Firstly a BIG thanks to Martin "Cheffy" for coming over to calm my nerves about taking a chunk out of my chassis.

I had a clearance issue between my exhaust and the upper chassis rails, like they want to occupy the same 5mm of space. So we/I have cut and lowered the rails whilst trying to retain the strength.

I know that I've removed a little strength by bending the tubes, but the curved sections are made from 2mm plate welded to form a box section.

The question is have I ruined my chassis stiffness?

I've attached a series of pictures to show what we've done.

ATB Dan.


Clearance



1St Cut



RE aligning



1st one in



Both in



Complete 1



Complete 2

Looks ok to me but it could be an easy area for the chassis to fold in the event of an accident.

If you're worried about this then you could add a couple of support bars as I've shown, I'd imagine that you wouldn't notice any difference when just driving the car though.
Rescued attachment Untitled-1.jpg

For normal driving it'll make no difference.
Yes in a crash it might fold. Then again, if anything has to give the passenger side is preferable (unless you've got a passenger!!).

Not all chassis have the two top rails anyway so having two with bends in looks fine....

Personally rather than make the curves from plate I would have made slices into the tube and bent it then welded it....

Oooo, why not just jack the engine up a bit? 5cm under the mount and tilt the engine over....

It looks like you have moved the tubes down almost exactly 25 mm. If that is the case I would have just welded another straight tube underneath and overlapping the cut off stubs of the original tubes. Add closing plates on the (cut at 45 deg) open ends that lap onto the original tubes and job done.

Cheers

Fred W B

I'd stick another diagonal in, going the other way to the existing tube.

Well I would if I could weld!

It'll be fine.

Mike

quote:

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Originally posted by Fred W B
It looks like you have moved the tubes down almost exactly 25 mm. If that is the case I would have just welded another straight tube underneath and overlapping the cut off stubs of the original tubes. Add closing plates on the (cut at 45 deg) open ends that lap onto the original tubes and job done.

Cheers

Fred W B

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id have moved the exhaust .

Cheers for the comments gents.

I've done the weld another tube underneath trick before and it always stuck me as an inelegant solution,

I can't weld stainless and waited 4 1/2 months for GTS to supply this one, so it was going to stay.

I didn't feel like the changes would be noticeable on the road and if I had a crash then I suppose it's the best side to go.

ATB Dan.

join the 2 curves with each other...

in an acident it will need to move the 2 instead of 1...

sow 2 as strong...

also you could add some plate 3mm in the curve...

Tks

looks really good to me
if you really want to belt and braces add a stiffener either upright or better at an angle the triangle is strongest shape remember
in an accident wot accident also theres a big lump of engine to stop the chassis from folding
cheers les g

Err, eh,what!!!

quote:

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if I had a crash then I suppose it's the best side to go

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I have been wondering about this in case it becomes a problem on my chassis (not got to the stage of installing the engine yet). My thought had actually been to make an elongated haxagon through which the manifold would pass, thereby doubling the effective strength of the cutout, but I am not sure if this actually works in principle in strength terms in a frontal impact - anyone care to comment?

Andy, I like the idea, but from when I made a crossflow car i made the exhaust hole a really close fit to the side panel.
It was a complete pig to fit and remove, out had to undrill all the rivets to remove, so i would imagine the hole required for the collector would be quite big.

Martin, I wasn't planning on crashing and i might have to sit there one time.

ATB Dan.

If I have to do it I would make the hole big enough for the manifold to pass through, so it would have to be pretty big. Hopefully won't come to that anyway.

Well it's all painted and i'm well happy with the results.

Andy i hope yours goes well.

ATB Dan.

iv worked alot with metal, all shapes and sizes grapes and qualitys, when you add a heat or put bends in any metal it makes it weak as the metal grains miss shape, but i dont think it will matter as you are only using thin box section not 40mm thk plat lol, i would of wormed up the manifold and bent it up as its not a structeral part. looking good though bet you cant wait to get it finished lol.

mat
p,s dont grind the welds of it will take strength away.