Ladder frame chassis rigidity & engine movement?

[Ant]

I have the opportunity of running at least two braces in the cockpit area to try and strengthen the chassis, and missing the seats, as my chassis is similar to an original style!
I have a single hoop roll bar, back brace and long forward brace going down to the main chassis rail. Some cars have the doors not opening and also large forward braces off full hoop roll hoops.

The major problem is I think this detracts from the original design and makes them into like a Transam style race car, where as this car is for mainly road use, but I am thinking is a ladder frame that much of a disadvantage over a space frame, some space frames may be no stronger than this simple design when put to the test?

Also has anyone considered the need to fit off the RHS Head a brace with maybe urethane bushes to limit engine movement, my last cobra had turn buckles on the cast heads and was all solid mounted, not that greater idea for road! - as am running oval (under car) pipes under one area of the chassis through about 3.5" of space, but there is plenty of room for muffler.

Cheers Ant

[Satanpez]

I've been reading up on chassis...but I'm no expert.

Do you have any sort of backbone in the car? IE, what's the trans tunnel made of, is it just 1x1 16 guage tubing, fiberglass, sheet aluminum?

It seems the easiest way to strengthen a ladder or space frame is to have a central backbone. Even normal roll cages don't add the same amount of strength.

-steve in nj-

[Ant]

Hi Steve

My tunnel is glass with no tubing, the ladder has a good x brace through to the gearbox x member and then its just two big hunks of 4X3 RHS going through to the front suspension the rhs kicks up after the engine mounts and has gussets in this area.

I think a backbone would help the central part of the chassis, the rear and front of the car is well designed and well braced!
Mounting the engine and transmission solid and making them part of the chassis would strengthen the center to within a few inches of the front suspension, but I dont know whether thats such a good idea.
My last Cobra has the motor solid with rod ends etc, maybe some hard bushes with a small amount of compliance may work better depending on design!

Ant

[750hp]

Ant - you will install a tailshaft loop, won't you? A broken uni will put that tailshaft in your lap, and probably spinning at a few thousand rpm.....

Was it just a little vibration that you didn't like about the previous solid-mounted engine, or was it stressing the chassis at the mounting points?