I am building mid engine Beetle and having started fabricating the trans tunnel (50mm box) am thinking that with coolant pipes, fuel lines, brake lines, wiring and shifter cables it might be a bit congested so was toying with the idea or running the coolant pipes (35mm id stainless) inside the box section.

Now, is my concern that the hot water pipe might cause the box section to expand/contract unfavourably reasonable or a bit ocd? Or should I run brake hoses, wiring and fuel line inside the box and keep the coolant pipes up centre of tunnel, which could be left open to elements at the bottom

Thanks

I personally wouldn't run anything in the chassis tubes. How you going to check the condition of anything you put in there. Only time you'll know there's an issue is when coolant starts pissing out the end of the tube.
Just a thought.

No one picked up on the point that Beetles are air cooled ?

I presume the OP is using a different water cooled engine than a 20hp Beetle engine

I can not see a problem with running coolant pipes in a tunnel, as long as they were clamped well in
and possibly insulated ?

If I was to consider this, I would use a constant uncut tube, with flexi hoses or similar at each end that would be serviceable
if required,

steve

The space inside a big box section is dead space, why not run something through it? I'd make sure you could get the coolant pipe out when the car is fully built but otherwise go for it.

we run main battery cable, clutch & brake hoses thro' the top tubes on the Furore, saves loads of faffing with clipping up & nothing to inspect. If I were going to run cooling pipes that way I'd want one solid aluminium pipe from front to rear & the ability to slide it in/out from either front or rear of tube once fully built, as long as you insulate it from vibration/chaffing inside the tube (we rubber grommet our pipes etc) then no reason not to.

The expansion due to heat in a coolant tube would be pretty irrelevant

quote:

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Originally posted by steve m
No one picked up on the point that Beetles are air cooled ?

I presume the OP is using a different water cooled engine than a 20hp Beetle engine

I can not see a problem with running coolant pipes in a tunnel, as long as they were clamped well in
and possibly insulated ?

If I was to consider this, I would use a constant uncut tube, with flexi hoses or similar at each end that would be serviceable
if required,

steve [/quote

Modern Beetles are water cooled!

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nick205 - 27/5/20 at 08:04 PM

quote:

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Originally posted by rusty nuts

quote:

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Originally posted by steve m
No one picked up on the point that Beetles are air cooled ?

I presume the OP is using a different water cooled engine than a 20hp Beetle engine

I can not see a problem with running coolant pipes in a tunnel, as long as they were clamped well in
and possibly insulated ?

If I was to consider this, I would use a constant uncut tube, with flexi hoses or similar at each end that would be serviceable
if required,

steve [/quote

Modern Beetles are water cooled!

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Modern Beetles are Golfs in dappy outfits IMHO.

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gremlin1234 - 27/5/20 at 08:46 PM

as far as I remember, the 'RAC blue book' prohibits things inside chassis rails, since they can't be inspected. so you would not be able to join any race series
I found it

quote:

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5.20.12. Not carry or pass any liquids or gases, other than air
at atmospheric pressure, in or through any tubes comprising
part of the chassis structure.

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https://www.motorsportuk.org/wp-content/uploads/2019/11/Blue-Book-2020-2.pdf

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coyoteboy - 28/5/20 at 09:14 AM

If I were planning on racing, I would not as I don't like the uninspectable nature of it.

In reality, I'm fine with the practicalities of it and so long as it's rubber-supported down its length it will likely be fine.

Assuming the chassis sees a 100C difference in temperature from one member to the next, you might be looking at ~1mm length change between any two members. In reality you're not likely to see the chassis tube get even close to that, so the thermal expansion will be tiny.

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jollygreengiant - 28/5/20 at 10:05 AM

For SAFETY reasons I WOULD NOT run electrical in the same tube as FUEL, BRAKE FLUID or WATER.

JMHO

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Simon - 28/5/20 at 05:43 PM

Will probably just be the coolant pipes in bottom two and wiring in one of top two. Fuel and brake lines can take their chances with the gear shift cables

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MikeR - 28/5/20 at 11:19 PM

Chapman ran client in a tube in one race car. It rusted. It was then banned. I appreciate you will be in a tube inside a tube, but how will you know it's not leaking and rusting?

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SteveWalker - 29/5/20 at 12:28 AM

A drain hole in the outside tube will tell you if there is a leak - often used in industrial and nuclear processes.

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Simon - 29/5/20 at 11:29 PM

I'll be using stainless steel

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02GF74 - 30/5/20 at 04:37 PM

quote:

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Originally posted by MikeR
Chapman ran client in a tube in one race car. It rusted. It was then banned. I appreciate you will be in a tube inside a tube, but how will you know it's not leaking and rusting?

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Will stainless steel rust?
If it leaks, the water level will drop, easy to spot.

I'm voting it will be fine as long as there are no inaccessible joins.

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Sam_68 - 30/5/20 at 06:09 PM

quote:

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Originally posted by MikeR
Chapman ran client in a tube in one race car. It rusted. It was then banned. I appreciate you will be in a tube inside a tube, but how will you know it's not leaking and rusting?

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Not one, several Lotus race cars ran coolant through their chassis tubes - all the Lotus 22, 23 and (I'm pretty sure) 24 models did it, for a start.

You can see the 'tails' for connecting the rubber coolant pipes that linked to the engine and radiator on this (replica) 23 chassis:


The tubes don't rust if you have antifreeze/rust inhibitor in the coolant, of course. Back in the day, you weren't allowed to use antifreeze in racing cars for fear of spillages making the track slippy.

Several spaceframe racers (including the 23 - note that there are 2 pairs of outlets front and rear) also used the chassis tubes to run oil through (which might be more useful for a Beetle engine), but the problem there was ensuring no contamination, if you blew the engine up.

In both cases, the trick is to ensure that the pipes that are carrying the fluids are one-piece and continuous, so that they don't leak if a weld cracks.

That aside, and racing rules notwithstanding, I don't think it's an entirely bad idea.

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