Original 4 inch vs. Billet Poll

[David Kirkham]

Fellow Car Nuts:

We are having a friendly dispute here in the land of aluminum bodied Chariots of Fire. The question is, assuming the same price (which is a BIG assumption that would undoubtedly prove to be UNtrue, but humor me please)...

If you were to purchase a new Kirkham and had your choice of the old original 4" style chassis or the new billet aluminum chassis we are making for a customer (remember, assuming the same price) which would you rather have?

For those of you who don't know about the billet chassis, here is the link.

http://clubcobra.com/forums/showthre...d=85278&page=1

Thanks!

David

[Power Surge]

The billet chassis is neat, but I would not want it in my car.

Since I like originality in my Cobra, I prefer an original chassis with original style suspension.

But I feel the original style chassis with the billet suspension parts your now offer is the hot setup for the average guy.

What I WOULD like to see, is you build a steel 4" tube chassis that uses the pushrod suspension. THAT, is what I'd like to see.

[ENTDOC]

original. The stainless option was acceptable but I would not buy one with a billet chassis.

[David Kirkham]

ENTDOC,

Curiously, what don't you like about the billet chassis?

David

[Lew Ledyard]

I am in the same boat with Entdoc. I like the period piece. My car isn't exactly like what was made in 1965, but it embodies the feel and spirit of what was available (although executed to a degree that is a million times better than the original). We have come a long way in the past 40+ years, but the compromises and short comings of the old design are part of the appeal for me.

That being said, my house is 150 years old, my newest motorcycle is older than my wife and I still think that the Rolling Stones are the greatest rock and roll band, so there is a pattern....

[RodKnock]

What are the benefits, to the consumer, of the billet chassis over the original 4"?

[David Kirkham]

Originally Posted by RodKnock

What are the benefits, to the consumer, of the billet chassis over the original 4"?

In theory (not proved until tested).

Aluminum chassis is on the order of 300% stiffer. It should handle much better.

The suspension has been significantly upgraded and tuned to the best we could make it.

CG of the billet chassis is moved back 2 inches. I know that doesn't sound like much, but that is about the same a small block is moved back from a big block. An aluminum small block with all the aluminum goodies (flywheel, water pump, etc.) is lighter than the old iron block and heads 289's of old.

Fianlly, no matter how you look at it, the aluminum chassis is pretty cool.

David

[mr bruce]

Seems like a waste of your machinery and talents, Cobras have been done everywich way already.Keep them vintage. you want to play with new tech, do something like a mosler, honeycomb samich chassis, new tech suspension, etc.

[ENTDOC]

David, for the same reason a JBL or Cutting Edge Cobra does not appeal to me. If I wanted the latest, greatest tech ,I would buy something on the order of RCR's SLC or similar. A cobra is a 60's car and a Kirkham( at least in its original design) embodies the best of that era in terms of duplication. I will compromise on modern brakes and better materials but not in execution or spirit.

[olddog]

Originally Posted by David Kirkham

In theory (not proved until tested).

Aluminum chassis is on the order of 300% stiffer. It should handle much better.

The suspension has been significantly upgraded and tuned to the best we could make it.

CG of the billet chassis is moved back 2 inches. I know that doesn't sound like much, but that is about the same a small block is moved back from a big block. An aluminum small block with all the aluminum goodies (flywheel, water pump, etc.) is lighter than the old iron block and heads 289's of old.

Fianlly, no matter how you look at it, the aluminum chassis is pretty cool.

David

I agree the billet chassis has a wow factor through the roof. 300% is impressive, but what does it mean in practical real world conditions? If you had 600 lb-ft of FE torque hooked to the ground some magical way, how many inches would the frame twist on the 4" round tube verses the billet?

What I am try to get at is short of racing would it really matter? Kind of like increasing Hp. At some point, short of all out racing it just doesn't matter on the street, other than the fact it will get you killed quicker.

PS:
I actually do not have an opinion until I understand the difference.

[Silverback51]

Well I have to say that from an engineering and manufacturing stand point it's very impressive.

When you did your FEM model analysis, what kind of loads did you apply and what were the resultant stress loads? Deflections?

How would this type of frame hold up to everyday use as far as fatigue?

