I just installed a set of Porterfield R4S's on my Datsun 280zx. Last night I did some 30-5 stops in my neighborhood until I could smell the pads - probably 10 times. Today I went for a ride where I did some standard stops - stop signs, etc in normal driving - plus a few 60-20 stops with medium pressure. I did not smell the pads nearly as much this time. The pads seem to feel better with some heat, but I don't have the sharp initial grab that I was expecting (given I was upgrading from organic pads). Maybe I need to bleed the brakes again or do I need to refine my bedding procedure?
(PS how come these things don't include instructions in the box?)
Porterfield should be your best source of info.
30-5 is pretty mild for bedding. Try 50-5, there's about 3 times as much kinetic energy and heat involved. The idea is to bring the pads up to temp and keep them there for a while. The more aggressive the pad, the higher the heat.
R4Ss are never terribly grabby, though.
Keith, thanks. I'm asking them too - no response yet, so I suppose I could use the old-fashioned telephone...
Your comment about "R4Ss are never terribly grabby, though." is a useful piece of info. This is my first set of "better than Autozone" pads - perhaps my expectations are unrealistic.
I'm kindof "Meh" on R4Ss. They stop well enough, but i find the initial bite pretty lacking. I'm fairly sure even the Metal Masters i run on my daily driver have a harder initial bite.
If you equate a sharp initial bite with good braking, the R4S is not the pad to use. If you just want good manners over a fairly wide heat range, they're an excellent choice.
Miatas never do have that overboosted feel you get with a lot of economy cars anyhow.
Especially for street driving, the difference won't be terribly noticeable. Repeated/heavy high-speed braking, however, will show you the big differences. When I upgraded to StopTech pads & ATE fluid I could barely tell the difference until I ran two track days at Road America back to back.
Porterfield replied to me - they said do about 100 miles of normal street driving and to avoid hard / 60-0 stops when the pads are fresh out of the box.
Thanks for the advice everyone.
I run R4 (not R4S) on my E30 chumper and the Lamb-o. I've been really happy with them. The bed-in procedure I've used is to drive 55mph wide effing open riding the brakes to hold the speed for about one mile the day before the race. (Interest of full disclosure, they are one of my only material sponsors, so I get the pads for free). After 14+ hours of racing they're still only 1/2 worn on the e30. The Lamb-o eats them faster than that, but it's faster (in a straight line, anyway) and a lot heavier.
That's a pretty mild break-in procedure (Mike, not Sporqster). I had one set of R4S that weren't bedded properly and glazed on me. Almost no bite at all. I bedded them again using my usual technique, and they've worked well ever since.
In addition to occasional street driving, I use the car for Auto-X once in a while. In the spring I'd like to do a HPDE as well, and was hoping these would be a good pad for these purposes given my car and novice driving ability.
Keith I'll try your method and see what happens. It feels like I have no bite, but it gets better as they get hotter.
Also, don't use the parking brake while they're still hot? Is this correct?
Street, autox and light track work well for the R4S. They'll be most challenged at the track if you're hard on the brakes or if the track is taxing.
It's a good idea to stay away from the parking brake with any hot pad. As a general rule, when they're really hot (such as getting off the track), try not to come to a full stop using the brakes. You'll get a transfer of brake material on to the rotor. Even more so if you clamp the pads to the rotor with the parking brake.
