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Can exhaust be ridgid?
craigdiver - 26/5/17 at 05:27 PM

Can exhaust be ridgid or does it need some flex component?

Engine is BMW 6 cylinder and original exhaust did not have flexis but probably had play in the rubber exhaust hangers. I'm using the landrover engine mounts that seem stiff, will the engine move much under load?

[Edited on 26/5/17 by craigdiver]

theduck - 26/5/17 at 05:37 PM

Just use rubber bobbins to mount the exhaust to the car?

gremlin1234 - 26/5/17 at 05:52 PM

engines move quite a lot, so you need some flex somewhere.
the other problem with a rigidly mounted exhaust is conducted noise.

40inches - 26/5/17 at 06:01 PM

quote:
Originally posted by gremlin1234
engines move quite a lot, so you need some flex somewhere.
the other problem with a rigidly mounted exhaust is conducted noise.


This is true. I have my silencers rubber mounted, but the manifold/down pipe joint keeps leaking, I am fitting flexi joints, hopefully that will cure it.

Nickp - 26/5/17 at 07:13 PM

My BMW 6 is on Landy mounts too but I've also fitted a Mini engine steady. The exhaust has no flexi and the silencer is sat on a single poly bobbin. Too early to say if this is gonna last without an issue.

ianhurley20 - 26/5/17 at 07:18 PM

My engine is on MX5 engine mounts and the end of the exhaust is on a rubber/metal silencer fixing (can't remember what I pinched it from) it has two studs each side of the rubber and it works fine :-)

SPYDER - 26/5/17 at 07:21 PM

quote:
Originally posted by theduck
Just use rubber bobbins to mount the exhaust to the car?



I'd just do this. The side-exit exhaust in my car is essentially rigid, end to end. Only the silencer is rubber mounted.
My mates Westfield was the same.
If your mounts are stiff the engine might not move much at all.

craigdiver - 26/5/17 at 07:32 PM

quote:
Originally posted by Nickp
My BMW 6 is on Landy mounts too but I've also fitted a Mini engine steady. The exhaust has no flexi and the silencer is sat on a single poly bobbin. Too early to say if this is gonna last without an issue.


Hi Nick, your not sounding too confident ;-), if you made your exhaust again, would you have fitted flexis?

Cheers

Craig

Nickp - 26/5/17 at 07:59 PM

quote:
Originally posted by craigdiver
quote:
Originally posted by Nickp
My BMW 6 is on Landy mounts too but I've also fitted a Mini engine steady. The exhaust has no flexi and the silencer is sat on a single poly bobbin. Too early to say if this is gonna last without an issue.


Hi Nick, your not sounding too confident ;-), if you made your exhaust again, would you have fitted flexis?

Cheers

Craig


No

rodgling - 26/5/17 at 08:25 PM

quote:
Originally posted by Nickp
My BMW 6 is on Landy mounts too but I've also fitted a Mini engine steady. The exhaust has no flexi and the silencer is sat on a single poly bobbin. Too early to say if this is gonna last without an issue.


Mine is on Land Rover mounts, the exhaust is sat on rubber robbins, no flexi section - it's been fine for 6 years. In that time I've had to replace a mount and a bobbin, I think, but the exhaust is completely fine.

[Edited on 26/5/17 by rodgling]

benchmark51 - 26/5/17 at 08:29 PM

My Pinto manifold was over the rail type, 4 into 1 and was rigid to the silencer mount. The mount was a big cotton reel type. I found that the silencer developed an internal rattle that quietened as it warmed up and I suspected the rigidity of the exhaust set up. I put in a short flexy pipe between the manifold exit and silencer and was surprised at how much the engine was now moving. I think including a flexy section is a good idea.

craigdiver - 26/5/17 at 09:47 PM

quote:
Originally posted by benchmark51
My Pinto manifold was over the rail type, 4 into 1 and was rigid to the silencer mount. The mount was a big cotton reel type. I found that the silencer developed an internal rattle that quietened as it warmed up and I suspected the rigidity of the exhaust set up. I put in a short flexy pipe between the manifold exit and silencer and was surprised at how much the engine was now moving. I think including a flexy section is a good idea.


Good advice thanks, don't think having the exhaust supporting the engine sounds like a good idea.