Clutch Slip - BSR ?

[b.r.i]

Chaps,

Uh-oh, that made you look.....

Had my Stage 1 PPC for around 6000 miles and today noticed that my clutch was slipping noticably during hard acceleration in 4th. Tacho needle shot up from 3 to 4K on the dial and then dropped to 3.5K without me letting loose on the pedal - could hear the engine increase also without associated normal thrust, with a small push in the back as the needle dropped, i.e. the clutch engaged/kept up with the torque.

Now, my question is this, my car has only 11,000 miles on the clock. Is the PPC the root cause or do I have a duff clutch?

[Edit] Forgot to add, I have a manual 6 speed Aero, and no my left foot was not resting on the clutch.

B.

[Dave N]

I've had the stage 1 on my car for a similar mileage, but cant say I've experienced any clutch slip at all. I've got the 1.8t which with ppc makes around 204 horses.

Do aeros have a bigger clutch?

My power increase was 150 to 204 = 58 bhp
yours will be 210 to 247 = 37 bhp

If the clutch is beefier than the one on mine I wouldn't expect it to be effected by the smaller increase. This may indicate a weakness that was there before you installed the PPC. Uninstall and see if you still get slippage. If so take it to the dealer and get them to check the clutch for you.

[b.r.i]

Not sure if Aeros do have a bigger clutch. Either way, 11K is unnaceptable even with the PPC. Its going back to the dealers - easier said than done of course as its bloody miles away.

[Vector-SS]

i have been experiencing the same problem too with the BSR chip. Thing is i havent had the BSR on for that long either. Also, i experience the slip in 3rd gear going around 60-70km/h. I have yet to ask my delear

[ctrlz]

Originally Posted by b.r.i

today noticed that my clutch was slipping noticably during hard acceleration in 4th. Tacho needle shot up from 3 to 4K on the dial and then dropped to 3.5K without me letting loose on the pedal - could hear the engine increase also without associated normal thrust, with a small push in the back as the needle dropped, i.e. the clutch engaged/kept up with the torque.

Just installed my Stage 1 software, so I will watch for this. I also have a 6 spd 2.0T.

The problem sounds like the clutch wasn't clamped hard enough for the torque until you got to 3500 rpm or so. Once the pressure plate got spinning fast enough, the centrifugal assist kicked in and clamped the clutch disc harder.

I think the 93SS clutch has centrifugal assist, as I think older Saabs had this. The system uses weights. Heavier weights will clamp harder, but require a higher rpm before they provide additional force.

I think you may have found the point in the rpm range where this all comes together. You may have to ease your way up to 4000 rpm before you can nail it. You really don't want to fry your clutch or flywheel.

[b.r.i]

Originally Posted by ctrlz

I think you may have found the point in the rpm range where this all comes together. You may have to ease your way up to 4000 rpm before you can nail it. You really don't want to fry your clutch or flywheel.

This is really noticeable now and seems to be getting worse, I think the clutch is fried. Never noticed it all all until about 2 weeks ago, or maybe I'm just a little more perceptive now that I've spotted it.

Surely the clutch is good for an extra 40 BHP, so perhaps a weakness - as there must be a tolerance for the heavy footed. What surprises me and makes me think the clutch is inherently weak, is that normally (95%) I pootle along at a fairly gentle pace, only occasionally do I floor it/give it welly.

I'm going to de-tune and take to the dealer.

[ctrlz]

Originally Posted by b.r.i

Surely the clutch is good for an extra 40 BHP, so perhaps a weakness - as there must be a tolerance for the heavy footed.

One would think so.

The BSR graphs show both extra torque and power at lower rpms. So the clutch may slip more before it really clamps. OTOH, the 6 speed is supposed to be able to handle much more power than the 2.0 can put out. I don't know if that means the clutch is equally rated. Probably not.

I agree with your idea to detune and talk to the dealer. Supposedly the Trionic logs max torque. I don't know if reloading the original software will clear that. I hope so. If I were a Saab tech I'd be looking at that number before I agreed to replace the clutch.

The other thing for them to check is the clutch linkage, to make sure the clutch is completely releasing. There should be a small amount of freeplay before the throwout bearing touches the diaphragm fingers.

[b.r.i]

Well I detuned and now it doesn't slip....typical. Not that easy to take to the dealer for them to sort it out...and now my car is really slow .

Oh well, I'll take it anyway and see what they say.

B.

[peterchurch]

Originally Posted by b.r.i

Not sure if Aeros do have a bigger clutch. Either way, 11K is unnaceptable even with the PPC. Its going back to the dealers - easier said than done of course as its bloody miles away.

Years ago when I had my old Saab I was at Saab City having some work done , while a chap was moaning to a mechanic about the fact that he had just shreaded his 3rd clutch and 2nd gearbox due to the upgrades that they had done to his Saab. I don't see why you should lose a clutch so fast unless you are hammering the car _very_ hard but it does stand to reason that it might have adverse wear issues would it be covered if you have had a PPC upgrade?

