Okay guys, time to do a little comparison!

A lot of us are running Porterfield R4-S brake pads. They're silent and have very, very little dust compared to the OEM Pagid 4-2-2 brake pads. Some people kept asking if they'd hold up on track despite being designed as a street pad. It's easy to answer that question from a technical perspective:

No, the R4-S (or any other street pad) should not be used on track.

EDIT: This is my opinion based on my first-hand experiences using the R4-S pads on my '07 V8 Vantage with 4-piston calipers. Another forum member, AXARUNNER, said he's using these pads on his V8 Vantage S, and he put down some blisteringly fast and very consistent times at Lime Rock during a track day we did together with AMOC. It might be that the pads used with the 6-piston calipers have a large enough surface area that it offsets the less-aggressive compound. Below you'll see the extreme chamfer of the R4-S pads as used on the 4-piston calipers. I haven't seen the 6-piston pads for comparison, but you'll see how the surface area of the 4-piston pads is very small relative to the overall pad size.

They're designed to operate in a specific heat range, and track conditions will expose them to temperatures beyond their design specification. Exceeding the maximum temperature for which the pads are designed will result in brake fade. That is, the loss of braking ability.

But what's that mean in plain 'Murican? Simply put: If you go too fast, you won't be able to stop.

What's too fast? Let's call it 100 mph. If you're doing it repeatedly, I wouldn't go above 80-90 mph. This estimated 'limit' is based on my own experience using these pads in my car in a wide variety of situations, and are basically what I'd consider the high end (if not maximum) of speeds the R4-S can handle to safely bring you to a complete stop during hard braking. Your results may vary. I made a video a while back about these pads. (It was my first ever 'talking to the camera' video, so go easy on me lol.)


While an 80 mph limit is perfectly sensible for many, some of us just aren't sensible. And if you're going to be driving on a track, you NEED brake pads that can handle it.

So I shot an email to Stuart and asked about the R4, Porterfield's track-oriented brake pad. Porterfield doesn't list these pads on their website but Stuart took care of it and sent them my way. Here they are:



Right off the bat you can see a difference between these and the R4-S pads. The R4-S pad material is heavily chamfered (beveled). These pads aren't chamfered at all - the pad material is completely perpendicular to the backing plate. The lack of chamfer gives the most braking surface possible, but has an increased chance of brake squeal. A chamfered pad, like the R4-S, has less braking surface, but greatly reduced noise.

What I'll be doing over the course of the summer is testing out these R4 pads and comparing them against the R4-S pads I've been using for the last several months.

My expectations:
Better initial bite when warm
Better high speed braking
Better heat tolerance on track
Worse initial bite when cold
Worse brake dust
Worse noise

 

I did a quick introduction video on my YouTube channel discussing the general differences in the brake pads. Here's a few pics to show the physical aspects of them.

No chamfer on the R4 (left), serious chamfer on the R4-S (right)



The contact patch of the R4 is 43% larger than that of the R4-S. Alternatively, the contact patch of the R4-S is only 70% as large as the R4 pad



Also worth mentioning: The R4 does not allow for the use of the brake pad sensors. I don't use them anyway, so it's a non-issue for me. If you zip-tie the sensors out of the way, there are no issues, errors, etc - you just don't get the functionality of the brake pad warning. Not a problem if you pay attention to your car and your brake pads.

I'm about to install them, and the next post (below) will be updated to reflect initial impressions for street driving.

 

Street Use

Took the car out for a quick spin last night, first time driving it since installing the brake pads. Just did a quick 10-minute jaunt with various types of braking - slow speed, normal, neighborhood stuff as well as high-speed back road hard braking. No noise at all. This morning I drove it to work, same thing. If that's continues, I'm gonna be extremely happy! I don't care about dust so much, but noise (squealing, specifically) I can't stand. I wouldn't be surprised if squealing develops as I put more miles on these because they're not chamfered, but I'm holding out hope! UPDATE: They definitely squeal.

Impressions*

Cold Stopping: Excellent (ambient temps ~68F)
Initial Bite: Excellent (comfortable to drive when cold under normal "neighborhood" conditions)
Stopping Power: Excellent (these things stop the car lol)
Noise: Lots of squeal (stop and go traffic, without anti-squeal compound or chamfering - plan to add both incrementally to determine the effectiveness of each).
Dust: Moderate (so far mostly stop-and-go DC metro area traffic, a little high-speed driving)
Rotor Wear: TBD

*Very limited use so far, so these can change.

