Ski Nautique Y-pipe exhaust |
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MNLakeSkier
Newbie Joined: February-24-2016 Location: minnetrista Status: Offline Points: 12 |
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Throttle out- anyway you could post a pic? I have an 89 as well and am about to do the same and just want to make sure I route everything correctly. Many thanks!
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Erik,
I did some searching and found this picture. I'm sure there are other examples posted.
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Goldcup101
Senior Member Joined: August-27-2016 Location: France Status: Offline Points: 104 |
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I restored a bubbleback last year. It came from the PO with the Y-pipe which I've left as is. I would have bought a new hullhugger muffler until I saw the price! Noise doesn't seem too bad to me but I never heard it with a muffler.
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1114 |
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I did a muffler delete on our '89 about a year ago. My son uses it so I hadn't driven it until last weekend. I really like the way it sounds. Not too loud, slight drone while cruising but not bad and sounds great wide open. For some reason the '89 was much quieter than the '92. They both have the same muffler except the '89 has smaller diameter risers and less HP. I like the way the '92 sounds so I wouldn't delete the muffler but I'm glad I did it on the '89. The only issue I had was getting the muffler tubing to bend downward after the risers. It may have been the type of tubing I used. I can take some pictures but it will be a few weeks. |
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gt40KS
Gold Member Joined: August-05-2017 Location: Wichita Kansas Status: Offline Points: 943 |
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I should finally have my engine by the end of the week next week (of course .... now that I'm swamped with work) and hopefully be able to get everything prepped and in the boat over the weekend. The exhaust will be close to the last part of the install, but I will definitely post some pics of the process then.
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JCCI
1995 Ski Nautique GT40 |
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throttle out
Senior Member Joined: May-11-2015 Location: Chelsea, MI Status: Offline Points: 153 |
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I don't have any photos of my boat but it looks identical to this.
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1989 Ski Nautique 2001 351 PCM w/ 1-1.23
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mspalatro
Newbie Joined: April-15-2019 Location: MA Status: Offline Points: 5 |
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I am looking to get rid of my inverta flo on my 1990 Nautique. Is there much of a performance gain to go straight dual vs y pipe?? I can see straight dual is a much bigger project.
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JoeinNY
Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5693 |
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It will sound different, but it is very unlikely there would be any performance gain from going to straight duals with anything near a stock engine. Mostly likely you would see no difference, slight chance the duals would be slightly slower. |
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gt40KS
Gold Member Joined: August-05-2017 Location: Wichita Kansas Status: Offline Points: 943 |
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What Joe said. Sound would be a bit different - not really better, just different - with duals. Did mine last year with no mufflers and Y-pipe into the one 4" outlet and IMO it sounds awesome. If there were any performance gains to be had it would likely only be with a highly modified engine that is going to require a lot more flow than a single 4" will allow. A stock, standard 240 (260) hp 351 would not require 2 - 3" outlets and in fact as Joe pointed out, this could be a detriment. Couple this with the HUGE pia it would be to run duals in our era of boat. I'd stay with the single 4".
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JCCI
1995 Ski Nautique GT40 |
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mspalatro
Newbie Joined: April-15-2019 Location: MA Status: Offline Points: 5 |
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The engine does have cam that is supposed to bring it up to 300hp. Everything else is stock.
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gt40KS
Gold Member Joined: August-05-2017 Location: Wichita Kansas Status: Offline Points: 943 |
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I'm running the Y-pipe system in mine with a modified GT-40 that is likely sitting at about 340-350 hp .... not thinking I need any more exhaust than I have with just the single 4" through the back. If she was supercharged as well then I'd be needing more - but that puts it well over 500hp. You have to remember that our boats are more or less straight pipes from the manifolds after eliminating the invertaflo - few bends and all very gradual, none sharp. |
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JCCI
1995 Ski Nautique GT40 |
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mspalatro
Newbie Joined: April-15-2019 Location: MA Status: Offline Points: 5 |
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I am going to with Y conversion. Looking through some old threads I saw there was a boat dr that sold the conversion kits. I checked his website and I don’t think he is still in business. Do you have any online recommendations to buy parts?? Also for the install, was there anything you had to take into consideration like the placement of the Y fitting?? And did you run hose right from Y to manifold or did you use additional fittings for bends??
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gt40KS
Gold Member Joined: August-05-2017 Location: Wichita Kansas Status: Offline Points: 943 |
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Check the other thread Michael - I have links there and some photos. No other fittings, just straight from the manifolds to the Y and the Y straight into the 4" hose to the exit. Do you have the 3" or the 3.5" exhaust risers?
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JCCI
1995 Ski Nautique GT40 |
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4112 |
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Don’t know who sold you the cam, but you’re not going to get 40 extra ponies from just a cam, with stock heads and intake. |
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