Anonymous
01-21-2003, 11:54 PM
Irish Wake
normal member in standard member. 1. 31/2" or 4" Exhaust Pipe
Lep, I need your help! I'm 400 miles away from the boat and I need your eyes. The new engine I bought has 31/2" risers on it. Will 31/2" copper exhaust pipe fit in place of the 3" that is currently in there,(between the stringers and the fish boxes)? Also do you think I will have to replace the 3" transom exhaust flanges with 31/2", or will that little amount of restriction be all right?
Thanks
Randy
Date: 07:31 p.m. on 03-16-2001
Leprechaun
premium member in standard member. 2. Re:31/2" or 4" Exhaust Pipe
Randy - I don't think the 1/2" diameter difference between what I have and what you apparently need will matter stringer/fishbox-wise. And I wouldn't go chopping the exhaust ports out just to redo with 3.5" ports. Run the new 3.5" exhaust hose to the exhaust ports and use a "Filler Gasket" of the old 3" hose to make up the difference between the 3" exhaust port flanges and the 3.5" inside diameter of the new hose. There will be no apparent exhuast flow restriction. Believe me.
As I have mentioned before, another of my absurdly expensive and incredibly time consuming hobbies is restoring classic Corvettes. Guess what size exhaust Chevy used on ALL hot-rodded small blocks as well as their hottest big-blocks? Would you believe 2.5" right to the mufflers and the muffler inlets/outlets themselves were closer to 2" than 2.5". This included all the 396/427/454 big-boys up to the 550hp 7000rpm L-88s that broke axle half-shafts like matchsticks. If 2.5" exhausts were good enough for Chevy's best (AND Ford's and Mopar's too for that matter, not that anything THEY made counts!;-})Then I think our little pop-gun motors can survive quite nicely with the 3 or 3.5" we use. Rgds, Leprechaun
Date: 08:23 p.m. on 03-16-2001
Irish Wake
3. Re:Re:31/2" or 4" Exhaust Pipe
As always, Thanks
Randy
Date: 08:43 a.m. on 03-17-2001
normal member in standard member. 1. 31/2" or 4" Exhaust Pipe
Lep, I need your help! I'm 400 miles away from the boat and I need your eyes. The new engine I bought has 31/2" risers on it. Will 31/2" copper exhaust pipe fit in place of the 3" that is currently in there,(between the stringers and the fish boxes)? Also do you think I will have to replace the 3" transom exhaust flanges with 31/2", or will that little amount of restriction be all right?
Thanks
Randy
Date: 07:31 p.m. on 03-16-2001
Leprechaun
premium member in standard member. 2. Re:31/2" or 4" Exhaust Pipe
Randy - I don't think the 1/2" diameter difference between what I have and what you apparently need will matter stringer/fishbox-wise. And I wouldn't go chopping the exhaust ports out just to redo with 3.5" ports. Run the new 3.5" exhaust hose to the exhaust ports and use a "Filler Gasket" of the old 3" hose to make up the difference between the 3" exhaust port flanges and the 3.5" inside diameter of the new hose. There will be no apparent exhuast flow restriction. Believe me.
As I have mentioned before, another of my absurdly expensive and incredibly time consuming hobbies is restoring classic Corvettes. Guess what size exhaust Chevy used on ALL hot-rodded small blocks as well as their hottest big-blocks? Would you believe 2.5" right to the mufflers and the muffler inlets/outlets themselves were closer to 2" than 2.5". This included all the 396/427/454 big-boys up to the 550hp 7000rpm L-88s that broke axle half-shafts like matchsticks. If 2.5" exhausts were good enough for Chevy's best (AND Ford's and Mopar's too for that matter, not that anything THEY made counts!;-})Then I think our little pop-gun motors can survive quite nicely with the 3 or 3.5" we use. Rgds, Leprechaun
Date: 08:23 p.m. on 03-16-2001
Irish Wake
3. Re:Re:31/2" or 4" Exhaust Pipe
As always, Thanks
Randy
Date: 08:43 a.m. on 03-17-2001