Last month you saw that I had removed the old engine and stripped the remainder of the running gear from the front end too. Well, this month things have been progressing nicely, and with an empty engine bay I was able to turn my attention to sorting the engine mounts.
On the Group A race cars the engine is chassis-mounted, unlike the road cars which use a big rubber mount to isolate noise, vibration, and harshness. Obviously, in a race car we aren’t bothered about any of that, and the primary objective is to hold the engine rigidly in place with minimal twist and flex under hard braking and acceleration. Therefore, rather than use a big rubber mount between the chassis and the engine, on a race car the engine is bolted directly to the chassis itself.
There are a couple of ways of doing this. The typically route it to weld mounting brackets to the chassis legs, through which one end of the engine mount is bolted – the other end of the mount is bolted to the engine block. There are even kits available with the brackets already pre-shaped and ready to be welded to the chassis legs.
However, from my experience of working on these cars, mounting the engine this way can cause issues with engine installation. You can’t simply lift the engine out of the top of the engine bay as you do on a road car, because the cross braces that go between the turret tops prevents you from doing so. And with the engine mounted directly to the chassis, you can’t drop it out of the bottom either. So, the only to fit/remove the engine in this applications is to lower the engine in the bay, and then try to fit the engine mounts to the block while it’s hanging there. This is fiddly and time-consuming to say the least – especially when all the engine ancillaries are fitted too. It basically makes the job of fitting the engine much longer than usual.
But I’ve had a plan for how I can have the best of both worlds. Rather than welding the chassis mount brackets directly to the chassis leg, I’ve modified them them to fit onto the front crossmember instead. This means that when it comes time to fit or remove the engine, I can simply drop the entire front crossmember from underneath with the engine still attached. Plus, it means that the engine is still solidly mounted (using the original Group A engine mounts) to ensure nothing moves under the stresses and strains of racing.
So, I found myself an old engine block, ordered a chassis mount bracket kit, and grabbed the Group A mount s I’d allocated for the build and set to work. A little bit of trimming to the brackets, and quite a lot of measuring and mocking-up to make sure it all first squarely, and this clever little tweak was soon in place. I then sent the whole thing off to Mark at MT Coatings to be powdercoated ready for reassembly.
I’m now in the process of collating all the new suspension parts (which include brand new alloy hubs, Group A Bilstein damper inserts, fully adjustable TCAs, and adjustable top mounts, which I hope to have ready and maybe even fitted in time for the next update.
In the meantime, though, I’ve sent the T4 turbo off to specialists Vince Osborne and Mark Arnold at Turbo Performance Ltd for a complete rebuild ready for a season of racing. You may be wondering what trick upgrades and billet bits and pieces they’ve fitted to eek a little more performance from the 30-year old turbo design. The answer, none. To comply with the regulations the turbo must be as it was when it ran in the BTCC days, and don’t forget that the only reason the T4 was fitted to road versions of the RS500 was to gain homologation. Therefore, the turbo we’ve got to use for racing is basically a standard version as fitted to all RS500s, race or road cars. But to make sure it lasts the season, the guys at Turbo Performance have given it a thorough rebuild, so it’s as good as new.
Next up, I’ll be refiting the race-spec suspension and getting everything ready for the new engine too…
Turbo Performance Ltd