Showing posts with label differential. Show all posts
Showing posts with label differential. Show all posts

2015-11-24

New LSD from Titan


My car was fitted with a limited slip differential when I bought it. I've never known what kind of LSD I had, and I've never had any problems with it. One time long ago I asked Caterham what type it was and they responded that according to their files it was a Quaife ATB.

When I took my rear suspension apart to change wheel bearings I took the opportunity to remove the half shafts and look into the diff. It had a cross in the middle, and according to this guide it was a ZF, or Titan! That meant it was a plate type diff, and on those the discs eventually wear out. So I took the diff out. (not very easy I should add)

It was a ZF diff. And it was not worn out. So now I had the options to put it back, refurb it, or replace it.

I decided to replace it with a Titan with different ramp angles. Mostly because I wanted to try something new, and it is said that the Titan is very good. And now when I know how to do it I can play with ramp angles and pre-load if I want.

I did the work myself which a first for me. It was not that hard but time consuming as I didn't want to mess up. I replaced the rear bearings and seals but left the pinion as it were. Tried to set 0.01mm backlash but that was not very easy to get precise. But I got close enough, I hope.

Here is a good guide. and here is the workshop manual.

The original ZF diff had 45/45 ramps and weighted 6691g.
The new Titan diff have 30/90 ramps, carbon plates, and weights 5902g. 40ftlb (54Nm) pre-load.

30/90 ramps equals no locking while trail braking, and heavy locking when accelerating out of corners. 45/45 means equal locking when accelerating and braking. When the rear wheels are locked the car will have difficulties to turn and understeer in tight corners. It also means the rear tyres will have a better chance to transfer power into the ground, both when braking and accelerating.

I'm looking forward try it, but I doubt it will happen before spring.
And hope I never need to take the diff out again.

Update: Two short test drives made. It works!

2011-03-10

Differential support

There are reports on broken differential mounts on the CSRs, so I have mounted support brackets to avoid a future disaster.  Some say they're not necessary if you have steel spacers on the diff mount, but all race CSRs have support brackets mounted, it is even in the regulations, and if they're not necessary I wonder why it shouldn't be necessary on the road models which are used on the track with sticky tires.

Caterham sell support brackets for race CSRs. Unfortunately they don't fit the road version! The reason is that the race CSR has the differential mounted in the center but the road version has the diff a couple of centimeters to the right. MOG racing also have an adjustable diff support kit but take quite a lot of money for it. Others (Gunnars garage) weld mounts onto the frame and bolt the diff through there.

EDIT 2011-10-11: Caterham now have a road-version of the diff strut available!

The original - doesn't fit


I didn't want to modify the frame so I bought the race support brackets from Caterham and modified them. Since I don't have any tools nor the skills about welding I went to a local firm to and asked them to do the welding for me.

I took the Caterham support brackets and cut the ends off. I let the welder make a L-profile with some angle to the sides. They are bolted on the existing diff cover holes and the seatbelt mounts.

Fitment check, then back to the welder
Removed excessive metal with a grinder, and then some black paint.
In place!
New holes in the trunk-plate.

Thanks to Tyresö Svets.