Budman II

iTrader: (1)

I have a relatively mild 489 with basically stock 088 heads, mild hyd roller, Holley 800 and Lightning headers. The Lightnings are currently exiting thru the transom with a set of Gil 4.5" muffled tips on it. I had left the stock Y-pipe installed on the transom assembly with the intention of hooking it back up to have a switchable exhaust someday. My question - will the Quick & Quiet style exhaust, where you have the exhaust going thru both the prop and the transom, help any with the exhaust flow? I know Corsa developed this system to be used in conjunction with the same type of muffled tips that I am running now. Was this system developed in an effort to eliminate some back pressure, or was it done to help muffle the sound?

I'm not really sure if the tips are costing me any power or not. I got them from a friend who had them installed on a Powerquest with the Merc 450 HP and Gils on it. He swapped to a set of non-muffled tips and noted no performance gain, but since he had the switchable diverters that also ran exhaust thru the prop, I suspect he was getting a little help with the exhaust flow.

One thought would be to go with the switchable exhaust and straight non-muffled tips, but I understand that it is not recommended to run thru the prop much above 3000 RPM, and that could become skull splittingly loud with the Lightnings at that speed. What I really need is a two-stage switchable exhaust, with the divertor to go thru prop coupled with a switchable tip. That way I could have an intermediate sound level to operate at cruising speeds and a balls-out non-muffled option to run at WFO.

MnFastBoat

I feel it helps, this is currently how I am set up.
Stock twin 502's original ypipe and diverter. However I have NO diverters in the Y at all. Removed them and sealed up the holes.
Installed Teague 4.5 switchable tips instead.
Exhause still can run out the ypipe with the tips closed, as well as the bypassed exhaust out the tips.
Only thing I am starting to think about is that I feel I am not having enough water flow out the tips at idle. Thinking the water is taking an easier path down the ypipe.

Budman II

iTrader: (1)

Sounds like you may have to install some type of bypass to dump some water after the diverter. My big question right now is whether the diverters that I am thinking about buying will fit my Lightnings. They were made by Lightning, but after talking to them it sounds like there were several different designs of diverters and headers through the years, and I have no idea how old these are. All I can do right now is look at the pictures and try to figure out if they will fit.

I would consider the Teague tips, but I don't think I have room for them.