im building a R1 engined kit car and want to know what diff im better of using? what will help with acceleration the best. The car will be used on the roads mostly but will see a few track days. Preferably a ford item but others can be considered as all the car is being custom built so any diff can be made to fit really.

 

I got told that atb's were best for 'light' cars as they dont tend to push on as much in corners than say a gripper etc.

 

ive always wondered how bike engined cars reverse lol

does the driver simply get out and push or do they have electric motors etc in em?

 

you can get a special box for them and some can go thru all the gears backwards

 

One of the problems with bike engine installs, is that while the gearbox ratios are very similar to car gearbox ratios, there is also a primary reduction between engine and 'box.
Overall, with a conventional ratio diff, you end up with an under-geared set up.
One of the favourite diffs to use is the 3.14:1 ratio Sierra 7" unit that was fitted to one of the old Diesels.
Unfortunately these are also extremely rare nowadays, and with them being so sought after for your sort of project, expect (if you can find one) to pay blood money!

Alternatively, and becoming popular now, is the diff from the Freelander. The ratio of this diff is 3.21:1.

Quaife manufacture ATBs for both models of diff

 

thinking about it, i got a diff from a 1.6gl sierra 4 speed, was on a type 9 box but fook knows what the ratio is without taking the cover off

 

Clean the ID tag carefully with a tooth brush and wonder wheels

If you still have access to the car it came off the code on the chassis plate tells you. It gives diff size, ratio and LSD info. There is a complete list of models and codes etc on the siera site complete with pictures to help you ID it