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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH1999 C4 to C2 Conversion
Leading reported evidence
Install eibach lowering springs without changing the stock shocks
Performed · outcome unconfirmed
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0
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0
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1
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Performed · outcome unconfirmed · Original poster
The PO had installed Eibach lowering springs without changing the stock shocks and that made the car too low.
Leading evidence: 'Install eibach lowering springs without changing the stock shocks' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'cv joints' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Install eibach lowering springs without changing the stock shocks' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
Remember that the car is now fitted with new B8s and H&R springs which obviously also changed its behavior.
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Performed · outcome unconfirmed · Original poster
Remember that the car is now fitted with new B8s and H&R springs which obviously also changed its behavior.
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Performed · outcome unconfirmed
Because breaking down axles sucks, generally breaking them down results in destroying the cv joint and used axles cost about the same as the deletes.
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The C4 bulkead was used on gt3 cars and Cups for the larger fuel tank as well as its orientation in the chassis.
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Unsuccessful attempt · Original poster
One of the previous owners had changed the factory springs with some Eibachs but without changing the original shocks which didn't help handling (sloppy steering at elevated speed) and made the car look slammed (way too low for my liking).
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Suggestion · Original poster
One of the previous owners had changed the factory springs with some Eibachs but without changing the original shocks which didn't help handling (sloppy steering at elevated speed) and made the car look slammed (way too low for my liking).
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Hi,
I have 1999 C4 996 that I want to convert to a C2. According to my mechanic this is a very simple job. Has anyone done it before? Any issues encountered during the conversion? Is it just a simple removal of the transmission and CV axles?
Thank you in advance for your help.
Thank you. I looked for threads and couldn't find any. I'll research further.
The CV boots are shot and it's likely that the CV joints have been damaged by lack of grease. We're still in the process of investigating. If the CV joints are shot also it would save a bunch of $$$ to do the conversion, not to mention the weight saving as well.
Just as a voice of opposition. I want to say that I was never that impressed with the 911, I had 20 years of Alfa Romeo sports cars, and except for its dependability and excellent engineering, the 911 was �pretty good I guess� as an actual driver.
but then I got this C4, and found out how amazing AWD sports car was like for driving in all weather and just it�s feeling is incredible. I�m hooked for life now!
Hi,
I have in the past (back in Europe) owned many vintage Giulias and loved the cars passionately. I would love to own one again but just like air-cooled 911s they are now reaching silly prices and are out of my financial range. I bought my 996 about 2 1/2 years ago just before the prices started to climb and got the C4 because the seller accepted my low-ball offer. I would have preferred a C2 to be honest. So while my mechanic is working on upgrading the suspensions we noticed that the CV joints boots were shot and that the CV joints may have been impacted (probably not though). So, I decided to have the front differential and transmission removed. It's actually a very simple job so I thought I would give the C2 a try and if I don't like it, I will revert it to a C4. My only concern frankly is how it may impact the suspension geometry. I'll update the post as I am driving the car and get a feel of handling.
Yes, very interesting to hear what you think. And yes, reversible if nothing needs replacing. However, to my knowledge there is no change in geometry/suspension other than 100lbs off the front end, like running on a half tank of fuel instead of full so if you are able to notice any difference it will be only at the edges of performance.
Ya, that seems like a fun experiment. Im sure since AWD was an option, that its probably the same suspension, i would bet! Good luck and let us know how it goes.
ok but I am changing the suspensions all round. H&R performance springs and Bilsteins B8. The PO had installed Eibach lowering springs without changing the stock shocks and that made the car too low.
I only had the car back for a couple of days and below are my first impressions after driving the it for about 50 miles (some highway/some back roads/some town). Remember that the car is now fitted with new B8s and H&R springs which obviously also changed its behavior.
-Steering is a more precise and not bouncy/shaky when hitting road imperfections (very likely due to new suspensions)
-It is a lot more sensitive to wind
-It is a LOT noisier inside the cabin. I need to look into that. Anyone having done it and has experienced the same thing, please chime in.
-I experienced a LOT more over-steering which really surprised me. I was going around a circle and gave some gas a bit early out of the corner (as I sometimes do to get a bit of fun out of the car) and for the first time in two years of ownership, the tail snapped which triggered the PSM.
I will update with more info especially once I've taken the car to the track and on AutoX events.
The extra.noise is a little weird but the handling part is about right. U r putting at least 15% more power to the back and u dont have the front helping. Personally i think the early psm is garbage and is not needed at our level of hp. I would disable it permanately.
I will be looking into the noise when I get back. I need to put the car on the lift. My car has a VF Engineering supercharger and pushes above 400hp so I think I will keep the PSM active. In all frankness I wish it didn't have the supercharger and I am looking into removing it but it's not that easy because of the ECU having to be remapped.
VF Engineering Supercharger
So, just for clarification - there are different �levels� to this conversion. The first being, just removing the Cardan shaft. This effectively disconnects the front diff/viscous clutch from the rear wheels/transaxle, but doesn�t get you any weight savings. The main difference between this conversion and the �level 2 full Monty� (where you remove the cardan shaft, whole diff, axles etc.) is that you need to get a set of axle stubs from a C2 to hold the front wheels on.
