SPEC Clutch and Flywheel conversion finally finished... initial review and questions! - The Unofficial BMW M5 Messageboard (m5board.com)

LeatherMan · 18th July 2005, 07:37

As some of you know I have been in search of a new transmission for the last few months. I finally found what I considered a suitable replacement about a month ago or more. Since I had the tranny out I decided to upgrade my clutch and flywheel and considering that I did not have $3K for the UUC V12 upgrade I went with the "newly redesigned" SPEC light weight aluminum flywheel and stage III clutch setup. I also installed a Rogue SSK and Rogue tranny mounts. I have put about 500 miles on the car over the last week and I am seeing a few issues. When I first installed the clutch it was VERY grabby and engaged about 1/2 inch off or the floor. I found this to be quite unacceptable especially considering that the clutch pedal pressure was definately stiffer than stock. Luckily, within about 200 miles the engagement point has raised about 4-5 inches to what feels like a more normal position. The clutch is also not nearly as grabby as it was, but this could also be my perception as I must be getting used to the new clutch feel. When I first started up the car I fought a bought with a 1/4 tank of bad gas with a bunch of misfire codes... the car was on jack stands for about 8-9 weeks or so. After putting in some 93 the bad gas seems to have worked its way through the system and the car is running fairly well.

However, I have to say that I find the clutch rattle or gear lash noise to be almost unbearable!!! Originally, I really thought that everyone that mentioned this issue was probably just the oversensitive anal type as I have put aluminum flywheels on 3 of the cars I have owned the past(not BMWs) and I have never noticed anything like this. I thought my car sounded like a Peterbuilt before... it now sounds like a rough running John Deer diesel farm tractor. Further, it seems that on occasion when I am taking off in first gear I get a noticable vibration or pulsing feel from the clutch/flywheel area that stops as soon as the clutch is fully engaged. The clutch is definately not slipping and it does not vibrate every time and thus I am not even sure that this is a real problem. Lastly, when I rev the car in neutral it seems to run rough/vibrate more than normal in the 2k to 3k RPM range(it also seems to rev out about 5 times faster than it did with the 60lbs dualmass FW) The way I see it have several issues that I would like some help with.

1. Is it normal for the engagement point on a new clutch to raise as much as 4-5 inches in 200 miles of normal driving?

2. What can/should I do about the clutch rattle/gear lash? From the little research that I have done it seems that calling powerchip may be the only hope short of taking out the new aluminum flywheel.

3. What is causing the "occasional" vibration/pulsing that I get during launch? Further... is it a problem?

4. Is the very slight but seemingly noticeable vibration/rough rotation of the motor at 2k to 3k RPMs an issue?

I will post more of my opinions as they form over the next few weeks... so far I am not feeling this new setup at all, although I can't say that any of the issues are the manufacturers fault as of yet.

Eric

MPRESIV · 19th July 2005, 02:45

I have the same SPEC setup.

I had Powerchip to raise my idle rpm from around 500rpm to 900rpm, it reduces the chatter noise by about 70%

And I have the same problem also and would like some answers.
First is the vibration/pulsing during launch (low rpm).
Second, when the engine is cold, I hear a slight squeeking noise when I drive the car from a dead stop. Only happens around 1000rpm. But that slight squeek noise is gone after driving the car for about 20 mins.
My tech guy told me that this is common for a high performance clutch kit

bmwusa · 19th July 2005, 07:17

Thanks for the write up, keep us informed if the clutch grows on you or if you get everything worked out, Josh

BmwNut · 19th July 2005, 08:05

Good to hear you sourced a tranny and got the car back on the road! I remember that being of some concern to you a few months back.
The roll over noise can only be fixed by the OEM dual mass flywheel, a new clutch with a sprung hub (IIRC), or raising the idle speed.
The vibration might be the clutch face skipping on the flywheel. How was the clutch broken in? Hopefully you didnt leave any bad deposits on the flywheel. I dont think it is going to be a huge problem, but if you start getting deposits on your flywheel then that is bad news.
I have only seen a friction point move 4-5'' in a car that had a self adjusting clutch, and when it wasnt set right after the install. Do you still have the self adjusting unit? If so that might be the problem, as it might have readjusted itself to a position higher up. I have seen that happen quite a bit. If it doesnt move anymore, then I wouldnt think of it as an issue.
Not sure on the engine. Is it throwing any SES lights or codes?
Hope some of that helps.

SCORPIO · 19th July 2005, 15:28

When the stock clutch got replaced in my car, I was freakin' out since the engagement point on the new stock clutch was so close to the floor. After a couple hundred miles it went to the normal point. I have 7k now on that clutch and everything is fine.

LeatherMan · 19th July 2005, 18:28

Thanks for the input guys.

I have been driving some more and I really think the clutch is engaging at the right spot. I definately did not get a self-adjusting pressure plate unless they hid the mechanism on the new SPEC design. The pressure plate looked like every other design I have seen and quite different from the factory pressure plate design. While driving to work this morning I was definately able to find a point in my clutch release that would make the entire car shudder. It is a very very small window and thus it does not happen unless I let the clutch out very slowly. It almost feels like my flywheel surface is warped or something. I have babied the car since putting in the new setup... I have not gone over half throttle and I have not gone over 4500 rpm. This is probably partly why I hate the setup as I have not been able to really drive the car in over 10 weeks.

I am at the 750 mile mark on the clutch... I have broken in several clutches over the years and this one feels like it has bedded. However, the shuddering thing is new to me... do you think it is safe to get on it yet?

Should I contact Spec about the vibrations?

Eric

tfung · 19th July 2005, 22:14

I also have a stage 3 Spec clutch, but matched it with a Dinan stage 2 flywheel.. I also have powerchip raise the idle speed to 900rpm, and there is virtually no gearlash noise... just a little bit if you try to listen outside the car, but inside is fine... (then again, my exhaust is so loud now, it covers nearly any small sound or rattle on the car, even at idle)

As for the pulsing, I also have it, but it only happens when I'm trying to slip the clutch in 1st gear or reverse, like parking or in slow traffic. If I release the clutch fast enough, there is no pulse at all... I take this to an attribute of a more agressive clutch, and it is probably designed to be just on and off. I may be wrong, but I think full racing clutches are the same as well?

However, one difference I have with your setup is that the clutch engagement point hasn't changed since I got the clutch installed. Also, the clutch pedal is a lot lighter than what it was before with the stock clutch. I did get the lightweight clutch option though...

HBRAMSTEDT · 20th July 2005, 05:41

This is a first class example of why it is important to do as much research on your mods. in advance. Understanding the mechanisms in detail, feedback from other others on similar mods, and if possible driving experience in a vehicle with similar mods. is important. I personally cannot understand the need for all the modding. that goes into M5s such as SSKs. I would bet everything that most of the extensively modded M5s on this board are slower than stock. Of course exceptions include well thought out major mods. like the supercharged projects and no-nonsense mods. like full Supersprint exhaust. However, the bottom line is having fun. As long as you are having fun that is what it is all about.

bmwusa · 23rd July 2005, 21:30

How are things going with the vibrations? is it all the time or only in 1st and reverse? does it make the whole car shudder, and has it gotten better as you have gotten more miles on the car? Josh

C2Turbo · 23rd July 2005, 22:41

The vibrations experienced (chatter) is due to the ceramic material used on the

stage III clutch kit (not recommended for a daily driver).......to avoid this

the stage I organic is the optimal choice for street use...