Mmmm....I may have a bit of an F1 problem....not bad as I’ve managed 7.5 years without one. I’ve probably been getting two separate issues confused up to now. There is definitely slight clutch drag on occasions when the car is very, very hot. Enough to creep the car in 1 or R. I’ve posted before that the clutch closes slightly when a gear is selected and that is when the drag occurs. When it’s in N there is no movement of the gearbox primary shaft at all with a PIS of 4.6. After hearing the clutch SV buzzing the other night I lifted the PIS the other night (4.6 to 4.8) but only had chance to drive it a short distance when already hot. From cold tonight it was fine until I started to increase the revs and it was flaring between gears and not very positive in sport. I reduced the PIS to 4.7 and it seemed perfect when hot. I now need to test it cold. What I noticed on the drive whilst making adjustments is the clutch control SV making a buzzing/energising noise. The attached is a graph of the system hydraulic pressure, clutch position and clutch SV current. Image Unavailable, Please Login Every 45 seconds or so, the clutch closes a few mm and the SV energises (signalled by the buzzing) to bring it back to full open. I also monitored the trans primary and when it does it, the primary shaft rotates confirming it is the clutch moving rather than the position sensor giving a faulty reading. So what’s causing it? First thought is keep it simple and bleed the clutch in case there is air in the system. After that.... It appears to be heat related and there are no external leaks I can see from the release bearing seals so I may be looking at an SV leak or possibly the release bearing is sticking? The clutch hydraulics are quite simple in that the SV is centred for holding position and moves one way or the other to open or close the clutch. I’m hoping it’s going to be simple to resolve but let’s see.... Any thoughts? Sent from my iPhone using FerrariChat
Thanks for the comments The clutch is on about 30% wear and that was verified a couple of years back when the disc was measured. That said it has about 25k miles on it but there are no other signs of wear. How could that explain the uncontrolled movement of the release bearing every minute or so and the TCU having to correct it? The movement is real as the gearbox input shaft moves when the bearing moves. I’m almost positive this isn’t an electrical issue. The grounds are pretty good as I cleaned most of them a couple of years back.
It'll be the SV or the driver embedded into the TCU. I may have a good used clutch SV that you can borrow to test.
Thanks very much Aldous.... Hopefully not the TCU driver! When watching it last night I was trying to see if the current or bearing moved first. Due to the slow refresh rate on the Launch system it’s impossible to determine. I may look at buying a new SV and if I struggle I’ll take you up on your offer. The other option could be replacing the 3 seals on it but it’s a lot of pfaffing when the SV itself isn’t that expensive. Can the clutch circuit be bled independently or does the actuator need doing also?.....if yes, that makes it a far bigger job that may have to wait until winter.
I'm seeing more and more TCUs go down. If it is the case of you I may be able to repair it. Replacing the o-rings on the SV isn't going to do anything for you, nor will it cure excessive leak off. If you do swap out the SV then it will be enough to bleed at the clutch.
I’ll order an SV tomorrow and if I get chance I’ll change it in the few weeks, work permitting. The TCU was a new unit from Ferrari probably no more than 3 years ago. I’ve noticed they’ve bumped the prices up hugely since then also. It’d be a bummer if it has failed. Thanks again....
I ordered a clutch SV (well 2 plus a pressure proportional) from alibaba as per 24000 rpm tried a while back. About £50 inc taxes each delivered to the U.K in 4 business days. Image Unavailable, Please Login I tested them first .... Image Unavailable, Please Login I installed the valve today and it works perfectly solving the drag and judder I got when hot. On the issue above it’s almost certainly a feature of the software. I’m guessing it is to stop the clutch sticking. In N the clutch closes to the kiss point every 50 secs or so. Image Unavailable, Please Login In gear with the brake pedal pushed it does the opposite....it opens slightly every 50 secs. The arrow is the gear selection point (I’ve said before the clutch closes slightly with my CS TCU when a gear’s selected) and the circled dip is the clutch pulsing open which it did every 50 secs. Image Unavailable, Please Login So it closes slightly every 50 secs in N and opens slightly every 50 secs when in gear with the brake pedal down. It’s too regular to be an issue and it doesn’t follow system pressure so it has to be a function of the software. Sent from my iPhone using FerrariChat
Did this also solve the flaring between gears? My F430 flares between gears but otherwise works well.
Currently my car will flare slightly between the higher gears but only when cold...by the time the engine oil is up to temp and you can use the revs it is fine. It seems to be a trade off on my car, as the PIS is now set at 4.7. I get zero flaring at 4.6 but find the changes too aggressive...it’s smoother as it is and I prefer that. I’ll drive it for a while and see how it goes then decide...I’ve always felt that since the CS TCU was installed it was all a bit tight.
If you change the PIS to 4.6 to remove all flaring the outcome is limited to aggressive changes only? What happens to the clutch bite when taking off - is it too abrupt? i'm trying to get rid of the flaring and have had the PIS changed to make it make it more positive on take offs. I can't adjust it any more without risking stalling at take off. Is there anything else that can be adjusted to reduce rev flare when changing gears?
Alan, The pick-up in my car has always been great even with the 2000 non-adjustable TCU and whatever the PIS is set to. Aggressive changes is probably over describing it I just prefer it a little more relaxed. I’d it were me I’d take your car to a real F1 expert to have it health checked and set up....there’s only so much you can do DIY... M Sent from my iPhone using Tapatalk
