Weights

[Ken Mason]

Interesting article by respected motoring historian Doug Nye in the latest Motorsport magazine. He has come across the scrutineer's figures for the 1966 Le Mans. The winning Ford weighed 1211 kg - 509 front 700 kg rear. The second placed 7 litre of Ken Miles and Denny Hulme scaled 1272kg distributed 517/699 front rear and the third place Ford was 1245 kg - 537 front 712 rear. As he points out the front rear figures don't quite match the total weight... But why the difference between the cars?

Also the Chaparral 2D in the same race weighed in at 892 kg - now that's light! The Ferraris? The works 330P3 of John Surtees and Mike Parkes was 989 kg distributed 415/572 front rear.

 

[Dutton]

Ken,

Interesting point.

My first inclination goes to the widely noted comments about competition 40s and how no two were the same (hence the potential difference in net chassis weight), but the amount of fuel onboard at the checkered flag may well have played a part.

Surely other more learned members of the forum would have an insight to pass along. What say you, boys?

T.

 

[Malcolm]

I had always thought that the original cars were lighther than this. It means that most replicas weigh about the same as the original cars, give or take. This will now allow some interesting comparisons, especially if you run your replica on "old" tyres like the Dunlop L and M sections or the Post Historic tyres.

 

[Manny]

Be careful with the comparisons relative to fuel load.

Some of these cars could hold a lot of fuel so as to minimize pit stops in long races that weren't that hard on tires (like Daytona and LeMans). If you look on the Ferrarichat vintage forum the pictures showing the teardown of a P4 (0846) show almost the entire sponsons on the car are fuel tanks. Jim G (who also is on this forum) has weighed his P3/4 Ferrari (the real thing) and had reported an empty weight of 1850 pounds. The LeMans data has a P3 (should be very close) at 2176, a weight delta of 326 pounds. In addition most weights I have found for a Mark II are showing between 2306 and 2450, and the LeMans data shows them at 2798, or 350-500 pounds higher than the oft reported dry wieight. Maybe the LeMans data had them with driver and fuel, or maybe full of fuel. This was supposed to be scrutineer's figures so it was likely taken before the race, and the cars could have easily been full of fuel at that point. Fuel weighs about 6 pounds per gallon, so 50 gallons could easily make up the weight difference we are seeing here. If the weight included a driver at 175-200 pounds, then we are talking only 150 pounds of fuel, or 30 gallons, which these cars easily held. Jims P4 had two bladder tanks that looked like they each could have held 20-25 gallons.

Either way, they are not consistent with DRY weights that I have see for the same cars in most other places. I have a spreadsheet that I was compiling and according to that most replicas are a good bit (about 300 pounds or so) heavier than the real race cars. Not that it isn't to be expected, just a fact of life. The only inconsistency I have seen is that a couple of cars that are reported as being as "exact" reproductions of MarkI and II's appear somewhat heavier than the other data I have found on the originals and I have no explaination of that, other than maybe the A/C and vent systems are adding some weight and that maybe they are using a bit thicker materials since these aren't race cars anymore.

 

[Randy V]

Factor in the weight of the driver and his helmet along with the fuel load...

 

[Mike]

Here's a reference; The set up on my ERA Mk 1 (1996 - Joe Huffaker of 'Huffaker Racing/Sears Point, Ca.) shows:

LF: 545#/21.7% RF: 529#/21.0%

LR: 736#/29.3% RR: 698#/28.0%

on the initial settings, which were tweaked to a final 1269# LF,RR 50.6% and 1239# RF,LR 49.4% balance/stagger and instructions to burn the left fuel tank/driver's side first.

The set up was with 10 gallons of fuel and 180 lb weights in the driver's seat. My car includes a Vantage airconditioner.

With a total weight of 2508#, if we subtract 60# for gas and 180 for the driver, the empty weight of the ERA comes out to 2268# with A/C. Thats the stainless steel semi-monocoque, not the early plain steel one. (Oh, thats with TFS al. heads).

 

[Malcolm]

Don't disagree with positions stated, but replicas hold fuel too! Maybe not as much though. My car can take 45 kg of fuel, 15 imp gallons. My GTDs dry weight is around the 1160 to 1170 kg mark.

Were the weights mentioned above at pre or post race srcutineering? If before a race then quite likely to have big fuel loads but not if the weights were taken at the end of a race.

I always thought the original cars came in at about 1000kg, hence my initial comment above. Can anyone state the factory spec weight here?

 

[Marcus]

The scrutineer's figures from 1966 Le Mans are very interesting but shouldn´t be taken too seriously. At least I doubt if they are a good basis for comparisons with today´s weights.
According to John Horsman in his book "Racing in the rain" the scales used by the scrutineers at Le Mans were always "apallingly inaccurate".
Interestingly almost never in favour of foreign competitors...

 

[Russ Noble]

A page I have copied out of a book, not sure which one, lists dry weight for original GT40 with 256 c.i. motor and Colotti at 1835lb/835kg; for a GT40P Mk1 with 289 and ZF 2000lb/908kg; and Mk11 427 and T44 2505lb/1137kg. It also lists start line (without driver) of 2450lb; 2470lb and 2660lb respectively.

There are obvious inconsistencies here between the dry and start line weights. I would think the dry weights would be in the ballpark but the startline weights are not comparing apples with apples.

Although, would a Mk11 really be 500lb heavier than a 289 Mk1? Possibly, heavier motor, heavier trans, dry sump system, bigger radiator, bigger brakes, bigger wheels and tyres, more bodywork etc etc

 

[JohnC]

Russ, wasn't there an insistence from Henry Jr. that the MKII have a full roll cage, despite the weight penalty. (This was in contrast to the MKI which had nothing to protect the driver in the event of a roll?)

Seems I remember this from Ronnie Spains' book.

 

[J. Salmon]

I cannot give a source, but I do think I read a figure of some 2700 pounds, but I also thought that was with fuel. I would think a car like the SPF would have to be dern close to the weight of an original, and something like an RCR would be a bit lighter.

Of course, as a Audi fan, "weight" is such a nasty sounding word. I like to think of it as "gravimetric downforce".

 

[fostereast]

Re: Weights/Safety

I think Henry Ford II forced a strict safety issues (which raised the weight of the new prototpye quite a bit) after Miles was killed in a prototype GT40. This was several months after LeMans '66.

Got this from a book.

 

[Manny]

I saw a 1968 MarkII for sale on 'Anamera where they quoted a fuel capacity of 140 liters. That would be 233 pounds of fuel at 6.3 pounds per gallon. So it is easy to see that much difference between a "wet" and dry weights....