I just came back from a drive and I’m wondering why my 3.0L I6 engine which has roughly 385HP is relatively quiet besides a low growl compared to my extremely loud lawnmower which as a tiny 6HP single cylinder? Would the muffler of my car make that much of a difference?
In: Engineering
Ever been to a race track? Race cars don’t have mufflers.
Cost. Your lawnmower is a piece of junk.
Also the more cylinders you add, the less THUMP the exhaust has to deal with. It becomes more of a steady air stream. This is easier to tune.
But mostly the mower is built to a price not a quality. Also, once you get a modern electric machine there is no going back. Quiet is worth paying for, and a battery every 7-15 years is cheaper than fuel now. If it has a LFP lithium battery it could go 20 years. Yes, batteries have come a long way.
Using long lengths of pipe for the exhaust filters out a lot of higher frequencies from the engine and reduces the noise. Anyone who’s ever ran an engine with any exhaust knows what I’m talking about. Even with headers only, it’s still very noisy.
On push mowers, there’s only a small canister-shaped exhaust or maybe something a little longer but not by much. The ones they have are far too short to muffle the sounds from the engine.
I’m not sure how much this factors in, but cars have a lot of plastic in the interiors and that might play a role in muffling the sounds but the main factor at work is the length of the muffler.
Also compare apples with apples. Lawnmowers operate at their highest power setting almost constantly when being used. Cars mostly cruise at about 30% power or less. Rev your car’s engine to 80% of its redline and hold it there. See how noisy it gets to an outside observer? When I throttle back on my lawnmower to empty the grass catcher, it is quite muted.
Your car is essentially a luxury product, with lots of extra engineering put into it and the sound was absolutely a part of the design process. A lawnmower probably didn’t have all that put into it.
Kinda like how my economy car is loud as fuck with it’s whopping.. 125hp. I highly doubt anyone put much thought behind the sound the way they would for a sports car
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