Exhaust Length

[twitchy]

I was told that making your exhaust system overall length longer will allow your engine to generate some extra horsepower.

For example, look at the BMW M series, coupe and roadster. The roadster has something like 15 horsepower less than the coupe since the exhaust system cant be made long enough in comparison. This leads me to my 2 questions:

-how does removing your exhaust system make sense in this case (a la race car, etc)

and

-if I was to make my exhaust system longer when I redo it in the spring (make it "zig zag" underneath) would there be any benefit?

[PAnut240]

Well for the coupe/roadster theory its simply because the coupe is a longet car, hence the longer exhaust. Now as for you wanting to make your exhaust zig zaged, BAD IDEA if you want power. All that will do is make excess backpressure inside your exhaust.

The race car thing with no exhaust, simple, highly built engines set up for no or little exhaust system. On your every day driver/weekend street racer you want a nice blend of free exhaust flow and backpressure. Flow of coarse higher. A nice strait exhaust with a good silencer/muffler at a reasonably sized pipeing will help you creat more HP than a windy, small, or over sized exhaust will.

To break it down really simple for our type of engine, no exhaust... Burned out exhaust valves/ o2 sensor. to restriced IE stock exhaust or clogged muffler.... clogged Cat converter and sluggish throttle response.

I hope some of my jibberish helps.
Later
Jim