1997+ 2 piece race rotors

[NSXGOD]

So do these have any performance benefit, or are they for bling like ken suggested??

I have not read Ken's post so I'm not sure what his definition of "bling" is. If you can drive fast enough they will be of some benefit to the handling by lowering the unsprung weight by ~10lbs. (total) If you have HP to get going and the tires to brake late, they will also be of some benefit by having more airflow compared to stock rotors = more cooling capacity, and the alloy selected along with the heat treating process and 2 piece construction with floating hardware allows for higher heat stress to be applied before they will even think about warping. They are not for everyone.

 

[nsxtasy]

So do these have any performance benefit, or are they for bling like ken suggested??

Despite my earlier quip (in jest, of course), two piece rotors DO have performance benefits over the stock rotors. However, I'm not sure everyone needs them. The performance benefit isn't in stopping power; it's in durability. When used on the track, OEM rotors and other one-piece rotors get hot on the outer "ring" that is the friction surface for the brake pads, and this outer ring heats up more than the center "hat". Since a one-piece rotor is, just as it sounds, little more than a flat metal disk, this creates stresses in the metal as the outer ring expands with the heat, and then contracts as it cools, while still part of the same piece of metal as the inner hat with does not. The advantage of the two-piece rotors is that the hat is a separate piece of metal, and there are special connectors between the hat and the outer ring so that the outer ring can expand with a flexible connection to prevent the stresses of a one-piece rotor. With extensive tracking of your car, you may find, as I have, that your one-piece front rotors last 4 to 8 track events before they must be discarded (when the cracks become deep/wide enough - basically, when you can feel them with the edge of your fingernail - when cool - is a good time to toss them). And you may also find, as I have, that two-piece rotors last longer, 6 to 12 track events, before they must be discarded. So that is the advantage of two-piece rotors. Whether it's worth the extra cost for the longer life, is up to you.

However, if you don't experience any cracking of your rotors - for example, perhaps you don't track your car - then you won't get this performance benefit. I have been using the same one-piece rotors on the rear of my NSX for the past forty plus track events, and they have never cracked, and they still have plenty of thickness. Based on that experience, I don't feel that two-piece rotors in the rear will give me any significant performance benefit. (Some folks may get them anyway, for appearance purposes, just so that the front and rear rotors are visually identical.)

 

[NSX-Racer]

Based on that experience, I don't feel that two-piece rotors in the rear will give me any significant performance benefit. (Some folks may get them anyway, for appearance purposes, just so that the front and rear rotors are visually identical.)

Just to add another benefit for some of this rear solutions with different rotors and calipers (e.g. the Brembos): You can change pads much easier and faster as a DIY on the track than with the stock brakes.

And: The 2 piece rear discs should last much longer than the stock discs already do (about the same relation as Ken described for the front brakes but after double the track events or more)

 

[Hrant]

The rear rotors get equally as hot as the fronts if not more. With little options for air deflectors or cooling ducts, a two piece floating rotor with enhanced vein design helps to cool the rear rotors more so than the OEM. When you couple this with less unsprung weight - and how many of you lost those 10 lbs lately, or got rid of that mid section donut heh - the floating rotor is a benefit over the OEM both on and off the track.

How much more is a relative term especially if they also enhance the looks

 

[nsxtasy]

The rear rotors get equally as hot as the fronts if not more.

I wonder whether this is really true, even with cooling ducts installed in front - and I say this because (a) the front rotors do most of the braking at the track, due to the transfer of weight to the front during braking, and (b) despite my front-only cooling ducts, I have never had any heat-related problems with the rear rotors - no cracking, no shudder, nada.

Has anyone measured front and rear rotor temperatures using a dynamometer after a hot track session?

 

[Ojas]

Has anyone measured front and rear rotor temperatures using a dynamometer after a hot track session?

I have not measured, but according to this article, with completely stock 91-96 brakes (splash guards in place, no deflectors, no ducting), fronts will be quite a bit hotter. It looks like it is possible to cool the fronts enough to run cooler than the rears by a some combinations of splash guard removal/modification, deflectors, and ducting.

However, on the stock 1997+ NSX (which is relevant to this product), the temperatures front/rear were the same. Not sure if this is due to difference in driving styles, but seems interesting.

 

[Hrant]

http://www.nsxprime.com/forums/showthread.php?t=31518&highlight=Rotor+temps

http://www.nsxprime.com/forums/showthread.php?t=18207&highlight=rotor+temps

By the way, several times we exceeded the Sears Pyrometer readings when measuring the rotors immediately after a hot lop and coming to the hot pit for measurement. The previous measurements around 500F were after a relative cool down lap, parked in the paddock.

HTH

 

[nsxtasy]

Okay, I'm convinced.

