Volvo I/O questions

rockdoc · #1 06-20-2009, 03:43 PM

Hey i/o guys, I'm looking at either the Volvo 5.0 GXi SX or the 5.7 GXi SX package for my '75 Sceptre. The 5.0 GXi is listed at 270 hp , the 5.7 GXi is 320 hp and the 5.7 Gi (throttle body injection vs multi port for the GXi) is 300 hp. Weights are all just over 1000 lbs dry motor and drive. The 5.7 GXi is about $3000 more than the 5.0 GXi.

Questions:
270 is fine for the Sceptre, right? (I'm sure 300 or 320 hp is fine too

)

what are the pros/cons of multi port vs throttle body injection?

time to replace the Ford 305 merc and get the Sceptre up and running! (anyone looking for a good ford merc alpha i/o setup?)

Thanks

Steve

Dilligaf · #2 06-20-2009, 07:13 PM

bigger engine will push it better with less effort and probably get better gas milage. i have a 350mag mpi and am very happy with it. my buddy has a 5.0 in his 22ft bayliner not impressed at all.

BigLew · #3 06-20-2009, 07:43 PM

I've got a Volvo Penta 290 with a 350 CID (5.7 L) with a Rochester or Holly 4 Brl rated at 260 HP. I also have a 140 gal. fuel tank- nearly 1000 lb. (@ 7 lb./gal). I want to go up to 300-325 HP because I just believe the hull is capable of the "next step" in performance. She is fast enough at top end- not a big concern to me. What I believe is that the fuel weight combined with the lower HP able to turn a more aggressive wheel is holding back the cruise speed. I run it at about 3000 -3200 RPM and get 22-23 mph by GPS cruising speed. I'd like to get that up by 4 or 5 MPH_ maybe a bit more.

The other choice is to replace the tank set up. My tank is 25 yrs. old and should probalby be replaced, so I was thinking of putting two in place of the one and have a regular tank of about 80 gal. and a second of about 40 or 50 gal. for long trips only.

This is just my thinking. The other question I have not answered is whether or not to go fuel injected or normal carburation. I know, everyone is into fuel injection, but out on the water if you have a problem with an injector/s or the controller chips almost none of us can work on it there. The only real option is a tow. At least I stand a chance with a carburator.

Just my 2 cents.

Fr. Frank · #4 06-20-2009, 10:16 PM

The most reliable fuel input system is common-rail injection. You can find it on many diesels, but not many gas engines.

1bayouboy · #5 06-21-2009, 05:01 PM

Is that with the dup-prop drive??? I just tried a Bravo III dual prop in place of my Bravo I and the difference is amazing. Better top end, better cruise mph and mpg, much cleaner wake at trolling speeds, and better tracking at every speed. If you're looking at I/O look at the dual prop.....

Islandtrader · #6 06-22-2009, 10:59 AM

You can never have enough horse power.

Fr. Frank · #7 06-22-2009, 02:29 PM

Quote:

You can never have enough horse power.

Yes, you can. You just can't have too much.