silverstone track day

I thought I would share my trackday experience at Silverstone GP circuit last Sunday in my CAV GT40. This was only my second trackday and so was a little apprehensive to begin with. There were no slow cars on the day, the field comprised of Porsche GT3's, TVR's,Radicals and fast Caterhams ,Ferrari 430,there was even a Porsche GT2. Needless to say that I was slow to begin with as I had only done Silverstone on my Xbox 360 before!.

After a few laps and my son acting as a co-driver I soon got the hang of the circuit and I was able to keep up with the Porsches, I even passed a lovely black Corvette Z06. I was really pleased with the Avon cr6zz tyres I had put on the car recently ;provided enormous grip and confidence. Driving a GT40 fast is a physical experience especially around slow corners when the steering feels quite heavy and strong arms are required, power steering would help.

It wasn't all plain sailing though, the day was marred by brake fluid boiling and giving a very soft pedal and a loss of full braking. In the afternoon I was having to come in after every two or three laps to cool down the brakes. I had not changed the year old DOT 4 brake fluid before the trackday.

I have now decided to put in Castrol SRF fluid, which is very expensive £40/litre!. Any advice on how to drain the old and put in the new fluid. Do I simply flush the system with the new fluid?.

Welcome to the world of track days! From that list of cars present I would suggest you were at a Goldtrack day? The Avons are good tyres.

To change over your fluid, so long as the Dot 4 stuff is not silicone based you should be able to flush it through. Quite likely there will be a different colour/clarity when the new stuff bleeds out. If it is a silicone based fluid it is a major clean out job before you put in the new fluid. Bleeding the brakes before each track day makes a lot of sense in my view. Also consider the AP race brake fluid. Not sure how it compares on price but it works well. Just because it is a race fluid doesn't mean it won't work on the street.

To help cool your brakes, when you know you are coming in, take the last lap slowly to cool everything down. Keep an eye out for cars coming up behind not on a cool down lap! Also good for engine cooling as well. And leave the car in gear and not with the hand brake on when you stop as that helps to stop heat soak into the pads and calipers.

Got any pictures to post?

pics from silverstone trackday