Then consider two-piece rotors for whichever end(s) of the car you are finding heat-related rotor problems.

 

[Ponyboy]

Also keep in mind is that one of the inherent advantages of a mid-engine design is that braking force is more equalized between either side, front and rear.

"Under braking, the combination mid-engine static weight distribution and dynamic weight transfer produces equal braking force on all four tires."

- from the silver covered NSX book with no title and author.

 

[Hrant]

I tested the rotors yesterday at Thunderhill where the ambient temp rose to about 93F+ and the paddock had a 114F about 3:00 pm.

In short, these rotors are absolutely awesome on the track!

I had more brake than my OEM Yoko tires on 16/17 wheels could handle - really (though the rears are on their last legs). And after taking it somewhat easy the first two sessions I really hammered them the rest of the day at least twice per session from 120 mph and 100 down to about 50-40 and absolutely no problem (we ran clockwise). In fact both Al and Ted rode with me, and both were impressed too.

And also, as the attached pics will show, after roughly 5 sessions or a total of about 110 track miles, the Carbotech Panther Plus did not leave as much dust as when I had the OEM rotors - in fact they look more like when I drive on the streets!

The one thing that we noticed on heavy braking (especially coming to turn 15 and 6 clockwise) is that the tires got confused which way to pull and noticed a kicking back into the steering. We think the fix is the Comptech clamps - something that we might consider to put/clamp only for track days. But further testing may be needed.

As for temps, during the first two sessions in the morning - good clip but not too hard - we were in testing mode, the fronts got to 350F and the rear was 450F after my normal cool down lap and measured in the paddock .... I thought this was about 100F cooler on the fronts and about 50F on the rears but as I said, I wasn't pushing hard.

By afternoon, the ambient temp was about 93F and rising. So took it out again and had some good runs with Ted in the car (so we have some 200 lbs of extra weight). Measured the temps: Front 480-500F and rear 580-600F .....!!! The Sears Pyrometer is not supposed to read over 517F so go figure! But the brakes held out perfectly giving me more confidence to push the car. No fade, no shudder. I use Motul 600; DaliRacing street air deflectors on lower level (though I have cut the front edge to avoid scraping) and the fronts have no dust shields.

I may have another opportunity to test the rotors again on September 24, at the same track going clockwise also. So validating these numbers would be great but I will try to find an infrared Pyrometer with higher readings.

Also as a footnote, in the afternoon my water temp gauge was reaching one level below the red mark so had to take a cool down lap after a few laps. As posted earlier, this seems to be a common problem at Thunderhill with ambient temps above 90F; did not have the problem in the morning though. I had already flushed the radiator using Honda's mix and added a bottle of Redline's wetter.

HTH.

 

[Hrant]

Updates

Conditions yesterday at Thunderhill going clockwise were the same as last time if not slightly warmer by afternoon. The asphalt on the paddock was closer to 123F and rising. It was a hot day and the track was hot and slick

The rotors worked great. Frankly, I don't think I am using the rotors as hard as I did my oem cryo treated rotors and even then I am/was relatively gentle on the equipment. I think the Carbotech Panther Plus works great with these rotors as the balance between front and rear is perfect. And dusting is surprisingly not bad so this might mean we are indeed operating in the optimal range of the Panther Plus. The brakes gave enough confidence that I was now doing about 123-125 mph of the front straight.

I did notice that the Comptech clamp helped quite a bit in the morning sessions where braking was absolutely no problem and no kick back in the steering. By afternoon, I picked enough marbles from the track that some of the minor kickback can be attributed to the marbles, but even then it was less than the last track event.

Temps were off the chart in the rears in the afternoon; I am guessing they must have been close to 600F - the fronts showed about 400F. Other times when the fronts were like 370F the rears were reading 520 to 540F (Pyrometer is supposed to read no more than 516F). This validates the last track experience where the fronts seem to run about 100F to 150F cooler than the rears.

TigerNSX in another post asked the wheel temps. The wheel temps using the 16/17 oem wheels were about 185F to 200F measured in the paddock; I have 15mm spacers so I am sure they would be hotter without. Docjohn's comment that he has seen temps of 250F with his SSR-C wheels is in the same range. {this was the post: http://www.nsxprime.com/forums/showthread.php?t=40667]

As for the Type R brace, we installed only the one infront of the radiator (we are working on a novel solution for the lower brace), and I could sense a big difference on the HWY where the front was rock solid stable. No occasional wandering at 80 mph. Did not notice any harshness because of the Comptech clamps. So for now I think I will keep them for daily driving too. Don Tempelton who was there too - noted that the clamps rub on full lock using oem wheels; I did not notice any such rubbing and I am ascribing it to the 15mm spacers. I will check this when I jack the car up.

