Greetings members of NSXPrime,
Intro:
I wanted to write about my experiences with the Science of Speed billet clutch system that I had installed in my 1991 Black / Ivory NSX.
( SoS Billet Clutch System )
Background:
For the past 3k miles, I've had progressively worsening clutch slip. I first noticed it during spirited acceleration when shifting from first to second gear, but it gradually worsened to the point that even during 5th gear 30 – 40% throttle I'd experience slip. For those of you who aren't familiar with a slipping clutch, it goes something like this. Starting at a high gear / low RPM cruise (something like 5th gear / 2500 RPM), aggressively depress the accelerator and hold it. The engine will rev up quickly, then RPMs will fall as the clutch tries to fully engage. Then after full engagement, the car will accelerate proportional to the gradual rise in RPM.
The previous clutch was a CompTech Powergrip Stage 2. The clutch pressure was probably ~ 70-75 lbs, with progressive uptake and smooth engagement, but it was by no means an easy car to drive in heavy traffic. My left leg felt like it was getting a Cross-Fit exercise session!
I dug through NSXPrime but had a hard time finding what I was looking for. I wanted to build a daily drivable clutch that is lighter than stock but designed to take more torque than the stock '91 system. After reading the excellent result of cptnsx's SoS Supercharger system with Laminova intercooler ( cptnsx's review ), I dug around SoS to look for a clutch and installation. As with many NSX fanatics, I'm interested in the total package, not only the hardware. I guess I was searching the Holy Grail of the perfect product, installed by expert mechanics, that care about their customers and cater to the NSX community.
From the start, I knew I had found a good shop. First of all, Chris is a consummate professional. Instead of pushing a product onto a customer, he asked what my likes, dislikes and end goal was. After much discussion and specification comparison, I made arrangements to drop off the vehicle as the development test-bed for the first SoS clutch install. I drove the vehicle down from the Vegas area and delivered it to Chris in Tempe, AZ. He was even nice enough to meet me on Saturday.
I had a brief tour of the old shop and looked at the clutch that was to be installed. The flywheel felt feathery in my hands, the the machining of the metal was impeccable, and balanced flywheel an automotive “objet d'art”. With a confident and hopeful mind, I left the shop with my family for some vacation in the greater Phoenix area.
Install:
The initial install took approximately 3 weeks. I understood that this would be a developmental process since the parts were being machined and fitted. Some of the delays were avoided since SoS has a transmission, bell housing and engine test bed to check for fitment issues. Since the original clutch housing didn't install cleanly, Chris informed me that he would send the housing back to get it re-CNC'ed and upgraded it to a billet part (instead of the original cast metal). Now, it could have been very simple for an unscrupulous mechanic to grind down some of the parts with a Dremel or a belt sander, but that is not how Chris and SoS operate. They kept me informed of all the details and reasons for delays during the install. Although it took 3 weeks for the parts to be properly fitted and tested, the excellent communication made is very tolerable.
After the installation, Chris took the vehicle for a test drive to ensure that the system was fully operational. And from the clutch function standpoint, it passed with flying colors. He noticed subtle noises that my tin ears had not pick up before and was able to diagnose some problems. They were quickly able to fix the problem and documented exactly what they were doing and why.
Driving Impression:
I've driven ~400 miles since the new clutch, but 80% of that was the drive back to Vegas. The clutch burn-in smell seems to be going away as I drive it around the city some more. The clutch engagement is smooth at ~ 40 lbs, very similar to stock set-up and much much lighter than the CompTech system it replaced. The clutch starts to engage at 25% off from the floor and is fully engaged relatively quickly. With it's higher torque rating and lighter flywheel, the shifts are a bit more abrupt <3500 RPM, but shifts >4000 RPM are heavenly. The lighter weight flywheel definitely helps in throttle response and rev-matching during heel-toe down-shifts as well.
Owners should note that at a stop and with the clutch depressed, clutch chatter is slightly audible, but it is barely noticeable in my NSX with CompTech header and exhaust. A friend who is an avid Porsche and Maserati fan couldn't believe how well if shifted and handled, and did not say anything about clutch chatter. ***Edit: Spoke to Chris last night who confirmed that the new clutch system will incorporate an assembly harness that will eliminate the clatter in the retail version, and photos of the new billet clutch cover attached***. For a performance clutch that can handle mild to moderate boost, it hits the sweet-spot in performance<>comfort equation. My vehicle is now definitely daily drivable.
Conclusion:
In business or management classes, when they talk about giving a customer above and beyond what they expect, they should use SoS and Chris as an example. Communication was exemplary. The attention to detail and treating the NSX as if it was their own and taking the time to do things right was a breath of fresh air in the era of poor service and worse workmanship. Here's a prime example: Due to the delays of getting the part properly fitted, I had to eat a flight from LV to Phoenix, but Chris even set me up with a free ticket when the time came to pick up the vehicle.
The SoS billet cluch is an industrial/automotive piece of art. Functional, well built and higher performance capacity than the original in every way. But as much as this is a review of the clutch system, it is a testament to the folks at SoS, especially Chris for developing a great product and supporting the NSX community. Their expertise, experience and customer service will definitely have me coming back to them for the next hit of my NSX modification crack-pipe.
I will periodically update the post with mileage, driving characteristics, track impressions, etc.
Please feel free to ask me questions, I will try to answer them as best as I can, if I don't know, I'm sure Chris and the crew at SoS can clarify.
