PART NUMBER: 61-03341NDF
This high friction racing material has grown to be a very popular choice for drivers who need the highest possible friction with a low pad temperature. Developed and tested in the vintage racing community the R4-1 gives an average coefficient of friction of .56 with peak levels up to .600. Having tremendous stopping power, the R4-1 pad material can reach upwards of .5 friction level when pad temperature is a very low 200 F .
Drivers can still have a high friction brake pad without worry of the pad becoming too cold to be effective when the car is driven only moderately. For use when pad temperatures are under 600 F and peak temperatures are not over 1000 F. Widely used on Vintage GT and formula cars the R4-1 has gained great popularity as an excellent auto-cross, off-road and rally-cross pad material. Great modulation, consistent pedal feedback and the same rotor friendliness as our other carbon kevlar compounds.
BRIAN'S APPLICATION NOTES: I first drove these in Vintage racing a Triumph TR4-A....which is the same weight as a Miata. I really liked the bite of these pads and they worked great at tracks like PIR. Finally decided to try them on our 2007 supercharged track and autocross MX5 and again the bite is great and they have low temperature performance that other race pads can't seem to deliver sufficient for use as your ONE choice for BOTH autocross and track and street driving in warmer climates.
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.
*** I experienced ZERO fade in all 3 sessions! ***
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.
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.