Improved shifting for side shifters, bolt on? Maybe., Experimenting tonight. Options

[Dr Evil]

I have had this though for a long time to try and remove as much slop as I can in the shifting system. The tail shifter is a bit trickier, but not impossible. I have a side shifter in my new 914 and so, while I build up a transmission for it to drive to Hershey this weekend (this will be the raffle transmission, BTW. Trial by fire!), I decided to see how simple it would be to remove some of the slop.

First, see how much of a gap there is between the shift selector comb and the rod.

This is a huge amount so any bit that can be removed should be an improvement.

Step one was to add material to the sides of the comb faces (Yes, Scotty, I welded). Then, I hand filed the faces and re-formed them to a specific profile. The metal that was added was hardened and a real bitch to file. I figured it was worth it.

The end result was a much tighter fit.


There are a few parameters that I will not go into that need to be respected to get this to work, but the preliminary results were nice on the bench. With the material added and profiled on the faces, the stick throw fore and aft to select gears decreases significantly. There is still refinement that needs to be done on the profile, but so far the preliminary results are encouraging.

Next, I will build a jig so I can directly observe and adjust my profile. And I will also be able to see where I can add material to take up the slack that one feels when they are in gear and can wiggle the stick back and forth.

Once I get this prototype done and tested, I can do this treatment to any side shift console on an exchange basis and it will be a quick bolt on improvement (I hope).
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[JWest]

The RennShift addresses the large amount of friction in the factory shifter and adds the gate springs that 99% of manual transmissions are blessed with from the factory. Reducing play is only part of the picture. Lots of weak areas in the shift mechanism - have to hit all the links as each improvement makes the next one the weakest.

Edited out the drama after a good night's sleep...but you still get to see it quoted...

[ablesnead]

Where as a Rennshifter addresses the problem at the end of the chain, my solution will address it at the source and will be far less.

I don't see a slam on your product at all...I have seen before a defensive attitude in your response to perceived criticism ..I have seen great respect and appreciation from this site chatter for the rennshift..I am saving to purchase one soon...in in hobby viable solutions at a cheaper price than currently available will generate buzz...its not automaticly a knock on an already existing product .You and Jake get some skin thickner
Rant warning - sorry - you brought me into this...

I find it interestingly sad that many 914 owners feel the need to attack and put down those that produce parts specifically for these cars. I don't belive that I have EVER wronged anyone in a sale, yet you guys seem to treat me like the evil corporation after your money. I'm not StuffMart producing crap in China to put others out of business...

The RennShift addresses the large amount of friction in the factory shifter and adds the gate springs that 99% of manual transmissions are blessed with from the factory. Reducing play is only part of the picture.

As for the price, this is a very small market. If not for the similarities with the 911 version, I would not be able to make this a viable product at all.

I did make a cheaper version for a time - the RennShift Jr. Most of the features of the RennShift for half the price. Sold 2 in as many years. Price is not everything...

Sorry, but I feel that you guys go out of your way much too often to alienate rather than support those that make products for these cars (and it's not just me).

If you can make this product work well then it will be a good combo with the RennShift. Good luck with your progress - when I tried this mod I found that the pattern was overly constrained so it took too much deliberation follow a square corner from gear-to-gear. Much like driving with a true gated shifter in a Ferrari - cool, but kind of a pain.