How To: Convert your AWD 996 to RWD

I've seen the topic come up several times around here, so I figured I should make a How-To thread for everyone. AWD removal is really easy. It literally can be done in your driveway in a few hours with just hand tools. Having the car on a lift is helpful, but not required; I had my car on jack stands. Unfortunately, I didn't take any pictures while I was doing it. The gist of the process is: 1. Put the car up in the air, I recommend at least 12" between the bottom of the car and the ground, more is better though. 2. Remove the under trays (all three of them) 3. Remove the front wheels 4. Remove the retention nut from the front axles (32mm IIRC) (this is probably the hardest part of the whole deal, that sucker is on there good!) 5. Remove the 6 bolts on the inboard side of each axle 6. Move to the back of the car and drop the front support for the transmission near the output flange for the driveshaft (you might need to support the transmission with a jack) 7. Remove the three bolts that hold the driveshaft to the output flange 8. Loosen the center support for the driveshaft (4 bolts) and remove the two bolts that attach the differential to the front support 9. Support the differential and remove the center support (careful not to break the plastic clips that hold the coolant lines in place) 10. Tilt the differential down and slide the driveshaft out, set aside 11. Support the differential up again and remove the studs that go through the front mount for it 12. Once the studs are removed, you should be able to tilt the diff down and wiggle it out, be careful not to bash the aluminum coolant lines on the way out 13. Remove the axles 14. Disassemble the outer CV joint to get the axle stub separated (this is a little tricky, but there are a couple threads on here about how to do it) 15. Clean the axle stub and remove all grease 16. At this point, I painted the CV part of the axle stub with several coats of Plasti-Dip to protect it from corrosion should I ever want to convert the car back to AWD. I should just be able to remove the coating with some paint thinner and not have to worry about surface rust 17. Reinstall the axle stubs and torque them back down (130 ft pounds or something like that?) 18. I put the center diff support back in my car, not sure if it's needed or not. It wasn't very heavy and it seemed to support/protect the coolant lines as well as possibly provide a little bit of chassis bracing 19. Reinstall the under trays and go drive your car I'm sure I missed a thing or two, but once you're under the car looking at stuff, it's not particularly complicated. If you can do something like a water pump replacement on one of these, you can do this. Reversal is pretty much the same process backwards. IMAG1390_zps4451c139.jpg Everything out: IMAG1391_zpsfd9f3a8c.jpg I love the car with the AWD removed! My butt dyno can definitely feel the missing weight and reduced parasitic drivetrain loss. The front wants to understeer a bit now under hard cornering, but I think I can remedy most of that with different alignment settings. ABS works fine, as does PSM. Since the whole AWD system is mechanical with no sensors involved, the car has no idea anything is missing. PtTownsend2013_c_zps3316e23f.jpg

Here is an arguably subjective question. Was your fuel economy improved or did you spend too much time with your foot in it to notice? Jason

Awesome write up Darrick. Thanks for posting.

Once the initial novelty wore off of being able to spin rear tires again, I have noticed a 1-2mpg increase in fuel economy. I used to average around 18-20 with it and lately I've been getting 20-21mpg (city driving).

Very interesting... I get ~18MPG on a Ballard to Redmond commute across 520. Maybe this is in the cards for me this summer.

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Ugh, you couldn't pay me enough to do that commute. My Renton to Redmond commute via 405 is bad enough.

Haha well I have driven from SeaTac to Redmond on 405 after flying home early morning and ended up right in rush hour. The difference is MARKED. 405 is stop and go the whole way, whereas 520 is rolling slow the entire way. The only diff is that I have to pay that damn toll.

The freeway part isn't too bad, it's the winding down into Ballard that would make me want to stab people. I'm amazed how many people live in an area that is about as far from freeway access as you can possibly get.

You sir have hit the nail on the head as to why I live here. You have to mean to go to Ballard. There is no driving through.

Darrick, any idea how much weight your Pcar lost with this conversion?

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Point of reference for C4/C2 comparison. My Ballard to Bellevue commute averages 23.2 mpg in a 2001 C2 Cab. 5 mi of city street and 8 mi of fwy/520 each direction. Travel east at 6 AM and west at 8:30 PM.

