So every once in a while I will get this question about replacing an F1 Clutch by an owner who’s looking to have someone install it that doesn’t have the scan tool to re-set all the clutch parameters on an F1/E-gear car. Some come up with these ideas about what’s happening in the car’s TCU or NCR obviously unfounded by any true understanding of the system. But yet and still they are willing to take parts that cost anywhere from $2000-$4000 and mess them up instead of paying to tow the car to someone that can do exactly what I am going to write about here.
Let me start off by saying this first. There is a ton of data now available on-line that did not used to be available to change one’s own clutch or have an independent shop do so. I wrote one such article years ago, documenting the process on Maseratilife.com before anyone else had in order to help facilitate people to do so. I’ve since moved all of those photos here to this web-site. However, even before I owned my own scan tool, I knew enough to know, to tow the car to Aston Martin of New England to have all the parameters re-set so as not to mess up a new clutch. So let’s talk about this, let’s discuss why you should just pay the $300 or so dollars to have the clutch parameters reset after such a costly repair.
Another misconception going into this is that the clutch wear algorithm is somehow inaccurate in these cars’ computer systems. So that when it states it’s 50% worn, that number in all actuality could be incorrect, and the clutch really could go at anytime. This ignores the fact, that the friction disc build thickness can vary in thickness size, and whether the flywheel has hot spots or the friction disc material itself has developed any sub-par issues like glazing from an incorrectly set up clutch. This is most evident in early model F360 cars that had auto-calibrated Kiss points. The build thickness isn’t taken into account when there is a build tolerance from one new friction disc to the next. In the algorithm the number is set to 5.56mm (depending on the clutch and tolerance build). A person literally could be running at 100% worn and the clutch be somewhat fine when that variance is in their favor. The car can “sense” hot spots, glazing, (or basically slippage) but it doesn’t tell you which one it is. Under the scan tool parameters it will be called Clutch Wear Index, Clutch Degradation Index or something similar. You could only be 50% worn and need to replace a clutch for this issue or a number of other ones.
Let’s talk about just four important parameters the TCU of F1/Egear cars store. We aren’t going to go into all of the sensory data because this would be very long and drawn out.
New Closed Clutch Position (NCCP)
Closed Clutch Position (CCP)
Clutch Wear Index
New Closed Clutch Position/Closed Clutch Position:
The NCCP is basically the closed clutch position from when the clutch was brand new. This figure is in millimeters written into the car’s computer from the Tech that usually installs the brand new clutch. This is the figure that all of the rest of the above parameters are built on.
So for instance, the car’s clutch wear percentage is an algorithm built from this number as it’s foundation. When this isn’t written in correctly a few things can go wrong, which is why it needs to be re-written immediately after installing the clutch and before bedding in or driving it.
One can learn quickly that writing in a measurement to far from the actual foundation point into the computer that’s not accurate can severely mess with how the clutch engages.
Additionally, the reason why this has to be re-written for every clutch change is because every new clutch doesn’t sit it the same location as it’s predecessor. So in sum, using the previous written data could either cause the clutch to engage or not engage correctly.
Closed Clutch Position:
This is a number automatically calculated by the TCU of the car, that CANNOT be changed by a Tech, in millimeters, telling the system the exact location of the clutch’s position. This is based off of the vehicle’s clutch position sensor, and the sensory data provided by it. This measurement is also why no matter how worn a clutch is the KISS or PIS is still accurate. (Although as the car’s clutch beds/wears in, periodic resetting could be beneficial to the life of the clutch to help it better engage).
Clutch Wear Index:
This is a figure given between 0-10,000 in the data log of information explaining whether the clutch is biting aggressively 0-3000, or slipping and not biting correctly at all 5,000-10,000. The target number is usually between 3,000-4000 in a new clutch. This torque transmissiblity curb is very important data as it tells you exactly whether slippage is occurring and at what rate.
This data is also reset with a scan tool after installing a new clutch, and adjusting the Kiss point. You want it specifically reset so that you can tell how the new clutch engagement is graduating. It helps to catch or identify an issue early on should something in the install have went wrong.
Kiss Point/ PIS
Now this is the one of the most discussed topics usually addressed in changing a clutch. Ironically, you can get away with just throwing a new clutch in a car and not changing it because this is always based off of the current closed closed position which we already have discussed cannot be played with. Now is it wise to do so, I think not.
Let me give you a working definition of KISS point or PIS. Essentially it’s this. Imagine you were in a three pedal car stopped at a light. The light turns green, you raise your foot to engage the clutch. The moment it begins to bite is the KISS or PIS point. That is what is being written into the TCU of these cars. The lower the point in MM written the faster, and less slippage that occurs. The higher point that is written, the more slippage that occurs. A previous PIS point can work on a newer clutch, but isn’t advisable because it could be too hard or too soft for a brand new clutch. Additionally, I always reset the PIS after the clutch has been properly bed in solely for engagement reasons.
Here is an example, I have a Gentleman named Joe that used the website in order to change his clutch. I drove down to him set the clutch up in a way to help bed it in. However, as soon as he followed the steps I asked him to follow to bed the clutch in, it began to stall out. This was normal, and I reset the KISS point again for a post bed in clutch. I might add he had one of the best engaging F1 systems I had tested in a while when I reset it.
In closing, let me offer my advice. Maybe we should again think of this, and understand the circumstances correctly. You just paid $2000 in parts, and you are concerned about protecting that with a $300 bill? Penny wise, pound foolish much? After all that work, you need someone with the proper education and back ground to protect it. It’s what’s best for the vehicle and the investment that you just put into it. Sure I am certain you will hear glory stories of people who have beat the odds, and come out on top. But you will also hear stories tomorrow of who won the lottery, yet you did not. This advice is free, do whatever you feel is in your best interest. The article was merely mean’t to inform you. Chances are we’ll probably never meet, and whether you used it or not is truly inconsequential to me.