I recently got hooked up with Matt at Morris Engineering to do some testing of a new 2-piece rotor setup. Matt is offering 2 styles of rotors, a very lightweight setup targeted at auto-x and light track duty that saves about 8 lbs per front axle (17.8 lbs vs 26 lbs for OEM) and a heavy duty 2-piece setup targeted towards heavy track use.

I've tested both setups this far on my car. First he lightweight rotors:
I ran them hard at the track, and ended up with vibrations. They stayed nice and cool though and prior to the vibe, performed very well with zero fade. I didn't have the ability to capture rotor temps with that setup, but the rotors aren't quite up to the abuse I put them through. However I ran them for 1 day in wet conditions where braking was less abusive and they were fantastic. So for light track duty and street or auto-x, shaving 16 lbs of rotational weight is great and they'll work great

Onto the heavy duty setup... Each is about 21.5 lbs, so 4.5 savings over OEM.

I recently completed 2 days of track driving at Palmer Motorsports Park in Ware, MA. For this event, I had a new set of Morris 2-piece rotors, these ones being a “heavy casting” setup. The castings were thicker than the first set, and while a bit heavier, they were intended to be a bit more robust. Still are fixed 2-piece design.

The rotors did very well. On day 1, I ran the 2-piece rotor on the drivers side and an OEM rotor on the passenger side. Captured temps after a couple sessions. The OEM rotor consistently ran about 30-40F cooler temps than the OEM ones on the first day when I ran the Morris rotor on the driver’s side and the OEM on the passenger side. Caliper temps were lower as well by around 25F. I did not collect “hot pit” data, so I don’t have anything good for the high end of heat witnessed, but with about 1 minute of cooling from partial cool down lap to parking in the paddock and jumping out to grab the IR thermometer,the max rotor temps were like 575F (hottest on the outer surface) – inner area by the rotor hats were almost 100F cooler. Very clear gradient working from the inner surface outwards. And I was happy to see the hats staying in the 200F’s for the most part. The OEM “hats” were closer to the rotor temps, so Morris have a clear heat dissipation advantage

On day 2 I ran Morris rotors on both corners. The braking was consistent, fade free, and uneventful. Zero indications of shudder and no noise from the pads either. This is an important detail because every time I’ve run the Raybestos St47 front pads in the past, they would start to howl after about 100 track miles. In fact, on Day 1 PMP event, the passenger side front did start to howl at the end of the day. The developing noise on the OEM rotor from day 1 was not present though on the Morris rotor once the rotor/pad were bedded, and there were no surface cracks on the passenger rotor which saw about 110 miles of track driving yesterday. The drivers rotor, which saw about 225 total track miles, did have some mild surface cracking.

Take aways – the version 2.0 rotors (thicker casting) held up exceptionally well at Palmer during about 225 total track miles. Temps were consistently cooler than the OEM rotor, and the caliper and outside pad surfaces were lower as well. From a fade perspective, I had zero, which is really a first for me for a 2 day event. I bled the brakes last night and had zero air bubbles from the front or rear, which I don’t think has ever happened before. Temps yesterday climbed to about 80F, so it was a warm enough day to have significant heat build up. And I drive fairly aggressively… so I’m confident I put these through the ringer! Lastly, I had my brother with me, who is probably 275 lbs or so, for all 4 sessions yesterday, so we were hauling significantly more mass around all day!

The thicker rotor, thus far, has cured the issues I developed with the “thin” casting that I tested at Limerock. More testing to come, but I’m very happy at present. No issues to speak of at all during the 2 days of recent tracking


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And the install time-lapse video:

 

Thanks for this. I'll be interested to see how long they're viable before needing replacement.

I'm curious what your brother did that pissed you off enough to basically call him a fat-*** on the Internet.

 

Hahaha I've been on his case to lose weight for a couple years! Getting my jabs in 😋

I'll keep the thread updated as I put on more track time. I've come to expect about 1500 miles out of a set of rotors. I'd settle for less if these continue to our perform OEM though! We shall see

 

If the heat dissipation is consistent for the life of the ring, the hat should last quite a while allowing you to replace just the ring itself and reducing costs, perhaps, as well as weight.

 

Do you know, are they only for the Brembo's?

 

Yes, these are only for 14" Brembo brakes at present.

 

Yup, part of the appeal of 2-piece rotors!

 

I'd really like to see some location temps to see how effective the dissipation is but that requires multiple people with temp guns waiting for you to hot-pit. Not exactly track-day equipment for us amateurs.

 

So I kinda did this... Consistently the outer edge was about 100F hotter than the inner edge by the hat. The temps increased pretty linearly going from inner to outer as well - no particularly hot spots. This makes sense as the outer edge has the highest linear speed so I would expect higher temps, also because cooling air heats up as it goes outward, it cools less efficiently by the time it exits the rotor

This was all just captured statically of course in the pits after a session. No live data during driving unfortunately

 

That's still a good measurement though. If the heat dissipation is linear, it will also mean no sections of the ring are heating/cooling excessively slowly compared to the rest of the ring. It's an indication of uniformity throughout the width of the ring, meaning less chance of a fault or weak spot within the ring itself. Those will not be fun if they fail on a track day.