Redmond to Kirkland, 6 miles each way in a 2002 C2 6 speed. Sub 14 mpg in the city, 23 if it's all freeway.

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I didn't put everything on a scale, but according to other threads about it in the Turbo forum, the removed components weigh about 80 pounds. The AWD system is quite impressive in how compact it is.

Could shed a few more if the transmission is wapped out.

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A C4S is 276 lbs heavier that a base C2 for the same year. So essentially what has been done is to make a slower C2, i.e. one that is still ~200 lbs heavier than a C2. The whole of a C4S is to make a car that looks like a Turbo, but doesn't perform like a Turbo. Really it is just pretty much a poser car: Turbo looks without Turbo price. While owners don't call them "poser" cars, they all say they bought the C4S due to styling. It basically has about that same weight with a lot less power as a Turbo. If you want the better performing lightweight 2WD version, you just get the C2. I am very confused and not really understanding the point to this thread. From my reading I am guessing this is a thread about gas mileage? For gas mileage, I would get 8 mpg on the track, 16 mpg in the city and 27 mpg straight cruise @ 75 on the highway when I had my 02' X51 C2. It had Euro GT3 front seats, no rear seats, Techequipe rollbar and Fabspeed mufflers. Weight on the scales with the 18x9/18x11 CCW race wheels was 3060 lbs. Swapping the seats from high-backs to fiberglass Recaros and mufflers from the OEM chunks of lead to Fabspeeds dropped almost 100 lbs, giving an idea of how heavy those components are.

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Don't rain on the Captain! He just wrote a "How To". He's modding his frickin ride. Accept it for what it is. He doesn't care about it being faster. He's got a great looking C4S that's 2WD; that weighs less, and in turn, a little better mpg's. A lot of P-car owners would desire to have a Widebody look in a 2WD configuration. "Turbo look without the Turbo price"? That was PAG's idea. They sold the idea and customers bought... ALOT. OT, I love 997 GT variants and the new 991, but it's not in my current budget to sacrifice getting one. I need back seats, so it's got to be a Turbo for now. I do not care to improve my current mpg's; 15 in my DD driving. I put less than 8000 miles peryear, so I'm good. But with a Turbo, if I need to merge onto the highway, and get past a few cars, I can do it faster than just about EVERY car out there.

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I would venture a guess that a 2wd C4S would pull more Gs on the skid pad, given the much fatter tires and wider track. Plus you get better brakes. The chassis weight difference should be minimal, as far as the extra sheet metal goes.

When I put my car on the scales at Laguna Seca, my car weighed in at 3607 or 3613 lbs. I don't have a sunroof. Standard Seats, 1/4-1/2 tank of gasoline, sans spare and hollow spoke wheels with R rubber. Whatever the published weights are, they're unobtanium. Will 276 lbs make a difference? You betcha, especially on the front end. Now if you ditch the heavy memory power seats, it'd be that much better. But then you make up for it a bit by adding in a cage. It's all give and take. For example, my Audi S4 Avant, without Spare was 39xx lbs, where the advertised weight was in the neighborhood of 3600 lbs.

Does anyone know how much this would cost to re-install if you had a independent Porsche mechanic to install it? Or a Porsche dealer?

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If you damaged any parts (I would need new half shafts, for example, due to my...disassembly method), that would need to be factored in. I think 2-3 hours of labor would be plenty to get the components reinstalled. Maybe a new flex disc while you're in there, but labor would be the only real expense if you keep all of the parts.

My front diff has experienced the displeasure of bearing failure, and while I search for a trust-worthy donor this is one fantastic option. 996 C4S' simplicity never ceases to amaze me... I can't express enough about how glad I am to own my childhood dream car, and not have it be a major PITA to maintain. Thanks Capt. Obvious for writing up the process!

This is a good write up, beautiful car! For those asking why- go look how much people pay to make their narrowbody look phat. You get many improvements in the C4S other than the "turbo look for posers". i just took out the cardon shaft for now for experimental purposes (drivetrain noise isolation, playing with tire sizes, etc). At this point I see a "C2S" as a 996 version of the GTS- all the luxury and options of a turbo with cheaper N/A motor. FOR THE RECORD THOUGH: Anyone interested in trying this- the FRONT STUB AXLE TORQUE is 340 ft lbs- not the 130 mentioned above. And replace that large 32mm nut everytime you loosen. i am interested how you "modified" for front axles to steal the stubs- do you have pictures of this? I always guessed a C2 stub would fit in the knuckle- but have not measured the two side by side to confirm. Buying these couldn't be TOO expensive and saves you the hassle of modifying parts you may want later.

