The car was taken out recently and embarrassed itself by bursting a rad,the brakes went soft and I realised I need more acceleration.
To start with I'm running the usual Polo rad, Sierra brakes (with braided lines)and 3.6 diff on a modded 2 litre pinto on bike carbs.
Can I have your suggestions for a replacement rad, brake set up and diff ratio therefore please?
Thanks.

Either the rad was faulty, or it got over-pressured. Check the header tank cap, and did teh temp gauge read particularly high? Is the gauge accurate?

Brakes, again should work just fine in such a light car. What is the history of the system (age of seals, fluid, type of pads used and are they vented) Which rear brakes?

If you want a shorter diff, 3.9 would be the obvious choice. Or more power!

Brakes going soft, have you got air in the system? If they faded then get some Mintex 1144 pads which will sort that out.

Rad bursting, it should have released pressure through the rad cap so faulty item.

Acceleration, whatever you have will always feel slow on a wide track, fast on the road that's just the way of things I am afraid.

I wasn't there on this occasion so I'm using the drivers descriptions. The brakes I thought well yeah I can see that on track but the rad did make me think.
The brakes are; front, vented Sierra discs, single piston caliper and standard pads. The rear is a caliper conversion the origins of which I just can't remember, with solid discs and standard pads. It's braded lines front and back and it was all new or reconditioned five years ago, including the fluid. I'm thinking Mintex discs, 144 pads and new fluid?
The rad was new when built but the expansion tank was donor. So I will start with replacing that with the rad. Are we saying the rad should have coped then?
I have a 3.9 with different cv connections to go on but didn't know whether to go further than that?
Cheers


[Edited on 13/6/15 by scoop]

Brake fluid should be changed every couple of years.....and std pads? I take it you mean unbranded ones. Get decent pads!

Rad should cope, what was the temp gauge doing? if overheating badly there may be a problem, so needs sorting but it can be difficult getting info from a driver who may not have been attentive or have much idea. Are yiou sure the rad has burst and not just the pressure cap let go?
Could be the fan thermoswitvh not kicked in after a few laps and then just stopping. If the fan didn't lick in it could well overheat. So you need top find out exactly what happened and when.

Have a measure up, you may be able to fit a slightly larger vw rad in for similar costs etc.

Proper branded competition pads are expensive, but they will make a vast improvement to cheap road pads. At the point that most standard road pads have faded to oblivion, competition pads are getting into their stride.

As well as the Mintex 1144, consider also the Ferodo DS2500 or even the DS3000. These have been used on a friends very competitive tarmac rally Honda Civic for the last five years, running standard discs until about 12 months ago. Despite the discs visibly glowing when entering the service area the pads continued to work, though wear rates were quite high at those temperatures (hence bigger discs now fitted). They also work perfectly well from cold, though improve with a bit of heat.

[Edited on 13/6/15 by MikeRJ]