Auto to manual conversion - hands-on, practical advice please

[5l32v4c]

Does anyone know if the 1985 US 32v 928s needs to have the firewall modified for an automatic to manual conversion? I guess the easiest way to know for sure is to get under the car but I thought I read somewhere that, from 1985 on, the firewall was already configured for it.

If anyone has done this on my model year car I’d appreciate learning from your experience. What I’d prefer to avoid, though, are people telling me it’s a bad idea based on how it might affect the car's value, whether it makes more sense to sell mine and buy a manual or which transmission is better.

Let’s just assume I’ve made up my mind and want to plan the job. I might hit a roadblock that makes me change my mind (technically or financially) but I’m looking for practical experience, not opinions as many threads related to manual swaps tend to go.

[honerboys]

i did this swap on my 84 - so i can't comment directly on whether the 85 has the mount for the clutch master or not - you can pull away the carpet and rubber matting inside the car to check - you won't be able to see the mount from under the car - it's actually between the brake booster and the firewall - from inside the car what you'll see is really just a bump in the sheet metal and a mounting system just like a brake master - large hole with two smaller holes on either side (see pic) - even if you don't have the mount it's not that big a deal to put one in - assuming you can locate a junk car with one and you or someone you know can weld - placement of the welded-in mount is key - if it's off the pedal rod binds and puts off-center pressure on master leading to premature fail of master - all the other pedal mounts were already welded in at the factory on mine - i really couldn't figure why porsche put those in and not the clutch master mount - my clutch operates very nicely after a year and a half - good luck on this - if you have the necessary parts sitting around this is a swap worth doing - at least it was for me

[5l32v4c]

Thanks honerboys!

[JK McDonald]

I know of one owner who converted a very nice 1986 928 from an automatic to a 5 speed. In the long run he said later that after considering all the work, expense and months of down time involved, he should have just bought the car he really wanted.

The theory that applies in this type of project is that with enough time and money anything can be done.

Good Luck, Michael

[honerboys]

hey michael - if your friend took months to do this conversion he was not working on it very hard - in my case once the mount was welded in it took about 2-3 days to do the actual swap - i do agree that the expense of this could be prohibitive - in my case i bought 2 of these cars for $1800 - one was a manual the other an auto - so i had all the parts here and ready to go - if i actually had to go out and procure all the parts necessary to do this i would not have bothered as it would probably be thousands of dollars - as for the OP if he wants to try this and as i said "if you have the necessary parts sitting around" go for it

[JK McDonald]

Hey Honerboy - Part of the reason my friend's 1986 auto to 5 speed conversion took longer than expected was because of his job in the oil field I'm sure. Life in the fast lane. . He also had problems chasing down some of the parts from the assortment of wrecking yard cars he used. The original donor car was sold out from under him while out on a rig.

I'm sure having a complete sacrificial 5 speed car handy would have made his project easier (and much less frustrating). Personally, although I enjoy shifting through the gears of a std 928, when stuck in heavy Dallas or Houston stop and go traffic I prefer a slush box.

Michael

[SwedeInSiam]

Originally Posted by JK McDonald

Personally, although I enjoy shifting through the gears of a std 928, when stuck in heavy Dallas or Houston stop and go traffic I prefer a slush box.

Michael

That's when a Corvette 6-speed paddle shift would be perfect were you get both auto and "manual".
Wish there was an easy way to swap one in.

[Mal81]

Another consideration is which transmission do you plan to use? If it's an early one, like mine, know that the synchros are weak, and you should have gone through (is a permanent 'fix' available?) before you start your project. For now, mine is shifting well with synthetic oil, but it isn't even as much fun to go through the gears as my Isuzu truck is, if that helps describe these early transmissions for you. IOW, Shifts need to be made gingerly and slowly.

Traffic and the manual don't bother me (live in the LA area). The clutch IS HEAVY, but I can leave it in 2nd (or even 3rd) in stop and go situations and not shift at all right up to 45 mph or so. Same also applies in town.

Good luck,

-M

[Danglerb]

Unless there is something really special about the auto you have, sell it and buy the 5 spd you want. About the only exception I would make to that is if you plan on sinking HUGE money into a full non stock remaking of the car, then the tub you start with doesn't matter that much as long as its straight and not full of bondo.

[stepson]

Originally Posted by danglerb

unless there is something really special about the auto you have, sell it and buy the 5 spd you want. About the only exception i would make to that is if you plan on sinking huge money into a full non stock remaking of the car, then the tub you start with doesn't matter that much as long as its straight and not full of bondo.

+928