Never heard of one and can't see how it would do much good. You are stuck with the main part of the exhaust manifold being inside the cylinder head, so what you do with the big single pipe coming out isn't going to make much difference, in the mind of this old dyno tuner
I noticed no performance or MPG gains from removing my muffler, though others may have a different experience. It sounds like it has en exhaust leak now though (which, in essence, it does, heh!). I like being able to actually hear the engine now (helps a lot for rev matching), but I want to get a glasspack muffler or something so it doesn't sound like a fartcan.
I removed my muffler year and a half ago. May not be accurate bathroom scales 8 pounds. No one has noticed any difference in the sound .there is a very small difference. Kinda like is it Pepsi or 2 Day old Coca-Cola . I'm always under or around 2000 RPM if anyway possible. not a lot of sound
could the exhaust be aimed at back tire to heat it up in winter time.
On rolling downhill from my house to start car --20 miles an hour in the summer 16 miles an hour in the 30s temperatures .be nice to use the heat on The tires .
Reckon Scott's underbelly puts any motor heat on the two front wheels. Versus nothing there at all.
I worked at a plastic foam factory last year. I've got every open space under the hood filled with plastic foam to hold The heat plus 12 foot under tray.
Probably doesn't help or hurt to warm the front tires .
Interesting way to track down exhaust leaks. Attach a leaf blower
to the exhaust pipe of the car ( duct tape) only when car is COOL.
Turn on blower and spray soapy water around manifold, pipes, and
muffler. Identify leaks, let dry, clean and prep surface area. Hard putty
leaks, and let set 24 hours to harden. Use muffler bandage on pipes
and muffler. Don't cover small hole in muffler end (moisture release)
As has been mentioned the Insight has the "header" portion of the exhaust built into the head casting. This is not ideal for a naturally aspirated motor, but can be very beneficial for a turbo application since the exhaust gases are still very hot as they exit the head.
The muffler on our cars is big and heavy. The resonator is actually a very nicely built straight through design like a cherry bomb.
I feel like it would be possible to use one high flow cat with a single muffler and upsize the exhaust tubing by 1/4" or so but that is an expensive route to get a very tiny amount of efficiency gain. You likely couldn't even feel it in your pants.
Go turbo though and it makes a difference. These little engines are begging for a low pressure turbo setup. As Willie has demonstrated!
So I've seen different threads about pros and cons about modifying the exhaust system to get a better performance exhaust. From removing the resonator and muffler and going straight pipe from the downstream oxygen sensor; to a catback system.
From the posts it seems like either of these options may give a couple of HP at the high end (with the reduction of torque on the low end), but that they do not have any impact on mpg.
I also read Cakley muffler mod and air intake modification (closing off the intake, then disconnecting the air intake resonator and leaving that open to act as the air intake).
So it made me wonder if the following would have any impact on mpg:
1) do Cakley's air intake modification
2) put a electric exhaust downpipe e-cut cutout valve to the exhaust system
a) thought one is to put it between the downstream oxygen sensor and the exhaust resonator
b) option two is to put it between the exhaust resonator and the muffler
The thought with the electric exhaust downpipe e-cut cutout valve would allow the cutout to be controlled with a remote to open or close it. So it could be used at the high end and closed at low speeds. Of course this would cause a slight weight addition.
I would be interested if this would help get to a improved exhaust system or have no/negative gain. And looking for the next "project" (the turbo seems a lot more involved than I'm looking for...at least for now).
I also had the muffler removed on my Insight a few years ago. I didn't notice any power or efficiency gains.
I do appreciate that I can actually hear the engine now since it makes rev-matching much easier, but it drones on the freeway and sounds kinda bad from the outside (sounds like it has an exhaust leak... which in essence it does).
I'm planning on getting a glasspack put on to hopefully make it sound better without making it any quieter. Even with no muffler, the car is a very reasonable volume (small engine, two cats, and a resonator).