You’ve got questions, we’ve got answers. We work with the Summit Racing tech department to help you tackle your auto-related conundrums. In this week’s Mailbag, we’re discussing two-chamber vs. three-chamber mufflers, and which produces the loudest exhaust notes.
Q: I have a 1989 Ford Mustang GT. The car has some upgrades like underdrive pulleys, ignition and coil, and a couple other things. The problem is, the car is too quiet. I have shorty headers, an H-pipe, and Dynomax Super Turbos. I want to use Flowmaster mufflers, but I don’t know whether to get the two-chamber or three-chamber. I have been told two-chamber mufflers are louder.
My friend has a carbureted Mustang 5.0 with two-chamber Flowmasters, and it isn’t as loud as another friend’s ’87 Mustang with three-chamber mufflers. Does carburetion or EFI have an effect on exhaust sound?
A: If lots of sound is what you want, go with the two-chamber Flowmasters. If the exhaust systems are equal, a car with the two-chamber mufflers will be louder than a car with three-chamber Flowmasters. The guy with the ’87 may have had bigger exhaust pipes, which will make the system louder. The type of induction system (carburetor or EFI) should not make a difference in exhaust sound quality.
I found that ignition timing has some effect on exhaust sound. That EFI car idles around 22-25 degrees of timing with the ‘spout’ connector in as it should be. The ’85 has a base timing of 10 degrees btdc with no vacuum advance at idle. ( The vac advance comes in later, it’s hooked up to the ported source on the carb.) Later ignition timing causes the exhaust at idle to be louder.
Also, a crossover pipe in the exhaust makes a difference in idle sound quality.
I’ve been doing “Exhaust Systems” for years.
If you “LOUD”…. Go with Glasspack’s,if you want quite I’d use Turbo or Chambered mufflers. Or you could go with stock Mufflers,,,just order mufflers for a Big Block Engine.(i.e.Caddy 472/500cu/in) You’ll have plenty of flow & Old Time Muscle Car sound.
It’s a lot {$}cheaper too. I also use [myself] Glasspacks in tandems (2 glasspacks on each exhaust pipe)if you have the room.
Put 2 in front closest to the Engine,then 2 in the rear.(as resonators)At idle/low RPM’s it will have a slight rumbling,,purring sound{around town} Then when you” Get on it” it sounds AWESOME!!! And the best part is there’s minimal “Back Pressure” (if any) and the ($)price is right.Everything that you need is available thru Summit Racing.(ps , I’d go with the Summit Racing Brand Glass packs,there excellent, great price) Have Fun!
MOTORHEAD~TY
Great idea, longer ones up front shortys in the rear