Has anyone installed a paddleshift system on the 901 transmission? I would be interested to hear about the experience....i.e. installation difficulties, cost, vendor, etc.

I don't think a paddle shift will work on a fully mechanical transmission, but I could be wrong.

The Cap'n

Could you imagine the work involved for the mechanism for that? Too much for too little return IMO. The "paddleshifters" for most production cars these days operate an automatic or CVT transmission except in the supercar applications. I was driving next to a 458 Italia the other day in traffic and his trans was sounding clunky and the car was lurching back and forth as the trans selector system was contending with the stop and go, cornering and general traffic conditions. No thanks... great on the track or probably highway conditions, but around town maybe not the best.

There's an outfit called Master Shift that sells aftermarket paddle shifter kits for a variety of manual transmissions. They tell me that their product will work on a 901 side shifter.....but it is godawful expensive....$2900 minimum. So I was wondering whether anybody else had been looking into something similar.

The question is ... "Why would you want this?"

Part of the fun of a 914 is that it has a manual transmission. Porsche is taking lots of Grief right now for not offering the new GT3 with a manual transmission. The German's say it is faster, but the buyers say it is, and I quote, "Boring".

I may want a better, newer manual trans that can handle more HP, but I certainly don't want a flappy paddle shifter in my 914.

IMHO, a sequential mechanical shifter would be a nice change for all around use, but paddle is not worth it. More of a novelty.

Some day when I get time I will develop a sequential setup....

How are you going to do a barrel in the 901? It would be much easier to pick a sequential from Hewland and do a new bell housing.

Here's something to start with... Sequential shifter for VW Trans

Sequential shifter for Porsche GT3

Why does it have to be IN the 901. All you need is a mechanism to put the shift shaft in the right place. No need for internal nothing.

Like that I want to see if I can simplify it and make it electrical rather than hydraulic. Lighter? Easier to route?

the E36 and E46 M3 SMG trans was a manual trans with the detents removed and had a external electrohydralic selector system bolted on.

A full stock rebuild done with dealer sourced parts could easily reach that figure, done in a retail setting. Would you want a $6K/7K tranny (with installation labor) in your $4K/5K daily driver?

The Cap'n

I can't find it anymore, but there was a Japanese manufaturer that was making bolt on, all mechanical sequential shifters. Basically, it was a sequential drum in the shifter that moved a rod out of the bottom in the H pattern. They were even advertising one for the early 911 with the 901 trans.

Wish I could find that website...

Ya, something just like that. Not too hard to design a drum that moves the external rod to a set position in a preprogrammed sequence. Basically a mechanical computer.

However, I could more easily make a hydraulic setup to make shifting unbelievably crisp with my other in the box modifications. I like making things I need to source some small hydraulic cylinders and get to tinkering....in a few months.

If you visualize the grooved drum, I think you will find that it is not possible for it to move a follower in two directions as required to follow the "H". The follower can only be moved along the axis of the drum. It could be made to work if the drum acted directly on the shift forks with one groove for each fork/slider. That's how motorcycle transmissions work (at least all the ones I've had apart).

Well, there are a few things that can be done. Two drums, plate assemblies, etc. Not impossible by any stretch.

Easier would be two solenoids and to program them to be at a certain coordinate with a certain number of shifter inputs. Easier in the long run with far less machining and expensive work.

How about one that moves the side shift console selector for and aft, and one that moves it up and down?

Then a shift lever with a rotating disk with electrical contacts to engage the correct solenoids at the correct time.

I would rather solenoids for a sequential. That would be easy. Click fore or aft = pre programmed position of the two solenoids. For actual shifting, that would take some more fancy stuff in the shifter area as far as sensors. Not worth it. I can make a standard shifter work in that capacity very well. I am working on a mechanical improvement for the external works. Again, I just need time. Not before I move to OH will anything be done.

Ah Yes
An idea a long time coming.Sorta like the SportoMatic only with the 45 years of
technology to help.Sensors to determine fork positions,clutch engagement,engine revs,
roadspeed,braking parameters,the possibility of double clutching selectively,and on and on.The engineering talent and money that went into today's masterpieces is staggering on the F1 scale.Linear actuators may be the answer in there,sorta like a hydraulic cylinder with fine resolution control of rates.This could be fun,hard work.
Stick?Nah,a 1969 looking version of the latest gizmo,turn signal stalks repurposed.
I had a look at the vid of the cable shift and I am impressed with the results.A melding of the available actuators and electric over hydraulic/linear may produce a mechanism to circumvent the agricultural trellis-work that is there now.I am in wonder that very same device actually won it's class at LeMan.
Click to view attachment

How about:
1 - we add an electric oil pump (high pressure) for cooling to the trans

2 - we take all the shifter forks off the shift rods and attach hydraulic rams to the ends in a bolt on endcap/tail cone.

3 - Hydraulic pressure from the pump drives the cylinders.

Actuate cylinders with a custom valve manifold or a microcontroller.
If you put a hydraulic actuator on the clutch lever, you could automate that too.

With of course the proper accessories

Excellent!

Guys,

Your comment about putting the shift shaft in the right place is exactly how the Master Shift (or is it Shift Master) system works. As I understand their system, it uses an externally mounted mechanism to move the shift shaft. The mechanism uses electric motors. The system has a computer that takes a signal from the paddle that in turn transmits the gear selection to the mechanism. It seems to me that using solenoids would be better than motors.....but with all that said, $2900 seems like a lot of $$ for such a setup.

Yeah...I like solenoids too. I visualize a system of 4 solenoids (ignoring reverse for a moment) The solenoids are mounted on the case at the shifter fork. The solenoids mount such that each solenoid pulls the fork into a certain gear. The solenoids are activated by a floor shifter in the cockpit. The shifter activates each solenoid indivdually via a switch mounted at each location in the "H" pattern. Upside: a lot of fun to set up. Downside: a ton of time to do it.

My idea used 4 solenoids.....yours is better I think. The shifter could have electric switches mounted at each position in the "H". So far as I know, solenoids only pull one direction; but maybe there are two way solenoid. If not, then each solenoid must have a spring to pull the shifter the other way....

The action of a solenoid is too fast for the clumsy 901.. Something would break...

I suppose that is why the Master Shift system uses electric motors. Are any other xmssns less clumsy?

#becauseracecar

I actually thought about this some more and came up with this:

Take a tail cone similar to a tail shift.
Install a cam through it horizontal & perpendicular to the shift rods.
Each shift rod has one rockerarm/follower and one camlobe on the camshaft.
Each camlobe has three heights: In, Middle (neutral) and Out.
The cam would have 6 positions each one 60 degrees from the last. (neutral is 1/2 way between rev & 1st)

If you turn the cam from the first position:
rev -> lobe1 = Out, lobe2 = Mid, lobe3 = mid
neut -> lobe1 = Mid, lobe2= mid, lobe3= mid
1st -> lobe1 = In, lobe2 = Mid, lobe3 = mid
2nd -> lobe1 = Mid, lobe2 = Out, lobe3 = mid
etc
etc.
Then your shifter is just a cog turning mechanism that can bump the cam one up or one down (CW or CCW)

This made my head hurt....

Instead of adding AC, power windows, power mirrors, paddle shifters and power steering, why not just buy a Boxster and be done with it? I have seen one or two of the above turn out ok, but most of been hack jobs that end up for sale.

OK...I just gotta ask....could a PDK tranny be mounted in a teener??