There's been lots of discussion about how to safely wire a genny for
emergency domestic use but has anyone successfully extended the exhaust so
that it can run safely in the garage?
I'm considering a piece of rigid pipe into the existing exhaust (clamped and
sealed somehow), connected to a length of flexible exhaust pipe and then to
a length of rigid out of a window or custom-made hole. Presumably all
pipework needs to be large bore to minimise back pressure. Sealing is
important for safety.
Any success stories?
I'll be interested in this too. I have a feeling it'll be a no-can-do
because if the genny is being run in a confined space (as in a garage
situation) then it might cause a fire situation - and trying to find a
betting company that will take odds on the insurance companies saying
"bog off" to any claims made will be like finding rocking horse pooh
for the rose garden.
I'm actually thinking of building a small lean-to on the side of the
garage for the genny. That way it would be protected from the direct
elements like rain and snow, and also reduce the noise nuisance for
the neighbours. And if it catches fire then it'll most likely
vapourise the lean-to without causing much other damage.
My fixed generators have exhausts extending through outbuilding walls.
They were already in place when the house was bought. I could certainly
take some photos of the pipe work if that would be of any use.
Again, my three gennies are in stone built outbuildings and have been for
over ten years as far as I know. The rooms are vented, though in summer
they are vented manually---we open the doors!
Try asking on uk.rec.engines.stationary
Much depends on the size of the thing, and how much use it's going to
But I wouldn't extend downstream of an existing exhaust. The gas has
expanded and cooled by this point, and moisture is condensing out.
Although you can build it, you'll get problems in service, especially
I'd favour cutting out (or buying as a spare) a new flange to fit the
manifold / cylinder head, then welding on pipe from there. Use
flexible pipe as necessary for vibration. Then when you're near the
end and probably outdoors, fit a silencer box. Arrange suitable
drainage for condensate anyway. Parts like U bends and silencer boxes
are available from performance car places (Peco used to be
convenient), but go to somewhere serving the kit-car market, not the
tweaked Nova and baseball cap idiots (retail markup varies
enormously). You can also just try browsing the parts catalogue at
Edmunds Walker and using light truck parts.
Lag the pipe. This is partly to reduce noise, partly to keep the heat
in (improves gas flow, reduces condensation problems). The dimpled
stainless steel used for aircraft pipe lagging gives a very neat
If it's a high performance engine, you may need to design a proper
system, and that will probably need an expansion box close to the
engine. There are any number of books that describe this ("Four-stroke
performance tuning in theory and practice" is the one on my shelves).
Die Gotterspammerung - Junkmail of the Gods
Not with that specifically, but I have seen loads of staionary engines
run via ducting to the outside world.
I am sure if you keep the pipe large, and stick a silencers somewhere in
it, it will be fine.
I run my 7.5 KVa Honda engined (GX390) generator in the shed with a 8 foot
flexible exhaust pipe attached
running out through a hole in the wall. No re-jetting and all has been running
about 5 years, although still need to discharge the exhaust into some sort of
its a bit noisy, especially when the power goes off as everything goes quieter
(no tv /
radios etc so you are aware of the contant noise of e.g. a generator.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.