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Bought these a while ago, won't be going on the car just yet but thought I'd post them up anyway
Everything is Alcon, I gave them the full car spec, and they were extremely helpful in guiding me through the various combinations of calipers and discs. I've gone small on everything to reduce unsprung weight, Plan B if I've cut it too fine is to add some caliper mounting spacers and go up on the brake disc diameter.
Front
Rear
Instead of adding extra weight by increasing the thermal mass by going the well worn and successful route of bolting on 993TT calipers and bigger discs etc my approach is a bit more racy.
4 pot calipers front and rear, front discs are 305mm dia. x 28mm thick and rears are 295mm dia. x 25mm thick. They should fit inside a 15" wheel which give me lots of clearance room for cool air ducting.
As I want my car on the light side of lightweight my plan is to manage the brake temps using plenty of ducted cool air. On the front I'll use a combination of the RS ducts and the outer edges of the upper and lower front grill openings. On the rear duct air using a NACA duct in the lower face of the cill cover panel. All air from these openings will be blown through moulded ducting which will be sealed against the caliper and disc to minimise leakage and pressure drop.
This airflow will be ducted to most efficient areas to cool on brakes which are to blow air into the centre of the disc and either side of the caliper body where the brake fluid is around the pistons.
Totally agree with this approach. I am leaving my C4 braking system standard as am hoping that the weight loss alone will make it sufficiently effective as it is. Adding bigger rotors and calipers is added weight and something I hope to be able to avoid. I will also go for cooling ducts at the front.
To try and keep this build thread mildly interesting while I slowly collect bits and even more slowly work on my car I hope no one minds if I share a trip down memory lane.
As the theme (or some owners might refer to as an obsession) of my 964 build is 'lightweight' hopefully the details of the below car will explain where some of my inspiration is coming from that I'm trying to include in my 964 build.
I've found no information on the web about this car so this could be a world exclusive.
One of my favourite car projects I've worked was the 2000 season Benetton B200 F1 race car, driven by Alex Wurz (as seen in the photo) and Giancarlo Fisicella. It wasn't the fastest by a long way so needs must the team needed to do something drastic to make it a more competitive car.
A loop hole in the rules was found and the design brief was simple, lighten our race car as much as possible and the changes needed to survive '12 qualifying laps only'
The team can't take credit of being the first in motor racing history to take this approach but we did a good enough job to force the FIA into changing the rules to prevent an expensive all out qualifying only car war between the teams.
As its past my bedtime I'll post up tomorrow evening the list of changes we made, well all the ones that I can remember as it was a long time ago and many other cars have come and gone since then.
Now for some details of the sort of tricks we got up to all in the name of finding extra qualifying performance
Renault V10 3ltr engine used magnesium heads instead of alumnium, these would do not much more than 12 laps before they would warp. Also I'm sure the revs limit would have been raised (not sure what it was but it would have been nudging close to 20,000 rpm), fuel mixture leaned to the max, minimum viscosity and capacity of oil used to squeeze out a few more horse power
All the electronic sensors not required for the car to talk to itself so it could run on the track eg ride height sensor, brake pad wear sensors, suspension pushrod load sensors etc were removed and a cut done wiring loom fitted
Exhaust pipes were made from 0.4mm/0.016" thick Inconel tube, these would crack both at the welds and wear the metal was stretched during the forming of the bends
Bodywork was one layer 0.15mm/0.006" thick carbon fibre on the outside and a 0.09mm/0.04" thick ply on the inside of 3mm or 1/8" thick paper honeycomb. You could see pin ****** of daylight shining through when held up to the light
We looked at vinyl instead of paint, this was heavier so the car was painted with one light coat of topcoat colour only, it looked fine on the TV but up close looked dreadful. Even using the lightest of paint coverage 20-30% of the total weight of the bodywork was paint
Old race worn carbon discs and pads were machined down to the bare minimum of thickness
The race fuel bag tank was replaced with a minimum capacity fuel tank, just enough for the car to splutter back to the pits on the last lap if we were lucky
The aluminium oil tank was chemically milled with patcwork of lightening pockets down a thickness of about 0.6mm/0.024"
A lightweight drivers seat was fitted, from memory it weighed around 0.6-0.7kg/1.32-1.54lb
The gearbox had the first gear ratios removed as no standing start required and I'm pretty sure every other gear was turned down to the minimum thickness before the teeth would break off. As reverse gear is required by the rules this was made in aluminium (might have been for race not sure) and the lightest viscosity oil and minimum capacity was used.
The lightest sets of tyres were picked form the range of tyres available to the team
All composite parts like the chassis, front wings, rear wings, floor etc were the lightest from the range of weights from the range of parts manufactured for each race
Think there was also a lightweight steering wheel with only the minimum number of button and swtches required
The single piece forged magnesium race spec. wheels which always cracked after about 2000km or 4 race weekends were lightened, the rim thickness was machined down to 1.9mm/0.075", wheels would go egg shape just from seeing a kerb or rumble strip, usually only got 12 laps out of a set
I'm sure there are other things we did that I've forgotten or didn't know about but doesn't matter as hopefully I've painted a clear enough picture of the lengths we went to in the name of weight saving
As the logistics involved in manufacturing the parts and building a 2nd version of car for each race weekend was quite a drain on the team only one qualifying special was used each race and the drivers took turns driving it.
