Gated shifer? Options

[kyhunting]

Racing application. Who is using a gated shifter? Which one? Do you like it? Is it worth the expense? I've been fighting with shifting issues.. like finding 2nd when looking for 4th. Last episode ended with broken rocker arms. I've adjusted and replaced everything from the shifter to the solid trans mounts. It will do fine and then all of a sudden I've found second instead of 4th which results in a over rev. I have concentrated on my shifting and can't find a correlation to what causes this to happen. Any suggestions would be appriciated.

Thank you

David

[john rogers]

Rennshift

[SirAndy]

Rennshift

(IMG:style_emoticons/default/agree.gif)

http://www.jwesteng.com/


http://www.jwesteng.com/porsche/914/rennshift_914.htm
(IMG:http://www.jwesteng.com/web_images/rs_package.jpg)


http://www.jwesteng.com/porsche/914/linkage_914.htm
(IMG:http://www.jwesteng.com/web_images/linkage_ss.jpg)

(IMG:style_emoticons/default/thumb3d.gif) Andy

[HAM Inc]

Go JWest, young man!

[grantsfo]

I went with the linkages from JWest. Very nice and it cleaned up my shifting problems.

[carr914]

Definately RennShift

T.C.

[zymurgist]

I put a Rennshift in my 911. Best money I ever spent on that car.

[Chris Pincetich]

+1 on Rennshift
I read elsewhere about extreme racin 914s that would have detectable chasis twist to the point that shifting in corners was super tricky. Not sure what level your 914 is at, if you are on race slicks, big HP, but no cage or chasis re-inforcement. I just AX, and the Rennshift makes finding the right spot purdy easy. The springs keep the shift lever in that 2-3 plane, getting anywhere else takes effort. Not a true gated shift solution, but a great improvement. (IMG:style_emoticons/default/beerchug.gif)

[scottb]

i too have the rennshift along with the linkage and couldn't be happier....

[SirAndy]

I read elsewhere about extreme racin 914s that would have detectable chasis twist to the point that shifting in corners was super tricky.

I have that problem. I have a cage, but it's not tied into the shocktowers. When i'm on sticky slicks the chassis will flex enough to cause binding in the shift linkage when trying to shift while cornering.

(IMG:style_emoticons/default/shades.gif) Andy

[HAM Inc]

When i'm on sticky slicks the chassis will flex enough to cause binding in the shift linkage when trying to shift while cornering.

I think the reason for that is the engine/trans rolling on soft motormounts causing the linkage to bind at the firewall.

[kyhunting]

Found the problem. Clutch cable tube that runs thru the tunnel had broken loose from the welds. When it is loose it raises up about 2". This allows the bottom of the gear shift lever to come in contact with it. This feels like the normal far right stop you would have when shifting into 4th. I have also installed the Rennshift and I believe it is going to be good.

[Randal]

When i'm on sticky slicks the chassis will flex enough to cause binding in the shift linkage when trying to shift while cornering.

I think the reason for that is the engine/trans rolling on soft motormounts causing the linkage to bind at the firewall.

I had solid mounts at the transmission and still had the 2nd to 5th issue, under hard G's in autox. Especially during a slalom where you are very busy.

I can't think of any situation at the track that would be as extreme, so prolly ok at the track.

[HAM Inc]

Randall I use to think that the binding was in the tranny itself. But subsequent testing and some design changes to my shifting system led me to the conclusion that the binding is at the bushing at the firewall.

What's moving and/or flexing to cause this is still a matter of debate (I'm not sure myself, though I think in the case of lesser G force induced binding it is likely soft mounts)
Whatever the case may be I think it is relative movement between the chassis and the drive train causing the link to bind at the firewall bushing, not in the tranny itself (it about has to be one or the other).

[Randal]

Randall I use to think that the binding was in the tranny itself. But subsequent testing and some design changes to my shifting system led me to the conclusion that the binding is at the bushing at the firewall.

What's moving and/or flexing to cause this is still a matter of debate (I'm not sure myself, though I think in the case of lesser G force induced binding it is likely soft mounts)
Whatever the case may be I think it is relative movement between the chassis and the drive train causing the link to bind at the firewall bushing, not in the tranny itself (it about has to be one or the other).

I'm thinking my problem is a bit different from yours Len. I was able to shift, but with chassis movement, even with a full cage (but no tie down to shock towers) I would get 5th instead of 3rd. Even though I was being as careful as I could pulling the shift lever back straight. No question this exercise was right in the middle of a corner with substantial G forces.

When this happens in a competitive autox, your run is over.

Question: Are the u-joints that Renn offers used at the firewall or in front of the transmission? Do they replace the firewall bushing?

[grantsfo]

Issue I was seeing was misalignment in hard turns when shift was on entry or exit. Hillclimb was the worst. And it seemed that issues happened the most as car was unloading from exit of a turn.

I went to firmer mounts and the previous mentioned linkage. I left my stock shifter in place and never had an issue again. I expereinced issues at the track prior to these mods. T2 at Infineon was a constant problem. Never had any issues at Laguna Seca put there were rarely any shifts under load at that track with my gearing.

[Randal]

Issue I was seeing was misalignment in hard turns when shift was on entry or exit. Hillclimb was the worst. And it seemed that issues happened the most as car was unloading from exit of a turn.

I went to firmer mounts and the previous mentioned linkage. I left my stock shifter in place and never had an issue again. I expereinced issues at the track prior to these mods. T2 at Infineon was a constant problem. Never had any issues at Laguna Seca put there were rarely any shifts under load at that track with my gearing.

T2 at Infineon led me to build a lockout to keep from going from 4th to 1st trying to get 3rd.

[J P Stein]

I have no problems now that my trans is a 2 speed. The 2/3 shift is a snap, up or down. It works everytime you have the guts to steer one handed. This leads me to believe the problem is in the 'H' crossover during which the shift rod rotates ....too much rotation gets ya the wrong effin gear. The in/out movement is
only about .3 inches between each of the 3 positions at the trans. If I had a solution for this I'd tell ya. J.Wests shift console mod may do the trick....but I aint gonna pony up the bucks he wants for it on a maybe. He can also keep his shifter.....that is a solution to a non-problem.....IMO.

[HAM Inc]

The Rennshifter rocks and allows for a creative person to design a gate that incorporates a reverse/first lockout that bolts to the top. This is key to consistent, fast shifts. (Was for me anyway.)
The console mod is the absolute cats meow. It is easy to install and makes a world of difference when coupled to his linkage. Can you say precise?!
I will say that in my experience with JWest that there is no "maybe" with his products, or his character. He sells first class goodies and if something doesn't work as advertised (it will) I would bet money that James will make it right to your satisfaction.
You just doen't have to go around with a crappy shifting 914!

[bam914]

Stock mounts and shifter work great in my race car. No missed shifts ever. I do not think I could drive a 914 that had a really good shifter in it.