And if you do not want to share this data, I can understand that you may consider it propriotary. But I am curious.

It's a work of art. Congratulations.

[ddcobra]

My vote is 100% billet sorry for the purist.

It's a work of art. Congratulations.

Don,

[ENTDOC]

to me , this is what a cobra should look like and when the hood is opened the guts should reflect a similar trend.


and this is what a billet suspended modern framed car should look like on the outside

[David Kirkham]

Originally Posted by Silverback51

Well I have to say that from an engineering and manufacturing stand point it's very impressive.

When you did your FEM model analysis, what kind of loads did you apply and what were the resultant stress loads? Deflections?

How would this type of frame hold up to everyday use as far as fatigue?

And if you do not want to share this data, I can understand that you may consider it propriotary. But I am curious.

It's a work of art. Congratulations.

If I remember right (maybe not, so this is for educational purposes only)

I think we used 1000 pounds up and 1000 pounds sideways on EACH wheel cycled 100,000 times with a 15,000 psi yield.

David

[David Kirkham]

Originally Posted by olddog

I agree the billet chassis has a wow factor through the roof. 300% is impressive, but what does it mean in practical real world conditions? If you had 600 lb-ft of FE torque hooked to the ground some magical way, how many inches would the frame twist on the 4" round tube verses the billet?

What I am try to get at is short of racing would it really matter? Kind of like increasing Hp. At some point, short of all out racing it just doesn't matter on the street, other than the fact it will get you killed quicker.

PS:
I actually do not have an opinion until I understand the difference.

You are right. Most of this whole exercise was WOW factor. What does 300% really mean? Not sure until I drive it! But be sure I will let you know. Should the car hook up better, yes. Will the customer actually drive it at 100%? Probably not; he is a really tame driver. But, we still had to engineer it as if he were going to drive it like a scalded skunk. But, that is the case with any of our cars. Our cars can usually out drive their drivers (I know they can me!) But, then again, so can a Ferrari, Bugatti, etc, and people still own them. Maybe it is just an inner feeling of WOW, THIS is what a car is supposed to be like--not that you could ever use it without losing your license.

David

[RodKnock]

Lew, you made it through a post with the Kirkhams without asking about them making the MAGNESIUM WHEELS! Progress.

David, I don't know what is meant by "CG", but would the exterior design change at all? If an expert, and we have a lot of them here on CC, were to look only at up top (i.e., engine compartment, trunk, interior, etc.), not from underneath, then would the billet chassis make the exterior look different?

I'm inclined to vote to make the car better, and the frame appearance isn't as important to me, but I would want everything that's visual to the eye to look period correct or am I asking too much?

[Richie18]

As long as the car's exterior shape and look are kept then i think by all means suspension performance/technology should be pursued. How many times does anyone see the suspension on any cobra owner's vehicles? And if they did what would be at all disappointing about a suspension that uses new technology?

Why not make the car be able to better handle some 500hp when that is what is typically seen in these cars?

A billet aluminum chassis would impress anyone.

[ENTDOC]

a billet aluminum chassis would not impress me I assure you

[RodKnock]

Originally Posted by Richie18

As long as the car's exterior shape and look are kept then i think by all means suspension performance/technology should be pursued. How many times does anyone see the suspension on any cobra owner's vehicles? And if they did what would be at all disappointing about a suspension that uses new technology?

Why not make the car be able to better handle some 500hp when that is what is typically seen in these cars?

A billet aluminum chassis would impress anyone.

I agree, that's what was attempting to say.

[Sharroll Celby]

Originally Posted by Richie18

As long as the car's exterior shape and look are kept then i think by all means suspension performance/technology should be pursued. How many times does anyone see the suspension on any cobra owner's vehicles? And if they did what would be at all disappointing about a suspension that uses new technology?

Why not make the car be able to better handle some 500hp when that is what is typically seen in these cars?

A billet aluminum chassis would impress anyone.

This sums up my feelings as well.


Would I be able to call my car a .........................COBRA? !!! lol !!!

I could deliver my Cobra lookalike thingy and you can practice building your billet stuff on my car. I will gladly pay you Tuesday for billet stuff TODAY!!! lol !!!