How much quieter are turbo charged motors than super charged or natural ? Does the turbo motor need a muffler to meet compliance ?

All turbo charged engines will be quieter on boost as energy is being withdrawn from the exhaust flow to drive the turbine.

Since they are naturally quieter, sometimes people take the opportunity to run them with minimal silencing. This results in an engine which is noisy at low loads.

If fitted with similar mufflers to a Nat asp or SC engine, the turbo will be quieter.

HTH.

Ran one on a boat through the prop. Increased the speed from 45 to 65. 4 to 6 lbs of boost sounded like a 65 MPH sail boat. All that could be heard were the waves slapping the hull or the hull slapping the water.

Is there any way to incorporate turbo technology into a super charged or N/A exhaust system, purpose being, noise abatement.

turbo superchargerd engines hAve been around in diesels for along time, Sonny Leonard has built turbo supercharged street engines he is in VA.

Excalibur32, Interesting, do you know why Sonny used that design ?

You use the supercharger for low-end immediate boost, allowing the big, laggy turbos to spool up then the SC disengages and the turbos provide the top end boost to the motor.

These are complicated systems but have made production - VW has a 1.4 TFSI that has a supercharger and turbo, Lancia's Delta Integrale rallye car has a turbo/super setup and I've seen a Skyline GTR with a S/C and twin turbo setup that made like 1000hp by a Japanese tuner.

LE-
I had a Aero Marine intercooled turbo BBC in my Eliminator Daytona. The exhaust was quieter than a supercharged engine, but was still loud since I used dry dumps, which turned up at 90*. At full throttle, it sounded like an Allison V-12, which was fun. The engine was very reliable and made about 900 hp (1 carb), but weak on the low end.

The boat was featured in Hot Boat years ago, so you might have seen it.
JE

The turbo thought comes from looking at options to efficiently lower the exhaust to a legal DB.

A couple of notes learned include;

1. A nominal, 540 to 600 CI Engine exhaust (both banks)will spin a turbo shaft resulting in 200 to 300 free horsepower.

2. A Aluminum housing will melt as exhaust temperature may even approach 2,000* F.

3. Heat becomes a major challenge for an enclosed bilge.

4. Relative to heat, fresh water is most manageable.

5. When salt water is used for cooling, electrolysis occurs. (try a salt water solution in a pan on the cook stove,even below boiling)

6. For fun, look at www.turbobygarrett.com

Any pictures of your old set-up?

Thanks
Jon