Porterfield R4-1 DUAL PURPOSE Pad - MX5 Rear

I'm running these pads on my Good-win-racing 6-pot BBK, as well as my stock OEM rear calipers and so far I'm very pleased with their performance. Very strong bite from cold and very good feedback from the pads. No sign of brake fade either during spirited driving (will hopefully get the chance to try them on track soon too). Noise is also not as bad as I imagined. They do squeal occasionally but nothing that I haven't come across with other pads. Brake dust is significant so expect to clean your wheels a lot (my recommendation would be to ceramic coat allow wheels so they can be cleaned off easily).

The parking brake also holds very well from cold (this was a concern of mine in particular with more aggressive pads that might not have such high friction when cold). I've tried them on a very steep inclines.

-- Joseph B., Ta L'Ibrag, Malta (Europe) ( MX-5 ND 2016 ) April 2020

I have these on the Willwood BBK 4 piston in front and the stock caliper in rear. 2 days at Miatas at Mazda Raceway Laguna Seca this weekend, brakes performed great. Total confidence braking hard into turn 2. They work fine on the street when cold too BUT squeak like hell. I'll be taking them off unless going to the track. I was hoping that would not be the case.

-- Brian O., Orange County CA ( MX-5 2016 ) October 2016

TL;dr: Install these with confidence, expect to clean wheels more often

Track: PBIR is a 2mile track with 10 turns and the main straight is ~6/10mile long.

For the Miata, most of the corners are 3rd gear and aside from main straight, you touch 4th briefly in 3 spots, short straights before corners 1, 4, and 6. Hard braking with H/T downshifts required at same places. Each corner was marked with apex cone and had the normal series of cones marking the braking zones for reference though I'm not sure what the spacing was between them.

Each Run group was on track for 3 x 20min sessions w/ approx. 45min between sessions. When I ran this format in a Mini on OEM pads/fluid, the 1st session went well with hints of fade in last lap of 1st session , definite fade midway thru 2nd session requiring me to pit after 15 min , and only 2 laps at pace in 3rd session before I pitted due to lack of confidence in braking system. Upon inspection, fluid seemed ok (not boiling) but pads had glazed rotors and were smoking hot.

Performance: 1st lap from pit lane I drove moderately to allow tires / brakes to come up to temp, all laps following were taken with progressively more pace as I explored the limits of the stock suspension (sport), tires and upgraded brakes.

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*** I experienced ZERO fade in all 3 sessions! ***
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I found the R4-1's to give excellent initial bite (no jerkiness) and good linear feel through pedal travel to ABS threshold. Once I found that point, I was able to (i think) get the most out of the stopping power of the pads. The pads were consistent in that every lap, the applied power matched the applied input. As the brakes heated up (my lap times were in the 1:45-1:50 range), their behavior did not change. When I got off them, there was no release lag.

In the 1st session, I reached ~100mph and was on the brakes at the 4cone brake marker with much room to spare.
By the final session, I was consistently passing 115mph (best lap when I nailed corner leading onto back straight 122mph ) and was was able to push my brake point to just before the 2cone marker, H/T into 3rd and take the "carousel" on the racing line. If only I was able to put together a consistent lap, I think I could have been down to the low 1:40's and with more practice I have expectations of breaking the 1:40 point regularly. At some point (soon, I hope), I'll put in a FSB and that should have a major effect on handling and lap times.

Ratings:
Initial bite: Excellent and smooth
Consistency: Best Feature, no difference (to my amateur butt) between 1st hard lap and last w/in session
Release: Good, not lag or drag
Durability: These pads lasted the entire event with no fade. Time will tell how long a $350 set (F&R) will last with mixed usage and 1-2 Auto-x + 1 Track event/month
Noise: ZERO on track, minimal on street
Dust: Significant. If that's the only price to pay, I'll work on my wheel cleaning technique.

Recommendation: Install these (coupled with Dot 4 fluid) and enjoy great street performance coupled with excellent Track performance.

If it matters to you, there will be some minor squeal at very low speed and you WILL have to clean your wheels more often to keep them clean or install Charcoal/Black wheels and it will be much less noticeable.

-- Donald R., South FL ( 2016 Miata Sport ) August 2016