Do you have to run mufflers ?

Please excuse my ignorance. Do you have to run mufflers on a motor or can you run a pretty much straight, blow throw exhaust right at the collector with a turn down ? How will the performance be affected ? Pro's/Con's ?

 

You can run straight-pipe-exhaust if you wish, and don't mind trying to avoid the "LAWMAN".

A street engine will perform better with some back pressure.
You can use these to have the best of both worlds.
http://www.carchemistry.com/ccinserts.html
Glenn

 

The proper backpressure is needed to scavenge the engine. A 4stroke requires less back pressure than a 2stroke for optimal power.
The less restriction the higher the powerband is moved and if there is too little restriction the powerband may be higher than the rev range of the cam or heads.
I have a 350 in a Supra with no muffler and it is quieter than my nova with dual 2.5" flowmasters. A good muff-man can set you up no problem.
-1fast72nova

 

Mine runs fine. Make sure to run it a litlle rich and dont' drive like an ass and 'Lawman' usually won't bother ya.

 

I run straight 2-inch dual exhaust, all the way out the back on my 60 El Camino. It is not too loud at all, but definitely not stock. I think the extra bends and length make it sound just right. Stock rams horn manifolds also keep it quieter than headers

Your plan for headers with a turndown will be very loud and you will attract unwanted attention from the law. Your performance increase will not be worth the headaches.

As a note of comparison, on my old drag race Camaro, with 3-inch pipes and flowmasters, it would lose about .15 seconds and about 2 mph running through mufflers vs open headers. It was certainly much nicer to hear more inside the car with the mufflers and saved taking them on and off all the time. I originally put them on the car to drive on the street (high 10 sec car, 14x32 slicks, fiberglass doors and front end, not at all any type of street car). I ended up running with the mufflers at the track, it doesn;t matter when you are bracket racing if you are a little slower.

 

"A good muff-man can set you up no problem."
I've always thought of myself as a good muff-man

 

Ok, so what you are saying, no muff's LOUD possible trouble with lawdogs. Also, may not achieve total perfromance of motor. Run muffler's, don't be concerned with powerloss, etc, etc,....Thanks for the info.


Muffman.........that's good.

 

Screw it dont run mufflers Our '55 Gasser has just open fenderwell headers, and my '59 Super Stocker has glasspacked side-exit exhaust with cut outs. If you have an old car and drive it responsibly, you probably wont get in trouble with anyone. Its worth the risk for me. I cant stand a quiet car. And as far as performance goes, open headers or straight pipes will increase it. It will only work against you if your exhaust is opened up too close to the engine. Driving a hot rod should'nt be quiet and too comfortable, if it is you might just go right off to sleep.
-Dean