Garth S

Local road construction today forced me to ease over a freshly formed concrete curb ... before asplalt had been laid up to minimize the cliff: Krunch with a capital 'K' was the ugly sound below, as I feathered the clutch in 1st gear, doing my best to float over the obstacle. No problem says he, departing while accelerating and shifting into second ..... and into .... CRAP - no third gear to be found

This minor scrape had jammed the short shifter (SS) by collapsing the formed dimple in the center cover that accomodates its lower protrusion in C4/4S/TT cars. I was left with 1st, 2nd, and reverse ..... so made it home in second gear.

Fortunately, this sort of a screw-up had been anticipated months ago when the SS mod was added .... by adding a removable 'dimple' cover vs. beating a pocket into the center tunnel cover, as discussed here.

It was a simple matter to remove the 4 screws and cut the aluminum tape sealing the cover, followed by a quick session with a ball pein hammer to restore shifter freedom - and water tightness, all in a few minutes. As a mater of fact, were I further from home, I could have simply removed the cover to restore full shifting to all gears, leaving the repair and replacement for later.

Having experienced this, there is some satisfaction knowing that this 'insurance policy' has paid out: had I done the conventional beating a pocket into the 4 ft long center tunnel cover, recovery from such a crunch would far more difficult .... and even less likely to be performed roadside if required.

RallyJon

Wow. Exactly why I have a short shifter sitting on my workbench that I haven't installed. With the roads around here and winter driving, this would happen to me in a week.

The mechanics of short shifters on AWD 993s are just ridiculous. It's a hack (no offense to your solution) and not worthy of Porsche. When will someone engineer this without dimpling the tunnel? Must be some way to raise the pivot point on either side of the driveshaft.

Don Plumley

Are you certain the shift guide tube was reversed when you installed the shifter?

Edit: or is this unique to C4's?

Garth S

Unique it is - there is no shift guide tube as in C2/2S: the forward drive shaft spinning in a torque tube fixes the shifters primary pivot position; therefore, to achieve a 'short shifter', the lower ball pivot must drop 25mm ... into a relief in the center tunnel cover.

hyphenf15

So Garth, is it worth the extra work to achieve a shorter shift? Are you very please with the end result, kinda pleased, would not do it again? I'd love to shorten the throw on my C4 and your pictures help me understand what would be required if I went down this path. I'm with RallyJon on somebody building a proper solution, but there is probably not enough demand to make it worth someone's engineering effort. Thanks for the post and any feedback would be very welcomed.

Jastx

I wished for a shorter shift when I had my C4S, but this mod is too intrusive, kludgy, and just plain bad. The compromises made are greater than the benefits.

Mike J

Nice work Garth!

I worked on another Rennlister's car a while ago (a C4S) where the shifting was stiff...turns out it had a short shift kit and the indentation hammered in the center tunnel had been hit by something on the road and squished enough to jamb the shifting rod. I had to drop the center cover and hammer it out...then it shifted just fine. Nice idea on the removable cover!

Cheers,

Mike

Garth S

Greg,
I am very pleased with the ~20% shorter shift throw - and the reduction in 'slop' by firming up the coupler at the trans: the latter can be done without altering the stock shifter ( trace the links back in my first post if interested ).
This is the only hicup since doing the mod, and was caused by a most unusual "off road" excersion - I am not deterred ... , for the car has never touched previously, driving over the worst excuses of frost heaved pavement at speed - in a chassis set at 138/125mm fr/rear.

I started this deal as a DIY experiment - and the book is still open for improvements: our shifter functions as a class II lever, with the fulcrum being the ball stud on the bottom, secured by the forward shift rod. the rear shift rod to the trans attaches by a pivot fork just above this fulcrum: this atachment is to the 'slider', which can be raised upwards in RWD cars ( by using a longer fork between the slider and rear rod) .... leaving the shifter **** an inch higher inside the car, but the tunnel cover untouched. AWD cars effectively have the 'slider' around the drive shaft, which cannot move .... so the standard short fork is retained, and out the bottom goes the fulcrum of the lever.

In an AWD car, only the RS lever is needed ( or mod the OEM lever): the lever I made is easily as strong as the original - so no compromises there. I saved the perfect tunnel cover in case I changed my mind .... and beat upon and chopped away at a twisted up one from a parts car. Perhaps it is that recovery of otherwise scrap that merited the " but this mod is too intrusive, kludgy, and just plain bad". Well, I'll be the last to claim that tray and cover as a thing of beauty .... but it works for now.

What's next .... well, essentially the same result can be achieved if one is willing to accept a shorter shift lever extension inside the cockpit - and not use the RS lever. This would increase the shifting effort modestly, and be achieved by cutting down a stock lever. If I get my hands on another lever, I will do just that .... and if the ergonomics and shifting effort compliment the shortened shift, it will be installed along with my unmarker, pristine center cover ... no dimple
I have done exactly this on my early 928 .... lopping ~3" off the lever: now, it sits at the 928 GT height, and snicks precisely amongst the gears. Shifting is near effortless, even with the lower mechanical advantage of a shorter lever.

Hummm ... think I'll start looking for a shift lever ..... for phase II of chop, cut and rebuild ...

Wilder

Garth, I'm the RLer with the C4S whose car Mike worked on. Please keep me posted on your upcoming project as I may be interested in doing same. I'm not overly excited about the dimple and I'm always concerned about bottoming out and scraping it again.

RallyJon

Oh no--so that's how far us AWD guys have fallen? Cutting the shift lever like a Honda Civic or something?

The purpose of the RS short shift kit is better ergonomics, it places the shifter closer to the steering wheel and reduces the extra throw. Moving the shifter, which is already quite low, ever farther from your right hand defeats the whole purpose of an RS shifter.

hyphenf15

Keep us in the loop. I'd still like a viable option to get a short throw shift without major changes. Thanks for the detailed information.

Garth S

Perhaps we understand the same issue differently ... the RS shifter in an AWD car does not change the lever height from stock - not even a mm: what does change is the extremities of the throw shorten ~12mm = ~24mm total. To achieve this, one must live with a dimpled center cover .... or forget about it and stay stock. The RS shifter does raise the shift **** an inch in RWD cars when correctly installed, which may be the purpose referred to.

To avoid the dimpled cover - and have a shortened throw, an alternate compromise need be made ...... shorten the upper part of the lever. Simple physics of levers & fulcrums ..... Many 928 shift levers have been successfully shortened, so my thinking out loud was that why not measure up and try this on a 993??? Actually, very easy to do - and I would be surprised if someone didn't speak up about having already done it.

At 6'6', I can reach anything, anywhere in this tiny cockpit .... so may not be suitably sensitized to the ergnomic norm for the shifter **** placement - and can only think of two ways to reasonably shorten the shifter throws without redesigning the entire system.

hyphenf15

Any updates to your project?

eclou

I put a factory alu **** on my 993tt and the different mount for the **** raised the height about an inch. Without having to cut the lever height down, I simply trimmed the tabs on the sides of the lever to allow the **** to sit about an inch lower than stock. Very pleased with the result

Garth S

The 928 is in the bay with the hoist .... and snow bound, so I won't be under the 993 anytime soon

Whenever I find an OEM lever, it would be a simple matter to shorten it an inch or so; however, that will likely do less to reduce the net throw length vs the additional inch at the fulcrum of the RS lever .... I haven't mapped it out yet.