Aluminium Frame for the SC cobras?

[RICK LAKE]

To the Master engineer at ERA. BOB what would be the problems of changing the ERA frame from steel to heavywall Aluminium? Is it even possible. The weight savings alone would be worth couple hundred pounds. More gussets would be needed and some areas would need more support. TIG welding would be the other problem and alot more time involved. Is it doable?? I had a brain fart Bob Rick L.

[ERA Chas]

Rick,
Would not a carbon body vs glass accomplish similar weight savings with less hassle and no structural/manufacturing questions??
I don't know, I'm just brain farting too...

[CobraEd]

The new Corvettes have hydroformed aluminum frames

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[Rick Parker]

What real life benefits do you anticipate with street driven vehicle by saving 100 lbs??

This makes for good conversation but rel life benifits are nil.

[john chesnut]

Just to throw my two cents in. Any weight reduction has a very noticable effect on not only track performance but also on street manners. If you haven't driven a 1900lb sport car you should try it! That being said the keys to optimum performance is a chassis that is torsionally stiff, suspension that maintains constant and optimum tire contact, has a low roll center, has zero scrub radius and zero bump steer through normal travel, center of gravity, has 50/50 weight, and with no significant weight infront or behind the axle center line! If you go through the expense of building an aluminum chassis you want to make sure that you address everything else too.
As I see it Cobra owners fall into a few different classes. There are the guys that only care that the car looks like a Cobra, those that want an authentic reproduction, and those that want the optimum performing super car with the heart pounding Cobra shape. I personally want the latter. I have always loved the Cobra and appreciate it's history buy want the ultimate in performance with out spending huge dollars to get it.

[strictlypersonl]

I regard chassis stiffness more important than any (very) small weight savings. There are many better ways to save weight.

Aluminum Chassis

[Roger Cormier]

Instead of Alum. how about Titanium ? Stronger and lighter.

[1ntCobra]

Originally Posted by Roger Cormier

Instead of Alum. how about Titanium ? Stronger and lighter.

How about uranium? Heavier, extremely expensive and radioactive.

[CobraEd]

One of the things that made the real Cobras so bad-ass back in the old days is that they only weighed 1,900 lbs. Most of our replicas now weigh around 2,300 - 2,400 lbs. That is a 400 - 500 lb difference, or about 25% !!!! That is huge.

Think about how fast our cars are now, and then imagine if you took 500 lbs out of it !!!


.

[flwolfman]

Lets see....aluminum frame, aluminum FE stroker, and a carbon body!! Jim

[1ntCobra]

Well what about good old magnesium? It caused quite a disaster for Mercedes at LeMans.

[Power Surge]

Original S/Cs were about 2600 lbs. Remember, iron heads, iron block, boat anchor toploaders, iron rear case.

The Kirkhams were able to build a 2200 lb S/C with an alloy motor, alloy trans, alloy rear housing.

Any Cobra lighter than that, would be FAR from an original type car.

[xracerbob]

I've been trying to do a weight concious build, and am trying to get to 2300 lbs dry weight. Lots of little things like a 14 lb flywheel, a 15 lb battery, lightweight oil lines, etc. plus the obvious ones- all aluminum FE, G-force T-5 instead of the toploader or TKO, Quicktime bellhousing, light weight starter etc. all add up to a significant savings. The next one I'm thinking about is magnesium wheels. About a 70-80 lb total weight savings and its unsprung weight to boot.

From the get go, I was trying to get to a power to weight ratio similar to the Indy lights cars I drove (1400 lb/450hp). Its not really possible, but I won't be that far off (2300lb/600hp). Those cars were so quick, particularly when set up in street racing (Long Beach, Toronto, Vancouver, Detroit) mode. They were all carbon fiber except the few suspension bits and the drivetrain. Light weight is a greater benefit than just putting in more and more HP. The cars turn, stop and of course, go better and are more fun to drive.

[ratsnst1]

As FAR AS THE ORIGINAL COBRAS BEING , SO CALLED HOT, THEY WERE HOT AS OF WORTH ALOT OF MONEY TODAY, IF YOU WERE TO DRIVE AN ALL ORIGINAL YOU WOULD HATE IT, AND I SAID DRIVE IT, NOT OWN IT. THE COBRAS OF TODAY ARE MUCH MORE HIGH TECH, ADVANCED THAN THE CARS BACK IN THE DAY.

[Tim Brewer]

Hey Rats, I think you hit the nail on the head, I agree. But about the aluminum frame. To reproduce an accurate Cobra chassis in aluminum, the tubing walls would of course have to be much thicker. So much thicker that the aluminum chassis probably wouldn't weigh much less than the steel chassis. I believe the only way the aluminum chassis would weigh substantialy less if it were made into a space frame.

[Tom Kirkham]

I have driven CSX3104 on many many miles. It is one of my all time favorite cars to drive. I have also driven many original 289 rack and pinion Cobras. Another great driving car. I have not driven any worm and sector Cobras, so my comments don't apply to them. If you can stand the entry fee, original Cobras that are set up correctly are fantastic cars to drive and live with. Actually I cannot think of a better exotic car to live with. I would dare say that an original Cobra has a much more advanced suspension than most of the replica Cobras...That would include anything with a live axle rear end...

[thorconstr]

I'm looking at a poster on my wall of 1965 427 SC CSX3022. The weight on the poster is listed as 2150 pounds. I don't know how much less an aluminum block and heads weigh, but it has to save 100lbs. So My car should be closer to 2000 lbs.

[strictlypersonl]

As measured by Sports Car Graphic in '65:

Specifications of Street and Track 427s

[RICK LAKE]

strictlypersonal Bob could an aluminium frame be built that is the same as the ERA SC one? I don't know what a carbon fiber cobra shell would cost but weight wise between fiberglass and carbon I would think a 50% savings. FFR and Super both built carbon fiber bodies. I thinking also about my heavy pindrives and rims. Should be able to knock 10-15 lbs off each wheel with a BBS. All shafts for the rearend and drive shaft go to either aluminium or carbon fiber. Rear lower control arms for the Jag rear goes to Aluminium or tube design like the IRS ford rear. Still brain farting Bob. The mega millions is just about right for the pickings. Did Jag ever make an Aluminium center housing? Catch you later RickL.

[Power Surge]

Originally Posted by thorconstr

I'm looking at a poster on my wall of 1965 427 SC CSX3022. The weight on the poster is listed as 2150 pounds. I don't know how much less an aluminum block and heads weigh, but it has to save 100lbs. So My car should be closer to 2000 lbs.

I doubt 3022 was ever 2150 lbs, that would take a LOT of effort to get that low.

The K-bros weighed their original Cobra, converted to SC specs, and it was 2600lbs. One of their KMP cars with alloy everything was only 2200 lbs.

I weighed 4241 about a month ago, and it was 2580. I have a glass body, but I have an alloy trans and rear case, so that kind of cancels each other out. My motor is all iron. My Shelby/Baer brakes weigh less than original Girlings. And I was still 2600 lbs.

On an original COMP car, there's no electric fans, you could have a small racing windshield, you could have alloy heads (rare, but could also be added). But you also have a diff cooler and pump (S/Cs also), and a larger 42 gallon gas tank.

I could see a full boogie comp car maybe hitting 2300lbs.

Cobra's aint THAT light.

I have a full bodied 1959 race car in my shop that's 980 lbs. Now THAT'S light.