Source One got to root issue on mine (SOS 350 on a mostly stock 1999). It was due to an improperly adjusted clutch pedal (previous install NOT performed by Source One).
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2k Miles - Slipping already - ScienceofSpeed Twin Carbon 700 Clutch & Flywheel
- Thread starter synikster
- Start date
Synikster - Any update on what happened with yours?
Mine seems to be holding up OK, but I am REALLY TIRED of the engagement. It has an extreme amount of chatter to it, and it is very on/off. I am going through another iteration of loud exhausts recently, and it is so obnoxious to drive around town. Trying to rev it up from a standstill and then the abrupt engagement with RPM drop is very annoying. I chirp tires regularly on takeoff
I hope it gets better with only 500 miles on it.
Mine seems to be holding up OK, but I am REALLY TIRED of the engagement. It has an extreme amount of chatter to it, and it is very on/off. I am going through another iteration of loud exhausts recently, and it is so obnoxious to drive around town. Trying to rev it up from a standstill and then the abrupt engagement with RPM drop is very annoying. I chirp tires regularly on takeoff
I hope it gets better with only 500 miles on it.
That seems like it'd be entertaining to watch. Video?Synikster - Any update on what happened with yours?
Mine seems to be holding up OK, but I am REALLY TIRED of the engagement. It has an extreme amount of chatter to it, and it is very on/off. I am going through another iteration of loud exhausts recently, and it is so obnoxious to drive around town. Trying to rev it up from a standstill and then the abrupt engagement with RPM drop is very annoying. I chirp tires regularly on takeoff
I hope it gets better with only 500 miles on it.
There may be a few videos out there! I'm temporarily back to a loud exhaust while I work on my turbo manifolds a bit more.
You've driven two of these - right? Vegas' and SFDreamers... Did you experience the same abruptness and shudder? I have very rigid engine mounts and am concerned about transmission damage from all this shaking. One nice thing about this clutch is that the floating midplate rattle is minimal compared to similar designs when the clutch is disengaged. I was prepared for far worse of a noise.
You've driven two of these - right? Vegas' and SFDreamers... Did you experience the same abruptness and shudder? I have very rigid engine mounts and am concerned about transmission damage from all this shaking. One nice thing about this clutch is that the floating midplate rattle is minimal compared to similar designs when the clutch is disengaged. I was prepared for far worse of a noise.
What motor mounts are you using?
I drove two of these clutches. This was around 2010-2011 roughly.
1. SFDreamers - I drove this while it was already showing much signs of slipping. I eventually drove it into a liquor store parking lot in prep for the tow truck. So it would be a bad example for you. With that said... the engagement was smooth HA!
2. VegasN$X - I stalled his motor twice. Had to keep the revs up but was always worried about glazing the clutch. He's also got a fully built motor so i'm not sure if it's an apples to apples comparison. I basically walked away from that drive thinking.. damn this car is FAST but there's no way i'd enjoy driving it or owning it. I'm soft in my old age.
I'm really not trying to be a fan boy here but I really love my OS Giken. It's broken-in enough now to where the engagement just gets better and better. It's pretty smooth now but it's not nearly as compliant/damped as a stock clutch which I like. I can pretty easily drive it and a passenger wouldn't notice any chatter. It does engage much more abruptly if you're forceful about it. For example, i've really had to practice my rev match down shifts. My window for a perfect rev match downshift clutch engagement is much smaller. Can easily unsettle the car because the bite can be abrupt. Sorry, I know you didn't ask! Just trying to provide feedback. Oh, the noise is still there.
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I'm using stiffened OEM mounts... Mac Attack specials of course!
This clutch is much better than OEM once I get it moving, but I hear conflicting reports on how much or how little you should slip the carbon (heat input). My experience sounds like Vegas'. He probably even has the older version RPS carbon with the organic Kevlar liner on the flywheel side that supposedly aids in smooth engagement.
Before buying this clutch to meet my torque goals, I was expecting it to be abrupt from my experiences with other high-torque-capacity clutches. However, all the marketing propaganda (and a lot of NSX, Corvette, and Supra user reviews) said it was a very smooth engagement with minimal shudder too. That is NOT the case with mine.
