ProMAX Level 4

[Riverside]

ORIGINAL: 333pg333
Surely I can justify running these brakes no?

Of course, just choose your spring & damper rates to suit. Car manufacturers spend months or years tuning this, although they are looking for a compromise between ride comfort & roadholding. You may be more interested in roadholding at the expense of ride comfort, as a race team would be.

The suspension attempts to keep the tyre firmly and consistently pushed onto the ground. Increasing the unsprung weight makes this job harder as more momentum is involved. If your suspension is out of synch you may experience porpoising through corners etc as the spring & damper attempt to contain the momentum of the wheel trying to bounce.

 

[John Sims]

ORIGINAL: sawood12

Well strangly enough too much rubber can actually impede braking performance as the weight of the car is spread over a larger area. Narrower tyres have more pressure exerted on them and as long as you don't overexert them you will get more grip ......

Not!

Try stopping from 100mph with 155 tyres and then 225 tyres. I know which ones I'd go for.

 

[Riverside]

ORIGINAL: John Sims

ORIGINAL: sawood12

Well strangly enough too much rubber can actually impede braking performance as the weight of the car is spread over a larger area. Narrower tyres have more pressure exerted on them and as long as you don't overexert them you will get more grip ......

Not!

Try stopping from 100mph with 155 tyres and then 225 tyres. I know which ones I'd go for.

I find it at odds with what I believe should be the case too, but it's true [8D]

 

[333pg333]

Yep, agreed. I have the KW 2-way race setup which should cope but I can contact them and ask if I need to change the springs or possibly the valving.

ORIGINAL: Riverside

ORIGINAL: 333pg333
Surely I can justify running these brakes no?

Of course, just choose your spring & damper rates to suit. Car manufacturers spend months or years tuning this, although they are looking for a compromise between ride comfort & roadholding. You may be more interested in roadholding at the expense of ride comfort, as a race team would be.

The suspension attempts to keep the tyre firmly and consistently pushed onto the ground. Increasing the unsprung weight makes this job harder as more momentum is involved. If your suspension is out of synch you may experience porpoising through corners etc as the spring & damper attempt to contain the momentum of the wheel trying to bounce.

 

[John Sims]

ORIGINAL: Riverside

ORIGINAL: John Sims

ORIGINAL: sawood12

Well strangly enough too much rubber can actually impede braking performance as the weight of the car is spread over a larger area. Narrower tyres have more pressure exerted on them and as long as you don't overexert them you will get more grip ......

Not!

Try stopping from 100mph with 155 tyres and then 225 tyres. I know which ones I'd go for.

I find it at odds with what I believe should be the case too, but it's true [8D]

I can appreciate that in wet conditions a wider tyre can increase the possibility of aquaplaning. M&S tyres are thin to cut through the surface to the hard ground underneath. But....the greater the contact patch the greater the friction.

F1 cars, and other formulae, have there tyre width restricted by regulation. F1 tyres were reduced in width to reduce mechanical grip.

Slicks are better than grooved tyres (in the dry) because a lager proportion of the tyre is in contact with the road .'. larger contact patch .'. more grip.

 

[333pg333]

ORIGINAL: John Sims

ORIGINAL: Riverside

ORIGINAL: John Sims

ORIGINAL: sawood12

Well strangly enough too much rubber can actually impede braking performance as the weight of the car is spread over a larger area. Narrower tyres have more pressure exerted on them and as long as you don't overexert them you will get more grip ......

Not!

Try stopping from 100mph with 155 tyres and then 225 tyres. I know which ones I'd go for.

I find it at odds with what I believe should be the case too, but it's true [8D]

I can appreciate that in wet conditions a wider tyre can increase the possibility of aquaplaning. M&S tyres are thin to cut through the surface to the hard ground underneath. But....the greater the contact patch the greater the friction.

F1 cars, and other formulae, have there tyre width restricted by regulation. F1 tyres were reduced in width to reduce mechanical grip.

Slicks are better than grooved tyres (in the dry) because a lager proportion of the tyre is in contact with the road .'. larger contact patch .'. more grip.

That's what I would have thought.[8|]

 

[333pg333]

ORIGINAL: MarkK

The six pot brakes are amazing on the Gt3s,everyone swaps to solid discs now though either Alcon,Brembo or Performance friction as the standard porsche discs don't last long when driven hard,they tend to crack,the six pot upgrade was needed as the original GT3 mk1 4 pot settup tended to overheat(on a gt3) unless you were ginger with them or had ventilation upgrades.I have 964 cup car calipers on my tuned turbo and for me they are more than enough for regular trackdays,although some harder pads might be nice.Brakes and suspension were the first thing on my shopping list, if careful no real problems with laying the power down (in the dry anyway)[] and it stops really well.

Mark, are you saying that the Porsche solid discs crack? I can believe the cross drilled ones do, but I wouldn't have thought the solids? Also are you talking about GT3 Cup cars or just regular cars doing trackdays. I am hoping to fit the 6 pots but will also try the GT3 master cylinder as our standard ones probably won't work properly?

 

[MarkK]

Hi,
The standard Porsche Gt3 six pot brake discs are crossdrilled and these crack really easily when used on circuit,lots of trackdayer people usually swap to an aftermarket solid disc as they last so much longer,this is on road cars and cup cars used on trackdays, the solid aftermarket type are also lighter and will reduce unsprung weight[] The aftermarket solid Discs are also floating discs so when you need to swap the rotor part you can retain the hub bit,so once you have made the initial investment they should be cheaper to swap too which is always good,and like i said last So much longer.If you are going six pot i would have a look at them i reckon the Alcons are the most popular that i have seen,my mate uses the Brembo floating solids and he says they rattle like anything.

 

[333pg333]

Thanks Mark. Yes I know the issues playing 'Join the dots' with the cross drilled rotors and that's what I assumed you were alluding to but I just wanted to check. I am a fan of PFC stuff so I may see if they have a rotor to fit. I'm certain they do. I know their calipers are very expensive and I will continue to check them out for the whole package however they don't do 6 pots. It's not that I want 6 pots for the bling factor (they do look good on Olli's car though) and unless you've ever held a caliper (6p) in your hand you can't imagine quite how large they are, but I have to believe that Porsche use them for a reason. I like the idea of the floating disc saving a bit of money over time too. I'll have to learn how to do that saving thing oneday.[]