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 !!!


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[flwolfman]

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

[1ntCobra]

Originally Posted by 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 !!!


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I think the only Cobra that was in the 1900 lb weight range was the flip-top, yet I hear people throwing around that number a bit. I believe that the Kirkham cars with their high tech light weight billet suspension parts fitted with an modern aluminum small block engine is still over 1900 lbs.

Perhaps the 1900 lb number is just more Shelby snake oil legend.

Actually I think most replicas are in the 2500 to 3000 lb range.

[SLHetal]

As far as original Cobras and their weights here is what I show:
427 Cobra unladen 2350 lbs.
289 Cobra unladen 2170 lbs.
Autokraft/AC Cobra unladen 2469 lbs.
I'm not too sure about any original Cobras weighing much less than that.
Sam

[1ntCobra]

Originally Posted by SLHetal

As far as original Cobras and their weights here is what I show:
427 Cobra unladen 2350 lbs.
289 Cobra unladen 2170 lbs.
Autokraft/AC Cobra unladen 2469 lbs.
I'm not too sure about any original Cobras weighing much less than that.
Sam

What is your source for those number? And what does unladen mean?

[Blue66]

I think the original 427's were very not very heavy

[WarrenG]

In addition to its benefits, titanium is more brittle than either steel or aluminum and you'd have to spend more on the frame than most spend on the entire car.

[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.

[strictlypersonl]

Weird as it may seem, most structural metals have a similar specific stiffness (stiffness/unit weight). There is no advantage to using one over the other except for gaining strength.

Titanium Fallacy

[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.