Mazda Gearbox / BMW Diff

[Pimmy]

When did the Mazda gearbox and BMW diff become standard ?

If you had a choice of gearbox and diff would you choose the Mazda / Bmw items or Ford versions and why ?

[upsidedownmark]

1) No idea
2) availability? mx5 gearbox is quite nice, rest I can't comment on!

[HustleRussell]

IIRC Caterham went to BMW Diff from C.2012>

Mazda gearbox was later, 2014?

The preferred options may depend on your priorities, There is no performance advantage with the BMW diff and it’s actually a bit heavier than the old Ford unit however the BMW units may be quieter in general than the Fords (some of which can be very noisy). Being that you are practically sitting on the differential in these cars you can expect some back axle noise regardless of which diff you have.

Again the Mazda gearbox offers no tangible benefit over the Ford, the ratios are damn near identical- The old Ford ‘box physically fits the car better. The type 9 is ubiquitous in motorsport and currently offers more options for modification if that floats your boat. People tend to agree that the Ford has a nicer shift action. Both gearboxes are very reliable in normal use although I have known both gearboxes to fail with a similar failure rate in racing.

Personally I wouldn’t let the diff sway me one way or the other (unless one was an LSD and the other wasn’t!) but would choose the Ford ‘box over the Mazda.

[Pimmy]

Thanks for your replies. I had been wondering if i should be looking for a car with the newer mazda gearbox / bmw diff rather than the older ford items.

[simon-jzik7]

Having built a roadsport with the ford type 9 and ford diff and recently purchased a 270r with the bmw lsd diff and mazda gearbox i have these observations

The bmw diff is definitely quieter than the previous ford unit which did whine

The mazda gearbox is noisier than my old type 9 and can whine/rattle at speed when it coming off load

Change is very similar, slightly notchy but only 2000 miles so still running in. Previous poster commented on ford bix having a better change but must admit i think they are similar

Reverse is under 5th which isnt ideal but its a sweet change, does the mazda box have synchron on reverse?

Regards ratios, i suspect the mazda box has a longer first 3.0 instead of 3.6? This coupled with a 3.9 ratio diff gives a good spread of gears

Fundamentally they are very similar and choice will be determined by age of car

[downsman]

I don't know much about the Mazda box apart from it's a tight fit.

Regarding the diff, I have knowledge as Caterham swapped to the BMW just a month after delivering my kit! I felt they should give me the newer version, but they disagreed.......

Anyway, my Ford diff did whine, and I ended up going to Road and Race to get another one built with an LSD. While I was there he told me about the Ford v BMW diff bearings. The Ford uses taper roller bearing that are very long lasting. The BMW uses cheaper twin ball races, and Phil told me he was already having to rebuild them for people with BMWs and he wasn't impressed with the engineering, plus it is a lot heavier and doesn't fit the chassis without a cradle.

Last month Car Mechanics had an article about servicing differentials- they used the one from the smaller BMWs like Caterham use. there was a picture of a collapsed twin ball race bearing which had been really chewed up, and they said that noisy diffs are a well known problem with them

[Pimmy]

Is it possible to replace the mazda gearbox with a type 9 and the BMW diff with a ford diff easily ?

[downsman]

Unless they've changed the chassis, the Ford diff should just, bolt in, but the propshaft and driveshafts will have to be changed. Changing the gearbox will involve new prop, and probably bell housing, so it would get expensive.

[HustleRussell]

Pimmy said:

Is it possible to replace the mazda gearbox with a type 9 and the BMW diff with a ford diff easily ?

Define 'easily'... you should have no cause to change, there is a broad selection of cars out there with different specifications so it's buyer's choice.

I wouldn't get fixated on whether it's BMW, Ford, Mazda transmission, none of it is rubbish. Get out there and drive some Caterhams.

[bcr5784]

simon-jzik7 said:

H

Regards ratios, i suspect the mazda box has a longer first 3.0 instead of 3.6? This coupled with a 3.9 ratio diff gives a good spread of gears

Fundamentally they are very similar and choice will be determined by age of car

Mazda box has much higher first and higher second in particular, so,all things being equal it would be my choice - but as said age of the car will determine what you will get.

[Spaceibiza]

I used to have a Sigma Supersport with the Ford titan LSD. That didn't wine much, but clunked quite a lot when turning corners. My new car has the BMW diff. That doesn't clunk or knock at all when turning, but it does whine more than the old Ford unit did.