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I disassembled the CV joint and used the stub (I coated the exposed stub in Plastidip to prevent rust from forming, it worked wonderfully). This is something I should have taken pics of, but if you do a search, there is a how-to thread about rebuilding your axles, which does have pics. C4 and C2 have different front hubs, so I doubt a C2 axle stub would have worked, though that is only a guess.

Interesting write-up. An idea if it is this east on the 997?

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997 AWD is different. https://rennlist.com/forums/997-foru...-awd-work.html

Just to add to this super helpful thread: RWD is done, Differential and Axles are out, Stubs are in...I guess I'm a 996 C4-2S now Quick bang to loosen the axles. Axle bolts off. Axles disconnected. Diff hanging by support bracket. Getting ready to drop. Out.

Your front lip has seen better days. LOL

Great Write-Up! You may want to make step 4 step 1. Removing the axle nut while the front wheels are still on the ground would likely be easier. Just putting that out there, because it is a mistake I have made way too many times.

Hello, I’ve got a question, please: I’m looking into buying a Carrera, preferably a C2, but all the cool colours and the nice options come with a front diff. So I found this thread! Would the C4 be very different from a C2 after removing the front transmission? And PSM would just operate on the back, correct? Captain Obvious, did you solve the front end problems after a new wheel alignment, please?

If you're comfortable spending a ton of money then do it. REID performance makes those stubs and machines off the extra meat not needed so that's why they are a little lighter. But don't listen to those who say you need to "hack" apart your axles. It takes some work for sure, but it's relatively easy to separate the hubs from axles without damage at all. And they go right back together when you want.

I am looking to undertake this project and turn my C4S into a "C2S". Not having a garage or access to air tools, is there anybody in the Denver area that would be interested in lending a hand or space for the conversion?

Pm sent thanks for all the info captain!!!!

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The C4 has less front trunk space than a C2. PSM operates through the brakes - independent of the drive components - so removing the front diff shouldn't have any impact.

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I find that PSM is much less intrusive now that the front wheels are completely undriven. Still works fine - but less frequently.

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Interesting. I guess that removing drive to the front wheels changes the dynamics of each wheels speed when traction to the rear is lost. My rudimentary understanding of PSM is that it essentially works by monitoring each wheels speed and applying braking independently to each wheel. One thing I'd be curious about is whether it takes into account the impact of braking one front wheel to force drive to the other. If thats the case I could see that removing the front diff would have some impact on its effectiveness. I honestly can't remember if PSM was available on C2 models - and if so I wonder if the software is different or the same.

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PSM is available on C2. Can't confirm whether the program parameters are the same, but I'd expect they are. It's just using the brakes and reducing engine power to reconcile wheel speeds to driver inputs.

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In addition to differential braking, PSM also retards engine timing for some slip situations. However, I do not believe that PSM is "on" long enough to direct power to the other wheel (like active brake differential in other cars).

Well I took the plunge yesterday and pulled the front differential, cardan shaft, and axles. With the use of an air impact wrench, the axle nuts came off in about 20 seconds and HIGHLY recommend anybody doing this conversion to find a shop with air tools. At this point, the big hangup is removing the c-clip on the outer end of the stub axle. No matter what I do with pliers or screwdrivers, I cannot get it to lift off the groove and release the axle. Everybody is tired after a long day - back at it today.

Looking forward to hearing your thoughts about the conversion when you take your C2S out for a drive. Looks like your your assistant is hard at work.

How about getting two new CV joints and leaving the half shafts complete? How much would they cost, non OEM? See if it�s worth to spend some money and save some frustration, me thinks. Also because, smacking or heating them up you�ll probably damage them anyway.

That is an option, but it's an expensive route to take when taking apart the factory CVs is free and you are unlikely to damage anything if you do it correctly.

