performance upgrade

atlmover · **Joined:** Mon Jun 09, 2014 10:02 pm **Posts:** 52

What's the best performance upgrade for my boat? I'm new to boats and curious if I can buybheadera , cold air intakes.. Etc. Is there a site I can use or go to? Any suggestions?

ric · **Posted:** Sat Nov 29, 2014 1:13 am

atlmover wrote:

What's the best performance upgrade for my boat? I'm new to boats and curious if I can buybheadera , cold air intakes.. Etc. Is there a site I can use or go to? Any suggestions?

On a fuel injected volvo? Nothing. Rip all the volvo fuel and ignition crap off and convert it to carb, throw in a nice cam, intake manifold, and a stand alone marine ignition and you'll be around 400hp without effort. It's just a chevrolet vortec 350 there's no secret to making power with it, it's highly documented.

atlmover · **Joined:** Mon Jun 09, 2014 10:02 pm **Posts:** 52

Can I buy headers ? Air filter? Maybe have a hotrod shop flash and tune the computer?

ric · **Posted:** Sun Nov 30, 2014 12:32 am

atlmover wrote:

Can I buy headers ? Air filter? Maybe have a hotrod shop flash and tune the computer?

Marine engines are restricted in their intake and cam sizes to get their rated HP. Sure, you can drop 5k on stainless headers and it will be a hell of a lot more reliable, but you won't see any power gains. Same with air filter.

A normal hotrod shop won't have the software it takes to flash a marine ECU. There's no power to be had in those either, they're not "detuned" they'e actually tuned quite well.

The difference between a 220hp 5.7GL carb'd boat engine and a 320hp 5.7GXi fuel injected boat is cam/intake. There's nothing stopping an owner of a 220hp 5.7GL carb boat from installing the same cam as the 320hp engine and a 650cfm carb and intake and making 320hp, because it will. In your case you can't upgrade your air intake system without ripping it all off, and you could do a cam but you're still restricted via. the intake. Pretty much you're stuck unless you want to spend about 3k and goto carb.

Or do what we all do.. who cares it's not a speed boat. Enjoy it. If you're having power issues getting on plane there's different props that fix that that don't hurt your top speed. I have a 22ft boat with a 220hp 5.0L engine and with tabs and a good prop it does 47mph and gets 6 adults on plane without a blink of an eye. It's amazing what a good prop will do.

atlmover · **Joined:** Mon Jun 09, 2014 10:02 pm **Posts:** 52

Thanks for the replies Rick. I have a dinged up prop and I sent it for repair and blueprint. I'm happy with the power the boat runs awesome . I just was hoping for an honest 55 mph.

ric · **Posted:** Sun Nov 30, 2014 11:28 am

There should be no issue getting 55mph out of your boat with the right prop. I have 60 less HP, more weight, and I'm doing high 40s.

What prop do you have now? Stainless? Aluminum? 3 blade? 4 blade? Pitch? Wide open throttle RPM?

atlmover · **Joined:** Mon Jun 09, 2014 10:02 pm **Posts:** 52

Its a 3/4x19 3 blade SS. Hitting 5400 rpm at 50mph. From a reply on here I was told 5000-5200 was max rpm but it was still pulling. (I didn't know that was the max until after the run). The guy repairing the prop said I had 26% slip rate. He said he would repair and blueprint it and it would really help.

Walt · **Posted:** Mon Dec 01, 2014 6:35 am

You are pretty much squeezing everything you can out of that boat. I have a smaller boat, more HP and can only go about 2 mph over you. I do have a K&N marine air filter, and that did add about 2 mph. Good luck! Keep in mind, you are trying to add a few MPH to something that you won't drive at that speed very long or often to something that only gets used a few times per year. I'd spend the money on embroidered towels and lighted drink holders if it were me.

atlmover · **Joined:** Mon Jun 09, 2014 10:02 pm **Posts:** 52

My prop is dinged up pretty bad. I just figure why not repair it to the best condition possible since I'm sending it off. I have a 3 blade SS. If yours had a 3 blade I'm sure it would run a lot more than 2mph faster. I saw a frenzy on here with the same motor I believe that was running 59mph.

RotaryRacer · **Posted:** Mon Dec 01, 2014 8:21 am

atlmover wrote:

My prop is dinged up pretty bad. I just figure why not repair it to the best condition possible since I'm sending it off. I have a 3 blade SS. If yours had a 3 blade I'm sure it would run a lot more than 2mph faster. I saw a frenzy on here with the same motor I believe that was running 59mph.

Four Winns provides pretty good performance data in their "Fast Facts" pamphlets.

http://www.fourwinns.com/upload/Documen ... s_2006.pdf

They say your boat with your engine should max out at 47-50 mph. If you are already getting 50 mph you are doing pretty good.

NOTE that going to the 320 HP GXi only increases the speed to 49-52 mph.

Once you get to that speed with a boat, you need huge amounts of power to gain significant speed.

Get the propped tuned up and be happy with your 50 mph boat. You will spend serious $$ to get 5 mph more.

atlmover · **Joined:** Mon Jun 09, 2014 10:02 pm **Posts:** 52

Hey Walt,

Where did you find the K&N marine filter? I see the filter for a carb setup but not a fuel injected.

Thanks

Walt · **Posted:** Tue Dec 09, 2014 6:33 am

atlmover wrote:

Hey Walt,

Where did you find the K&N marine filter? I see the filter for a carb setup but not a fuel injected.

Thanks

They didn't show mine listed either. I just measured the throttle body and found what I needed. Ordered it off Amazon.

http://www.amazon.com/gp/product/B000E5 ... UTF8&psc=1

atlmover · **Joined:** Mon Jun 09, 2014 10:02 pm **Posts:** 52

Thanks Walt. I'll measure mine and see if it's the same one. I can't help it I like to modify things. I'd like to put an exhaust on it too. I was looking at the corsa side exhaust. Having a hard time finding that kit too. Do you have any info on that?

ric · **Posted:** Wed Dec 10, 2014 7:39 am

atlmover wrote:

Thanks Walt. I'll measure mine and see if it's the same one. I can't help it I like to modify things. I'd like to put an exhaust on it too. I was looking at the corsa side exhaust. Having a hard time finding that kit too. Do you have any info on that?

Costs about 3 grand and does zero for speed

Jdpber · **Posted:** Wed Dec 10, 2014 10:05 am

but makes the boat sound great.. i am an exhaust man.. i lie to hear engines rumble.. the lap of a cam and the hum of the rpms..

www.iFourWinns.com

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