I’ve spent the day stripping and weighing the car I wanted some solid metrics against which I can measure the changes I plan to make to the car this winter.
Remember, I’m taking the slightly odd decision to have less power in my racer, as this will allow me to step down a class, and hopefully lose a lot of weight from the car which in turn will make me more competative in Class B.
So having borrowed Steve’s corner weight scales I set about taking a bunch of measurements to get a solid idea of weights of each major component. What followed was quite enlightening, well it certainly explains why the marshalls grunt a bit when pushing me around the paddock.
Firstly I weighed the car as it came back from the Birkett, fully fuelled and full of oil and coolant without driver
It weighed 555.4Kg, Gosh that’s quite a lot given that Tim’s Fury is 470KG in the same condition and our class weightlimits are 560 and 530Kgs respectively, although that is normally at the end of the race when we are not carrying much fuel. Still it’s pretty lardy!
Secondly I weighed the car with the driver in it. And … well you don’t really want to know! But I think there’s a couple of bags of spuds hidden in the car somewhere or a fragment of neutron star! Let just say that I can easily miss the weight limit by 100KG
Next I drained all the fluids, oil, water and the 25+ litres of fuel, the weight without the driver but dry with all fluids drained was 531.2Kg. So that is some 24Kg of fluids most of which was fuel. But there is probably 8 KG of oil and water in the car.
Next I removed the ZX12R, and the engine lump complete with the exhuast headers and dry sump pump, it comes in at 90Kg. Given that it puts out over 180bhp that’s 2BHP per kilo, a quite impressive power to weight ratio.
With the ZX12R, diff, exhuast and Drysump tank removed the car weighs 378.4KG, so the engine, diff and lub system and mounting hardware weighs 152Kgs.
Which actually gives me a bit of of hope, as the cbr1000rr is reputed to be about 65kg, add the diff at 27kg and say 10KG for exhaust and mounting hardware and I could be looking at a saving of around 50KG on the dryweight on the car + whatever I can off load from the lard arse in the drivers seat. That’s got to be a reasonable goal for the winter, to offset the slight drop in power that the new engine will have.
Incidentally the Diff weighs in at 26.8 Kg without the CV joint cups, the Nova diff I’ll be using weighs about 27 dead including the cups so allowing for the mounting hardware there is probably a couple of kilos to be saved by making the effort to get it into this chassis. I wasn’t going to do this as it generates a bunch of other issues, like a different handbrake assembly and changing the driveshafts so on. But with a small weight saving to be made it must be a good idea. Also after a day dissassembling the engine bay the one thing I can accurately say is that is is absolutely full of lithium CV\Diff grease. It is absolutely everywhere and yucky as hell.
Swapping to the Nova diff is worth it just to keep the engine bay clean, but the other advantages of engine driven reverse, weight saving and so on make it a no brainer.