Well I'm genuinely impressed with those of you who were able to expand the c-clip and just tap the race to remove it from the axle shaft. I spent 4 hours playing with it on Saturday, and another 3 on Sunday. No luck! Screwdrivers of all sizes, pliers, snap ring pliers - no matter what I did the clip wouldn't move inboard or stay expanded long enough for me to disassemble. I finally gave in to brute force, placing the axle in a vice, expanding one side of the clip and beating the living daylights out of the race with a hammer. With that kind of persuasion, the race started to move back and finally broke free. Elegant? Not in the least bit. Effective. It sure was. With the race out, the stub axles were easy to clean up and reassemble. As others have said, it's amazing how compact the AWD system really is and it's an amazing piece of engineering. I ended up reinstalling all the braces underneath the car, and taking the additional step of removing the front differential mounting bolts and hardware associated with the system. I cannot give an accurate review of the car in RWD, as I haven't really gotten on it yet. First impressions (just driving around town and on highway) are: I can feel the weight gone from the front. Steering still feels tight, but the car feels like it's floating more at highway speeds and through corners I feel the transmission more. Not sure if I need to re-tighten the transmission bolts, if the trans needs to settle now that it's not connected to anything upfront, or I'm just overly sensitive, but I'm much more aware of my shifts. Shifts feel slightly clunkier...hard to explain and I'm keeping an eye on it The car still grips like hell. Porsches are just amazing (and overengineered) machines. The car still feels so planted at moderate speeds and it's not unruly by any means (you C2 owners can attest to this). I intentionally lifted the throttle on an empty onramp and the rear end felt planted. Where the AWD car wouldn't change feel at all doing that, the RWD car has a slight "sway" to it. Not dangerous or unnerving, but you can feel the weight shift of the back end more. Running 295s in back, I think it's going to take a lot to really break the back end loose. I'll report back after I drive the car for a month and can push it more. Happy so far as I'm looking for a more visceral feeling and to really connect with the car by stripping out as many driving aids as possible. With the conversion done, I'm one step closer to that goal! Cheers, Andrew

A reminder that removing the AWD may result in a slower car. The C4S was faster than any C2 in factory testing on the Nurburgring. See here on the bottom of page 81. https://rennlist.com/forums/996-foru...l#post14125769 With the 80 lbs removed, it should accelerate faster at slower speeds, and it may be faster in lower speed racing. The stability provided by the AWD, and I suppose extra drive traction, are probably what makes it faster at higher speeds. Or maybe it is the fatter tires or better brakes, who knows. Does anybody think they put AWD on every 996 Turbo for some reason other than to make it a faster / better car?

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I see your argument, and raise you the 996 GT2.

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The GT2 must be quite an experience, I don't think I could handle it. And the C4S is such an excellent car, and plenty for me.... after 1.5 years still loving it. I also should add that the AE is undoubtedly faster than the C4S. I was out driving and thinking about this subject, and I also like the safety that the AWD adds. The viscous coupler (VC) is first class technology, when a wheel spins it transfers the power to the other wheels. So this car is safer whenever you are driving, and especially useful in poor road conditions (rain, snow, loose surface, etc). I think Porsches have always been made "rough and ready" and to me the AWD adds another dimension of utility and safety. Oddly I don't think I've ever heard of VC failure, or the failure rate is very low.

Good work Andrew. I would suggest talking with your indy to get the car dialed in now that you've removed the awd system. My indy recommended adding a GT2 rear sway bar when I went 2wd. Not sure if you track the car but another benefit/side effect of 2wd is you are less likely to overheat your steering. This was problem for me after 3-4 track sessions with awd intact.

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Thanks for the thought! Off to my indy tomorrow to discuss full suspension refresh, and will absolutely ask about the GT2 sway bar. Highly considering PSS10s and Powerflex bushings all around, but judging some of the bills I've seen, I may be exploring other options.

Very interesting description, any gues if 997.1 has the same process for 4-to-2 conversion? Which is even more interesting - is there an easy way to make a 4wd carrera s out of a c2s by combining some sort of a kit...

