Donzi X18 Exhaust

[chasiliff]

I have a Donzi image dilemma.

I just got my '73 X18 running. Actually, Ken Chapman in Arnold, Md. did the work and did beautiful work getting my Volvo AQ271C duoprop engine and outdrive in the boat. Now it's running. It is fast. It is smooth... and it is loud. What do you all, experienced Donzi lovers, think about changing a classic X18 Thru-hull setup to a through outdrive exhaust system? Would I kill it in your eyes? Should I suck it up? Should I pay out to try to get a quick and quiet setup retrofit? Or should I go the modern quiet route and make it bearable for the admiring public?

Thanks. I would love to hear your thoughts.

Oh, it is fast and manageable with the duoprop. With the C5 set of aluminum props it was showing 65 on the pitot speedometer at 5500. I'll have to get GPS on it.

If you're looking for someone professional and reasonable to work on your boat who knows Donzis, I can send you Ken's number.

[jl1962]

Don't swap out the thru-hull exhaust, just get some mufflers. For instance, limit on Lake George is 90 dBs at idle , 3' from the exhaust and I am just under. My boat is still plenty loud, the mufflers just take some of the bark out. A good set should be no more than $500 installed.

My .02 cents.....

[VetteLT193]

If you really want it quiet, you could get those Gibson downturn exhaust pipes. They are bolt-on so you can easily go back to stock. they basically take a 90 degree turn down and into (under) the water while going slow.

I think they are about 400 bucks... I've never seen it on a classic Donzi, but I like the fact they are quiet while going slow, shouldn't hurt performance going fast, and easily unbolt if if you want to go back.

[Lenny]

Are you running 4" or stock 3".? I have a NEW set of Corsa 4" with baffle if you are already a 4" set.

[BUIZILLA]

you'd be VERY surprised how much just a set of rubber flappers quiet things down..

[The Hedgehog]

I did a Captains call retrofit on my x-18. Mine is a Bravo1 setup. It works well. I don't have any idea if it would work on a Volvo.

Ditto what Buizilla said on the flappers.

BTW, if you want some slip in baffles that would work in 4" tips I have a brand new set laying around. They are good to 415 hp. I was going to put them on my 502 to satisfy the Alabama Marine Police from time to time when I went down to the busy end of the lake. I scored a good deal on some Gaffrig switchable tips that get along better with my blown motor so these are still brand new and in the box.

[BigGrizzly]

My opinion is quick and quiet or a set of CMI switchable tips or the new CNI mufflers. they are expensive but are the best quality.