Good investment to convert 87 to 89 S4 from auto to manual ?
 

Hello all, I hope this question is in the right part of this forum. Please let me know if there is a better forum for this question. I have been seriously been investigating purchasing a 928 for a few weeks now, and have a basic idea of what I might want to do, but wanted your advice as 928 experts. Right now it is obvious that manuals are in much more demand than autos, and with the supply being inverse to the demand, manual 928s in general seem to bring quite a premium compared to autos. My plan would be to start with a well maintained but middle mileage car, probably between 90 and 140k miles. I would definitely not want to disturb one of the well maintained low mileage cars that would only get more scarce over time. The plan would be to use all existing 928 factory parts, and try to make it like it came out of the factory as a manual, even the small details like the gauge cluster. People wish there were more manual 928s in general, so I would be hoping to increase their numbers a touch as authentically as possible. I know the project and maintaining a 928 in general can be costly, and I'm ok with that. My real question to this community is, would the "928 market" and 928 enthusiasts see this as added value above the same 87-89 s4 with an auto, or would the car be less attractive/ valuable since it had been modified from original? The last thing I want to do is spend a bunch of time and money on a project like this, and end up with a car that is worth less than what I paid for just the car, and a bunch of people pissed at me for "ruining" a nice car. Thoughts?

I don't think it will be certain to add any value - most buyers would likely be a little concerned about such a major modification. Usually these AT - MT modifications are not done super well and so aren't really comparable functionally to an original MT car. If this modification was done by a recognized 928 mechanic that would have some value add (but would be very expensive and I'm not aware of any who would do this for you). You may also get some better traction if you documented the conversion here on rennlist step by step pictorially and were clear on all the changes and sourcing to bring it to stock manual condition.

However the real reason for most to do this is for your own enjoyment. If you then participated extensively in local 928 events with the car you could build up some (local at least) trust that the conversion was robust over some number of years. In the short term without attribution to a 928 expert OR a history of successful operation I think it likely just hurts value.

Alan

Modified cars are almost always worth less.

Unless you can get an auto car with a tranny that's gone bad and a manual car that's been crashed (or something along those lines where you get both cars for next to nothing), the cost of the cars plus the time/effort of doing the conversion would not pay for itself.

I don't think you'd end up with a 'bunch of people pissed at you' for it, except for a few purists who seem to exist just to get pissed off at others.

Something to remember is that the 928 is a GT, not a sports car.
The auto 'fits' that role quite well. One of the reasons there were so many made.

thanks Alan, great reply. Definitely seems like something that if done, needs to be done right and with care. Like the idea of participating in the forum. I would enjoy the project but would also want to know the Porsche community appreciated the project, as there will never be more 928s, only less. We will see, a lot depends on what cars pop up for sale.

My suggestion if you want a 5 speed buy one
put the money you didn’t spend on a conversation into anew set of shocks and tires and drive the car

No.

The parts (cost) and time/effort sums up to more than the difference in price between an auto vs. man S4.

I have 3 auto and 3 manual 928’s. I prefer the autos.

thanks all for the input, i appreciate it! if i end up buying something, i'll let you know! let the hunt continue........

IMO the only manual conversion worth doing would be to the Corvette Z06 6-speed transmission that 928 MS sells the kit for and why I did that to my existing 79 5-speed. The much smoother and faster shifting from the more modern transmission makes the car faster and with a modified powerplant the gear ratios work much better with the extra HP, but I'm not a purist by any means and mod my cars for my own enjoyment, which is why my 928 also doesn't have a roof and has 911 hardback sport seats in it.

https://cimg9.ibsrv.net/gimg/rennlis...572251a78e.jpg

financially no. The only mod to the body of the car is really the firewall mod, and it's difficult to screw that up. Cutting the tabs in the shifter hole is the only other mod to the body. The rest is just swapping parts. I've done the auto to manual conversion and it was easy to do. I'm in the middle of the mod to the 6 speed and it is a multitude more difficult.

investment for smiles per mile? absolutely. The pay off is every time you drive it.

In reality, there are so few auto to manual conversions (probably less than 20 worldwide) we don't really know what the impact will be on value to a buyer after the conversion. even fewer of the 6 speed conversions (5 or less). It really boils down to what the owner wants.

Love the seat transplant! This is just the 2nd one I’ve ever seen done, the other used a set from a Cayman I think. Very good idea, at least to us non purists. I have to believe that the Vette transplant is a blast, but costly for replacement rear tires!

Would you mind posting a few more photos of your cabriolet? A side view at least.

golden advice.

I have this exact swap in mind. I have an 87 auto with rubstrip delete and a 43k mile 89 manual donor with a salvage title and dreadful reconstruction effort. Cannot and wouldn't want to title it for the street. In its defense, it has an X-pipe, no cats, GT mid-mufflers and RMB. Loud as expletive deleted and fast as expletive deleted. :-) wicked.

In addition to master cylinder, pedal and shifter modification there is a wiring change at the CE panel and spare tire well to get the reverse lights to work. You'll need the starter lockout relay jumper, too.

I'll acquire the master cylinder mount from Carl. No need to reinvent the wheel.

I do this because I want to, not because I expect to make money on it. A/T to manual swap values are in the mind of the beholder. Effort is not insubstantial. In my case the entire drivetrain is being swapped.

If you want a manual, buy one - great advice.

Thanks a ton for all the input!

Just as a side note:

Ya didn't get any 'hate', didja? :D

Nobody railed against 'destroying the originality' with this.

You were given practical, realistic advice about it.

The community on here is pretty cool.

If you want to find a car, start with the 'for sale' sticky thread. Start at the back and work towards the front. Older posts and ads aren't removed or marked 'sold', so anything more than a few months old could be 'stale'.