[b.r.i]

Originally Posted by peterchurch

Years ago when I had my old Saab I was at Saab City having some work done , while a chap was moaning to a mechanic about the fact that he had just shreaded his 3rd clutch and 2nd gearbox due to the upgrades that they had done to his Saab. I don't see why you should lose a clutch so fast unless you are hammering the car _very_ hard but it does stand to reason that it might have adverse wear issues would it be covered if you have had a PPC upgrade?

I know what your saying but as mentioned previously, 95-99% of the time I'm going to work which is not a fast or even remotely hard route, and normally I don't press on even in the slightest as its not anywhere near possible.

The odd ocassion I do hammer it is normally for a short blast of a mile or so and even then just to overtake.

So having the PPC for 6K, there is no way this is a result of that without a dodgy clutch in the first place. All cars I've had previously have been tweaked much more and no problems encountered with the clutch.

So I'm a bit perplexed - is the PPC pushing out too much torque for the clutch or do I have a duff clutch from the outset? Have others (apart from the stated above) experienced this effect?

B.

[rando67]

I glanced over this thread and think this might be the trans body valve problem ... (my quick two cents)

[ctrlz]

Originally Posted by rando67

I glanced over this thread and think this might be the trans body valve problem

What is this valve and what does it do?

[rando67]

I'm not an expert on this but the transmission valve body is the brain of the transmission. Often it is called the control valve. It's this control valve when shifting gears that gets stuck! Yes, it gets stuck. The gear getting stuck causes the car's engine to flare, give more power, on the order of about 1k RPM. If this is the problem you are having Saab considers this trans defect potentially damaging the engine. Of course you have to have a tech from the dealership witness it to clearly get a warrenty work on it since its costly. I think Saab looses most of the profit on the car with this job since its major work.

I had this changed under warrenty at around 20k miles (w/out BSR). I have added BSR since then.

Here are some links if you want to surf:
http://search.about.com/fullsearch.h...20body%20valve
http://www.tciauto.com/valve_bodies.htm
http://images.google.com/images?q=wh...r=&sa=N&tab=wi

[b.r.i]

hmmmm, interesting.

I will try to get the car to the dealer on Friday, failing that it will probably be in a few weeks due to a business trip to NY.

B

[Bladey]

things like this worry the cr@p out of me and put me off the ppc. However,... don't forget that the Hirsch car puts out a little more bhp than the stage 1 ppc. stage 2 hirsch is 252bhp. AND NO CLUTCH MODS.. so going by that I would say that the standard clutch and gearbox can easily take the 247bhp of the ppc stage 1.

I also spoke to a chap at Abbot Racing, .. nice bloke and very helpful, he said that the car can eaily take 250bhp and more. Abbot racing take there tunning upto 250 bhp as well.. so all fingers point to 247bhp from the ppc being acceptable ... but of course, I'm not a saab engineer

Maybe it is just a weak clutch and the ppc shows it up...

I have the same car BTW 6spd Aero, and i want mine to go faster too, but i've covered nearly 60,000 miles now, and it scares me!

[CHUCK85122]

I just installed stage one yesterday ans I think that a note this fact too!! RPM going very fast from 1000 to 3200 and then drop to 2900...but not always!!! So not 100% sure and they have a lot of trafic on morning weekday to go to work...Will check that better later this week!!


BTW my car got only 21000km (13000 miles)

[ctrlz]

Originally Posted by rando67

I'm not an expert on this but the transmission valve body is the brain of the transmission. Often it is called the control valve.

Valve bodies are only present on automatic trannies. The part basically consists of a complex maze of passages which route tranny fluid. There may be intentional restrictions along the way, as well as check valves. The fluid goes to accumulators and ultimately the clutch packs. There are probably some electronically controlled valves in a computer controlled transmission, but the basic ideas are the same.

This whole business is very different from the diaphragm pressure plate and friction disc on a manual tranny, which is what I thought we were talking about.

[rando67]

Originally Posted by ctrlz

the diaphragm pressure plate

Is there a control valve involved with the pressure plate (on a manual tranny)?

[b.r.i]

Originally Posted by ctrlz

This whole business is very different from the diaphragm pressure plate and friction disc on a manual tranny, which is what I thought we were talking about.

I was thinking this too...manual surely is just a mechanical setup.

Well its not 'slipping' now if thats what it is, so I may re-PPC and see if it comes back. If so, it must be the clutch being not able to take the extra power/torque in which case this would apply to the Hirsch product too, therefore the clutch must be weak (at least on my car).

B.

[Bladey]

Hmm I can't see it applying to the Hirsch Car. The fueling and delivery of the BSR stage one is more aggresive than the Hirsch car.. maybe more power coming in all of a sudden where the hirsch car builds up more smoothly. ... just a thought