E46 CSL Subframe Strengthening

[LeinsCSL]

As I think I mentioned to a few people last month, the CSL was going in for some preventative maintenance work at MProve: http://www.mprovesolutions.com/ This is mainly because I've been hearing too many horror stories about subframe cracks, and being an early one the car is very soon to fall outside of BMW's 10 year goodwill period, so I thought I'd bite the bullet and get the whole area strengthened up for a bit of peace of mind

I had a quick check around over here in Ireland but no-one seems to be doing this sort of work, and having seen a couple of recommendations for MProve (based outside Warrington) I got in contact with them. On speaking with Matt there, he informed me that he had already done the work on a few CSLs, and many E46 M3s including his own, and there were basically two options:

1) Just an epoxy resin injection on both sides of the subframe

or

2) Strengthening plates and the epoxy resin injection, plus all new subframe bushes

He recommends the second option for anyone planning to track their cars, but even though I don't I still thought it was the option worth going for to avoid any worries going forward. The whole procedure would take about a week, mainly because the resin has to set properly over a number of days before putting it under any stress

Anyway, I dropped the car over to MProve, and was quite impressed with their set-up. It's out in the middle of the coutryside so lots of space, and as well as the subframe repair/prevention work they also run a race team and a detailing business out of there (a few tasty motors around the day I arrived ). On getting it up onto the ramps, Matt showed me the potential weak points, and to both his and my surprise it was all intact, not even any hairline cracks

Here are a few before pics:

[LeinsCSL]

So about 6 days later I got the call from Matt to say the car was ready and all the preventative work had been successful, which I was very pleased about due to it being required for its trip to Munich and back! It didn't need a new floor, and I've got full confidence that it's all strengthened up now for the future

So in short I would have no problem recommending MProve as their work is excellent and Matt is a thoroughly nice guy to deal with

Finally, a few pics of the strengthened car:

[Nikey30]

Looks like a top job Jeff, mine is getting booked in with MProve in the next few week, looking at your pics their work looks good.

[plumber vic]

Hi Jeff
what sort of money are we talking about

[LeinsCSL]

Originally Posted by Nikey30

Looks like a top job Jeff, mine is getting booked in with MProve in the next few week, looking at your pics their work looks good.

Yeah delighted I got it done now when I had the chance Nick

Originally Posted by plumber vic

Hi Jeff
what sort of money are we talking about

Works out at £1000 for the strengthening plates and resin injection, then extra for stuff like new OEM subframe bushings Vic. Cheaper than a new floor anyway!

[Monkey]

I've done one of these repairs on a car at work. I used the Turner Motorsport repair kit, but after seeing the kit I'll make my own next time.

I recall the repair coming to around £1000 over here as well. The car I repaired did have a huge crack around the o/s/f rear subframe area which is the main area. There was also a fairly substantial crack at the back of the n/s/r rear subframe mount, a less usual area for the failure but I have seen a few.

In this case its neccesary to drill at either end of the cracks to stop the spreading, and then weld the cracks shut. Instead of the resin, I opened up the chassis leg inside the rear of the car and welded the 2 skins together to increases strength.

I have a feeling I'll be doing a few more of these in years to come!!