It is not easy to drive and has definitely decreased the life of my transmission and axles. If it doesn't improve after another 500 miles it will be yanked.
This clutch is much better than OEM once I get it moving, but I hear conflicting reports on how much or how little you should slip the carbon (heat input). My experience sounds like Vegas'. He probably even has the older version RPS carbon with the organic Kevlar liner on the flywheel side that supposedly aids in smooth engagement.
Before buying this clutch to meet my torque goals, I was expecting it to be abrupt from my experiences with other high-torque-capacity clutches. However, all the marketing propaganda (and a lot of NSX, Corvette, and Supra user reviews) said it was a very smooth engagement with minimal shudder too. That is NOT the case with mine.
It is not easy to drive and has definitely decreased the life of my transmission and axles. If it doesn't improve after another 500 miles it will be yanked.
I've corresponded directly with Rob Smith (RPS) on my issue. He has been responsive, friendly, and helpful.
For my issue, he believes it is due to not lapping the two discs splines with my transmission shaft during installation. Basically, the same instructions he gave Cody directly and the one I linked to in my earlier post #33 . My release bearing was clean and greased, my transmission input shaft bearing is in good shape (not worn), so my engagement shudder must be due to the clutch discs binding up slightly on the transmission shaft as they are engaged.
Rob asked if those were in the SOS install directions and I said they were not. If Rob has been instructing his NSX customers over the last 8 years on this critical installation step, then my issue is due to faulty SOS install instructions..
So now, I need to remove my transmission and clutch to use lapping compound on these discs to insure they slide smoothly on the tranny input shaft. If I don't, I am subjecting the clutch to premature wear and subjecting my transmission to undue stress.
So now I can safely say that SOS has sold this product with faulty install instructions. They were alluding to this exact cause of syniksters problems in this thread by saying it sat outside and corroded. BS. With SOS performing the install on Syniksters car and Hughs two failed clutches, it is pretty clear that they didn't know how to install these either.
I'm a little pissed right now as I don't have the 10 hours needed to change the clutch and work on it.
Thank you SOS.
Dave
For my issue, he believes it is due to not lapping the two discs splines with my transmission shaft during installation. Basically, the same instructions he gave Cody directly and the one I linked to in my earlier post #33 . My release bearing was clean and greased, my transmission input shaft bearing is in good shape (not worn), so my engagement shudder must be due to the clutch discs binding up slightly on the transmission shaft as they are engaged.
Rob asked if those were in the SOS install directions and I said they were not. If Rob has been instructing his NSX customers over the last 8 years on this critical installation step, then my issue is due to faulty SOS install instructions..
So now, I need to remove my transmission and clutch to use lapping compound on these discs to insure they slide smoothly on the tranny input shaft. If I don't, I am subjecting the clutch to premature wear and subjecting my transmission to undue stress.
So now I can safely say that SOS has sold this product with faulty install instructions. They were alluding to this exact cause of syniksters problems in this thread by saying it sat outside and corroded. BS. With SOS performing the install on Syniksters car and Hughs two failed clutches, it is pretty clear that they didn't know how to install these either.
I'm a little pissed right now as I don't have the 10 hours needed to change the clutch and work on it.
Thank you SOS.
Dave
hi Dave --
No, we do not include the lapping instructions because we do not recommend this procedure. Let me explain first what it is. By using a lapping compound, you essentially are "grinding away" both the female and male joining parts by placing an abrasive paste between the surfaces and working them together. RPS recommends this procedure based on their experience of building multi-plate clutches for Toyota Supras which uses a single plate clutch. Because their clutch uses a length of splines that are much longer than factory, it uses a portion of the input shaft that was not designed for the clutch hub to ride on. Because of this, they recommend using a lapping compound to "grind away" a portion of the input shaft that their clutch sits on.
Now let me explain why we do not recommend it: when we designed the NSX clutch with RPS, we specifically designed the hub to sit in the profile of the factory twin disc clutch. We are able to do this by using a nested design that allows the clutch plates to sit in the factory position. In addition, on the single disc 6-spd transmissions, Honda machines and coats the input shaft in the entire length of the profile which the twin disc clutch sits on. In our testing of using a brand new input shaft, we verified that the fitment allows the clutch disc to easily slide with the same tolerance a factory disc slides with. Having users use the lapping compound in our opinion is not appropriate in the case of the NSX. By using the lapping compound, you open up the possibility of the installer not appropriately cleaning and removing the compound (causing issues ob long term lubrication) and masking an issue that would be better to be discovered during installation rather than being covered up and masked. In addition, by modifying the input shaft in this way, the fitment may become sloppy increasing noise from the clutch.
