Care to compare and contrast? are both equally as capable of is the GP hands down worth it?

 

I have both.

Both are dedicated motorsport cars with FIA rollcages, seats and harnesses etc. The JCW is a circuit racing car and GP2 is a tarmac rally car.

I have driven both on the track completely stock and in various forms of modification.

The biggest difference is the tires, because the GP2 comes with dedicated type R track tires which make an enormous difference. However, even when you put those tires on the JCW the GP2 still has it all over the JCW.

The vast majority of the advantage of the GP comes down to the suspension setup. It is a track orientated setup, and just holds corner speed so much more, is more settled in transitions and handles bumps in braking much better. Also you can lower and balance the car, which makes big improvements again.

The other differences, ie bigger brakes, aero, mild power increase make very little difference really.

Having said that, if you spend $2k and put a decent quality set of coilovers on a JCW, and then put the track tires on, they are neck and neck.

 

Exactly what I wanted to know!

Did you have issues with the brake caliper Pistons? I know a lot of people here say they must be swapped. If I can get essentially the same car in the R58 JCW with the bilstien coils and tires thenI am just going with the r58. I am no pro I will just be doing track days at my local track for fun not competing.

 

The pistons on both the JCW brembo 4 pots and the GP2 brembo 6 pots are essentially the same. With serious track use and heat they gradually crumble and collapse. I have not heard of a catastrophic failure, more just you start to get uneven pressure and uneven pad wear, and then when you change pads you find damaged pistons.

My JCW brembo 4 pots probably went through 3-4 sets of track pads before I rebuilt them. I have been more proactive rebuilding the GP2 calipers because I knew it would become a problem.

Good news is there are kits to rebuild them, I saw on another thread there is now a dedicated kit for the 4 pots now.

Either car if you know that it is going to do a lot of trackwork it is probably worth fixing the pistons straight up. If you are just doing the occasional track day don't worry and see how they shape up

 

Yeah there is this kit: http://www.racingbrake.com/Save-10-o...p/bb-41bsp.htm

Looks not that difficult: https://www.racingbrake.com/SearchResults.asp?Cat=7123

So did you only have to rebuild the front?

Also do you even need the dust boots? They likely melt off anyway.

 

Oh and one more question. Would shims prevent the piston deterioration?

 

Shims would help slow piston deterioration. however, rebuilding the pistons is a better and permanent solution. shims can make it a little harder to fit in new pads as well.

The dust boots / piston seals do need rebuilding every now and again, but that is pretty normal for any tracked car.

 

Without dust boots to keep the grit off the pistons , you will seize up the pistons soon and have no brakes.

 

Which is why you rebuild them every now and again