[alan_b]

When the weather gets a bit warmer I’m going to take the gearbox out (again) to fit an uprated clutch plate. I have a new Sachs clutch in it at the moment and it simply can’t take the torque. I think that Abbott (and Speedparts) do one but I am wondering whether anyone knows of another source of uprated clutch plates which is a little cheaper. Also, is it possible/advisable/cheaper to get a one-off made up for the 9000?

Cheers,

Alanb

 

[alan_b]

Just a follow-up to my last post: I’ve read a few people (e.g. Zeke on the TSN BB) who have suggested that it is the pressure plate rather than the disc that needs to be upgraded. I see that Sachs do an up-rated pp for the 90-93 9000 (part no.883082740). Does anyone know whether this will fit my 95 Aero?

Alanb

 

[wrighar]

Blimey, what torque are you pulling!!

My aero, previous year, has been pulling well over 310 ftlb's and 248 bhp for 7 years, and is on it's original clutch at 130,000 miles.

Still no slipage but very close to the end now.

Andrew

 

[Eric van Spelde]

Seems that (uprated) clutch pressure plates come with two torque ratings: one that applies for use with a normal organic-lined clutch disk, and a higher one for use with a copper puck type 'racing' clutch. So indeed, if you don't want to go to the latter you need a beefier pressure plate - but if you can live with the characteristics of the racing disc, the other way round is just as viable an option. FWIW the copper four puck disc that Saabine has now feels absolutely fine to me, and the availability of one negated the need to swap flywheels in order to fit the 90-93 9000 2.3T set up, which would mean I'd have to have another flywheel lightened, and then the whole assembly would still be a kg or two heavier than what I have right now.

Don't know about the difference between 90-93 and later 9000 2.3 set ups apart from there being a different part number for the discs on either.

 

[zeke]

Alan, I'm zeke on the TSN. I may have met you
at dyno-day in Uxbridge. Just a few other things that I didn't say on the TSN thread: I
was getting slip with my clutch, which only
had about 30k miles on it. My software was
a bit milder than what I have now - it dynoed
at 290 ft-lbs of torque - but still I'd get slip in
5th gear under high boost. I was told by
Karl and Dr. Boost that it was the PP, and
sure enough when I took it apart, the clutch
looked fine with hardly any wear on it. I ordered a new Sachs Race Engineering
pressure plate, and now, with much more
'aggressive' software (probably a little more
than BillJ's) I get no slip. I did use a new
stock clutch, though. I would give John or
Fredrik a call at Maptun: I'm sure they could
send you one, too.

 

[alan_b]

Thanks Robert (zeke),

Yes we did meet! Mine was the 311bhp/310lbft - about-to-blow-up-aero

My clutch and PP only have 2k on them and my friend (Alex) who helped me was pretty caredful to check the flywheel surface. It seems that about this sort of torque the stock clutch is marginal. Some people don't get slip and some do.

I see the that SQR do a Sachs Race PP but I've always had difficulty getting a reply from Frank. Right, so Maptun it is. I think they cost about £150-200???

Alanb

 

[mark e]

I had problems with a "regular" new clutch slipping whilst I was knocking out about 300lbft of torque (before I knew better

). Anyway, the concept of increasing pressure helps, and to further expand let's take a brief, simplistic look at the principles...

What we're talking about is not just friction coefficient which is a measure of friction between moving surfaces, but another property commonly referred to as "stiction". In practice what this means is that for a clutch to slip, there will be a finite amount of torque that has to be reached to break the binding (stiction). Beyond that, a lower amount of torque can maintain the slippage.

To avoid slipping you can either go for a higher pressure plate or use a paddle type clutch. Each ahs it's own plusses and minuses. I've got a paddle clutch fitted, and the plusses are:

<ul type="square">
[*]very positive bite
[/list]
<ul type="square">
[*]significantly lighter pedal
[/list]
The minuses are:
<ul type="square">
[*]difficult to feed in smoothly
[/list]
<ul type="square">
[*]gets very judderry under stop start traffic
[/list]
The alternative of increasing pressure gives the plus of a "smoother" action at the expense of the pedal getting heavier, which is a bind in stop start traffic.
The problem with clutch slippage is that once it starts, it gets worse as the extra heat generated glazes the surface of the friction material and thus reduces it's friction coefficient; it then starts to slip more, creating heat, more glazing, more heat etc... and eventually clutch burn out.

As to which to go for, it's down to a matter of personal choice. I've "taught" myself how to drive with the AP paddle clutch and the niggles about the lack of smoothness are, on balance, outweighed for me by the lightness of touch. But that may not be to your taste, especially if you do a lot of town driving. If you want to try it, then PM me. BillJ, /john, Leon and Gassy have all driven mine- maybe they would like to comment on inital reactions to the clucth too.

From memory, the AP clutch is circa £170 plus VAT from any distributor. Delivery is normally 6-8 weeks.

Good luck!

 

[billj]

Originally posted by Bubbles (fka Mark E):
[qb]BillJ, /john, Leon and Gassy have all driven mine- maybe they would like to comment on inital reactions to the clucth too.[/qb][/b]

I didn't drive it in traffic, but it just felt like a clutch to me