Nice video! I track a C6Z and have always liked the ACR's (Gen 4 & 5) and have been giving some thought to picking up one of the new Gen 5 ACR's the last few months as I can not stand the look of the new C7's! I was considering picking up one when I made my last track car purchase (the Z) at the end of 2010 but then they unfortunately decided to stop production of the Gen 4's in 2011 which forced me over to the Vette as I consider it the only other track worthy alternative in that price bracket. I've been waiting to see some track video of a new ACR at a location that I'm familiar with to get a guage on how they perform and T-hill is pretty much my home track so it's nice to be able to see a video and be able to put speeds etc. into perspective as I've only ever seen a couple of Gen 5's out there the last few years. Compliments on your lap time, the car looks like a blast to drive and seems to have a lot of potential! I see from your video that they added a bunch of berms around corners over the winter on the new section of the track which allows you to use a more flowing line than in the past, so the track looks to be about a little faster than it was last year.
I had a blown shock and had to send my coilovers out for service so I missed that event that you ran but I know Rich and was talking to him the monday afterwards and he was commenting on how well your car seemed to handle and how much downforce the car seemed to generate in high speed corners! The white C7Z that he was driving is actually is wifes car (she runs the Optima too!) and it's stock with some used R7's from his track car on it and he mentioned that he was pushing hard to keep up with you on one of the sessions that he was alone in the car when you guys got down to in the 3:05 range. As someone mentioned earlier Rich is a very fast and very consistent driver and actually won the first round of this years Optima Challenge at T-hill back in February (ironically his wife took 2nd in her class too lol) so he was pushing the car hard and imho shows that the new ACR is a much faster car stock to stock than the C7Z! The last time I ran the 5 mile was last summer before the berms were added and it was the typical 95+ weather which slows the track down quite a bit. I'm thinking that with the cooler weather and the berms being added the track was probably 4 seconds a lap faster than it was last time we were out in August which matches up with the fact that the last time we ran Rich was in the 3:09 range with his wifes C7Z (versus 3:05 this time). That same event the last time we were out in August Rich got down to 3:01's in his C6Z without aero, I'm was in the 3:03 range with my car (with aero) and somewhat embarisingly for me Rich turned a 2:59 in my car driving it for a session. So applying the same 4 second difference that would have comparatively been around a 2:57 for him in his car, a 2:59 for me and a 2:55 for him in my car. How much time do you think that you were leaving on the table that track day?
Thanks, I love the C6Z and the C5Z for that matter- amazing track cars that can take on anything in the right hands. Very moddable. My friend bought a C7Z auto and suffered through overheating problems every track day, even with ambient temps in the 40s and 50s if you can imagine that. He needed the auto because his knee struggles with a clutch pedal. The solution was to short shift at 5,000rpm, but that was no fun so he just sold the car last month. Mike also felt that it was harder to drive at the limit than other cars he's tracked, he never felt comfortable pushing it to the edge. My hats off to Rich and his wife for being able to drive the car that quickly.
From what I've heard about Rich, he's a faster driver than me but the mighty ACR helped me make up for the difference, haha. Especially based on those lap times that you guys have done, that's awesome. This was my second time on the 5-mile and the first time at Thunderhill with the ACR. I think I'm leaving a lot on the table especially in turns 1, 2 and 8 where I could be several MPH faster, and I don't know the west side very good yet. I'm taking my time to work up to the limits with the huge aero that this has, and enjoying the process. I think I could shave off maybe four seconds as I get to know the track and the car better. Rich is a gracious guy, I enjoyed talking with him. He lent me a scan tool as my car went into limp mode a couple of times. The good news is that it was a known issue, and a software update at the dealer has already remedied it. I got one of the first ACRs so my software was not up to date.
I have to say that the ACR has blown my mind. I tracked my 2013 Viper GTS for the past three years before getting the ACR and can't say enough about the performance of the GTS. The GTS feels very similar to the C6Z and ZR1 (I have some seat time in both of them, and a little in a C7 Z51). However the ACR is a significant step up in every way compared to my GTS. Confidence inspiring, no drama, very predictable at the limit. Consistently, my friends that are advanced drivers have been shaving 3-4 seconds off of their lap times in their ACRs compared to their previous Vipers (most had TAs). It's not just the downforce which is brilliantly executed and adjustable front and rear, its the suspension and oh those brakes. Wow, the CCBs have really impressed. I can brake at the very last minute, over and over without a hint of fade, drama, or change in braking feel. The coilovers let you dial in not just damping, but of course the ride height which greatly affects how much downforce the diffuser exerts. And you can easily change the rake to dial out understeer if you need to. I'm an infant at understanding those adjustments but am trying to learn from those that know.
