Engine Modifications for 5.7l Alpha engine.

[210_Sea_Ray]

I have a 1990 210 searay, i was wondering what engine mods can be made to it, ot make it faster and louder, without haveing to purchase the captain cove(or whatever it is called)<br /><br />If this is in the wrong section, i apologize.<br />Thanks for any replys!

 

[John_S]

Re: Engine Modifications for 5.7l Alpha engine.

Well, if your 5.7L is in good shape, and it is a 2brl model, going to a 4brl w/intake, is a reasonable improvement. Next engine option would probably be going to vortec heads, and vortec intake, and 4brl. After that, expect to spend allot $$$s to get anything more. To get additional speed by the hp mods, you will need a prop change, as well. You should find plenty of threads on these mods, here on iBoats. Keep in mind that even the improvements above, will not be huge. Depending on many other things, the 4brl might get 5-8mph, and vortec heads, another 5-8. <br /><br />Unless you are going to do a significant engine build-up, exhaust mods, are not going to buy you much, but more noise. Not sure if available for your merc drive, but there is a bellows for the genii drive, which will make more noise, when on plane.

 

[mkast]

Re: Engine Modifications for 5.7l Alpha engine.

Everybody that has read these forums has asked at one time or another, what they can do to make their boat go faster, and not spend a lot of money doing it.<br />The real story is:<br />Your power package is at it's limit.<br />You might replace the two barrel carb with a four barrel, you might even notice a speed improvement. But after all is said and done, the mods made to the engine, for the amount of REAL speed gained, won't be worth it.<br />If you are not happy with the boat you have, sell it and get a boat that will make you happy.<br />REAL speed increases come from replacing the four cylinder engine with a six, replacing the six with an eight, or replacing a small eight with a big eight. All of that costs money.<br />Remember, for more speed, you need to burn more fuel.<br />One of the web sites stated (if you drop off your boat at the local marina) each MPH will cost about $1500, on average.

 

[QC]

Re: Engine Modifications for 5.7l Alpha engine.

I agree 100% with mkast.<br /><br />Not to slam John_S at all, but I personally don't believe all of those suggested mods combined would total 5 MPH . . .<br /><br />BTW, welcome to iboats!

 

[210_Sea_Ray]

Re: Engine Modifications for 5.7l Alpha engine.

Thanks guys, what i really want i guess is more rumble. without having to do alot of mods to it. can i just purchase a y pipe and run an exhaust out the side, of course doing it like the professional i am. Thanks.

 

[John_S]

Re: Engine Modifications for 5.7l Alpha engine.

Guys, the poster has to do the research, and only he can answer the question "Is it worth it?". I listed the two most popular improvements, for a 5.7L 2brl. Does't mean I would do both mods, either. I wouldn't do it on a tired engine, and I have no interest in making more noise. <br /><br />As far as speeds mentioned, they are guesstimates. I remember reading one of those "rules of thumb", that for every 6 hp, you gain about 1mph. Yes, allot of "ifs" in that rule of thumb. But, given a 5.7L is 210hp, and a 4brl vortec engine is close to 300hp, I would bet it is noticeable. If the poster is considering the vortec upgrade, needs to also consider the condition of the drive. 300hp, puts that at its limit. <br /><br />If he needs power to plane, cubic inches is the answer. But, I'd try some tabs first.

 

[QC]

Re: Engine Modifications for 5.7l Alpha engine.

Well like you said John, only he can decide and it sounds like he does want to go thru transom exhaust at a minimum.<br /><br />210 guy, <br /><br />Actually you have a Y pipe now, and it directs the exhaust from both manifolds into the single prop outlet. It would need to be capped off and the stuff between the Y pipe and the manifold risers removed. Then you need to punch two holes in your transom above the waterline. You need the through transom exhaust tips with internal flaps (to keep water from getting back into the engine from the exhaust). Then you need to run exhaust hose from the risers above your manifolds to those adapter tips that run through the transom.<br /><br />

<br /><br />Double check your local regulations. Where I boat they are checking exhaust noise levels; I made it by 1 decibel <br /><br />You can find this stuff at eddie marine dot com (iboats does not seem to have this stuff or I would've linked you there )

 

[wvit100]

Re: Engine Modifications for 5.7l Alpha engine.

You'll enjoy the boat more without all the noise. It's fun for the first 30 minutes and then it's just loud. You can't talk while the engine is running and people just don't want to hear that out on the lake. My 21' Stingray runs 63 mph with a stock 350 and through the prop exhaust, and it's quiet while it's doing it.

 

[FreeBeeTony]

Re: Engine Modifications for 5.7l Alpha engine.

If it runs good..............leave it alone!

 

[mkast]

Re: Engine Modifications for 5.7l Alpha engine.

Go down to the local drag strip, make a recording of the afternoon.<br />When the urge hits you, pop the tape in and play it loud!<br />LOTS cheaper.<br />Other boaters will thank you.

 

[QC]

Re: Engine Modifications for 5.7l Alpha engine.

LOL @ Tony<br /><br />Also, I agree that a louder boat is usually obnoxious. My first two boats were through prop and I never wanted through transom. The latest one has through transom and it is really not that much louder at the helm as wind noise is probably more of an issue. However, I am embarrassed when I start in a small cove or at night when there is no noise whatsoever. I have also had compliments on the throaty sound and the Supreme Being actually likes it which I never thought she would . . . <br /><br />If I had a choice at no cost, Captains Call all the way . . .

 

[Bondo]

Re: Engine Modifications for 5.7l Alpha engine.

Ayuh,....... I built a set of Loud Pipes for My Barge,...... <br />It took 1 day to get Sick of the Rumble....Well,... Maybe a few Weeks....<br />And,.....<br />I've been trying different ways to Quiet them Down,.. Ever Since......

 

[Olds Eddie]

Re: Engine Modifications for 5.7l Alpha engine.

John S mentioned that a 350 with vortech heads makes 300 hp. I believe that it also takes a roller cam to get that kind of power/eficiency.<br />A stock motor with through transom exhausts makes an entirely different noise than a well tuned high output race preped engine.

 

[John_S]

Re: Engine Modifications for 5.7l Alpha engine.

Eddie,<br /><br />All the merc vortecs do come with roller cams, and if I was going to upgrade to vortec heads, and didn't have a roller cam, would install one. As far as advertised hp with the flat vs roller cams, merc didn't make a distiction when used in the same non-vortec 350 engines. I haven't checked recent merc vortecs, but the ones from late 90's, had the same part number as the roller cam in the non-vortec (mid-90's).

 

[paulie0735]

Re: Engine Modifications for 5.7l Alpha engine.

........... I love the smell of an argument in the morning!!!!!!<br /><br />More speed in that boat will only come with an additional 30 - 50 hp so you can spin a bigger prop, that won’t happen with bolt on's, if your serious than pull the engine and do it properly. Loud will come with the new engine and a through transom exhaust conversion. If that’s out of your budget than forget it and just get out and enjoy your boat for what it is and leave the fast and loud to the rice and famous!