Carrera 4 Leichtbau - replica
12-09-2013, 07:53 AM
#1
Three Wheelin'
Thread Starter
Carrera 4 Leichtbau - replica
So.. I've been toying with the idea of doing a C4 Lightweight replica for a while.. just because the RS things is so common and this would not be. Plus my car is a C4 so it would theoretically make more sense than an RS rep.
Something along these lines.. however the more I look into it the more difficult it seems to do it properly. Several problems that mean that it would either be an incomplete replica or that the cost would be prohibitive..
1. Braking -The original car had dual master cylinders with a bias bar for front to back - expensive (if possible?) to replicate
2. Rally gearbox,as used on Porsche’s old 959 Paris-Dakar contenders. It features two switches on the centre console that allowed the driver to adjust the torque split of the centre and rear differentials - Impossible or impossibly expensive to replicate
3. Engine - My cup style rebuild would probably not be too far off spec but as you can see from the engine bay the Leichtbau has no heating.. not possible in Uk
4. Exhaust system - Illegal for most tracks and expensive to replicate.. see pic below.. I could of course just go for an off the shelf double exit exhaust from another manufacturer..
5. Wheels - Magnesium D90s - Have some normal D90s that look the same but rears are 9" .. never seen those for sale?
6. All 22 cars were made to slightly different specs so this makes it even harder to make a rep. the white car is probably the best known so something based on that.
So, I could do something that cosmetically looks like a Leichtbau from the outside... but to do something close looks near impossible.. your comments?
http://www.maxted-page.com/resourcel...f75ccb7dc7.pdf
Something along these lines.. however the more I look into it the more difficult it seems to do it properly. Several problems that mean that it would either be an incomplete replica or that the cost would be prohibitive..
1. Braking -The original car had dual master cylinders with a bias bar for front to back - expensive (if possible?) to replicate
2. Rally gearbox,as used on Porsche’s old 959 Paris-Dakar contenders. It features two switches on the centre console that allowed the driver to adjust the torque split of the centre and rear differentials - Impossible or impossibly expensive to replicate
3. Engine - My cup style rebuild would probably not be too far off spec but as you can see from the engine bay the Leichtbau has no heating.. not possible in Uk
4. Exhaust system - Illegal for most tracks and expensive to replicate.. see pic below.. I could of course just go for an off the shelf double exit exhaust from another manufacturer..
5. Wheels - Magnesium D90s - Have some normal D90s that look the same but rears are 9" .. never seen those for sale?
6. All 22 cars were made to slightly different specs so this makes it even harder to make a rep. the white car is probably the best known so something based on that.
So, I could do something that cosmetically looks like a Leichtbau from the outside... but to do something close looks near impossible.. your comments?
http://www.maxted-page.com/resourcel...f75ccb7dc7.pdf
Last edited by jack.pe; 12-09-2013 at 08:10 AM.
12-09-2013, 08:00 AM
#2
Three Wheelin'
Thread Starter
More info on the Leichtbau
The Stuttgart manufacturer's willingness to build small runs of specialized high performance variants is the stuff of legends, but the Carrera 4 Lightweights may be one of the shortest and most specialized ever, more rare and exotic even than the fabled 959. It is so specialized, in fact, that Porsche didn't even bother to give it a 17-digit vehicle identification number. The Carrera 4 Lightweight makes do with just its model designation, 964, and a three-digit sequence number.
Porsche never homologated the Carrera 4 Lightweight for any racing series. That is not surprising given its short run quantity, which never would have met a rational sanctioning body's definition of "production".
Developed following Porsche's experience with the 959, the Carrera 4 used a four-wheel drive system with electro-hydraulic control of the transfer case clutches. Lateral load, speed and acceleration sensors work with the electronic brain to maximize its performance. In the C4 Lightweight two switches give the driver the ability to tailor both the front-rear and lateral torque split of the transfer case and rear differential. Widely held to be superior in performance, but less highway friendly, than its successor system on the 993-series, the 964 Carrera 4 made the perfect basis for a loose-surface competition car.
The body was seam-welded for strength and rigidity, the suspension lowered an inch and a half and fitted with 7" front and 9" rear 16" diameter Cup alloy wheels with wide rubber to match. A competition clutch and flywheel replaced the standard C4's dual mass flywheel. Power steering helped the driver cope with rapidly changing road conditions and the brakes were upgraded with dual master cylinders with a balance bar to adjust front-rear bias.
The side windows are fixed plastic with sliding panels for ventilation and access. Doors and trunk lid are aluminum. The engine cover and "tea tray" rear spoiler are fiberglass. There is no body sound deadening or carpets, no air bags and only minimalist interior panels. A pair of Recaro seats with five point belts, a stout aluminum roll cage with removable door bars, a tiny competition steering wheel and a factory-installed Halon fire suppression system complete the package. Out the door the Carrera 4 Lightweight weighed just 1,100 kilograms, a wispy 2,425 pounds.