We will be at Thunderhill 3-mile on 4/23 and 4/24 with NorCal Shelby Club. Should be about 9 Vipers plus a few friends in GT3s. Come out and join us, say hi if you can make it.
My name is Todd, I'll be the only orange Viper there
Last edited by VENOM V; 04-15-2016 at 01:30 AM.
Todd you mean 4/23 and 4/24.......
Hey Tod, my names Ron! In regards to the C7Z once I heard that it was going to have a supercharged engine I completely wrote it off as a track day car. You do not have to be a rocket scientist to assume that you are going to run into heat issues tracking a car with one of those especially as hot as it gets up a T-hill lol! Little did I know that the problem seems to be worse than anyone could possibly have assumed as you mentioned your friend experienced first hand! Plus honestly imho compared to the C5 & C6 I think the design is ugly, just to angular for me. How Rich and his wife manage to have zero issues with their car is beyond me but he beats on that thing and it just keeps on going. Compared to our cars which both have Katech engines in them it feels pretty gutless and lacks top end. He took me for a ride and on the back straight he's WOT and we both start rocking back and forth in the seats trying to make the car go faster looking at each other laughing lol!
Regarding the times l've only done the 5 mile 4-5 times now but the back side is interesting in that you can go faster than you think you can around a lot of those corners you just have to hit the right lines and have faith as a lot of the exits and entries are over little hills and crests. From the video I think that you should be able to pick up about 3-4 seconds on that side alone. You mentioned you thought that you were loosing time on 1,2 & 8 and those 3 are corners where you just have to have faith in your aero which having gone from having no aero on my car to having a setup similar to a World Challenge Vette I can tell you takes some getting used to. It's truly a viceous circle, the faster you go the more downforce you have hence the faster you could have gone. Thinking of the repercusions from finding and possibly passing the limit though in those corners is not something that I think any of us want to picture! The thing that you have to remember is that there are 20+ corners around the track, 1 and 8 are probably potentialy the most dangerous and honestly you are going so fast that a few extra mph through those is going to result in a fairly limited reduction in overall lap times. In our cars Rich is hitting 156 at the end of the straight and going through T1 in the 100 range, I get hit with aero drag so I'm doing about 148 and pretty comfortably in the 100-110 range going through T1 and T2 is in the 85+ range so I think you can probably carry about an additional 8-10pmh on T2. T8....well I tend to think that anything around 100-105mph is fast enough through there lol but you might have bigger cajones than me ;-) I'm not surprised to hear that Rich helped you out with the scan tool. We're ddrive vette's but at the end of the day we're all car lovers and track nuts. He is a service manager at a Chevy dealership but he apprecaited cars for what they are like most of my track buddies. A couple of us drive Vette's but none of us fall in that group that is blinded by brand loyalty and that feel the need to validate their purchsaing decision at the expense of anothers thankfully. If I ever see you out there I'll stop by and say hi otherwise keep your eye out for us and swing by and introduce your self if you see us. Rich is usually in his yellow c6z06 aka the rumble bee, I drive an orange c6z06 with aero and a bunch of carbon on it and my buddy Mike who came over from the P car camp with his cup car runs a light blue C6Z06 with aero on it too.
Also noticed your thread on your experience with CCM's. I think that you guys basically have them same set up as we have on our cars. I've been tracking with them CCM's on my car now for 4 seasons w/ about 20-25 days per season and done a lot of CCM pad testing both for my self and also worked with a brake company to develop their pads. You are going to be impressed with theperformance of your CCM's but you will notice that your pad wear rate is going to increase as your rotors wear. The key to CCM life is brake cooling! Although I know you have brake ducts I'm not 100% sure what exact set up you guys have on your cars but on mine I run oversized brake ducts with hoses routed driectly to spindle ducts to keep them cool. If your car does not come with spindle ducts, get them! These rotors wear through oxidation due to heat, more specifically at temps over 700c the carbon fibre strands that are in the CCM (carbon ceramic matrix) that your rotors are made of will simply start to turn to dust. You posted a side shot of your rotor and pad in your other thread and if you look at it you will notice some small voids. If you look closely at your rotors you will also notice what look like stands embedded on the rotor face. Those are the carbon fibre strands that will oxidize due to heat and when they do leave those voids. Normally CCM brakes (because the rotor surface is near diamond hard) work through adhesive friction or the friction caused by a transfer layer from the pad that is applied to the rotor rubbing against the brake pad when the pedal is depressed (similar to rubbing two pieces of rubber against each other) not abrasive friction like with iron rotors where the pad wears against the rotor surface (like sandpaper) wearing both away over time. When those voids on the rotor surface start to develop abrasive friction does start to become a factor (but only to the pad surface) which accelerates pad wear. On a new set of rotors front I will see about 5-6 track days, rears get about 40-50% more life. After about 2 sets of pads that drops down to 4 maybe 5 track days for a set of fronts, then falls further down to about 3 days on a set of fronts when the rotor is close to being worn out. If you have any questions abot the CCM's feel free to ask as mentioned I have a ton of time on these, have run through multiple sets of rotors and littleraly have stacks and stacks of used pads! Also can you look at your pads and let me know what compounds are printed on the back of them? Just curious what comes stock on your car!
