964 track car - RS spec or other?

[bryn_p]

Morning all,

I'm seriously thinking about building a 964 track car to replace my trusty E30. I have a LHD C2 Tip ripe for the job.

Obviously I need to convert it to a manual first, but after that I am wondering whether to upgrade the car to RS spec or use other aftermarket suspension/brakes etc.

Are there any old threads on here detailing what the RS spec includes exactly?

What are people's thoughts on the best option - use RS bits where possible or just use other aftermarket stuff?

Any tips on the best suspension set up?

Cheers,
Bryn.

[clubsport]

It may be worth geting hold of the Porsche 964RS sevice information technik booklet from Porsche, it lists all the differences for the different RS versions alongside those of the standard C2.

Lets, just say, you could achieve a good car by using non RS parts and saving a few £££, no need for magnesium wheels and KW suspension is often fitted in place of original, improvement for less £££ than original.

[Nurburgsingh]

One word...

MANTHEY!!

[anonymous-user]

964RS spec changes (from memory, so may not be spot on!)

Engine / Drivetrain:

Blueprinted engine rated @ 260 hp (only +10 hp from standard, but it feels a lot more)
Lightweight flywheel
Limited slip diff
Revised gear ratios
Slightly modified gearshift linkage

Suspension / Chassis:

Seam welded chassis for extra rigidity
Solid uniball front suspension top mounts
Lightweight alloy uprights
40 mm lower ride height, 40% stiffer springs
17" Mag cup wheels (7.5" front 9.0" rear)
Stiffer front and rear anti-roll-bars
Shorter rear trailing arms
Lightweight steering rack with no power assist (LHD only, RHD has standard PAS)
Turbo brakes & vented discs (modified ABS program)

Bodywork:

Aluminium front bonnet
Lightweight plastic bumpers
Rolled wheel arches to improve tyre clearance.
Thinner side & rear glass
No underbody corrosion protection!!!

Interior:

Recaro racing seats
Completely stripped out interior - very minimalist.

I can't remember the total weight saving, but I think it was something like 150 kg over a standard C2. May have been even more. I owned one for several years and found it way too stiff, even for a track car. The front was way over-damped too. But the weight savings and other tweaks made the car much more nimble than a standard C2. Brakes were awesome too.

If you're creating a track day car, I would target a weight saving of at least 100 kg and fit the turbo brakes etc. I wouldn't stiffen and lower the car as much as the original RS, maybe go +20%-25% over standard. I wouldn't go silly with the power either.

[tony.t]

My track car is based on a 964C2 so I've a reasonable idea of what's involved and what works well and what doesn't work quite so well.

Building a track car from what you already have is a pretty big topic and to a large extent depends on your budget.

In brief I would use proven aftermarket stuff in preference to Porsche 964RS parts as they're often cheaper but better. I have used a fair amount of Porsche RS stuff on mine but it's mainly from the 993RS as it's generally superior to the 964RS parts.

For suspension I'd look at the aftermarket kits for the RS, use the 964RS anti roll bars,I've fitted the 993RS front hubs and wishbones which work very well and you'll probably need to run spacers at the rear. Best bet is find someone who's done it before as the setting up is as important as the parts.

For your donor car I would have a full weld in cage and try and source one the 993 supercup gearbox's that are sometimes available left over from the racing .

[steil]

I thought the RS was also seam-welded so a fair difference from a C2 or C4 shell.

[NineMeister]

steil said:

I thought the RS was also seam-welded so a fair difference from a C2 or C4 shell.

You are right, but it is very little that a MIG welder cannot sort out with a couple of hours work.

[bryn_p]

That's some great information, thanks gents.

The car won't be a mega-budget project but I do want to do it properly. I'll look in to the KW V3 suspension and RS roll bars, and some bigger brakes.

The engine is due a rebuild anyway - what are worthwile upgrades whilst its in bits?

NineM - I'm not far away from you - is seam welding the shell something you would undertake if I deliver it to you bare?

Thanks again,
Bryn.

[ian964]

If you're going to strip it to a bare shell and deliver it to Colin, you should look at some of the other things that he does for his RS Clubsport replica e.g. full welded cage, sunroof removal.

[NineMeister]

bryn_p said:

That's some great information, thanks gents.

The car won't be a mega-budget project but I do want to do it properly. I'll look in to the KW V3 suspension and RS roll bars, and some bigger brakes.

The engine is due a rebuild anyway - what are worthwile upgrades whilst its in bits?

NineM - I'm not far away from you - is seam welding the shell something you would undertake if I deliver it to you bare?

Thanks again,
Bryn.

Call in next time you are passing, it would be easier to show you all the options on brakes, suspension, engine and shell rather than write about them. In the meantime, have a look at www.9mRS.com and you can see where a 964 conversion ultimately leads to.

[bryn_p]

Oh dear, I can see the budget for this getting rapidly out of control! Although the donor car has no sunroof so at least that's one thing I can cross off the now very long list!

Great site though, the finished article looks fantastic.

Will have a think and then call in sometime in the next few months - the donor car is still in Japan anyway.

Cheers,
Bryn.

[NineMeister]

Thanks Bryn, I'll look forward to seeing you and your donor when it arrives off the boat.