The next test should be running those rotors with R compound tires and see their true potential. [Now if I can get those wheels - the party on these forums knows who he is - I can move on to the next plateau ..... ]

So bottom line, DaliRacing has introduced a great product. These rotors rock. Now if the manufacturer can use FoliaTech paint or some higher temp paint for the veins, or cad plating, perhaps they will withstand the heat better and look even more bling bling as well

HTH

 

[NSXLuvr]

looks promising.

Q: Why don't the cooling slits(?) on the disc reach the edge of the disc? According to a previous thread, that would be similar to the Type R discs and reduces the likelyhood of the disc cracking.

thanks for the testing Hrant.

 

[NSX2play]

... I have never had any heat-related problems with the rear rotors - no cracking, no shudder, nada.

I have. I have StopTech AeroRotors in the front and Powerslots in the rear. The last track on which I ran my car is very, very hard on brakes and the rears now shudder. The fronts are fine. For this reason I am thinking of putting my OEM rotors back on or maybe Project mU rear rotors.

BTW I [foolishly] bought the rears thinking that it would look better with slots front and rear - only to find out that the slots on the rears are cut in the opposite direction than the fronts! (I know, the rears are unidirectional and could have been reversed, but I did not do the installation myself). A year later I made a conscious decision that all my mods are going to for go, not show and have never looked back.

... Now if the manufacturer can use FoliaTech paint or some higher temp paint for the veins, or cad plating, perhaps they will withstand the heat better and look even more bling bling as well

If you have ugly veins then you need to see a plastic surgeon. If your car has ugly vanes then it needs paint or plating. But why be vein about vanes? They are there for go, not show (see previous comment above!).

 

[NSXHSC]

The slits on the Type-R discs do not go to the edge of the disc.
I believe that discs with slits that go to the edge are more likely to crack.

looks promising.

Q: Why don't the cooling slits(?) on the disc reach the edge of the disc? According to a previous thread, that would be similar to the Type R discs and reduces the likelyhood of the disc cracking.

thanks for the testing Hrant.

 

[Hrant]

Good catch Michael (NSX Maven) But at my age, veins and vane are almost synoymous, both are rusty

I did check the Comptech clamp for clearance; there is no rubbing with 15mm spacer. I should have checked it without; I will do that next time.

--------------

Also I forgot to note, once again we had radiator overheating issues after 3 hot laps at the track. And once again, half a cool down lap with short shifting resolved the issue but for only another lap or so and then the needle rised to about 1 to 2 levels before red. If the water temps are getting so high, I can only imagine what the oil temps would be Fortunately, Mobil 1 with EXP4 should give some comfort as the latter is heat stable to 500F - whether that means it will help Mobil 1 to be heat stabel too is a good question. http://www.exp4additives.com/products/detail.asp?itemid=3&catid=7

Now if we could get the vendors to introduce a combo Accusump and oil cooler that would be great too, hint hint ....

Compare the picture below with the one posted above when new. As I noted, the performance is there - no questions about that; but a little bling bling look would be nice too

 

[NSX 3.0]

Hrant,
I would be very curious to know what the problem was with your overheating issues at the track. When you get the fix done please let us know.

 

[2slow2speed]

Hrant,
I would be very curious to know what the problem was with your overheating issues at the track. When you get the fix done please let us know.

Hi Steven,

FYI, It's a normal occurance at Thill when it's hot, I was at the track on Friday as well, the morning sessions were ok, but later in the afternoon I could not go more than 4 or 5 laps at WOT without having overheating problems as well, and that was with the NSX-R hood.

Ken

 

[NSX 3.0]

Hi Steven,

FYI, It's a normal occurance at Thill when it's hot, I was at the track on Friday as well, the morning sessions were ok, but later in the afternoon I could not go more than 4 or 5 laps at WOT without having overheating problems as well, and that was with the NSX-R hood.

Ken

Ken,
I ran into the same problem a few weeks ago and it also was a very hot day. I had my coolant flushed a few days before the event and I too was getting hot after 5-6 hot laps. I found out I still had some air in my lines and had to burp the car about five times that day. What I think the problem was and I might be wrong is my cap on my SOS tank was not fully screwed on tight.


What I found out was the car runs fine in day to day traffic etc and does not loose any coolant or get hot. Just yesterday I took a long drive and had to make a stop and left the car sit at idle maybe ten minutes I got in and saw my needle at the red zone. I shut it off and looked in the back and saw some steam coming out of the cap so I let it cool and drove home with no problems.



When I got home I let it cool all afternoon jacked the back up and burped all four points of the system and I did get a little air from the front two. I went to open my cap on the tank and I had no pressure at all when I took it off usually I get a blast of it. What I found out is you almost have to push down twice to secure the cap tight which I did not know or do my own stupidity at fault.