Regards,
Ron
HPC 4300 FF is the stock pad compound on the ACR. That's the same compound as the ZR-1.
Last edited by greygt3; 04-16-2016 at 01:14 AM.
Actually the ZR-1/C6Z06 w/ Z07 uses different cpad compounds front and rear. The OEM pads use a Textat T4300 compound front and Pagid S600 rear. If memory serves me right the front pads have the compound laser engraved on the back of the pad close to the Brembo part number. The rear pads have the compound etched into the metal back plate top center.
Are you sure about the ACR pad compound you listed and that car uses the same compound front and rear???
Here is a picture of the two pads side by side. ACR pad is on the left and a new ZR1 pad on the right. These are front pads only.
Last edited by greygt3; 04-16-2016 at 02:23 PM.
Thanks for posting the pic and have to say I'm a little confused now lol. All of these pads are supplied to Brembo by TMD Friction who own Pagid, Textar, Mintex and a couple of other more industrial oriented friction material brands. CCM brake pads are most commonly based off of endurance racing oriented pad compounds and they (TMD Friction) then work with Brembo and the OEM (Dodge or Chevrolet) to test and find the most suitable pad compound out of their sub brands catalogue of friction compounds. For the front GM chose for the ZR1 the Textar 4300 compound and Pagid S600 for the rear as mentioned and is laser engraved on the pad. These are both brands owned by TMD friction. But on the ACR pads that you posted it does clearly show HPC 4300 as you mentioned, but HPC is not one of TMD's sub companies or even a brand that I can find any info on so that is strange. I wonder if they are just re-naming the compound to try and avoid people cross shopping the pads. Also noticed that the ACT version has dual cutouts for the pad wear sensors as you guys run them both on the inner and outer pad versus just the outer like we do. Also your pad shape has a much larger radius cut into the bottom of the pad than ours (like on the GTR CCM pads). The reason for this has to do with the finish of the inner 3-4mm of the rotor being not very abrasive so traditionaly with ZR1's as the pads wear you end up with a 1-2mm higher raised 3-4mm wide band of friction material there than the rest of the friction (pad) surface. It does not seem to affect brake performance but it does look a little weird when you pull and inspect your pads. So don't be surpised if you see that if you run ZR1 pads on your car.
Ron,
Good info on all fronts, thank you. I appreciate the feedback on CCB pad longevity Vs. rotor age, that makes sense and backs up what Rich explained to me.
I'm with you on being a track rat first and brand-loyal second. My previous track cars were a surprisingly fast late model Camaro with a forged 418 c.i. and full aero, and I raced a Mustang last year in the SCCA. I would have considered the C7 Z06 as well if it had delivered to the hype, sad that it didn't live up to its legacy. After tracking my 2013 Viper for three years with exceptional performance and virtually no reliability issues, I've become a huge fan of the Vipers. And when the ACR came out, I could not resist. Couldn't really afford it, but was weak in the knees. You only live once, lol.
One question on CCBs- What do you base rotor replacement on? We are supposed to weigh the rotors, however I know that the ACR test fleet never had a rotor failure in all the testing they performed. I am wondering if I should weigh them, or perhaps replace them when pad life has shortened significantly.
I look forward to meeting you at the track one day soon.
Todd
No problem giving feedback on the CCM's. Back when I started tracking with them on my car in '11 unfortunately there were really no vette guys hardcore tracking their cars with them. You had the typical I go to one or two track days a year guys but as far as getting advise or feed back from them the only thing they are really good for telling you is that the brakes seem to work lol! So it's been a bit of learning by trying type of thing for me over the years and just testing a lot of different things. Fortunately based on what I have found more and more guys with my car brand like Rich etc. are starting to come over which will benefit us all in the long run as we really need to increase the amount of cars running these in order to get costs down.