Hi, this is the reply from my mechanic:
"The stub axles from your original halfshafts were disassembled and bolted back into the hub. This stub shaft holds the bearing and has the reference ring for your ABS wheel speed sensor."
I think I'm good.
I own a C2 and drove my friend's C4 and personally, I wouldn't convert a C4 to a C2. I would enjoy whichever I had for what it was. The C4 had a very planted feel. Not saying I preferred one over the other, but I definitely wasn't thinking that the C4 needed to be converted to a C2. I used to own a 997.2 C4S and that car felt great as well.
That said, I hope you enjoy its new configuration. I believe a C4 chassis with RWD is how the 996 GT3 is setup, so even Porsche thought it was a good idea.
Having owned many different 996 cars I have always enjoyed the awd variants the most because of the planted and confidence-inspiring feel vs the more twitchy and floaty C2. I think the rwd cars are more sensitive to poor alignments and bad suspension/tires and once properly “sorted” would feel equally as good (coil-overs, Pilot Sports etc).
A Rwd converted C4 is still very far from a gt3 in suspension terms though. The C4 bulkead was used on gt3 cars and Cups for the larger fuel tank as well as its orientation in the chassis. The knuckles differ and in an ideal world one would install 996 gt3 front knuckles, stub axles, front coilovers when converting along with gt3 sway bar. Gt3 knuckles and their 142mm spacing will require swapping calipers or using custom brackets along with 350mm gt3 rotors. The various stages of the conversion are all covered in previous threads but it is clear that the list of requirements to do this right is ever-expanding:
996 gt3 front calipers (142mm spacing)
996 gt3 front rotors
996 gt3 front coilovers
996gt3 front strut mounts
Wavetrac tbd (street use, less expensive) or Guard LSD + shims
New diff bearing
996gt3 front and rear sway bars
Front and Rear ajustable sway bar links
996 gt3 left upright
996 gt3 right upright
2x spindle 996 341 131 04
2x front bearings 999 053 054 06
8x cover bolts 999 217 042 09
Front left heat shield 996 351 801 30
Front right heat shield 996 351 802 30
Left 996 c2 br line bracket 996 355 501 06
Right 996 c2 br line bracket 996 355 502 06
2x front hubs 997 331 605 01
To get the proper feel when converting an awd car to rwd I believe in the all or nothing approach: leave it as a C4, or change out the following parts at VERY LEAST when converting:
-Coilovers
-Gt3 or other adjustable rear sway bar
-limited slip or torque biasing differential
One correction.
The gt3 uses the c2 gas tank in the c4 body. It fits in there weirdly.
And one comment.
A full conversion could be done with c2 parts and not gt3 parts but honestly there is no difference in brakes or geometry for the c2 and c4 so why bother spending the time or money
Hi, you have a good point. I am not too worried though because if I don't like it it is very easy to put back on the car and have a C4 again. I want to give it a try during a couple of AutoX events before I decide one way or the other. So far the car behaves incredibly well on the highway. It's like on rails but then again that may be purely due to the new suspension I didn't feel a bit of lightness on the front end. Extra power as mentioned by others? I can't say that I did feel a difference.
To be clear, I wasn't suggesting that converting a C4 to RWD makes it equivalent to a GT3 in terms of suspension. I was speaking in a very limited scope as indicated by my text.
Yes, I do realize that I need an alignment as I mentioned in a previous post. I was just giving my first impressions as the car is now. I will update once the alignment has been completed.
Thank you for your comment but let's not get ahead of ourselves here. I am not trying to turn my car into a GT3. One of the previous owners had changed the factory springs with some Eibachs but without changing the original shocks which didn't help handling (sloppy steering at elevated speed) and made the car look slammed (way too low for my liking). The car now seats an inch higher, suspension is a lot firmer and body roll has been seriously reduced. I am not an expert in car suspension but I would call that a major improvement no? And all this under $3000 instead of the "all or nothing" suggested which would have probably cost close to $15000. So far, I'm happy and, in my humble opinion, that's what matters.
Aside from raiding the GT3 parts bin, there are two very simple ways to go full monte on the RWD. 1. break down your stock axles or 2. buy my RWD kit (Phenix has it for sale on his site).
Step 1. remove everything in front of the trans.
Step 2. install the axle deletes.
Step 3. throw your AWD components in a box, they can be reinstalled at any point in the future
$840 for a set of axle stubs designed and made in the US, with US sourced materials. These are a low-volume product which require the utmost precision for fitment and ABS function. They aren't cheap, but neither are new front axles and these weigh less than the factory axle flanges.
Yes very expensive especially since one can reuse the stub axles from the original half-shafts once disassembled and bolted back into the hub. Why is a conversion kit necessary?
True but I will have to change the CV joints anyway if I decide to put bring the car back to C4 specs. The boots were shot and probably the CV joints. Actually, this is what prompted me to do the conversion to C2.
You can get (stock) axle stubs for WAY less than that� that�s just a silly price. Made in the US? I�d prefer made in Germany (where the cars are actually made 😉
� When I�m servicing my Ford or Chevy I�ll be sure to source parts made in the US of A�
