comments on PFC 90's

[Tom F&L GoR]

comments on PFC 90\'s

Went to Lime Rock Park with PFC 90s in the front, R4 pads in the back, stock calipers, Porsche bandaids, have long ago removed proportioning valve seal. Locked up front tires enough that I was done after 30 minutes; new (NOS) BFG R1 is now a triangle with the steel cord showing.

Braking is mostly once per lap from 135-140 to mid-third gear, then decreasing right turn radius. Yes, it's the right front that is gone, but I'm not that bad that I don't remember to brake in a straight line. My problem was I could never sense the lock up until a) smelled or saw tire smoke, b) steering didn't steer, or 3) car jumped when brakes released and wheels were turning again.

Corner weights with simulated me in car shows RF is 80 pounds light, so that doesn't help either.

But basically, with traffic on the course, the laps times were erratic and I think there was enough cool-down and warm-up difference between the R4 and PFC90 pads. But that's my question - anybody else have experience with these pads and the dreaded/common front wheel lock-up?

 

[Tom Glenn]

Re: comments on PFC 90\'s

Tom, I have used PFC 90 and they wear like iron. However they are NOT linear and my experience was 1) no grip until they warm up (really disturbing at the end of a long straight). 2) once they are warm the grip keeps increasing until you must reduce pressure on the petal or you get front lock-up and they relase poorly. I now use EBC yellows in the front for someone who is easy on the brakes and EBC greens or reds in the rear. If you are ******* brakes I like Brakeman # 3's front & EBC reds rear.

 

[GTS Dean]

Re: comments on PFC 90\'s

Tom,

The 90's produce good torque, but the biggest problem is that they have poor release characteristics compared to many other pads. A common complaint about the OEM Brembo front calipers is that they flex and won't release consistently. I don't know which one's fault it is, but the combination is not the best on a Viper.

I have used PFC 93's up front in the past, but they are out of production for Vipers. I really loved them - huge bite, *very* easy to modulate, but got SUPER hot and were harder on the rotors. I currently run Brakeman #3 or #4s, which are a stock inventory item at Woodhouse. Price is very reasonable, but they have a high wear rate. Ultimate torque is not near either of the PFC's, but the curve is very flat and they release better than the 90's.

All Vipers that have the battery behind the driver's rear tire suffer from a light front right tire. I have always considered this to be a serious and fundamental design flaw for use on a road course. Because we have the fuel filler on the right, we are stuck with the stereo amp and battery being moved to the wrong side and it adversely affects corner weight with only a driver on board.

 

[Tom F&L GoR]

Re: comments on PFC 90\'s

Thanks, guys.

Tom, your description of the end of the straight is surprisingly accurate. I never knew where to place the initial braking point because the braking seemed to vary lap to lap (traffic). Sometimes I could keep up with the (changing) pad grip, other times not. The release characteristics (a little new to me) is probably why I don't like them; can't find a comfortable "process" to apply and unapply the brakes. And Dean, I forgot about the battery back there. I'll cut the RR spring seat a little to see if I can't get a little better front wheel balance.