In any case in regards to your questions I base rotor replacement solely off of rotor weight. Their is a min weight printied on the hat of each rotor assembly (this is why they only come pre-assembled). Once I get to that, they get pulled and replaced. The pitting or what I call "worm wood" look that starts to appear on the rotor surface due to oxidation of the carbon fibers will get worse as I mentioned and it will accelerate pad wear but rotors cost too much to just junk prematurely so I just deal with it. If you look at your hat you may also notice that there is a min thickness listed on there too. The ceramic in the CCM matrix that the rotor is made of is near diamond hard, so that does not wear and if by chance you do somehow manage to wear a rotor to the min it will have been way, way under weight for a long time so jsut ignore the min thickness. When my rotors are new I just run the first 3 pad sets on the front and then I will start pulling the rotors and checking their weight each pad replacement after that. As I mentioned I get about 5-6 pad changes out of a front rotor on average but I also run additional brake cooling. Attached is a picture of what I call the "worm wood" look that a more used rotor is going to take on and which causes increased pad wear.
IMG_0639.jpg
And in this one you can see the spindle duct that was fabbed up attached to my drop spindle. Cool air is ducted from the front of the car through 3.5" tubing connected to the spindle duct directly against the rotor/rotor hat.
photo 8.jpg
As mentioned if you guys only have some type of bolt on blade or wing thingy to divert air flow over the rotor, you really shoudl consider getting something like this if you seriously track the car to cool the rotors which will cut down on wear. I'm guessing something must be availabel for the ACR-X or something if they are not on the car stock already.
Lastly here is an example of what is mostly the oxidized carbon from wear that I keep mentioning comes out of your rotor after using it for a few days at the track. There goes a few more grams of rotor weight lol!
photo 1.jpg
Last edited by Werks; 04-17-2016 at 10:54 PM.
Ron,
Some of the best CCM brake info I've come across. Thank you for sharing your wealth of knowledge on the subject. We could definitely use more of your input in the Viper community! When are you going to place your order? Lol.
I am also a Nor Cal tracker and look forward to meeting you at an upcoming track day.
Hello Everyone,
Warren from RacingBrake. We are the brake company that Ron mentioned to have worked with him in testing our sintered brake pads exclusively developed for CCM rotors.
We used two brake platforms "Corvette ZR1" and "Nissan GTR" to test and develop our CCM brakes with a goal in search of the ultimate brake set up. You can search GTR forum and find more information where those GTR hardcore track drivers discussing their brake issue and finding their brake solutions where Ron is also a tech contributor there.
http://www.gtrheritage.com/forum/10-...nd-suspension/
Search "RacingBrake" or "Brake"
As to the brake pad compound, my bold observation is that both Viper and Corvette brake pads should have the same compound, the P/N variation should probably apply to the brake pad shape where Viper has more cut out at the bottom which is a newer model similar to Ferrari's F458 to F430 Scuderia which we observed on those changes very closely, as it's hard to imagine that Brembo is likely to develop a different/special compound for such a low production car like Viper, while the similar pad (although vary in shape/sensor connection etc.) was used in Aston Martin, Ferrari, Corvette (C6/C7), Camaro Z28 and now Viper.
In fact our brake pad for ZR1 the height was reduced from OE's 85mm to 78mm to eliminate the excessive bottom contact to the rotor flange which I believe Brembo has found the same discrepancy on ZR1 pad and made the change for newer models like F458 and Viper.
You can click below link describing more details about how we improved the OE pads.
http://www.racingbrake.com/Brake-Pad...pd1395-3r7.htm
Thanks! We're all car guys so anything that I can share or help you with I'd be more than happy to. As I mentioned back when I started running CCM's at first there was very little knowledge of these products (except from the P car guys but their rotors are actually different than ours) so everything I had to learn first hand. Over the years I've been able to try a whole bunch of different stuff and also as Racing Brake mentioned did all of the testing and development of his CCM pads. So I have built up a pretty good understanding of things lol. If there is ever a CCM specific thread started I'll give input and pass on any tips that I can. One little one though is I just noticed in my picture of the carbon dust under my rotor you can see a metal punch laying on the ground. That is available from Harbor Freight in a 3 pack of different sizes for something like $9 lol. The middle one (pictured) is the perfect size to use to clean out the drilled holes in your rotor face. They start to get filled with a plug of really hard brake pad deposit material over time. So as part of my regular post track day maintenance I go over each rotor and use the punch to unplug all of the holes. If you don't after a few track days your rotors are going to look like solid (un drilled) rotors because the hole will be completely covered with pad deposit and you are not going to be able to find the holes lol. So hose of you that track your car may want to start doing this too.
Bookmarks