Switching 964 C4 to C2 and losing weight

porsche gt3 · 07-22-2014, 08:10 AM

Hi,

I have a C4 that I am considering switching to a C2. Does anyone know how much weight I can save by doing this? I dont want to lose creature comforts in the car, but am considering changing seats to gain a little more weight savings. How much weight can i save on the seats and can you recommend some comfortable lightweight seats. I want to keep the interior somewhat stock looking.

Thanks for your help

Dueller · 09:10 AM

You can remove motors on power seats to lose about 10 lbs each. Even still a pair of stock seats weigh about 95 lbs. Set of recaro pole positions weigh about 35 lbs a pair. But they're fixed back so back seat access is limited. Any reclinin after market quality seat is not gonna save you more than 20 lbs total. You can lose another 50 lbs or so with rear seat delete/sound deadening removal and rs carpet kit.

Diffrench in weight between c2 and c4 is about 220 lbs.

Canine64 · 07-22-2014, 09:20 AM

Got my street legal (occasional track) C2 down to a legit 2785 with 1/4 tank of gas. All lightweight interior, Sparco 1 piece seats, no radio/speakers, no A/C or lines, no sound deadening, rear seat delete, Otto Fuchs 17" rims. The DAS roll bar adds weight but whatever. Also have a Fabspeed cat bypass and Maxxflo exhaust. Looking at exhaust options to lighten further. The diet really did wonders to this car.

porsche gt3 · 07-22-2014, 09:42 AM

Thanks for the info.

I removed my primary muffler and was planning on installing a lightweight flywheel when i switch over to 2 wheel drive. If I leave the seats alone, i should see a savings of around 300 lbs or an aproximate 10% savings.

Do you think the weight difference will be noticable on acceleration and handling?

Dueller · 10:36 AM

Your ride height will be higher so you'll need to adjust that. I saw a formula somewhere that suggests every 100 lbs is the equivalent of 7 additional hp.

I don't think conversion to 2wd, a flywheel and muffler is gonna get you 300 lbs.

porsche gt3 · 07-23-2014, 05:02 AM

Thanks for your help. I forgot about the ride height adjustment. I figured the trans should get me 220 Lbs, primary muffler and lightweight flywheel another 60 lbs combined and I am losing 20 lbs for a grand total of 300 lbs reduction.

Cheers

johnsjmc · 07-23-2014, 05:59 AM

Quote:

Originally Posted by porsche gt3

Thanks for your help. I forgot about the ride height adjustment. I figured the trans should get me 220 Lbs, primary muffler and lightweight flywheel another 60 lbs combined and I am losing 20 lbs for a grand total of 300 lbs reduction.

Cheers

To get 220 lbs from just the trans is unrealistic unless you also remove the front differential and half shafts. The remaining hubs will still be heavier

Dueller · 07-23-2014, 08:56 AM

Doesn't the c2 and c4 have dif ferment power steering systems? I may be wrong.

Elombard · 07-23-2014, 09:34 AM

I dont think you can do it if you dont change the front uprights/hubs and pull the front diff and axles etc. They reviewed one in excellence a few years back. Did you see that artical?

KTL · 10:23 AM

I would just change the seats altogether with a more suitable track driving seat. Seems like a bit of work to remove the original seat motors and then you're left with seats that can't be adjusted?

Quote:

Originally Posted by Elombard

I dont think you can do it if you dont change the front uprights/hubs and pull the front diff and axles etc. They reviewed one in excellence a few years back. Did you see that artical?

I recall the same as Erik. There was an article in Excellence about it and they had some challenges in dealing with the AWD electrohydraulic sensors but they eventually figured it out.

But you don't need to change the uprights. I think you could just disassemble the CV axles and leave the empty stub axle installed in the upright. Basically the same as if you were to remove the axles from a 85-earlier 911 by unbolting them at both the trans side and the wheel side, leaving the stub axle in the trailing arm. In this case, the 964 front axle is not a bolted outboard connection but you still can gut the CV axle to leave just the stub in the upright.

Porsche designed the front uprights to accept both the C2 and C4 mechanicals. They share the same upright, wheel bearing. The difference is in the hub the round part that carries the brake rotor and holds the wheel studs, and how the hub is connected to the upright. Check it out. Pretty cool how they made both assemblies work with the same upright

Have you considered doing a transmission swap? I think this is a good idea to ditch that complicated G64 transaxle and forward drivetrain. Switching to the G50 964 trans simplifies things a bit in terms of eliminating the power takeoff that comes from the front of the G64 trans to send power forward to the front axle. The 2WD G50 trans is much simpler in terms of future service/repairs as well.

The downside to the G50 swap is you have to change the rear axle shafts. But in the overall picture, replacing axles is not a huge cost.

Dueller · 11:07 AM

If it were mine I'd do the flywheel, some easy engine performance mods, take out a little weight elsewhere ( seats, sound deadening, rear seats/carpet kit/door panelS), etc and dominate rainy track days w 4wd.

Then tell everyone it's a rare RSA 4.

boba · 07-23-2014, 11:35 AM

Quote:

Originally Posted by porsche gt3

Hi,

I have a C4 that I am considering switching to a C2.

Thanks for your help

The best way to complete this transition is to sell the C4 and buy a C2.

porsche gt3 · 07-23-2014, 01:40 PM

I was planning on removing all the C4 drivetrain components( trans, front diff. etc.) and replace the trans with a G50 that i own.

I bought the C4 with the intentions of making the swap. C2's manuals are hard to find and much more expensive then C4 manuals.

I believe the PS system is the same for the C4 and C2, but the brakes are high pressure on the C4 compared to low pressure on C2.

Does anyone have the link for the article in excellence on the C4 to C2 conversion

Elombard · 07-23-2014, 03:18 PM

No Link but I think I saw in excellence last month that LA dismantlers was offering a kit to do the swap. They worked with the guy that did the swap in the article. Yeah C2 964s are getting rare and expensive.

Dueller · 07-23-2014, 03:53 PM

At least on my 87 Carrera I was able to remove motors fom rails and convet them to manual only in my seat swap. I couls have bolted my stock seats back in sans motors keeping only manual adjustment. On power seats theee are two motors....on for for/aft and one to adjust seat back

My modded rails for aftermarket seats