997 AWD system is much different as far as I know and this process would not work. As for converting a C2 to a C4, it would not be possible without extensive modifications to the chassis of the car to make room for the AWD components. Also, the cost of acquiring the parts required for the conversion would be prohibitive (read: significantly cheaper to sell the C2 and replace with a C4).

Thank you to everyone who posted on this thread, great instructions and photos assisted me in removing the front diff from my 2002 C4. I was starting to get "rough" noise up front when accelerating while cornering (for some reason left turns worse than right turns) then the occasional click/grind rotational noise up front on a slow speed right hand turn (neighborhood speeds). Thought it might initially be a wheel bearing but with everything I was reading I settled in on it being a bearing or something else in the diff up front. I'll be doing a rebuild at my leisure of the front diff so wanted the car to be functional while I took my time with that repair. Only other point of interest might be that it's a tiptronic transmission... I'm not seeing any special instructions for this conversion with the tip transmission, seems like it should be ok as is? I do hear a little more of a different noise when accelerating through a corner, possibly transmission location and coming from the drive shaft being disconnected and missing? Andrewck notes possibly more noise in his post above as well. The car is different without the front being driven through corners. Not sure yet if I like it as I'm used to the AWD kicking in in the corners. As i'm planning on going back to AWD I won't be doing any suspension work to account for the C2 although if this was going to be a permanent mod I can see the need for some adjustments for sure. Any feedback on the "extra" noise or tips on issues I should anticipate with doing this with a Tip transmission are appreciated.

�Poser�, guy (or kid) is hilarious. Nice to have option if I want to mix it up. Thanks for the post.

The process is affects on the car are the same whether it is a Tip or manual. Did you simply remove the cardan shaft, or did you remove the entire front diff and disassemble your axles? If you just removed the cardan shaft, you're still going to hear noises in the front diff because it is still being rotated when you drive, it just doesn't have any power being sent to it.

I don't normally hang out over here in 996 land but I have a 997 I am getting ready to do the AWD delete. From the forum members I talked to it sounds like the job is very similar. https://rennlist.com/forums/997-foru...wd-delete.html

Thank you SO much for this post. And pardon me if the question is redundant - Just 1 question. Is your car manuel just to double check ? If not, is the process any different for a automatic transmission? Since I have the automatic transmission on my 96000 mile C4S I want to be double sure it will work out just fine if I remove everything on the Front diff and axels…THANK YOU again!

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HI Just to be clear. You removed your front DIFF and have a automatic transmission? No parts required when everything is removed? Before I remove everything I just want to be 100% sure nothing is required on the removal. Thank you.

has anyone weighed all the AWD components? Curious what the total savings is.

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Hey Andrew, reviving an old thread as I�m curious how you have been enjoying the RWD conversion. My front diff has a slow leak and I�m not confronted with either rebuilding it or just having the shop take it out altogether. From what I�ve heard, a lot of people like the RWD feeling so I�m tempted to just have it removed. Any additional comments you may have would be appreciated!

I�m not Andrew but I can comment on two things in this thread: First, weight savings is around 85 pounds. The C4 cars weigh something like 105-110 more but some of that is the Viscous portion of the transmission that can�t be removed, frame bracing, and some other slight differences. I have driven for 1.5 years without the AWD system. I honestly miss aspects of the AWD but there are some pluses to RWD. The C2 feels a little quicker in a straight line, lighter on its feet and the Mpgs do seem a little better. For Turns I might give a slight nod to the C4. There was something about leaving from a stop with the C4 that just always felt awesome though. 996s in general feel planted but the C4 has an extra dose of that compared to the C2. Also I�ve barely driven in the snow in either configuration but the AWD was slightly better in my brief experience. I had to deform a front shaft and sold off my front diff to someone in need near me so there�s no going back without tracking down the parts.

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I don�t miss AWD for a second. Just took the car up in the Colorado mountains and on some curves it feels alive. AWD always made the steering a bit anemic IMO. I am not a track guy, and not looking for the fastest car on the road. The RWD conversion made the car exactly what I think it should be. All that being said, I am looking to sell the car since I�ve got a couple of other projects in queue.

I feel strongly that PSM was much more intrusive when the FWD crap was still intact on my 996. My front diff has been hanging from a rafter in my garage for at least half a decade now...and there it will stay, unless I get a wacky project idea.

I remember test driving a C4S before buying my current C2, and while the C4S felt more planted in tight, slow turns, particularly in 1st gear and on the throttle, once at higher speed, I didn�t notice much difference.

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I've always thought the 996 all wheel drive system would be perfect for some kind of tube frame AWD go-kart type project.

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Capt! 997 AWD swap? Would you consider 997 RWD conversion knowing what you do?

Converting a 997.2 to RWD is a lot more work than just removing the all wheel drive system because that system is controlled with computers which are of course tied into multiple systems in the car. I believe converting a 997.1 (Carreras only) is the same as the 996 because they used the same viscous all wheel drive system through 2008.

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OK, yes, 997.1 or 996. So, in your humble opinion, nothing more but given your experience, is the awd delete worthwhile or more just bragging rights?

If I were to do it again, I wouldn't do it without also installing an LSD.

Well, good point, it is nice to know from your perspective. Thanks for your candid opinion.

The suspension on my C4S is in need of a refresh after 137k miles. I'm planning to go RWD at the same time due to my slowly deteriorating front diff. Does going RWD change anything when it comes to suspension upgrades? Like should I plan to go with adjustible coilovers assuming that I'll need some flexibility to tune?

Just finished this "upgrade" this weekend. Havent test driven it yet. Some extra details in case anyone else is wondering: Most bolts/nuts are 15mm. There are 2 14mm bolts holding up the gas tank "straps" that must be removed to loosen the straps in order to remove the plastic shield under the diff. Dont worry, the gas tank wont fall. There is a small 10mm bolt in the center support to disconnect the plastic coolant hose support (it is very fragile!) You MUST remove the studs holding the diff to the front support (unless maybe youre using a lift) in order to drop the diff. It cant slide back far enough without jeopardizing the coolant pipes. These studs are 7mm,. I used a pry bar to separate the transmission from the driveshaft flex disc. Then I proceeded to drop it and remove from the center support. Most of your time will probably be spent trying to separate the CV joint knuckle. Its a PITA but it is doable. I decided if I ever reinstall the AWD Ill just buy remanufactured CV joints Only question I havent solved yet is how best to protect the open flange on the transmission.

I know this is an older thread but I'm thrilled I stumbled across it. I've been thinking about this for my 996.2 4S. I've been holding off on the project because I live in the foothills in Colorado (above 7500') and it certainly does get snowy here. I also drive my C4S year-round. I have a set of snow tires I swap back-and-forth with my regular tires depending on road conditions. I have a short commute (all within my little town) - about 20 minutes each way. I appreciate the fact that Porsche was building non-AWD cars for a very long time and with the engine weight over the rear drive axle, intuitively it seems like a RWD 911 would be almost as good in snow as an AWD. There are certainly plenty of press photos of old school 911s tearing it up in the snow but I'm not so naive to discount the fact that those are indeed "press" photos. Have any of the folks on this thread deleted AWD in a C4S driven in true 4-season weather, including icy/snowy roads? My 4S sits so low that I don't go out until after roads are plowed (otherwise I AM the snow plow!), but we do have fairly prolonged periods of snow-packed roads in the hills. I know the project is reversible, and I'd use the Rennline or Reid Performance axle stubs anyway to simplify reversibility. I'd just rather not go through the process of converting it from AWD to RWD if it's going to make the car generally useless when the snow falls. Thoughts?

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Porsches are great in the snow if you have proper size dedicated snow tires. Keep them narrow. I don't drive my 996 in the snow but did get caught once in awhile in my 964. At times you could see the s-shaped tracks from other drivers sliding off the crown of the road into the gutter because it was so slick and my car was remarkable. Gentle on the throttle input and no spin at all. On the other hand my rsr clone with 345s could slide on a single snowflake. Are you in evergreen?

Yep, I'm in Evergreen. I run the Porsche recommended sizes for snow tires, which I think are 265 rears and 225 fronts. I never let my tires get old and I just don't cut corners on tire quality. Whatever they are, they're the sizes noted in the owner's manual.

