OK OK, so I am not actually running a second diff! But what I am doing, while I am still fabricating the car and its not too much bother to add an extra bracket here or there, is to allow for the installation of a different Diff.
What I have decided is to try to fit a plated diff. This should aid traction both off the line and out of corners. Many people use a Quaife ATB diff, but these are effectively the same as an open diff, as soon as one wheel lifts, or indeed becomes light, it flares up as all of the power is transmitted to that wheel and not the wheel with traction. However the advantage of it is that Quaife make a nice ready sealed unit you can just bolt on! But thats never stopped me trying! By using a plated diff the preload on the diff should help stop the lifted, normally inside, wheel from flaring up as much.
I have decided to modify a mini racing diff, as all of my running gear is mini and it should therefore just bolt on using the original CV’s and whatnot. I spoke to the head huncho at minispares and he told me that he could make different ramp angles and washers if I needed them, and indeed he would make me a sealed housing for it. As the diff is normally inside the gearbox it sits in oil and so there a great big holes for the oil to flow in and out of, but as mine is sitting in the air I need to keep that oil inside! However he recommend to make a ‘bath’ for the oil to sit in as he thought i would need more oil to promote life!
I therefore set about a box to mount over the diff! Below is a picture of the final article. The groove in the diff is to allow for a good seating face for an O ring. I am hoping that there is still plenty of material left, only time will tell!
Below is the lid
The only problem of doing this was access to the sprocket mounting holes. These are now located inside the oil and so I firstly needed to seal it and secondly if i wanted to change the sprocket I need the nuts to stay put. I could have made some blind holes in the box, but this would have made the machining much more difficult and I preferred the buts to be steel rather than ally. So I made up a nut ring as shown below. the ring itself was the thinnest bit of sheet steel that I thought I could reasonably weld to, hence the melt away parts.
To seal it and hold it in place I siliconed it to the base of the oil bath. Obviously when I come to take the procket on and off I will need to be somewhat careful or the ring might just fall off!
Anyway, this now gives me the option of changing diffs on a test day to see which performs the best. Obviously it may be total tosh, but Ithought it would be good to have the option, and to do it now whilst fabbing up the car seemed like the best time, as I had all the measurements in my head!
Tags: Differential
