SALE! Exhaust U-Bend prototype tubes

[David Kirkham]

Guys,

FOR SALE!!!

Here are some 20 prototype tubes for sale. These are the first tubes off our mandrel CNC tube bender when we were prototyping the exhaust for a 427 Right Hand Drive and 351 small block head tubes. The radii of the tubes is 3 inch and 5 inch. The tubes extend all the way out the body.

The tubes are for sale for $10 each + shipping. This is a screaming deal. First come first serve.

EDIT:

The tubes are 2 inch diameter with an 0.0625" wall, steel.

David

[Jerry Clayton]

whats the od and thickness of the tube and are they ss or mild steel??

[Three Peaks]

Originally Posted by Jerry Clayton

whats the od and thickness of the tube and are they ss or mild steel??

Same question. I need a 2" OD with a 90 degree bend for my gas filler tube.

Bob

[David Kirkham]

The tubes are 2 inch diameter with an 0.0625" wall, steel.

David

[David Kirkham]

Originally Posted by Three Peaks

Same question. I need a 2" OD with a 90 degree bend for my gas filler tube.

Bob

What radius are you looking for? What length legs? We may have one in stainless floating around here.

David

[Three Peaks]

David,
That would be perfect. I need approximately 8-9" x 18" legs. I'm using an original style chassis so it should be very close to what a Kirkham would use.

I'll PM you for payment/shipping info.

Thanks,
Bob

[WardL]

David, I have the standard SPF exhaust headers and heard they are what is best, but I question that statement. Are there any basics or calculations to determine the optimum design? When you were bending tubes, were you bending them to fit or did you have some particular calculated design in mind? I what other criteria can you design for besides diameter and length? I'm assuming one goal is to have the same length tube out of each port? I'm not going into the design business, but would like to know what is "best" for my engine. Any comments would be very interesting. Thx!

[David Kirkham]

Originally Posted by WardL

David, I have the standard SPF exhaust headers and heard they are what is best, but I question that statement. Are there any basics or calculations to determine the optimum design? When you were bending tubes, were you bending them to fit or did you have some particular calculated design in mind? I what other criteria can you design for besides diameter and length? I'm assuming one goal is to have the same length tube out of each port? I'm not going into the design business, but would like to know what is "best" for my engine. Any comments would be very interesting. Thx!

There are myriad design considerations when making an exhaust system--equal length headers being one of them. On a Cobra, however, there really isn't enough room to do that. Other considerations we take into account are different alloys (stainless being better than mild steel, but costing more). We use stainless alloy 304. 321 is even better, but it is quite hard and expensive to find. 321 is much more resistant to heat than 304, but we have never had any issue with 304.

When we make an exhaust system, we either make them by hand, jig them, and then CNC program them...

OR

If we have complete CAD data, we will design them in CAD and then program them into our mandrel CNC tube bender.

As for detailed exhaust theory, I'll ask my brother Thomas to comment. He is an encyclopedia on such topics. My field is manufacturing and alloy selection.

David

[David Kirkham]

Bob,

Is that an 8 or 9 inch radius with 18 inch legs?

Are you making a copy of a street car or an S/C car?

David

[Three Peaks]

David,
Building an SC car. The leg lengths I'm looking for are approx. 8-9" coming out of the tank and approximately 18" vertical up to the filler. Can't tell for sure what the radius would be, but the 3 or 4 bends in your picture on the far right look about right. I can't get perfectly accurate measurements as the body isn't on the chassis just yet.

What do you use on your SC models? My tank isn't a standard tank for a Shelby. I believe the person I bought it from told me it was from a Superformance. Fits perfectly and the filler tube lines up just about perfectly.

I sent you a PM last night.

Bob

[David Kirkham]

Referring to the tubes on the right in the photo above--the bends at the top are are 5 inch radius bends. I'll look to see what I can find in a 90 degree bend. Also, we use a rubber filler hose to go to the gas cap. That way you have a little play to get things to line up properly. The longer the rubber hose, the easier it is to work with.

We don't have any extra stainless tubes right now. They are being used on a SOHC install

David

[maurice19]

David,
You are full of teasers lately, SOHC and a Daytona look coupe. WOW

Maurice

[Three Peaks]

David,

If I could get one of the 90 degree tubes on the right with the legs cut to 8" and 18" I would be good for now. I don't need the entire tube length, just the 90 degree elbow. Let me know on shipping.

Bob