Finally installed the SACHS 2 w/ 764 PP.
Bedded in gently about 250 miles and did some SC driving lately which I hadn't driven in awhile because of stock pressure slip.

What I notice though is in SC mode there is quite a bit of turbo surging and sudden sling shot effect at about 5k-7K with abrupt onslaught of power.

Also notice that at one point when hammering the throttle (SC) it felt like the clutch wanted to slip but couldn't but all the energy transferred to what felt like all four wheels spinning. I didn't feel car acceleration but felt as if it was like throttling out of a mud hole with very little traction. So much so that i backed it off.

So I wonder now is it smoothing the clutch disk with some left over spotting causing the odd behavior or something else.

In normal mode (SC off) driving is much more linear. Highly preferable over SC mode. (?)

 

Did you notice this before or has it been too long? It sounds like you need to upgrade your vtgs. That might help smooth things out while giving you more power.

 

Sounds like a tune issue to me. Mine pulls so linear and smooth in both modes. All you get is sheer acceleration. You really need to watch the tack in second.....so easy to pip the limiter. Maybe you need other things looking in to.

 

What is the mileage on ur rear tires?? With the new EP1, and 8K on a rear tire with 12K on the other rear (1-blowout), I notice a lot of straight line slippage with full acceleration in second out of first gear (keeping some rpm during shift to avoid turbos coming off). i hope it is tire slippage and not clutch slippage, because in all other gears really don't notice slippage. Incidently, what's the average life for these turbo clutches with normal use....currently 41K on the clock?

 

My stock clutch had 70k on it when I sold it with the fvd tune, no slipping ever. Also, mine was very linear as well. Plugs?

 

Charles, if you can do a 3rd gear full-throttle datalog from 2k rpm to redline that would be useful (do it in both normal and sc mode). Sounds like timing is being pulled in the mid-band and then back to normal at 5k rpm giving you the surge feeling at 5k. Certainly doesn't sound normal. I have the same clutch and it has no problem holding even with upgraded vtgs.

 

The other thing is that the clutch should be gently worn in for the first 500-800 miles iirc. At least that's what I was told.

 

Bedding it in gently over the first 500 is very wise. If you have a new flywheel and a new clutch maybe less but most are using the old flywheel which has been just roughed up. Some flywheels probably needed changing too.....especially if they have been slipping for a while. One can only hope the installer looked at things properly and has made the right judgement on reusing the flywheel....and not got too caught up in offering a budget repair to keep customers wallet happy.

 

What does "gently" mean?

 

gen·tle (jntl)
adj. gen·tler, gen·tlest
1. Considerate or kindly in disposition; amiable and tender.
2. Not harsh or severe; mild and soft: a gentle scolding; a gentle tapping at the window.
3. Easily managed or handled; docile: a gentle horse.
4. Not steep or sudden; gradual: a gentle incline.
5.
a. Of good family; wellborn: a child of gentle birth.
b. Suited to one of good breeding; refined and polite: a gentle greeting to a stranger.
6. Archaic Noble; chivalrous: a gentle knight.
n. Archaic
One of good birth or relatively high station.
tr.v. gen·tled, gen·tling, gen·tles
1. To make less severe or intense: The peaceful sunset gentled her dreadful mood.
2. To soothe, as by stroking; pacify.
3. To tame or break (a domestic animal, for instance): gentle a horse.
4. To raise to the status of a noble.

 

I would start looking at your turbos. I just went through a similar issue. Upgraded clutch to a Sachs AWE Stage 2.5, and still felt like power wasn't "developing properly - kin of exactly as you describe. Turned out that the vanes on the VTG Turbos were getting stuck. The problem escalated and ate out my "new" spark plugs with less than 1500 km on them... it was a mess. So I would start there. Make sure the actuator rods are ok and lubed properly, and functioning. Else you could be looking at sever expenses down the road - as was in my case.

 

lol...

I had a conversation with one of the techs who works for a reputable transmission rebuilder. He suggested many start/stops in the first several hundred miles, not to "baby" the clutch.

 

OK. Wrong word. But for all of that gently in my books means don't dump it or give it wot in second third forth etc. In fact try not to give it wot unless you are squeezing on the power "gently" until the throttle is pinned. And on the don't baby the clutch. I tend to disagree with that. If you have a brand new flywheel with factory crosshatching pattern and a new clutch vs a used flywheel that has been roughed up with a bit of emery or a sanding disk it just doesn't take as easily we've found. A flywheel that already has heat spots and is not dead flat, which a used 997tt one wouldn't have then once again its not going to take as well as quickly as a nice new flat flywheel. Don't baby it isn't advice id be giving unless it's someone else's work i was happy to see go bad. Oh and btw not meaning to beat my own drum here but we've been building transmissions for god knows plus deal in oe clutches and do installs so we kind of know a little bit about what we are doing.....well i hope so after all these years.

 

How you break in a clutch depends on the type of clutch you are using, and the material it is made of.

If you follow the break in procedure which you have described on an ATS Carbonetics, you will end up with a grabby clutch that only engages up top on pedal release, with a very harsh jolt between shifts from 1-6.

 

I would agree with you where a segmented plate is concerned. These really need to bite into the contact area so glazing from too easy a brake in is best avoided. These button type clutches don't like being slipped. Best to dump it...like an on off. But with an organic disc it is different especially on a high torque/output engine such as a 997tt. The clutch is small diameter with a very small surface contact area and it's amazing something so small can hold so much torque really. The dual mass flywheel is also very thin on the surface contact area and is very susceptible to warpage from improper use (overly slipping on the take up or, using a slipping clutch at wot or under low rpm high torque situations). Porsche advise the DM flywheel is often a throw away in many circumstances depending upon mileage and correct operation that's why it's really best to deal with a clutch slipping issue immediately or avoid wot or high torque load where it can slip and burn the contact area. Once subjected to abnormal slipping the contact area warps and cannot be recovered as it's not machinable. Cost of F/W replacement often results in many taking a chance it will take to a new clutch. The easier the run in the better chance you will have that it will no longer slip at high torque moments and i agree stop start traffic is the faster way to bed one in rather than freeway.