I hope this provides some clarification.
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Glad to hear!
No, we do not include the lapping instructions because we do not recommend this procedure. Let me explain first what it is. By using a lapping compound, you essentially are "grinding away" both the female and male joining parts by placing an abrasive paste between the surfaces and working them together. RPS recommends this procedure based on their experience of building multi-plate clutches for Toyota Supras which uses a single plate clutch. Because their clutch uses a length of splines that are much longer than factory, it uses a portion of the input shaft that was not designed for the clutch hub to ride on. Because of this, they recommend using a lapping compound to "grind away" a portion of the input shaft that their clutch sits on.
Now let me explain why we do not recommend it: when we designed the NSX clutch with RPS, we specifically designed the hub to sit in the profile of the factory twin disc clutch. We are able to do this by using a nested design that allows the clutch plates to sit in the factory position. In addition, on the single disc 6-spd transmissions, Honda machines and coats the input shaft in the entire length of the profile which the twin disc clutch sits on. In our testing of using a brand new input shaft, we verified that the fitment allows the clutch disc to easily slide with the same tolerance a factory disc slides with. Having users use the lapping compound in our opinion is not appropriate in the case of the NSX. By using the lapping compound, you open up the possibility of the installer not appropriately cleaning and removing the compound (causing issues ob long term lubrication) and masking an issue that would be better to be discovered during installation rather than being covered up and masked. In addition, by modifying the input shaft in this way, the fitment may become sloppy increasing noise from the clutch.
I hope this provides some clarification.
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Glad to hear!
Hi SOS --
You are apparently incorrect.
First of all, RPS designed this clutch years before you began reselling it. AFAIK, LoveFab was the first to install this clutch and it is still working fine MORE THAN 8 YEARS LATER on a 600HP+ NSX.
Guess how Cody installed it? HE FOLLOWED THE RPS RECOMMENDATIONS ON LAPPING. I suggest you read this short thread:
http://www.nsxprime.com/forum/showthread.php/94927-New-RPS-Twin-Disk-Clutch-Review?p=883981&viewfull=1#post883981
The poor track record of failed SOS-installed twin carbon clutches reaffirms my belief of taking the recommendation of the clutch designer any day over yours. They designed the clutch and have more experience with clutches than you do. Please stop pretending that you know more than they do.
I understand why the lapping is required from RPS. I wish I had stumbled on Cody's thread before installing it instead of just following your basic install instructions. This is perhaps the root cause why some of these clutches have no problems, and others do. The variations in condition of the transmission shaft between all of our NSX's needs to be accounted for during installation of the aftermarket clutch discs. The tight tolerances on the RPS clutch disc splines from the factory requires they be lapped to each users particular transmission input shaft. Any decent installer knows to clean off the lapping compound before a small amount of anti-seize or hi-temp grease is applied on the splines so please don't use that as an excuse. I was meticulous, clean, and followed every SOS instruction except for that recommended by the clutch manufacturer during installation. As I told Rob Smith, I wire-brushed the transmission input shaft splines, cleaned with brake cleaner, and lightly greased. This is any good practice when ensuring smooth fitup with the new discs.
I have a $2400 product purchased from you that does not work in my vehicle. Addressing the incomplete installation instructions will require about 10 hours of my labor to remove the transmission, mic the clutch discs for thickness and wear, lap the disc splines, clean everything, regrease, reassemble, and then reinstall in my car.
What compensation are you able to provide that will help with the significant extra labor charges I am now forced to do?