After doing that I took the car out and just beat the heck out of it ran it hard for a good thirty minutes. I came home and let the car idle to see what it would do and the needle did not move from the point it always is at one tick under half way. My fan would switch on and off and the needle was right on never moved so I hope that was my problem with the cap not being on tight.

 

[Hrant]

While we digress from the thread, Steven you raise an interesting point with burping the air and checking the cap for pressure. I will test those options.

Another option that was mentioned by Shad at Comptech was trying to remove the plastic shroud around the radiator fan. True, it will allow more air to flow out of the radiator. But the hassle to put that on/off was too much. But I am sure it will be a positive solution for a dedicated track car. The gasket is also a possibility according to him but less likely on the later models.

Yo your royal Ken, I saw you when I was in line for lunch but by the time I was through the line, you were gone; couldn't find you near your car either. Came back again in mid afternoon to chat, and you were gone for good! It can't be my deodorant or was it What was the dealio with the disappearance act, mechanical issues? ........ even Don missed you

A side note: Don Tempelton has now gone over the edge! He bought a 30 ft trailer for his NSX; it has sleeping area, TV, kitchen, bathroom with shower as well as a kennel for one, two or three or four ..........

 

[2slow2speed]

Yo your royal Ken, I saw you when I was in line for lunch but by the time I was through the line, you were gone; couldn't find you near your car either. Came back again in mid afternoon to chat, and you were gone for good! It can't be my deodorant or was it What was the dealio with the disappearance act, mechanical issues? ........ even Don missed you

A side note: Don Tempelton has now gone over the edge! He bought a 30 ft trailer for his NSX; it has sleeping area, TV, kitchen, bathroom with shower as well as a kennel for one, two or three or four ..........

Hi Hrant,

I ate lunch very quickly and then walked around the paddock area checking out the various cars out there, saw your NSX and checked out the rotors on your car, they looked pretty good, hope that they are working out for you.

In your earlier post you mentioned that they were thicker/wider, were you referring to the hat? I'm assuming that the width of the rotor itself is the same as the OEM one, otherwise there will be issues with fitments with the OEM caliper.

I saw Don very briefly prior to the drivers meeting and heard about his trailer, he seems to have caught the bug hard, LOL.

Had to leave early to be able to make it back to the SF Bay Area to meet some friends later that evening.

Ken

BTW: I'm still patiently waiting for the NSX-R suspension, my Tein RA's are shot

 

[Hrant]

Hi Hrant,


In your earlier post you mentioned that they were thicker/wider, were you referring to the hat? I'm assuming that the width of the rotor itself is the same as the OEM one, otherwise there will be issues with fitments with the OEM caliper.

If I recall the thickness referred to the rotor plates and not the rotor itself - at least that was my visual inspection when I held them next to each other. I will have to measure the thickness of the plates and compare to the oem plates.

But this must be true for the rear rotors because DaliRacing's rear rotors weigh almost the same as the front, whereas the OEM rear is 2 lbs lighter than the oem front. So by simple deduction, if all the weight saving is in the hat, then the rear rotor must have more mass; and to do this the plates have to be thicker no? But, I will verify this with my digi caliper measure.

So you are going with Type-R heh! Why not go all the way with Comptech pro suspension? According to Andrie and Kip, it's the best

 

[NSXLuvr]

since we are going OT, I don't understand why the California NSX's keep overheating. I drive in 95+ degree heat from May - September and have No cooling issues on my car. That just doesn't make sense. It is because of a specific area at Thill or could it be something else. I'm sure we all hope its just bubbles, but that doesn't quite explain all the overheating issues.

I remember another thread where a NSXer from Arizona went on vacation to Germany and talked to the Procar NSX guys. He found out it was a defective head or something like that. I will do a search and see if I can find it.

 

[Hrant]

I don't understand why the California NSX's keep overheating.

Well, I could say because we drive harder/faster on the track but then that is all relative .....

Frankly, we too are somewhat puzzled

It just happens that I tend to observe most of the overheating (going clockwise - the only few times that I have driven in ambient temps above 90F) at the back of the track between 14 and 11, 10-9 and 9-6 and all of these are WOT all initiated with some high rev down shifting starting at turn 15 going to 14, and 12 to 11 ......... Since most of the time air/wind blows from the NW to the NE, going in the opposite direction NW to NE might be a contributing factor. But I am purely guessing. It would be nice to ask the car clubs we attend with if they notice this too.

 

[NSX-Racer]

I remember another thread where a NSXer from Arizona went on vacation to Germany and talked to the Procar NSX guys. He found out it was a defective head or something like that. I will do a search and see if I can find it.

It was DangerMoney and he talked to me not to Procar. It was a defective head gasket and you could read more about that in the Nuerburgring story on my website.

 

[The DON]

so who else has tried these 2 piece rotors other than Hrant?