong as standard. None have failed with the high powered Cosworth's here in the U.K. and they are very cheap to buy














http://s896.photobucket.com/albums/ac16 ... G_0772.mp4

They have loaded all the CAD drawings onto their 5 axis machines and will update as the process develops. Material used is a 080M40 high tensile steel which is used for shafts and stressed pins, so well up for the job!

They've decided to make the main mounts that hold diff in beam from billet, which is a very high grade with high tensile strengh. Doing it this way, there's no chance of movement from welding etc, plus the sections will be very thick unlike bits plate but still lightweight being alloy, these will rummbled which is like deburing the surface and peening all in one stops any sharp edges etc were stress points could form then will be anodised for protection.

Mine ready to go on...







Some updates from Mark. He's machined the underside of the mounts that feeds the threaded section through the wing mount of the diff itself.





Main beam brackets complete, they look epic!!!!

















Mark has done the CV flanges and fitted them onto his diff using a Cossie joint.

I'll be getting the first unplated kit next week to fit to my car since it's all ready and waiting to be fitted up and tested. I'll go out and give it some abuse, then remove it all and give the thumbs up.













Here's another update, the prop flange all finished...





UPDATE

The prop adapters have been finished off so I should have the first kit at some point this week to test.



Here are the mounts fitted to a beam with Supra diff in place. Clearly still unplated, but fitted for test.






And the main diff mount CAD drawing which will incorporate bushes like the others that will be machined all in billet. So there's no welds at all in this kit.







Almost done



Diff mounts done, whole thing ready for plating now I think...







Pic of the top plate, awesome stuff!

[SK Racing]

Impressive work, to say the least.

[Släggmek]

Awesome parts, just got to love the seriousness and degree of attention to detail that has been put into the project and the design work. And thanks for taking the time and bother to photograph it all and uploading it here along with a good description for us all to see .

I´ve read somewhere about the Supra gearboxes being just about bullet proof, so it seems very worthwhile to use the differential, too. I remember a local Supra (2nd gen) that was converted way back in the late eighties with a Chevrolet smallblock V8 engine and as far as i know the original driveline of the car was kept intact as far as possible aside from modifications needed to mate the engine to the tranny bellhousing and gearshaft. A real nice build and i never heard of any breakdowns. Last thing i heard it is still around and running somewhere here in the north of Sweden. Some stout machinery the japanese put out when they set their minds to it, only making it better by re-using it in a Ford .

[Cochyn]

Sounds like an awesome car Yes the gearboxes are quite good, but like everything mechanical, there's lifespan limits and no doubt the Supra diff will die a horrible death as well.....especially with the way I push and drift

Hopefully the whole kit will be finished and plated by next week so I can fit to my focus and have a bit of a test Will take some videos of it

[Släggmek]

Yeah, quite tasty for a Toyota , the shaded black over brilliant red paint job makes it stand out kind of like a Transformer toy robot on wheels, and the exhaust sound is true motoring music . I think the exhaust was made by Borla, at least the end tips looked like theirs.

As for IRS differentials, my experience is that some are quite stout even though they´re small. I fondly remember the ones under my own seventies Datsun; although they weren´t limited-slip i only whipped 1 to death and even that took a while since the car was already a performer when i bought it, breaking a fatigued driveline joint merely a month later... ´Think i´ve still got the second differential gear, intact, still lying around somewhere as a piece of memorabilia from the car. It´s been said that the same type was used in the Subaru light pickup trucks of the seventies and eighties, but that being an limited-slip version being even tougher, that seems to have made it into some Datsun 610´s and the like by the hands of crafty owners. But now i digress from the main subject, as always... . I guess just about anything can be broken, if you put your mind to it - i know i did back in the day, having a real good time checking the limits and collecting some knowledge the hard way.

Well, the best bet besides the Supra differiential i think would be if it was possible to get a Dana 30 differential gear set into an IRS housing, or maybe if you could build a new casing out of the centerpiece of the common straight axle they´re usually found in (Volvo 200 and 700 series uses the Dana differential gear in their axles as far as i´ve been told, and the damned things easily withstands the torque of a moderately hotrodded Chevy V8, like the one in that Supra). Just my on the subject. The 900 series uses an IRS setup which propably is just about as tough (Volvo guaranteed that somewhere above 200 HP could be thrown at the straight axles, it might have been 240 for the 700 series but i don´t have the exact figures at hand). Around here they´re still both plenty and cheap at the junkyards, might not be the same in the UK i guess. The connecting plate at the front of the differential might even be possible to adjust through some machining to fit a classsic Ford RWD driveline (the sizes are almost a match).

As for non-Ford replacement gearboxes, BMW:s seem to be a good although not simple choice when the Type 9 and it´s successors reach their limit of strength, but as i understand that requires some heavy work being done to match the bellhousing (usually by cutting & welding the front portion of the housing from one box to the other) and other parts to the Ford engines. I just might ad that swapping in a BMW gearbox is a commonplace conversion in many serious Volvo builds, that might say something about the raceproven strength of that Dana final gear in those cars.

[Cochyn]

Diff kit finished and plated! :drool:

[Stiggen]

How mutch does the kit cost?

Regards


//Stiggen Ove.S-Racing
http://www.garaget.org/Stiggen-OSR

[Cochyn]

Around £580 depending on where you source a diff. So I believe that's 5,750 SEK?

[Cochyn]

ALL FINISHED!!!!!

[Skinkis]

Around £580 depending on where you source a diff. So I believe that's 5,750 SEK?

Not sure if I read that right, does that price include a diff, or is it just for the actual mounting kit, and a diff can be sourced by the buyer at a later stage?

[Cochyn]

I just used a currency converter on google, not sure if it's accurate

The kit is £480 and the diffs you can source from most breakers or salvage yards for between £60-150

[Cochyn]

[Cochyn]

Mines sitting pretty at top of the drive, but can't go anywhere because I need 2 new exhaust bushes

Can't thank Mark @ MK Motorsports enough for all his hard work in developing this kit. Amazing craftsmanship and beyond helpful with any issues that needed resolving. Legend!

[Cochyn]

MOT'd up, new oil in diff and the usual tinkering done for another year. Thanks SCS








And Jimbo's Saph now complete...

[Cosyboy1979]

Hello from England. Im looking for asupra diff conversion fitting kit? I have the diff so just need a fitting kit? No e available in the UK at the moment. Does anyone have one to sell? Thank you.
Adam