We've been seeing that many of the 1.5T 10th gen Civics out there experienced the stock clutch slipping and not being able to hold much more power than stock. We were curious when our 10th gen Civic clutch would give out and it came sooner than we hoped. After a turboback exhaust, intake, and some tuning, 4th gear started to spin the clutch and it just couldn't handle the power. In order to continue forward with our project and keep adding more power and torque, the only option we had was putting a new clutch in.
We were sitting right around 280 lb ft of torque and after having done many dyno runs on the car already, our clutch started to slip in the high load, high torque area of the rpm range as shown below. You can see that the RPMs jump up quickly in the datalog, and then settle back down as the car continues to progress through the run. You can audibly hear it in the exhaust note when on the dyno.
When this happens, you really have no other choice than to put a new clutch on. The car can still drive under normal circumstances but several more pulls on the dyno or the road and the disc material will start to get eaten away from the heat built up as the friction becomes too much to handle. We actually found that even though the clutch wasn't appearing to slip in the higher RPMs, it was making less power which means it wasn't grabbing hard enough to hold even though it appeared like it was. For our purposes, we can't really continue testing and generating meaningful data until we have a clutch that grabs. For anyone else, you can get away with driving on a small amount of slippage for a little bit, but it'll soon catch up to you and will need to be replaced.
We went with a Spec Stage 3+ clutch to handle the transfer of power to the wheels. This is a unique clutch with a carbon semi-metallic pad material that Spec claims has a very high friction coefficient while still maintaining good driveability. We actually planned on using the factory flywheel to keep the theme of driveability going but once we pulled off the clutch, we changed our minds and decided to throw in Spec's steel flywheel. They also offer an aluminum version but we didn't want too light of a flywheel as that causes a little more chatter and less streetability. The steel version is a better upgrade for a street car, in my opinion.
After installation, on a scale of one to ten, ten being the stiffest, the pedal stiffness went from a 1 to about a 2. In other words, it was a noticeable change, but only barely. Whereas the stock clutch almost had an unknown point of engagement, the Spec Stage 3+ engagement point is easily noticeable. If you're not used to it, it will make the car lurch forward much easier than stock. This is exactly what we were looking for. The stock 10th Gen Civic clutch is so forgiving and soft that you can barely tell where it needs to be to engage quickly. This isn't the case with the Spec clutch. It's still kind of crazy how soft the pedal still is compared to other clutches I've felt.
After a few heat cycles and pulls, our clutch is now ready for more significant abuse as we continue to modify!