The engine is basically the stock 3.6 liter 964 RS but without catalytic converters and specially tuned with performance camshafts, altered engine management and all the aid and comfort which Porsche specialist assembly, fitting and blueprinting can provide. Even conservatively rated with 265 brake horsepower, the prepared 3.6 liter RS in this Carrera 4 Lightweight has only 2,425 pounds to move, less than ten pounds per brawny Stuttgart pony.
Porsche never homologated the Carrera 4 Lightweight for any racing series. That is not surprising given its short run quantity, which never would have met a rational sanctioning body's definition of "production".
Developed following Porsche's experience with the 959, the Carrera 4 used a four-wheel drive system with electro-hydraulic control of the transfer case clutches. Lateral load, speed and acceleration sensors work with the electronic brain to maximize its performance. In the C4 Lightweight two switches give the driver the ability to tailor both the front-rear and lateral torque split of the transfer case and rear differential. Widely held to be superior in performance, but less highway friendly, than its successor system on the 993-series, the 964 Carrera 4 made the perfect basis for a loose-surface competition car.
The body was seam-welded for strength and rigidity, the suspension lowered an inch and a half and fitted with 7" front and 9" rear 16" diameter Cup alloy wheels with wide rubber to match. A competition clutch and flywheel replaced the standard C4's dual mass flywheel. Power steering helped the driver cope with rapidly changing road conditions and the brakes were upgraded with dual master cylinders with a balance bar to adjust front-rear bias.
The side windows are fixed plastic with sliding panels for ventilation and access. Doors and trunk lid are aluminum. The engine cover and "tea tray" rear spoiler are fiberglass. There is no body sound deadening or carpets, no air bags and only minimalist interior panels. A pair of Recaro seats with five point belts, a stout aluminum roll cage with removable door bars, a tiny competition steering wheel and a factory-installed Halon fire suppression system complete the package. Out the door the Carrera 4 Lightweight weighed just 1,100 kilograms, a wispy 2,425 pounds.
The engine is basically the stock 3.6 liter 964 RS but without catalytic converters and specially tuned with performance camshafts, altered engine management and all the aid and comfort which Porsche specialist assembly, fitting and blueprinting can provide. Even conservatively rated with 265 brake horsepower, the prepared 3.6 liter RS in this Carrera 4 Lightweight has only 2,425 pounds to move, less than ten pounds per brawny Stuttgart pony.
12-09-2013, 08:08 AM
#3
Three Wheelin'
Thread Starter
12-09-2013, 08:37 AM
#5
Three Wheelin'
Thread Starter
Does anyone know what the easiest way would be to get hold of the rear engine deck-lid and wing in fibreglass? that seems to be what the original used..
12-09-2013, 09:03 AM
#6
Three Wheelin'
The issues would be, a) what would that do to the resale value b) what would the wear be like on the clutch packs c) how would it actually handle on tarmac - i understand the manual system is design for fixed torque splits on loose surfaces so it might just understeer like a bitch on tarmac.
12-09-2013, 09:06 AM
#7
Burning Brakes
http://www.gettydesign.com/911_tailbases.html
Trending Topics
12-09-2013, 09:06 AM
#8
Three Wheelin'
Dual brake master is easiest done by modding an off the shelf race style floor mount pedal box like this thread.
http://www.impactbumpers.com/forum/i...91-quozls-911/
http://www.impactbumpers.com/forum/i...91-quozls-911/
12-09-2013, 10:00 AM
#9
Rennlist Member
One of my favorite 911s for sure. #1 is tucked away in a beautiful collection not to far away from me right now. The doors weigh nothing! I'm not 100% sure, who is, but I think the magnesium rim "legend" has been put to bed... the rim are aluminum.
12-09-2013, 12:47 PM
#10
Addict
Rennlist Member
Rennlist Member
I was at a PCA concours/car show in Portland a few years back. They were parking cars in the lot as they showed up. Was surprised when I see the C4 lightweight drive up. No one seemed to give it any more of a look than a regular 964. I though it was either a very good replica or real. I spoke with the owner and lo and behold, it was a real one. I educated quite a few people there on exactly how rare this car was in Porsche lore.
12-09-2013, 02:56 PM
#13
Race Car
hey Jack - thanks for all the great info - super article too. Gorgeous headers and lots of neat lightening holes in that rear bumper beam 
I'd go in the direction of what you really want and can use best - parts of all of them?
I'd go in the direction of what you really want and can use best - parts of all of them?