Thank you,
Dave
My personal clutch install pictorial:
Start with a fully-built engine:
<a href="https://www.flickr.com/photos/97146708@N02/17172885027" title="1 by David McCreary, on Flickr"><img src="https://farm9.staticflickr.com/8704/17172885027_7550360ba2_o.jpg" width="702" height="384" alt="1"></a>
Add the clutch:
<a href="https://www.flickr.com/photos/97146708@N02/17192619458" title="2 by David McCreary, on Flickr"><img src="https://farm9.staticflickr.com/8848/17192619458_994fea7883_o.jpg" width="477" height="382" alt="2"></a>
<a href="https://www.flickr.com/photos/97146708@N02/16758126154" title="3 by David McCreary, on Flickr"><img src="https://farm8.staticflickr.com/7745/16758126154_e2c45158f0_o.jpg" width="477" height="394" alt="3"></a>
Attach the cleaned transmission with a good input shaft bearing:
<img src="http://www.nsxprime.com/photopost/data/500/tranny21.JPG" />
Ready for install:
<a href="https://www.flickr.com/photos/97146708@N02/16757852914" title="3 by David McCreary, on Flickr"><img src="https://farm8.staticflickr.com/7724/16757852914_dffd4ce469_o.jpg" width="708" height="476" alt="3"></a>
hi Dave --
I'm sorry, but you are incorrect. Let me be clear - the NSX does not need lapping compound. The factory service manual does not recommend it, and neither do we. Because a pictures are worth a thousand words, I took two brand new clutches off the shelf and disassembled them to explain this. This is a brand new factory disc and brand new twin carbon clutch disc:
As you can see, the twin carbon clutch is .8% larger on the ID and .6% larger on the OD. The shaft ID and OD on the NSX remain within the same tolerance along the entire length of the interface of the shaft to the clutch hub. Again, the NSX does not need lapping compound and these pictures should explain why. Lapping compound should not be used, and we would prefer that any burr on either the shaft or hub be identified by the installer during inspection, rather than being covered up by lapping and not identified. I hope this explains to why we do not recommend lapping compound.
I'm sorry, but you are incorrect. Let me be clear - the NSX does not need lapping compound. The factory service manual does not recommend it, and neither do we. Because a pictures are worth a thousand words, I took two brand new clutches off the shelf and disassembled them to explain this. This is a brand new factory disc and brand new twin carbon clutch disc:
As you can see, the twin carbon clutch is .8% larger on the ID and .6% larger on the OD. The shaft ID and OD on the NSX remain within the same tolerance along the entire length of the interface of the shaft to the clutch hub. Again, the NSX does not need lapping compound and these pictures should explain why. Lapping compound should not be used, and we would prefer that any burr on either the shaft or hub be identified by the installer during inspection, rather than being covered up by lapping and not identified. I hope this explains to why we do not recommend lapping compound.
hi Dave --
I'm sorry, but you are incorrect. Let me be clear - the NSX does not need lapping compound. The factory service manual does not recommend it, and neither do we. Because a pictures are worth a thousand words, I took two brand new clutches off the shelf and disassembled them to explain this. This is a brand new factory disc and brand new twin carbon clutch disc:
As you can see, the twin carbon clutch is .8% larger on the ID and .6% larger on the OD. The shaft ID and OD on the NSX remain within the same tolerance along the entire length of the interface of the shaft to the clutch hub. Again, the NSX does not need lapping compound and these pictures should explain why. Lapping compound should not be used, and we would prefer that any burr on either the shaft or hub be identified by the installer during inspection, rather than being covered up by lapping and not identified. I hope this explains to why we do not recommend lapping compound.
Let me be clear too: It's not that I am incorrect - it is you who are directly disagreeing with the clutch manufacturers recommendation. I'm just pointing it out so others who have had failed clutches (that you blame on installation error) can understand what may be a leading contributor.
Your pictures don't show up, but do you understand that you are only talking about ~0.006" difference? I'm not sure if this is a max, min, or average difference, but it is practically negligible nonetheless. Sorry, that argument does nothing to make me want to avoid using lapping compound like the manufacturer suggests.
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shawn110975
Suspended
I have a stock dual clutch in my 92 with a 6-speed tran and added dual input shaft and I don't have this problem LOL
OEM all the way baby.
I hate seeing 2 well respected people/company clash like titans makes me sad.
my dad always says if the 2 bulls push each other long enough both will get tired and walk away :wink:
OEM all the way baby.
I hate seeing 2 well respected people/company clash like titans makes me sad.
my dad always says if the 2 bulls push each other long enough both will get tired and walk away :wink:
I'm still confused... So why are so many SOS twin carbons failing? All of them had faulty installs?