As a car project it was a lot of hard work but great fun to be involved in and this qualifying special would end up 3 to 5 places closer to the front of the grid so mission accomplished.
Great post WC. Enjoyment only marginally compromised by the cake I was eating as I read it; think I know where to start in transferring the lessons into the 993
M.
Ps. Love that livery, wurz and fisi both drivers I liked in period.
thanks Matthew, thought you would enjoy reading about it, I was eating cake when I wrote it
Been a while since my last post, not had a chance to touch my car for a few weeks, too busy working 14-15 hr days, 6 days a week a long way from home but my mind has not been idle.
I've found a company that can bend tubes to large radii so hopefully they can make me RUF style roof/A-pillar hugging front roll cage section.
Have a friend ready to do some roll cage stress analysis once I get around to measuring up my car and model up a roll cage on CAD. I'm interested to know if the roll cage can take the loads on its own without help from the body shell. If safe/stiff enough then it will be off with its head and all roof metal from the bottom of the windows up with be replaced with carbon.
A friend of a friend is also trying to get me a deal on titanium bolts so I can replace all the unsprung bolts on the car with something lighter and corrosion proof, thanks to Rob964 for making me look at the underneath of my car with long term maintenance in mind, its given me some more lightweight ideas to consider
Also trying to call in a favour with a couple of bearing companies about replacing the steel ***** in the wheel bearings and CV joints with ceramic *****. Already had confirmed down sized 100mm lightened CV joints from the stock 108mm joints can take the torque and their life is similar. Weight savings from these mods overall and on the unsprung weight is not to be sneezed at.
Need to do some shopping for 993 RS front wheel carriers, thanks Thomas C2 for your concise write up, very helpful. Offered a very good deal on some super lightweight 6-point seat belts but just trying to justify the cost to myself before shelling out the cash.
Lastly big thanks to drknauf 'Magic Mike from Miami' below is a bit of photoshop fun.
Ignore the slammed stance as mine will be RS height and for the untrained eye the car has been treated to a rain gutter delete, flush colour coded door handles, one piece door windows, side indicator delete and one piece sill panels. Also got a few other body mods in mind to smooth out the shape a little as most of my driving will be crossing Europe. I'd prefer to save fuel money getting there and back so I've got more to spend burning up and down mountains.
- nice touches. That will look very smooth, and subtle enough that people will look for a while to identify what's different. I especially like the smooth sill panel.
..actually, are those one-piece windows a tried & tested mod ? -from experience (on VWs), these can be a real bitch to get right and to remain working properly after more than 5 minutes...
This car is going to be something really, really special... following with bated breath.... and hoping I can roll a few of your ideas back to my car as well.
With regard to brakes can i ask why you did not go the carbon/ceramic route? was it just cost? I beleive weight is about half so there are big savings to be made.
..actually, are those one-piece windows a tried & tested mod ? -from experience (on VWs), these can be a real bitch to get right and to remain working properly after more than 5 minutes...
I've never seen wind up one piece windows on a 964 or any other flavour of air cooled 911 come to think of it.
I've got a few ideas of how to make it work reliably and agree it will take a bit of fiddling with to get it right
Originally Posted by jack.pe
This car is going to be something really, really special... following with bated breath.... and hoping I can roll a few of your ideas back to my car as well.
With regard to brakes can i ask why you did not go the carbon/ceramic route? was it just cost? I beleive weight is about half so there are big savings to be made.
Thanks Jack, apologies for lack of progress, being away from home and working all hours keeps getting in the way of everything other than my thinking time and sporadic hunting/gathering time.
shout if you want some ideas, I've got plenty going spare
Good question on the brakes,
Money no object, ceramic Porsche discs without a doubt for the exact reason you've mentioned. As for carbon discs, nothing better for racing but are too dangerous for the road use, impossible to keep them at the right operating temperature.
Trying to think ahead I have chosen brake calipers that should work with 350mm x 28mm ceramic Porsche discs. Hoping to swap over later on when this technology becomes more widely available at a reasonable price.
Powerflex black series suspension bushes bought for all round, debating what to do for rear spring plates ERP or get a custom set made
Bought a pair of Porsche 993 GT2 front alumnium wheel hub carriers. One was handed around work with lots of oohs and aahs as we were pleased to see that Porsche added extra thickness in the areas needed to increase the camber and toe stiffness. Both these suspension geometry stiffnesses have a huge effect on handling. Weight saving over the steel 964 wheel carriers is 2.68kg/pair (I'm hoping to round that up to 3kg after maching a little excess fat off I can see with the shape) so a double win for the GT2 parts, well worth the money IMHO.
Now looking at how much unsprung weight I can safely remove with titanium suspension bolts. £/kg saved its not cheap but the only downside to too little unsprung weight is not having parts stiff or strong enough. Anything that can be done to help keep the tyre in contact with the road is only a good thing.
Also calculated that I can drill a 12mm hole down the middle of the front wheel bearing M22 retaining bolt if its made from a stronger steel without reducing its strength.
As long as work doesn't get in the way, I'm hoping to finish modelling my rollcage this weekend so a friend can stress it for me
Working my weigh through a list of sizes and lengths for the unsprung bolts on the suspension so I can price up titanium bolts/nuts
In the meantime until I can post something interesting you'll have to make do with a video of one of my old car projects being spanked up Shelsley Walsh hillclimb
Ohh, the sound is pure music and what a hero Kenny Brack is
12-10-2014, 05:55 AM
