Differential

[adamnreeves]

I am after a 3.62 LSD diff for my build. Searching EBay last night I see that the ford Sierra Cosworth utilised this differential. I am pretty certain that this is a type B 7" or 7.5" so can be used in a westfield SEight V8. I am going for the R380 gearbox. Has anyone gone with this combination, if so, does it work good?

[Mike H]

I'm pretty sure there are a lot of R380 with 3.62 diffs around.  You may find the owners don't use first gear very much though as it's all over by about 30mph.  That in itself isn't necesarily a problem as you'll have plenty of torque in other gears.

I'm using a 3.14 diff with a Cossie T5 box which gives me a full 5 gears - it just took a long time to find.  Also the T5 box needs either a TVR bellhousing or one from John Eales (or the MG specialist that makes them but I can't remember their name - Browns or something like that), both of which aren't cheap.

R380 is straightforward drop in with no reall gotchas.

Mike

[adamnreeves]

I'm pretty sure there are a lot of R380 with 3.62 diffs around.  You may find the owners don't use first gear very much though as it's all over by about 30mph.  That in itself isn't necesarily a problem as you'll have plenty of torque in other gears.

I'm using a 3.14 diff with a Cossie T5 box which gives me a full 5 gears - it just took a long time to find.  Also the T5 box needs either a TVR bellhousing or one from John Eales (or the MG specialist that makes them but I can't remember their name - Browns or something like that), both of which aren't cheap.

R380 is straightforward drop in with no reall gotchas.

Mike

I did look at the T5 very early in my budgeting and thought quite costly and wasn;t sure if it would fit without at least modification. Well done though mate, as I came to the conclusion that the T5 box is not only good because it is very strong but also the ratios are very good providing good acceleration in lower gears but top gear is very high ratio (if I have that the right way round?) I think, something like 0.63? giving excellent touring, quite literally the best of both worlds?

I think I have convienced myself to re-evaluate the T5. When I orderd my Chassis I stated R380 does this rule out the T5 anyway?

[Mike H]

does this rule out the T5 anyway?

I'm not sure that it does to be honest but I may be wrong - factory may be best to advise.

Perhaps the following will help:

The opening of the tunnel on my chassis is 13 inches wide and all I have to mount the T5 on is a flat plate welded to the top edge of the bottom chassis rails.

I'm guessing the R380 is similar from what I've heard.

The T5 (in my car) then uses the standard small ally casting from the Cossie that bolts to the gearbox tail with 2 big bolts.  This has a threaded M12 hole on the underneath which you then use with a Type 9 'cup' style mount that you can get from Westfield. You fix the Type 9 mount to the chassis plate with a couple of M8 nuts+set screws.

The chassis plate was undrilled so I had to trial fit the engine and box to get the correct position for the M8 set screws.  I seem to remember supervising while Barry shuffled around under the car <!--emo&

Best to check with a R380 owner or the factory to be sure if you can change your box.

Would I do it again? Not sure yet as I haven't driven the car and won't be able to compare it to anything.  Although Ian Crokers' brother uses the same combination of diff and box in his V8 Ginetta and Ian reckons it works well so that's good enough for me.

It has worked out more expesive than I first thought (as always) as my box needed a rebuild £650, bellhousing with concentric clutch slave £380 and the box was £150 to start with.

If I was to start again I would go straight to GearboxMan.co.uk for advice.

HTH

Mike

[adamnreeves]

does this rule out the T5 anyway?

I'm not sure that it does to be honest but I may be wrong - factory may be best to advise.

Perhaps the following will help:

The opening of the tunnel on my chassis is 13 inches wide and all I have to mount the T5 on is a flat plate welded to the top edge of the bottom chassis rails.

I'm guessing the R380 is similar from what I've heard.

The T5 (in my car) then uses the standard small ally casting from the Cossie that bolts to the gearbox tail with 2 big bolts.  This has a threaded M12 hole on the underneath which you then use with a Type 9 'cup' style mount that you can get from Westfield. You fix the Type 9 mount to the chassis plate with a couple of M8 nuts+set screws.

The chassis plate was undrilled so I had to trial fit the engine and box to get the correct position for the M8 set screws.  I seem to remember supervising while Barry shuffled around under the car <!--emo&<!--emo&

Best to check with a R380 owner or the factory to be sure if you can change your box.

Would I do it again? Not sure yet as I haven't driven the car and won't be able to compare it to anything.  Although Ian Crokers' brother uses the same combination of diff and box in his V8 Ginetta and Ian reckons it works well so that's good enough for me.

It has worked out more expesive than I first thought (as always) as my box needed a rebuild £650, bellhousing with concentric clutch slave £380 and the box was £150 to start with.

If I was to start again I would go straight to GearboxMan.co.uk for advice.

HTH

Mike

Thanks for the info and the URL, I have visited their site and definitely agree, worth a look. Sorry to hear your extra expense but it sounds like the initial cost of the box was cheap. I haven't really looked into the cost of this part but had thought that the cost of a gearbox will be in region of £1000-£1200 no matter what. Cheap box more money on refurb. Expensive box, no need for refurb. Well in my idealistic world anyway  

[adamnreeves]

I'm pretty sure there are a lot of R380 with 3.62 diffs around.  You may find the owners don't use first gear very much though as it's all over by about 30mph.  That in itself isn't necesarily a problem as you'll have plenty of torque in other gears.

I'm using a 3.14 diff with a Cossie T5 box which gives me a full 5 gears - it just took a long time to find.  Also the T5 box needs either a TVR bellhousing or one from John Eales (or the MG specialist that makes them but I can't remember their name - Browns or something like that), both of which aren't cheap.

R380 is straightforward drop in with no reall gotchas.

Mike

I forgot to ask, did you make use of an LSD diff?

[Mike H]

Yes I did.  My original 3.14 was a type A 'open' diff - ie with 'push in' drive shafts.  I sent it off to Road & Race Transmissions who turned it into a type B limited slip.  They supplied the second hand lsd and flanges.

Mike

[SNAKE]

I run a 4.3L  with an SD1 box and a 3.62 LSD in my sprint car, which gives me 135mph on the rev limiter in 5th, and have found this to be the best compamise. I have tried a 3.92 but found that it limited the top speed with no gain in acceleration just gave me even more wheel spin!

I dont use first gear at all, I found that my 64ft times were slower if i did, times are usually 2.3 ish on list 1A rubber.