Hi Excalibur! Nice boat you have even a better engine
We already discussed this item on this forum (about full time mufflers) You'll find a lot of info
viewtopic.php?t=1228
In a "general" statement, you can say there are 3 different ways of muffling the exhaust noise
1. Diverters...With electrical or pneumatic (airpressure) diverters, exhaust is routed through the prop or the transom tips (open exhaust). As you mentionned, no good option as you do not have the Y pipe (engine has to be taken out for installing etc.) Advantage: almost no noise when routed through the prop...Disadvantage: can not be used over 3000 RPM on High Performance engines (like 496 HO) or severe engine damage will occur
2. Switchable mufflers...these can be a complete replacement (with integrated muffler) exhaust tips (electrical operated) or a clamp on system (bolt on) pneumatic actuated. Advantage: good muffling when in closed position (docking / harbours)...and can be runned at WOT (with some powerloss) ...in open position they will
NOT affect engine performances
3. Full time mufflers...can be obtained as a in-line mufflers, as replacement exhaust tips so with integrated mufflers, or as a clamp on mufflers (they clamp on your actual existing exhaust tips) Advantage the "better" mufflers (CMI's) will muffle @ +- 85 db which is very low noise Disadvantage; No mather how constructed, no matter what brand full time mufflers will always take some performances
(the better the brand, the less HP they will take
BE VERY CAREFULL with cheap mufflers Like Edd..., Re...Mar etc. IMO they are "junk" and +-copied (from the good ones) and are not any good on High Performance engines (496 and better) etc...you might see - 400 RPM and creating so much backpressure
engine damage will happen or if they create no backpressure, they won't muffle at all...in both cases a waste of money!
CMI just released their new full time mufflers which have been tested up to 1500 HP with minimal powerloss. At idle they are closed (85 db) and opening as RPM increase to lower the backpressure on the exhaust. Like the tubular headers, CMI is the best -no one comes even close- but superiour quality & performance has a price...
We sell all the above mentionned systems...so if I can be of any help, just let me know
H
