My Notes on a True Manual Steering conversion on my '01 C4 Cab

Hi all. About a year ago I reached out to Martin of 944-manual steering fame, and asked if he had thought about doing something for the rather populous 996 community (at least as compared to the 944 at this point). He had thought of it, and offered to sell me his first attempt at cost. The power steering that had rolled Dr. Ferdinand over in his grave like a sufferer of bed-sores was now slowly-but-surely crushing my own soul into the shape of an accountant (or maybe it was an orthodontist--I can't recall for certain), so I was in no position to refuse. I paid up, but hastily. These are my notes. 2001 C4 cabriolet; Goodyear Exhilarate, 235/40R18 & and El Crappo Chumpness 205/50R17 front tires (oddly, no detectable difference in steering effort); Alleggerita wheels; Nakamichi stereo head unit. The rack fit like original equipment. My nearby and well-respected Porsche shop was impressed with the workmanship. It is very hard to move around in parking situations, in spite of re-gearing Some precision and quickness of steering has been lost due to the ratio change The ratio change was about 30% shorter gearing I would never consider auto-crossing this, at least with stock alignment--again, too hard to make quick, sharp turns Would likely make an excellent car for a real track I enjoy the road feel immensely I will eventually (but before too long) replace my control arms with caster-adjustable ones to ease-up the low-speed resistance I wouldn't have believed it, but the elimination of the pump (kept plumbing) has improved very-low-rpm torque (I don't stall on hill-starts now) Happy to answer any questions.

So you're running crappy mismatched tires, some precision and quickness of steering has been lost, it's difficult to move around in parking situations, you'd never consider auto crossing etc... Sounds like a real "upgrade"... No questions here...

As long as you're happy with it...your car, after all. Definitely not something I'm interested in pursuing...when I decide it's time to ruin the driving experience, I'll take the easier/cheaper route and remove the refrigerant from the A/C and adjust my coilovers to the "bruised kidneys" setting.

^^ LOL....yep. Hmmm.. I remember a time when power steering was considered an upgrade. Sounds like we are going backwards. To OP, what size serpentine belt works for that...eliminating the power steering pump? Just curious...

I'm very interested in doing this after reading the about the 996 CSR. Years ago I converted my PS to MS by simply looping the lines and loved the feel. How did you guys decide on the gear ratio? Did you put an idler pulley in place of the pump?

So "upgrade" is in the eyes of the beholder. And to clarify, no one but I knows if I was running mismatched tires, because I didn't tell anyone what I was running in the back. I did mention that I tried both 235s and 205s on the front so that I could at least provide input from the perspective of both narrow and wide fronts--both would have their (dis)advantages vis-a-vis my offered commentary. I'm not sure what impact mismatching F/R tires would appreciably have on quickness of steering anyway, unless you went really crazy in the back. But I don't claim to be an expert. By the way, Exhilarates are by no means crappy for that class of tire, and are rapidly working their way toward the top of both consumer and professional reviewers alike. Further, I believe I mentioned that I really like the driving experience in general. But that's not really the subject; my notes are posted here in case anyone considers the "upgrade"--they should know what they're getting into and what they want to get out of it. I also mentioned that I had an interest in trying the manual conversion and that I was going to be a test pilot. In other words, I knew going in that I wouldn't know what I'd get out of it. So I'm not complaining, I'm offering the benefit of early insight into what will likely get asked about soon enough anyway (indeed it has already been asked about many times). Re: some (good) questions and points: As luck would have it, there is an eliminator pulley that worked without modification or change of the belt. I have the link for it and will post later, but all I had to do was remove the pump, plug that end of the hydraulic line (left it in place in case I hated the conversion and wanted to revert), install the pulley, and put the same belt right back. The gearing change and the design and machining are all the brain child of Martin from mwthemachineshop.com who has done 944 conversions for a while now. I'm guessing he looked up the gvwr and weight distributions and then applied a best guess from experience. Again, I'm a test pilot, so I think we both expected that it could require some tweaking up or down. But hard as it is to turn in a parking lot, I don't think the solution is gearing any shorter, as it would start to require too much input rotation to make sharp or abrupt turns. I remain somewhat optimistic that a few degrees change in caster will be a better path for that. But that of course would come at the expense of ultimate handling capability--since caster translates into camber in a hard turn--and a little bit of road stability (i.e. return-to-center). Some additional perspective, per the eye-of-the-beholder line of thought: I kid about the feeling I get when driving a power steering Porsche, but that's what it means to me . I've had a 912E which was an absolute dog of a performer, but I absolutely loved it. I thought it was the apex of german engineering--it's greatest achievement. Simple, rugged, honest, efficient, reliable ... I could go on. Since then I've only driven my friends SC model, which is in some respects not all that far off (though very far off in others). When I came across my 996 I wasn't interested in getting in one--just in getting out of my '01 TT Quattro (great car, but a serious mouse issue). I liked it a lot more than I thought I would. I've even grown to legitimately like the fried eggs (now I've done it...) But I needed a daily driver, and I needed to love my daily driver, and I hated the experience of the power steering in this particular car. It felt incongruous to the rest of it. But clearly there are advantages to modern power steering. In fact I'll freely admit that I seriously questioned whether I'd stick with the manual steering for the first month or two. That 8 degree positive caster that's making my parking garage a lot less fun--without power steering--makes high-speed cornering a lot more fun--no matter what. That's why Porsche gave it to us. And you get the best of both worlds with power steering, and honestly the 996 implementation provides a lot less slop between clockwise and counter-clockwise input than most, and a lot more road-feel than most. I just really like old-school stuff, and simplicity. So I wanted to give it a try. A few months more, and with the right tires on, I'm getting very comfortable with my trade-offs, and really enjoying it. But I don't think this is ideal for everyone. I haven't auto-crossed in a very long time, but I suspect the input effort and the shorter gearing would be a challenge that requires some creativity to overcome.

I find it funny that I had bookmarked Martin to ask about a 996 MS conversion since I kept running into him searching "Porsche Manual Steering". There was another company that specialized in hotrods but did custom manual racks too. Since you've already done the legwork and got it installed, I know which vendor I'll call. Very interested in the special pulley though. I wonder how the engine would feel with an under drive pulley plus eliminating the PSP.

did it five years ago ... http://986forum.com/forums/boxster-g...ring-rack.html not sure what martin is up to these days; in the case of my rack he just reinforced the torsion bar and replaced the hoses w grease nipples - no change in ratio. note also that tarett is making a dummy pulley now that gsr isn't around any more, but as noted in the thread i linked only required if not running AC. also note that the porsche dummy pulley only works on dfi cars. 986 should have more weight on the front wheels than a 996 so y'all should see less steering effort than me (also, as noted, i was on 245's).

Tarret engineering indeed. Https://www.tarett.com/items/996-997...pdk-detail.htm I still run my AC with this setup.

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Your thread from back then was a significant inspiration for this endeavor.

be aware of your toe settings as well. i gave myself a bit more toe on the front and the steering started to fight me a lot more.

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Mr. Radium King in a different thread you did the best write up on fuel trim I have yet seen, and I reposted it on other threads and included your name to give proper credit. Uh-oh the Deputy Thread Police want to give me a citation now...

hey man, thanks. and to the OP i love the extra power and road feel the manual steering provides.