malcolmd

So what's the forum's view on the clutch question?

It seems to me that there are really two separate issues, that is, apart from the cost. Firstly, there is the question as to whether an upgraded clutch should simply be an accepted part of any engine upgrade process (much like the need for an auxillary oil cooler with HP > 400). The second question is really only relevant if the answer to the first is "no" or "maybe"! It relates to the question as to how driver friendly the LWF and upgraded pressure plate is in the given roll planned for the vehicle compared to the ease of the OEM dual mass unit.

I do not know how much torque the OEM clutch can bear, but clearly there are many high output TT's out there who appear to cope adequately with the OEM unit. For how long, I don't know! Clearly there will be a engineering related limit, however, other more intangible factors will influence whether a clutch will stand up to the demands of a higher torque engine. This largely will be determined by how kind or unkind the driver is to the clutch. It is easy enough to even "cook" a high performance clutch with wanton clutch abuse. I am sure Kevin and others would recommend the clutch upgrade, especially for the Stage 2, largely to provide a comfortable margin of excess capability thus ensuring a greater likellihood of a trouble free outcome for the customer. This would fit with the Porsche philosophy to over engineer rather than just make do.

I would be interesting to hear from those who have upgraded high torque engines, who might like to discuss the why's and wherefore's of there decision to or not to upgrade the clutch, and there subsequent experience - good or bad. Those with the clutch upgrade might comment on the user friendliness of the LWF mechanism, compared to the dual mass OEM.

I hope Sebastian doesn't think I have hijacked his thread?

Malcolm

TB993tt

My tuner always upgrades to LWFW for anything but a K16 package. I don't have a technical explanation as to why they deem it neccessary, think it was to do with taking weight off the flywheel ? -Depending on the steepness of the boost induced torque curve real torque over 640NM will fry a stock clutch set up....If your stock clutch is holding then your torque aint real or you have a very smooth linear torque delivery up to peak

After "smoking" many "750NM" rated discs I used a sprung metal one from Protomotive which held 750NM no problem but was a pig to use.

Things have moved on well in the last few years and the latest offerings rated to 800+NM are superb, organic (with metallic bits) non sprung discs which personnally I find no problem for use in traffic and have commuted in rush hour city traffic plenty.

edit: for clarity by "smoking" I mean the clutch slipping as the engine revs through peak torque in 3rd gear upwards.

malcolmd

TB
I have forgotten to mention the pure "performance" benefits of the LWF - i.e. the significant reduction in inertia and subsequent power loss in the drive train that this induces. I recall Jean's tread on this point previously where he discussed the effective change in simulated vehicle weigh through the use of a LWF. (see clutch weight savings poll: 10-28-06).
Thanks for sharing your experiences

Malcolm

Jean

Malcolm,

Kevin had sold me an excellent clutch that so far is working very well with my car. I have not attempted any high boost runs with it, but at least on the track at 0.9 Bar it is flawless, as well as on the street. It is very smooth and drivable on the street ever since I fixed my clutch slave problem. I agree with TB, the Protomotive clutch was a real b!tch, no slip whatsoever on startup, a great drag racer's clutch

I know of people with very serious power that have kept the OEM dual mass flywheel with a high torque PP and metal clutch and they love the setup. Clutch and PP are a must to be changed, LW flywheel is not a must, but a nice to have.

Full Boost

Mal,

I have the LWF and Clutch set up fromViperBob. I cant say I am 100% happy with it - although it seems to be getting better with practice.

On the Track - it is wonderful - on the street not so....

The benefits are faster revs (as already discussed) and a strong, solid snappy (?) feel to engagement. I also have a PMS/Sachs pressure plate and some sort of VB special plate - he says it is rated WAAYY past my HP limits - or expected ones.

It is really a drag racers clutch - in or out - however I must mention I was having all sorts of issues with gearbox F$%K ups (courtesy of my local Porsche Centre) and now that i have reverted back to the standard shifter and semi solid motor mounts the shift feel is excellent.

Would i do it again - not sure about the LWF - but pressure plate and clutch plate, yes.

Is it necesarry - i think so 100% - I also use the "while I'm in there" motto and didnt want to do the clutch agian when i get more HP.

Hope this helps,

Simon.

sfbanchs

what shifter did you have prior to reverting to the stock one? i recently put a short shift kit in my car

malcolmd

Hey Guys - thanks for you input. Looks like the consensus is a definite "yes" for the clutch and pressure plate, with the LWF being optional. I would adhere to Simon's concept of "while you're in there" and do these mods when my time comes. In the meanwhile...

I'll await news from Sebastian who must be getting very excited by now.
Malcolm

Full Boost

Sebastian,

I had an RS shifter installed along with LWF, Sachs/Porsche Motosports PP, and A VB clutch plate. (I believe he gets these specially made) whilst i was getting the G/box rebuilt and a few other things done....
Needless to say the whole thing was a massive F*%K up and i have since redone most of the work performed by Scuds.

I changed shifter as with the amount of ripple strip jumping I do - it was the LOWEST point in on the car.... imagine the impact of being in 4th and then hitting the kerb causing a shift back into 1st....

Get semi sold mounts - and all will be good. The difference is F all...

Simon.

MOD500

In my limited knowledge, I think the reason why some tuners say a LWFW is a must for certain tuning packages is that the bolts on the DMFW can elongate over time at higher power outputs .... I guess the quicker rev acc of the engine means the inertia of the DMFW causes bigger stresses on the securing bolts? Also the higher rev limit of modded engines might be a n issue too?!

I assume as the bolts enlogate, the FW gets somewhat loose, the bolts then impinge on the flywheel and act as stress nucleators causing cracking, meaning the FW might break up altogther in a worse case?!

This might be BS though

sfbanchs

i m just gonna do what kevin tells me and he told me that his kit will fry my clutch. Still waiting patiently

ACEparts_com

All this tune up talk has made me go for a Kevin special stage 2 as well. Darn you. I don't even live in the same country as my car yet still feel I need it

sfbanchs

why didn't you stick with rs tuning? since you already started with them? Kevin should pay me a commissions for all this, JK
I know he works hard for his $$

Who else is going to join in?

ACEparts_com

I was getting overboost issues due to the oversized cats. Kevin's kit is designed for them.

malcolmd

Well Sebastian, I'm getting close! Your final apprasial may well be the ultimate determinant. I hope your shoulders are broad....

Ziad

I've had Kevin's Stage 1 for over 12months now. The package is superb to say the least. I would say that the Stage 1 problably gives me around 480-490hp with race fuel (not dynoed it, but did 2 drag runs vs 997tt manual and was quicker both times - not an exact science, but it's indicative - waiting for the DVD of the event so I can post it - but that's another story). Forgive my ignorance, but I always thought that you'd need to open up the engine (e.g. changing Cams, etc.) in order to get any real performance gains north of 480-490hp?

Kevin, what's the cost of the Stage 2?

Thanks