BMW E92 M3 Track Project Part IV

Fitting the roll-cage (as documented last month) was actually a backwards step as far as weight is concerned as it’s added 50kg to the car. Therefore I needed to look at where else I could shave some kilos from the car. I unbolted one of doors and was shocked to find it weighed in at a massive 36kg so a substantial weight saving could be made if the doors were replaced with carbon light weight versions. I knew the GT4 factory cars from BMW used them to get the weight down, so getting a set wouldn’t be too much of an issue. With a plan hatched, I emailed my German connection who had been very reasonable in the past and he said that he could get the doors no problem, as well as a set of wings and a bonnet both in the GTR-style.

When I saw the front wings or ‘fenders’ as the Germans like to say, I fell in love with them. I didn’t need any convincing – I could see they were functional even if they were a bit OTT looking. The vents in the rear and along the top are not just for show; they let air pressure out of the wheelwells.

With the brake duct cooling blowing air from the splitter to this area, these would be essential, otherwise the air that is squashed under the front of the car would be blowing up into the arches with nowhere to go. Once the wheel-wells are full of air it will try and escape back out anywhere it can, which can cause front-end lift or turbulence which would upset the air flow down the side of car. It’s quite logical if you think about it, and is the reason many race cars run slotted wings – even the new GT3 RS road car has them to increase the downforce – I was sold!

Next up was the massively vented bonnet which would aid cooling and also prevent a build up of air-pressure under the bonnet. I discovered the carbon doors weighed in at a barely believable 6kg each. With locks and Plexiglas glass I guessed that we would be looking at 10kg total, but that’s still a 26kg weight saving from the original doors, giving a total weight reduction of over 50kg – almost exactly compensating for the weight of the cage.

I mentioned to my friend Dave (the one who suffered engine failure in his E46 at the ‘Ring) that I was going to be getting some carbon panels for the E92 and it transpired that he was also interested in some for his new E46 M3 project car that he’s turning into a dedicated track weapon. When I was making the order I said I needed another rear wing for my friend’s car and eventually this turned into me getting a full GTR/GT2 wing and selling my old one to Dave!

The order was placed and in typical German efficiency it was ready in three weeks. Not wanting to trust our precious cargo to a courier Dave and I said we would go to collect the carbon. However, just three days before we were due to depart Dave discovered that his passport had expired… which meant I had a 26 hour round trip on my own, which I wasn’t looking forward to it at all. Fortunately, my mother, a keen reader and my (number one) fan offered to come with me. As I am in my 30s and she is in her 60s we joked about her coming on a road trip and she bet me that I wouldn’t mention it in my Longterm report that she came along for the ride (you lose mum!). I’m sure most of us, if we’re honest, would say the same – mums are the best how ever old you are…

Anyway we set off and 26 hours later we were back in the UK with a van load of carbon goodies – I even got a set of M3 GT4 front bumper carbon canards thrown into the deal.

So with the weight of the cage cancelled out my attention turned to other weight saving measures – the car is never going to be a road car again so why not go the full hog! The air conditioning was something I always said I would keep but the front roll-cage bars have made it a little awkward to retain the heater matrix and the actual pump, radiator and pipe work comes to quite a bit of weight, so you guessed it, they will never see the car again.

Then there was the dash – this was another item that was never going to go back in the way it came out, due to the massive pillar gussets while the iDrive screen, stereo, speaker and airbags were just going to be dead weight anyway, so a cooking E90 320d dash was purchased from eBay for the bargain price of £50. This was then chopped, stripped and butchered to within an inch of its life, before being sent off to Banbury Flocking to freshen it back up in black.

The battery weighed in at an obscene 26kg and although I am yet to obtain a lightweight replacement, I absolutely refuse to put that boat anchor back in the car.

Back when I had my Escort Cosworth, I had a Recaro SPG and a little later a Carbon Tillet GTA seat – these combined, compared to the lovely red SPG-XL Recaros I have now, would equate to a 15kg weight saving. So again the SPGs will be shelved for something else at a later date if not sold on…

The rear screen and side glass has been replaced with 3mm Plastics4Performance Plexiglas and the front door glass with 4mm items. There are lots of other bits and bobs, trim parts, underbonnet covers and plastics that I have also removed. I have probably forgotten other parts I have removed, but as a whole you have the details of the bulk of it and I hope this will all add up to a nice large sum of weight saving – I’m just chomping at the bit now to see what it actually weighs…

At my family-run business we have a paint booth that we use for our own daily repairs (mostly on vans) and we have a handy all-rounder by the name of Rob Green, who can prepare, repair and paint almost anything. When I brought the carbon panels to work he was amazed by them, but also horrified by the amount of work involved. He knows this isn’t an old van and that I’m not any old customer and also knows it will have to be perfect for me to be happy.

This is not to say that there was anything at all wrong with the panels. They are just carbon and so they have a lot of preparation around them to get them perfect… This is mainly pin holes around the edges of the panels from tiny air pockets and the doors have two predominant lines that run through the middle about two-inches thick.

On inspection they are reinforcement areas on the inside of the doors, but for some reason show through. The normal eye probably wouldn’t see them and a typical race car wouldn’t normally worry about them, but me being the perfectionist I am I wanted it to look like a car that BMW might have built itself.

Also the small vents in the wings had to be cut out by hand and seeing as no-one else relished that task (probably put off by the thought of me standing over them watching), I drew the short straw and it took me ten hours to do the pair with a bit of perfecting by Rob at the end. All the panels were filled, rubbed down and given a few coats of highbuild, filler-primer and then after they were all dry, we wet and dried flat the lot all in one day, it took us 13 hours of hard work! As anyone knows with paintwork, it is all about the preparation – the actual painting is the easiest part and the finished product is amazing – all the carbon looks phenomenal.

As the whole car was going to have to be painted inside and out, I also got inside the car and rubbed the whole car down – all the cage, the floors and in every nook and cranny. I then hoovered, panel wiped, and hoovered and wiped again until you could eat your dinner off of it. Like everything in life, it’s all in the prep! Hopefully next month it will be painted…

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