When you find one, make sure you look it over properly. There's a link to a good PPI checklist in Worf's (Dave's) sigline, post #6.

Do not convert an automatic to a manual. You will spend a gob of time and money and end up with a car that not many will want or buy, with greatly reduced value.
If you want a manual transmission car, buy one.

+1
The only time such a conversion makes any sense is with a car you already own and are too attached to sell it. Even in that situation it's not a good financial decision.
Buying an automatic with the plan of converting it makes no sense at all.

Building a 100% track dedicated full race car is a different story.

If you look at the sum of the comments it's pretty clear that the terms conversion and investment should never be used in the same conversation as a 928. Hacker hit the nail on the head. If you have an attachment to a car and it happens to be an auto and you want a manual then it may be the ticket. If you follow the advice, of buy a manual, when you look at the money you would spend to buy, you may well end up with something other than a 928. These cars are a journey and not for everyone.

no offence, as I do very much like 928s but unless it is a low mileage museum quality car, 928 and investment should not be in the same sentence. These are very old cars that have extensive electronics and wiring is now 40 years old. They require a lot to bring these cars back from unmaintained, and they are not easy to sell, let alone a converted car. Go get a well maintained manual 928 that someone else put loads of money into and needs to sell and enjoy.

I don't understand why people say the conversion devalues a 928. I don't see the logic. There are many much more invasive things done to 928's that doesn't devalue them. I would say that track time in a 928 devalues it more because of the known impact of TBF, but people do it all the time.

For a peak into the future of 928 manual swaps, Google the sportomatic 911. Most converted, with conversions demanding higher prices.

SPORTMATIC.................That's a blast from the past.Did a few of those conversions way back when.
I had also thought about doing a auto to stick conversation on my 79,started to acquire some of the parts,but could never find a "good" used trans to finish the project.I found a lot of "used up" transmissions,so I went with the 4 speed auto update instead.

I'll just drop this right here:

https://rennlist.com/how-tos/a/porsc...mission-384147

thanks drooman, i really like this comparison idea. i was having trouble finding a much clear info on the topic of the value of the conversion, except this link:
https://www.porscheclubgb.com/region...11-sportomatic

it basically says that the manual conversions used to sell for higher than sportomatics, but now that all of the cars are so old the trans type doesnt factor into value very much. is this what you were hinting at you saw happening, or something different?

thanks for the link! i think the how im not so worried about, as there is a lot of good documentation, including the link. Im still trying to decide, "should i?"

Sorry to say but, No.

Many here have correctly pointed out that if you want a manual S4, buy it, and buy the very best one that you can afford. But that really wasn’t your question.

Based on your first post you expect to make a profit from the conversion. The premium that a manual brings on a car like you are considering is maybe $5 - $7K. But keep in mind that is for a factory manual car, not a conversion, and a car in very nice mechanical and cosmetic condition. I’ve not calculated all of the parts and time costs, and there will be many that you don’t know about at this point having never “experienced” S4 ownership, but I don’t see it making money for you.

Good luck.

I did an auto to manual conversion several years ago.Used a very nice 83S. and a crashed donor car. Did I think it would increase value? Nope. Did I give a crap about other opinions? Nope Did it increase my personal enjoyment of an awesome car? YEP !

Read this thread with interest. many good inputs here. The only one that made me scratch my head was this one:
Here, Alan says that if the conversion is not done well, the end product may not have the same functionality as a factory MT car. At least that's the way I read it.

I would only add that, if done well with 5-speed parts from a 5-speed donor car - there is no reason it will not have the exact same functionality as a OEM MT car. Secondly, if an AT to a 6-speed conversion is done with a properly engineered kit, again, it has been shown that all functionality of a factory MT car is attained - and arguably even improved upon. The carbon-fiber synchros of the Tremec T56 trans shift as smooth and easily as a hot knife through butter, and are a huge step forward from the old brass knuckles in the 928 Trans. In addition, after having done so many of these conversions to a 6-speed; the gear ratios in the T56 and the FDR in the attached Getrag LSD are wonderfully suited to the 928 power band. All 6 gears are useful, and FUN. The finished car accelerates like gang busters!

Do the conversion because it may enhance your resale value? I wouldn't. Whether it increases the sale-ability of the car or harms it will be dependent on the buyer. But I wouldn't do this conversion as an investment.
Do the conversion for fun and because you really want a MT 928? Absolutely.

Were I bent towards a manual conversion, the 6-speed upgrade would be a no-brainer. Know that you can add carbon-fiber syncros to the 5-speed 928 box via a Greg Brown rebuild, if you want to stay original. Otherwise, six speeds with at least one of them overdrive is very appealing for those of us that go touring. As Carl mentions, the ratios in the Tremec box are well suited for the 928 torque curve. Plus, internal pieces are easily available, something that can't be said of several the Porsche gearbox pieces. Know in advance though that the value of such a conversion is in the driving experience. Like most non-factory mods, the payback at sale time will depend a lot on the particular buyer, and by whom and how well the conversion was done.

With everything else I do on my 928 if I could not have done the auto to manual conversion as well as Porsche had done it, I wasn't going to do it. Fast forward a good number of years, and after breaking a couple gears as well as splitting a case, the thought of stocking transmission parts was not appealing to me, and when I made the move to go with an ITB setup and hotter cams I decided that the 6 speed and the aftermarket support was much better suited for what I wanted. Gaining the extra gear was a draw but the stronger gearboxes and the range of gear ratios was the big deciding factor as well.

+1 on this. Being able to run 85 MPH at 2,000 RPM on a highway cruise is pretty nice.