(Updates to continue)

 

Track Use

The pads did well on track, which was expected since that's specifically what they're designed for. Didn't have any issues with fade or stopping power. Easy to modulate, and easy to balance the pads' stopping power with the tires' traction in hard stopping like you'll do at the end of a main straight. Dusty, but that was also expected. I'll be inspecting my rotors as soon as I get a chance to see how those handled the pads.

The biggest downside: After the track day, the pads squealed like CRAZY in normal driving. It was unbearable, especially given the 7.5-hr drive to get home in stop-and-go giant-traffic-jam I-95-is-literally-hell driving. I intended from the outset of this comparison to do incremental testing, so the pads are staying on the car until I've done that. I put the pads on dry - didn't even use anti-squeal. I'll be doing that, as well as giving them a mild chamfer, then seeing how much of a difference that makes on a track pad's noise levels.

 

I'm looking forward to your impression on the vantage. This is the combo I use my Lotus and Cobra for street 4s and track 4. One word of advice regarding the dust and you will get lots. It can be very caustic to bare aluminum wheels. I don't know what type of wheels you use on your vantage but I trashed a nice set of halibrands by leaving the dust on too long and letting it get wet. I haven't had any issues with it on painted wheels but I am also a little more vigilant about removing it after a track day.

 

Great advice, I appreciate it! I need to do better at keeping my car clean - I've been getting pretty lazy since I put on the R4-S pads because they dust so little lol

 

Yes to all the above. I just put a new set of R4 (front and rear) over a week ago. The bedding was done on the track. The noise only happens when pads aren't up to temp and during low speed to stop. The better bedding was done, the less noise on street. I'm on my 3rd set of R4 for the V8V

R4 definitely has more dust compare to R4-S, but less than OE Pagid.

 

Post #2 added!

Good to know they'll be reasonable for overall use. Really hoping a good bed-in prevents noise. If they're still loud, I'll chamfer them. If the noise continues, I'll do the "stop squeal" stuff. Planning it this way to see how each method does in reducing noise

 

Hey guys, since I won't be needing the R4-S pads anymore, I'll be selling them. Tons of life left, $215 shipped in the 48 States. Hit me up if you want them.

Marketplace listing: https://www.6speedonline.com/forums/...rake-pads.html

EDIT: SOLD!

 

"Street Use" post updated

 

I have Raybestos ST-43 race pads on my track car. Apart from the noise and dust, one other word of warning if you plan to use race pads on a street car - they will chew up your rotors, particularly if they don't get up to temperature. Most people who track regularly know that pads and rotors are basically wear items, like tires, and expect to go through them quickly. But using them on a street car you might be surprised how quickly they can chew your rotors.

For a beginner on the track, street pads are fine - most beginners don't brake hard enough to really cause them to fade. Once you get more experience, and start braking harder and later, then absolutely you need to change to track pads. Even more important than pads, you need high temp brake fluid. High temp fluid needs to be changed a lot more often than regular brake fluid. I once got overconfident, and left the fluid in too long, and completely lost my brakes without any warning going into turn 1 at Mid Ohio - fortunately, the only turn at that track where losing your brakes is salvageable without hitting a wall!

 

I"ll second that I ran a set of Porterfield R41's on my Cobra for track duty but left the rears on one summer during street use. After about 600 street miles my rear slotted rotors weren't slotted any more.
This is why I usually run the combo of r4s for street and r4 for track the pad material is fairly similar and bedding goes much faster and street use is cleaner and easier on the rotors

 

More info added to Street Use post above.

I'll be keeping tabs on rotor wear. I had practically no wear on my rotors prior to installing the R4 pads (the R4-S pads were very gentle). I hate to sound wasteful but I'm not terribly worried about wear on my own car (but I'll still be noting it during all this). I've got Wilwood 2-piece rotors and replacing the discs is relatively inexpensive because the hats are reused.

 

Added content to the Track Use post.

Updated the first post with an italicized "EDIT" to reflect a chat I had with AXARUNNER during our track day at Lime Rock last weekend, comparing R4-S performance on track for the 4-piston vs 6-piston brakes.

 

FYI
My wheels were black with brake dust after the Lime Rock TT event.
The pedal feel was softer than I like and as such I didn't have the level of braking confidence that I typically like...
On a side note, it was fun meeting telum01 aka Richard at the AMOC event. I sure wish more of the 6 speed members were there as it would have made a memorable event even more so... Please join the AMOC and plan on attending the outing next year.
Cheers to all and Happy 4th!