The manufacture's recommendation is based on experience with a different vehicle's transmission, as described above. It does not apply to the NSX for the reasons detailed above. I've e-mailed this link to RPS to have them chime in as well.
The photo seems to be showing up ok, but to explain: the clutch hub of a factory disc measures .21mm and .15mm tighter than the billet twin carbon clutch we are discussing. In addition, the male tooth width is slightly less as well.
We do not recommend this procedure due to the reasons outlined: 1) the factory service manual does not recommend it 2) it may mask another issue, or cause issues if not properly done 3) most importantly, it is not necessary as substantiated by the photos shown above.
Dave, this is Rob Smith the president of RPS Performance Products. I'm so sorry to here you are having problems with one of my products. I know it is easy for me to say because I do not have to do the work, but if you do take the clutch out of the car to inspect the spline, I would love to see the clutch and inspect it myself with all of the tools I have here to get to the root cause of your problem.
I agree with Chris at SOS that lapping the discs on an NSX is not needed and probably will have no effect on how the clutch performs. RPS recommends using lapping compound on cars where our splines do not line up where the stock disc rides like Supra's and Corvette's. We are able to cut our NSX hubs to ensure our splines do line up where the factory disc lines up so luckily you guys don't have to go through the trouble of lapping the splines. The post you refer to from Cody at LoveFab is from 2007 before we moved the splines to the stock location.
Kind regards,
Rob Smith
Well, I stand corrected then. My earlier posts were due to correspondence we had on the need to lap and how new kits would ship with lapping compound. Then, the search I did here uncovered the old post from 2007 where Cody did this procedure on the dual disc CF clutch which collaborated with what I had just been told. I am just repeating what I have been told by reputable folks.
How would this inspection work? Will I receive a new or rebuilt CF clutch to swap in?
Thanks,
Dave
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Shawn, you aren't making the power the people in this thread are. I liked the Oem clutch too for the eight years and 70k miles I had it. It still had plenty of life when i took it out and gave it away.
Believe me, i don't want to be in this situation either. But the fact is that I am basically screwed with a $2500 clutch with less than 500 miles on it that that is painful to drive from a stop. Once going, I like the inertial weight and response, the light pedal, and the supposed torque capacity. Even modulation is not a show stopper since i have only stalled it once.
If you spent $2500 for a product that made you sad to drive your NSX, and troubleshooting would cost you a good 10 hours of your time with no guarantee of success, wouldn't you be a little pissed too? Would you just "walk away?"
How would this inspection work? Will I receive a new or rebuilt CF clutch to swap in?
Thanks,
Dave
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Shawn, you aren't making the power the people in this thread are. I liked the Oem clutch too for the eight years and 70k miles I had it. It still had plenty of life when i took it out and gave it away.
Believe me, i don't want to be in this situation either. But the fact is that I am basically screwed with a $2500 clutch with less than 500 miles on it that that is painful to drive from a stop. Once going, I like the inertial weight and response, the light pedal, and the supposed torque capacity. Even modulation is not a show stopper since i have only stalled it once.
If you spent $2500 for a product that made you sad to drive your NSX, and troubleshooting would cost you a good 10 hours of your time with no guarantee of success, wouldn't you be a little pissed too? Would you just "walk away?"
Hi,
just posting to bring back an unanswered question:
if bad installation is the cause, then why did some Twin CF clutchs installed by SOS also failed ?
just posting to bring back an unanswered question:
if bad installation is the cause, then why did some Twin CF clutchs installed by SOS also failed ?
There is only one that has been brought to us - which is the unit out of Hugh's NSX. It was determined that one of the clutch discs were machined improperly by the manufacture. This was found unfortunately after the discs were relined and reinstalled. This clutch, as well as the other two from that manufacturing batch were replaced and destroyed at our expense. The clutch from "synikster", which was installed approximately 5 years ago was from another batch, and did not have the same symptoms. The symptoms to us sounded like a bad hydraulic system, or a master cylinder not adjusted properly (both master and slave were changed after the car was purchased from the original owner which we performed the work for). We requested the clutch to be sent to us for inspection, but have not received it.
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