I’m also in Evergreen and I’ve seen you out and about in your C4S. I believe it’s the same color as my 2002 C4S was (Midnight Blue Metallic). Beautiful car. My C4S was also my daily driver and I installed winter wheels and tires every October. I kept the AWD system intact on my car, but even with AWD and winter tires I was unable to drive up my driveway when it was really slick with ice or hard packed snow. I had to back up my driveway in those conditions! Here’s a pic of my old C4S with my winter setup, parked in downtown Evergreen.

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Nice. Mine's actually Lapis Blue, just a little bit lighter than yours. I guess you sold it by now? Thanks for the compliment on mine; I really love the car! My driveway is super easy. I'm just south of downtown and don't have any tough hills to navigate, fortunately. I used to daily a 986.2 S Boxster year round. Blizzaks in the winter seemed to do the job on that little number. It's now my wife's fair weather car.

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I traded mine many years ago at Porsche of Colorado Springs for a 997 Turbo cabriolet (which is also gone). My 996 C4S eventually popped up here on rennlist and is now owned by a gentleman in New York. Lapis Blue is a gorgeous color. It suits the curves of the C4S nicely. I�m currently driving a 991 Turbo S cabriolet in Mahogany Brown Metallic. It�s more of a fair weather car, although I do put proper winter tires on it. Hopefully I�ll see you at a PCA or a Porsche Breakfast Club event. I�ve loved every 911 that I�ve owned. I still miss the 996 C4S.

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This point keeps getting brought up over and over again with the incorrect conclusion. The C4S had superior tires in this test. With the same compound all around the C2 would be faster. You simply don't make a car faster by adding drivetrain loss and weight to a car that isn't traction limited.

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To each his own. But let's explore the question. What is absolutely the most important part of any car? --- The contact patch! Applying power to all four contact patches is always better than applying power to only two contact patches. If you think two wheel drive is better, then would you also propose that two-wheel braking it better than four-wheel braking?

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I would suggest you read this https://www.autoweek.com/car-life/co...iction-circle/ There is little to no benefit to applying power to more wheels than you need to.

The viscous all wheel drive system in these cars is designed for high speed stability, not traction. The viscous coupling is slow reacting and transfers minimal torque to the front wheels under most conditions (even driving in the snow).

Awesome writeup! Since I couldn't find any detailed DIYs for a 997 RWD conversions I figured this would work for my Targa--whattaya know it did! Another argument for 997.1 as 996.3... For anyone else looking for guidance, Capt. Obvy's DIY is definitely the way to go. Rennline's vid below will have you fussing with the knuckle, which is entirely unnecessary. Just undo the two 7mm bolts supporting the front diff and remove everything from below. Note: one of my support bolts was tricky-- they are dual threaded and the front-facing thread section seemed to have lost its way. I vice gripped and tapped it to freedom, then removed with the ratchet. One last point to anyone worried about investing in a major setup just to get the 32mm hub nuts off: I was able to free them with a $100 Earthquake XL 1/2" drive torque wrench with a 150psi pancake compressor (rated at less than half the wrench's minimum CFM). I was done with one side before the generator even kicked on. Also, I was able to free the nuts without the "loosen before you jack" advice. I had even pulled my wheels for cleaning and just held the rotor, which didn't even move. I did hit the nuts overnight with PB. As always, YMMV. To tighten, buy a digi torque adapter rated past 340 fp or use a breaker bar/manual torque wrench of less absurd dimensions along with Bruce's method . www.youtube.com/watch?v=8LZ1bO3CMWo