Cheers,
Intro:
I wanted to write about my experiences with the Science of Speed billet clutch system that I had installed in my 1991 Black / Ivory NSX.
( SoS Billet Clutch System )
Background:
For the past 3k miles, I've had progressively worsening clutch slip. I first noticed it during spirited acceleration when shifting from first to second gear, but it gradually worsened to the point that even during 5th gear 30 – 40% throttle I'd experience slip. For those of you who aren't familiar with a slipping clutch, it goes something like this. Starting at a high gear / low RPM cruise (something like 5th gear / 2500 RPM), aggressively depress the accelerator and hold it. The engine will rev up quickly, then RPMs will fall as the clutch tries to fully engage. Then after full engagement, the car will accelerate proportional to the gradual rise in RPM.
The previous clutch was a CompTech Powergrip Stage 2. The clutch pressure was probably ~ 70-75 lbs, with progressive uptake and smooth engagement, but it was by no means an easy car to drive in heavy traffic. My left leg felt like it was getting a Cross-Fit exercise session!
I dug through NSXPrime but had a hard time finding what I was looking for. I wanted to build a daily drivable clutch that is lighter than stock but designed to take more torque than the stock '91 system. After reading the excellent result of cptnsx's SoS Supercharger system with Laminova intercooler ( cptnsx's review ), I dug around SoS to look for a clutch and installation. As with many NSX fanatics, I'm interested in the total package, not only the hardware. I guess I was searching the Holy Grail of the perfect product, installed by expert mechanics, that care about their customers and cater to the NSX community.
From the start, I knew I had found a good shop. First of all, Chris is a consummate professional. Instead of pushing a product onto a customer, he asked what my likes, dislikes and end goal was. After much discussion and specification comparison, I made arrangements to drop off the vehicle as the development test-bed for the first SoS clutch install. I drove the vehicle down from the Vegas area and delivered it to Chris in Tempe, AZ. He was even nice enough to meet me on Saturday.
I had a brief tour of the old shop and looked at the clutch that was to be installed. The flywheel felt feathery in my hands, the the machining of the metal was impeccable, and balanced flywheel an automotive “objet d'art”. With a confident and hopeful mind, I left the shop with my family for some vacation in the greater Phoenix area.
Install:
The initial install took approximately 3 weeks. I understood that this would be a developmental process since the parts were being machined and fitted. Some of the delays were avoided since SoS has a transmission, bell housing and engine test bed to check for fitment issues. Since the original clutch housing didn't install cleanly, Chris informed me that he would send the housing back to get it re-CNC'ed and upgraded it to a billet part (instead of the original cast metal). Now, it could have been very simple for an unscrupulous mechanic to grind down some of the parts with a Dremel or a belt sander, but that is not how Chris and SoS operate. They kept me informed of all the details and reasons for delays during the install. Although it took 3 weeks for the parts to be properly fitted and tested, the excellent communication made is very tolerable.
After the installation, Chris took the vehicle for a test drive to ensure that the system was fully operational. And from the clutch function standpoint, it passed with flying colors. He noticed subtle noises that my tin ears had not pick up before and was able to diagnose some problems. They were quickly able to fix the problem and documented exactly what they were doing and why.
Driving Impression:
I've driven ~400 miles since the new clutch, but 80% of that was the drive back to Vegas. The clutch burn-in smell seems to be going away as I drive it around the city some more. The clutch engagement is smooth at ~ 40 lbs, very similar to stock set-up and much much lighter than the CompTech system it replaced. The clutch starts to engage at 25% off from the floor and is fully engaged relatively quickly. With it's higher torque rating and lighter flywheel, the shifts are a bit more abrupt <3500 RPM, but shifts >4000 RPM are heavenly. The lighter weight flywheel definitely helps in throttle response and rev-matching during heel-toe down-shifts as well.
Owners should note that at a stop and with the clutch depressed, clutch chatter is slightly audible, but it is barely noticeable in my NSX with CompTech header and exhaust. A friend who is an avid Porsche and Maserati fan couldn't believe how well if shifted and handled, and did not say anything about clutch chatter. ***Edit: Spoke to Chris last night who confirmed that the new clutch system will incorporate an assembly harness that will eliminate the clatter in the retail version, and photos of the new billet clutch cover attached***. For a performance clutch that can handle mild to moderate boost, it hits the sweet-spot in performance<>comfort equation. My vehicle is now definitely daily drivable.
Conclusion:
In business or management classes, when they talk about giving a customer above and beyond what they expect, they should use SoS and Chris as an example. Communication was exemplary. The attention to detail and treating the NSX as if it was their own and taking the time to do things right was a breath of fresh air in the era of poor service and worse workmanship. Here's a prime example: Due to the delays of getting the part properly fitted, I had to eat a flight from LV to Phoenix, but Chris even set me up with a free ticket when the time came to pick up the vehicle.
The SoS billet cluch is an industrial/automotive piece of art. Functional, well built and higher performance capacity than the original in every way. But as much as this is a review of the clutch system, it is a testament to the folks at SoS, especially Chris for developing a great product and supporting the NSX community. Their expertise, experience and customer service will definitely have me coming back to them for the next hit of my NSX modification crack-pipe.
I will periodically update the post with mileage, driving characteristics, track impressions, etc.
Please feel free to ask me questions, I will try to answer them as best as I can, if I don't know, I'm sure Chris and the crew at SoS can clarify.
Cheers,
Attachments
Last edited:
Thanks SOS!! :biggrin::wink:
