Does it matter where a muffler is located in an exhaust?

I have a broken baffle in the muffler of my Lemons Civic, and in thinking about replacing it, am wondering if it matters where in the system I put the muffler, for packaging reasons.

The car already has a turbo, so that helps keep it quiet. Really quiet, like nearly the quietest car on track with the muffler and the current dynomax super turbo standard shape muffler. The way the stock exhaust design is routed, after passing the rear suspension on the passenger side, it takes a 90 degree turn into the muffler, then another 90 degree out of the muffler to go out the back. Like this:

In order to facilitate a ghetto made air diffuser in back, I would prefer to make the exhaust go straight out after the rear suspension, instead of having the two bends. There isn't much room between the rear suspension and rear bumper, so I could use one of the smallest bullet mufflers I can find, about 12" long, and it will work OK, and will probably be quiet enough with a turn down and the turbo.

The other option I thought of is mounting a much longer round muffler in the exhaust tunnel. This would be up fairly close to the turbo, maybe 2-3' of piping from the turbo exit to the start of the muffler. It will allow for a larger, and therefore quieter muffler in the middle, and then no muffler will be needed at the end of the pipe. I need to stay under 90db for most tracks here in the northeast.

TL;DR: What difference will it make in mounting a muffler in the middle of the car compared to the more standard location close to the rear bumper?

Do you even need the muffler? As you said the turbo acts as one abet not a really quiet one.

I'm not familiar with the underside of the car in question, but being a race car could you cut out the spare tire well and move the current big muffler farther up and/or forward?

Ith a normal civic, straight out increases the sound level by about 50%.

Add a turn down and you should be golden.

Edit: every change in direction in the exhaust path cancels some sound waves.

I'd put the muffler where ever it is easyist. I don't believe performance will be much different. Sound tone my change, but not volume.

Certainly someone will correct me if I'm wrong.

The closer the muffler is to the engine, the more effective. Or at least, the less you'll have a drone as certain frequencies resonate between the muffler and engine.

Tailpipes are important too.

Everything after a turbo is generally just unneeded backpressure, put a straight through muffler in the middle with a turn down at the end. You'll be fine. We did that and met the 95db limit on our 2.2L powered turbo car and we dumped it in front of the driver's rear wheel.

Our Starion Lemons car has no muffler, just a side exit in from of the rear tire. The turbo keeps it quiet enough.

Knurled wrote: The closer the muffler is to the engine, the more effective. Or at least, the less you'll have a drone as certain frequencies resonate between the muffler and engine. Tailpipes are important too.

The further up in the system the muffler is the less harsh the sound will be. Also the less likely it will rust out due to condensation.

My GLH had no muffler at all, except the turbo. It wasn't very loud at all, and sounded GREAT at full boost!

I think I'll try no muffler at all and see how it sounds. I'll probably get one that can be swapped with an exhaust clamp at the tailpipe for if we ever run afoul of sound restrictions or if we ever have to go back to N/A for turbo issues.

I would be worried about the heat from the muffler in the middle of the car. If no muffler is too loud then maybe some some bullet type would be enough.

Placing the muffler under the trunk is great for keeping pizzas warm.

I like to use the $20-30 summit racing straight through types. I fit 2 on both of the side exit in front of rear tire exhausts I made. They do make an improvement, the turbo car was nice and quiet but the supercharged car not so much

I've done the no muffler thing too. The smaller diameter tube you use the less noise comes out.

For sound reasons, it matters some. Mufflers cancel some sounds, but their main function is to change them into something else. If you put it clear at the end, it will do the best job of actually muffling. If you put it too close to the front, you'll have 12' of tubing just waiting to amplify other waves on different wavelengths in the passband.

For turbo use, there is a school of thought that putting it further back has benefits by leaving a larger volume of air before any restriction to reduce pulses being kicked back that could push back on the turbine. I don't know if it actually amounts to a hill of beans on a dyno.

Further back is a little less restrictive in general (for a given muffler), as the exhaust has cooled slightly by that point, so the volume being pushed through the muffler is slightly less.

In reply to rslifkin:

but, warmer gasses move easier thru restriction (less dense). Catch 22...