I'm cross posting to this thread just to help future searchers. I did my write up over here: https://rennlist.com/forums/996-foru...l#post19783987 Largely following @Capt. Obvious , I converted my C4S to a C"2"S over the weekend. In response to one of the early an unhelpful posts, I'm one of a select few who don't get all gooey for the 996 Turbo. I had plenty of budget when I bought my 996, but I don't like the garish wing and rapacious intake gashes that mar the rear end of the Turbo. I also have a thing for the 996 heckblende. Yes, the Turbo has a more robust motor. Metzger blah blah blah. Don't care. That isn't why I bought my Porsche. I'll enjoy my M96 until she craps the bed and then I'll do a Renn2.7 swap. The C4S body is dead sexy, and that's why I bought it. Now to the meat of the post: This is not a daunting project. Echoing others from this thread, Porsche's engineering for the AWD system is impressive. Simple, lightweight, and well organized. So why did I want to make my AWD a RWD only? A few reasons: First, my transfer case was showing some leaks. Nothing bad, but it would need attention at some point. It will be free to a good home, provided someone wants to come pick it up in Colorado. Second, I want more tire options than the limited options available for the AWD setup. Now, different tire diameters aren't such a problem. Third, I no longer drive the 996 in particularly nasty weather or heavy snow. I don't pamper her, but I have an old Land Cruiser I now drive in winter and when the roads are crappy. Finally, why not? I like the idea of a slightly more tossable 911 and I had loads of free time over the Thanksgiving break. Everything is pretty light. The transfer case is cast aluminum and if you remove the front axles and the drive shaft first, nothing is particularly heavy or unwieldy. My approach was a little different than the Captain's, because I had my entire suspension out at the time doing coilovers. Below is my step-by-step process as best I can remember. It will help if you spray a little PB Blaster on the hardware before you get started. Pop center caps off the front wheels. Loosen front axle nuts. (Nut is 32mm. I had to stand on a breaker bar to loosen the nuts.) Loosen wheel lug nuts/studs. (Nuts are 19mm.) (Makes it easier to remove.) Jack up & secure car. Remove wheels. (Nuts are 19mm) Remove all plastic splash guards/trays. (I needed a flat screwdriver for front clips, 10mm socket/ratchet, T�20, T�30 drivers/bits.) Remove 2-piece V-shaped brace under differential. (Four 16mm bolts) Disconnect axle shafts at differential. (5mm hex, I think. Maybe 6mm.) Counter-hold other side. Press axle shafts out of wheel carrier. I put a dead blow hammer on the axle stud and hit the dead blow with a 2-lb sledge. Remove axle shafts from vehicle. You'll have to separate the outer part of the axle shaft at the joint. The teeth on the outer part of the shaft integrate with the ABS system at the wheel carrier, so you'll need that section. Rennline and a few others sell "conversion stubs" for $750-1000, but that's totally unnecessary. That said, separating the axle shaft was singularly the most difficult part of the process. Because I'm a barbarian, I cleaned out all the grease around the bearings and then I took a chisel and 2-lb sledge to the bearing races. Several healthy blows later, the ball bearings are on the floor and the axle comes apart. You're committed at this point. Go to rear of car. Support transmission with jack, then remove the rear bracket from the body where the drive shaft meets the transmission. (Nuts are 15mm.) Remove 3 bolts attaching drive shaft to transmission. (Bolts are 15mm.) Remove plastic bracket supporting coolant lines. Remove 10mm bolt, then gently wiggle plastic bracket to unclip it. Remove bolt that holds transfer case to body mount. (15 mm, I think.) Remove 4 bolts/nuts at the T-case body mount (15mm). Work the drive shaft loose and set it aside. Remove 2 nuts on the front transfer case mount. (15mm) Cut the plastic splash guard under the gas tank. (You won't be able to drop the transfer case otherwise.) Super easy with a hack saw. Wiggle transfer case down and off the mounting studs. Be careful to not damage the aluminum coolant lines. This was pretty tricky, as the rubber mount bushings need to flex a lot to get the transfer case off the studs. Put all the brackets and braces back in place. It seems to me that while you want to get the axle nuts nice and tight, fully torquing them to spec isn't necessary (and may not be possible). It seems like the only purpose of the axle stub is to maintain ABS functionality, since the front axle doesn't "drive" anymore. I haven't reassembled things yet (working on suspension still) but I plan to just use blue Loctite and get the axle nuts as snug as possible. You now have a rear wheel drive widebody N/A 996! Red arrows note various bolts described above. This is from the front of the vehicle looking toward the engine. The horizontal brace has a 10mm bolt that holds a plastic bracket in place to support the coolant lines. The rest of the bolts are either 15mm or 16mm. The red arrows show the bolts for the "V-brace" under the transfer case. The green arrows show the nuts that hold the transfer case on the mounting studs. The orange lines show where I cut the gas tank splash guard with a hacksaw. The blue arrows show the bolts that hold the drive shaft guibo to the transmission. (Top one is hidden by drive shaft.)