Tom's Track Car - BMW E46 -Lots of updates


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Soo back to an update... This time I'll keep it a bit smaller and document the progress.

At the end of the last big post I said about the stiction in the rear end I noticed properly when lifting it up on the ramp, don't always get the full effect jacking up one side of the car due to the tension in the ARB. Decided it was something I was going to tackle to free up the suspension travel in the rear end to hopefully let the wheels track the ground a little better and stop it lifting the inside wheel in some corners as the damper can extend with less resistance as well as trying to reduce the little bit of wheel hop I get from the rear end which I think it down to deflection in the polybushes as it was improved when I upped the preload on the subframe bushes last year. That's my rational anyway for the following changes so we'll see how we get on.

First job on the cards is to drop the rear end off the car. Starting with the ARB, driveshafts, diff and brace. Camber arms also pulled off and these are going to be completed remade with bushes for the inner joint rather than a polybush.

Dropped the rear arms off the car. When I built the car I did fit two ball joints to the upper and lower mounts in the rear trailing arms the same as fitted on the M3's

Dropped the subframe off with the upper arms in place, nice to see the powder coating is still looking good 3 years on from building it originally, just a film of dirt all over it, will give it a good wash before refitting.

Pushed out the the poly bushes out from the suspension, at this point I decided while it was all off and fitting ball joints to the 3 rear arms... trailing arms, upper arms and lower arms, that I would do what I did for a friend a year or so ago which was make solid mounts for the subframe as well as the diff to stiffen up the rear end as well as raising the subframe as much as possible to give a little bit of roll centre correction while I am at it, Jordan has been running a set of bushes I made for him two years ago with great success so why not do the same on my own car.

First job in the process of making the bushes for the solid mounts was to order some 3" round aluminium. This then became an evening job I have been chipping away at in the evenings, here I've got the material mounted and supported on the lathe. Starting to face off the material and parallel turn it to the correct diameter.

Using the lathe I roughed out the diameters of the bushes on the material and parted of the majority of the way through the material before removing it from the machine and finishing the last bit of the cut with a saw.

To finish them off it was a case of drilling holes through the middle, finishing off the diameters to specification adding chamfers. I spent a lot of time measuring the subframe and the underside of the boot floor and designed each bush to move the subframe up, clear the factory subframe studs as well as still be able to use the E46 brace fitted to the front of the subframe

While I was working on making all the solid subframe bushes I did get delivery of the VAC Motorsport upper arm bushes. These are nice and simple aluminium sleeves with a rose joint in the middle held in by a circlip. I was originally going to make these myself but in the end with the money saved on making all the other bits I thought I would buy the mounts for the upper arms and the RTAB.

I cracked on last week and got the rest of the mounts machined and finished.
The photo consists of:
4 Subframe mounts
2 Front diff bushes
1 Rear diff bush
2 Vac upper arm inner
2 Steel CDS rings which I have machined to the correct diameter for the ball joints front left which will be welded to the camber arms to replace the inner camber arm poly bush
I am just waiting on the final piece to the puzzle which is a pair of Millway solid rear trailing arm bushes to finish off the solid rear end.

Fitting the diff bushes was a little more awkward as the solid bushes require a lot more force to fit, I tried to get it mounted in the hydraulic press but wasn't able to get the correct angle due to the ARB mounts so opted for the more simple big bolt and a long bar to pull them in.

Subframe mounts were a lot easier to get into the press so they were pressed in without issue. This is a top view looking at the top of the subframe, you'll notice the bushes don't have a top hat the same way the poly bushes do, this has enabled me to bring the subframe right up to the boot floor to get some roll centre correction.

Quick test of the subframe on the car to check for clearance. Looking good so far but we will be 100% sure when all the driveline is connected back together with diff, prop and drive shafts. Little bit of mud still lurking around the rear end of the car from my off last year at Oulton, will be getting the jet wash out to clean all the rear end up, wire wheeling back some of the boot floor and repainting/stone chipping some areas while it's all off again. The original spring seats are looking a bit untidy and want to clean up and paint the trailing arms pockets.

Last job this week has been fitting the VAC Bearings into the inner of the upper spring arms. Nice simple design which was pressed in easily with the hydraulic press and secured with a circlip on the other side to prevent any movement.

Once I've finished tidying up the rear end with some paint I will start to build it back up and have some more photos from that soon. Will come back with another update soon.


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Great work as usual Tom, I would love access to a lathe (and I don't i'd end up there all the time haha).

Have you consider true rear coilovers then doing away with the top arm? I run HSDs (came on the car) and they offer a conversion to change to true rears, means you then have access to many linear spring rates (than being limited by manufacturers of non-linear seperate springs), also you could get a spring perch-less arm to save weight too I guess.