Hey guys,
Just wondering if anyone knows whether or not I should be using a 915 shift rod from the 915 shifter up front to go through the 914's firewall, or can I use the 914's shift rod. It doesn't look like they'll mate up but I don't have the various parts to test it out.
Thanks.

You would need to be more specific on your application to get the right answer.
What trans are you using, rear shift rod, & what not.
Why a 915 setup or is it an early tail shifter part that you have ?

I believe you can use the 914 rod and fab the rest of it once on the other side of firewall.

Need more info about your build... pics make things easier too.

I'm using a reversed 915 shifter welded to a 914 bottom end (1974 car) and the stock rod through the firewall. But I'm still using the side-shifter 914 transaxle so it makes sense in this case... would have been easier (at the shifter) with an early car and a tail-shifter.

Eventually a 915 will go in because it's a fun project. At that point, unless I go with a cable shift system, I'll have to replace the shifter-shaft with a 911 style bottom-end and turn the base around.

Good luck... give us more info.

OK, sorry guys, I haven't had much experience in posting.

First pic is the currently installed 914-4 shifter.

Second pic is a 915 shifter with an installed WEVO shift kit.

I am planning on using a 915 transmission.

I would imagine I need a proper 915 connection at the shifter up front to attach to that poly ball joint.

Thanks.

Dino

That's a side-shifter (late) /4 shifter. The early ones are configured like a 911 with a socket-piece for that plastic cylinder. There's a piece missing from the 911 tower that fastens a bracket to the two holes on the right that supports the rod. The early /4 shifter has the same piece.

You'd have to use the early shifter with a tailshifted 915, and a later one with a side-shifted (converted) 915 unless you wanted to install a well engineered cable-shifter. Those will work in any installation.

This isn't a trivial installation since there are several ways to do this, and the 915 has to have it's R&P swapped to the driver's side of the case to get forward gears unless you want to run it inverted.

WEVO solution: This uses roughly the same rods you already have for a side-shift 914 transaxle. They do have to be converted but requires no gearbox changes in the main part of the case.

http://wevo.com/Products/TransmissionProdu...15SideShift.htm

Another: This kit is made by a guy in Germany. Apparently George Hussey (Automobile Atlanta) is sourcing them now. I'd buy it directly from the German dude if I could. This is a better version of the old Vellios side-shift conversion that approximated the factory 916 side-shift installation. NOT a drop-in solution. The case has to be machined internally for this to work.

http://www.autoatlanta.com/Porsche-914-Sid...t-Kit-srch.html

I've only scratched the surface so you have a bunch of decisions to make!

I bought the 916 kit from Martin in our members vendor section. The shift rod info is also covered in the thread.
http://www.914world.com/bbs2/index.php?showtopic=102988
I am using a 915 Renshift shifter with a PMS shift rod and firewall bearing with Martins 916 kit.

Thanks guys, terrific information. Really appreciate it.
Dino

I did some further searching and found the parts diagrams, and yes, there is a difference in the way the rods mount. If the nylon cup at the base of the 915 shifter is the same diameter as the 914's rod coupler, it'll work fine. Something tells me it isn't though. I'll have to look further.
Thanks again guys.
Dino

The cup part number is the same for the early 914 and the 915 shifter. I don't know about the early 914 shift rod though since i used the PMS shift rod and firewall bearing instead.

Hey Steve,

Yeah, I wish I had the financial luxury to do the same. His price is a bit steep for the rod. All in good time. For now, at least I know the part numbers and how it should attach. Not sure what I'm going to do about the tail/side shifter issue on the 915. It's such a straight forward thing from an engineering perspective, but it has to be done right, otherwise the driving enjoyment goes down the tubes since shifting is such a big part of the equation for having fun.

I've done A LOT of reading on the pros and cons of WEVO and Martin's solutions. And both are pricey, relative to my budget anyway.

Although I'm researching the shift rod issue and what to do down the road with the rear/side shifter solution, I am actually more concerned about the 1st and 2nd gear ratios.

I know a lot of guys run out of 1st gear (3.08) quickly with the 901 tranny, but it uses a 7:31 ring and pinion. The 915's 1st gear is a 3.18 with a 8:31 RP. Some guys are talking about just taking off from 2nd gear. This is made all the easier if you have the shorter 2nd gear from a Euro tranny. Anyway, this is all talk for now, as any of the these changes involve great expense in gears and labour for installation.

Thanks again for the insights on the early rod and I'll keep researching. Hopefully in the next year or so, I'll make more progress on my car. Life keeps getting in the way.

Thanks.

Dino

Here are two pics from the parts catalogue for the 915 tranny.
Dino
Click to view attachment

2nd pic, i read recently we are only supposed to post one pic per reply at a maximum of 500K.
Dino
Click to view attachment

It all depends on the size of the motor and what you are trying to accomplish. My first six was with a stock 2.7 with webers. I thought the stock 914 gear box was fine and I beat the hell out of it. I even did 1st gear burnouts with no problems, yes I was in my mid twenties and pretty immature. The 2.7 finally started to die after 15 years of abuse, so I replaced it with a stock euro DME 3.2 motor. On the track and autocross I would start out in second and I was quite happy with the stock 901 gear box, but it drove me up the wall on the street. Starting off in second was a pain and first gear was too low. The other gears were also too short. So I saved up some money and bought an 86 915 trans. The gear ratios should be correct for the motor, but it will be awhile before I get it on the street due to rustoration issues.

Hey Ron,

Thanks for the info. I think everything you said is dead on. I'm moving in the direction of eventually doing a 3.6 with a 915.

Looking again at the PMS kit, I noticed that it has the pieces I was thinking of.

Thanks.

Dino

Hey Steve,

I completely agree with your logic. It certainly depends on the engine choice. It sounds like you had a terrific time with your 2.7 901 combo. That a blast that must have been. It also sounds like you got bitten by the "more power" bug. I'm glad to hear that you found the 901 a perfect match for the 2.7. I think it's a great tranny as well, and perfectly suited to a 2.7 or lower sized engine.

I'm going with a 3.6, and I've waffled over whether or not the 901 can handle the torque. I'm pretty much resigned to using the 915. I've got my eye on a Euro tranny, which has slightly different gearing than the USA tranny. I like your choice for the 86 915. My understanding is that Porsche reduced the size of the bearings and thus had more aluminum surrounding them, which prevented the ovalling from occuring with higher powered engines like their 3.0 RSR.

Thanks again for the insights Steve and good luck with your project. Sounds like it'll be great.

Dino

If you haven't purchased all your parts yet, I have a ready to install 915 trans with Martin's 916 conversion and Wevo shifter for sale.