I have updated my Jag based Cobra with Wilwood Disks and calipers at the front - they came off a racing Mustang when class rules changed allowing upgraded brakes and are brand new. They came with "Polymatrix A" racing pads and despite Wilwood saying they are Race only seem to work very well on the street. The down side is the rear is now very under braked.

To fix this I am intending to scrap the Jag Booster & MC and switch to twin MCs with balance bar. A check on Mike Polan's Brake calculator shows that pedal pressure will be a problem (Around 135 lbs) unless I switch to high friction Coeff pads at the rear as well which will bring the pressure down to around 120 lbs at 0.8G.


Description

Putting Polymatrix A pads on the rear will go a long way towards balancing the system but I am not sure about what the down sides of using them on the street are. They seem to have very superior cold stopping - maybe even better that street pads - but might squeal (So far not!) Normal pads have a CF of 0.3-0.4 the Poly A pads 0.55 to 0.675.

I'm in the process of doing similar with my fury - Poly-A (carbon metallic) onto Willwoods. The warnings are apparently they can chew through cross-drilled disks, but the chaps at Siltech have been racing these for ages and don't think they've observed that - more a case of strong warnings to be sure they have liability in the right place. Rally-Design (who sold me the calipers) were suggesting that I go to solid disks. At £40 each (for my car) I'm willing to see if I wreck a set.

The only other warning I've heard, but I've not been able to verify is that they can generate more dust.

Go for it.

I was always under the impression that racing pads were very temperature sensitive and that from a cold start would have a lower coefficient of friction than street pads. However the situation was reversed at higher temperatures.

It was this inconsistency that I assumed was regarded as undesirable for " granny doing the shopping" scenario that all manufacturers have to consider.

Is this no longer the case?

Cheers!

quote:

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Originally posted by v8kid
I was always under the impression that racing pads were very temperature sensitive and that from a cold start would have a lower coefficient of friction than street pads. However the situation was reversed at higher temperatures.

It was this inconsistency that I assumed was regarded as undesirable for " granny doing the shopping" scenario that all manufacturers have to consider.

Is this no longer the case?

Cheers!

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quote:

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Originally posted by v8kid
I was always under the impression that racing pads were very temperature sensitive and that from a cold start would have a lower coefficient of friction than street pads. However the situation was reversed at higher temperatures.

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I expected that the pads would have very little cold bite but in fact their behavior when cold bares out the CF charts and seems more than adequate. Wet behavior - I don't normally drive the Cobra in the rain so can't comment on that.

In fact they have nearly double the CF of street pads per this chart:


Wilwood Street Pads

Which leaves the question - are the Poly A the perfect street pads - if not why not?

Carbon metallic pads traditionally have a habit of filling aluminium wheels with iron filings. They work better with 420 stainless discs but it's very difficult to make vented discs from it.

Many of the newer pad materials don't suffer from the big friction variation between cold and hot operation, unlike older 'race' pads. I use the ferodo ds1.11 pads in my wilwoods, wet/dry, cold/hot they're very good.

Ian

I wouldn't fit any of the Wilwood pads, they all seem to feel very wooden in use and overheat quite quickly.

Hawk or Performance Friction makes some excellent pads.

Is it true that components for a car on the road need to be 'E' marked to show conformance with the appropriate standards?

If a pad was either not marked as such or specifically marked for off-road use and then the car was involved in an accident then the police or insurance would have a route for prosecution or voiding?

quote:

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Originally posted by onenastyviper
Is it true that components for a car on the road need to be 'E' marked to show conformance with the appropriate standards?

If a pad was either not marked as such or specifically marked for off-road use and then the car was involved in an accident then the police or insurance would have a route for prosecution or voiding?

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