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zelatore
06-05-2009, 02:57 PM
Well, it's not Donzi performance talk, but it is performance talk.

On the phone today with a prop shop I use a lot and when he heard I was just finishing up the procharger he got really interested. Seems he has a 22' Cobalt with a Volvo 5.7 and duo-prop drive and he wants more out of it. Right now, he's pushing it to about 58-59 GPS, but he's re-worked the props several times to find the perfect fit so he's pretty much getting everything he can out of the stock set-up. I believe he's got about 250 hrs.

He'd like to do push it up around 70 mph and thinks he could do it with another 100 hp or so. (I'm not sure about that...) I don't think he'd have a drive problem putting that kind of power down since they run the same unit behind the 8.1s, but there's just not much of an aftermarket for Volvo motors. He thought about trying to convert a Merc Procharger application to fit his Volvo, but I don't think he realizes what a PITA that could turn into.

My thinking is his best bang for the buck might be swapping in a low-hours take-out 8.1. He wouldn't get 70 mph out of it, but it should offer a decent improvement over the 5.7. Or would it? He'd be picking up a fair bit of weight if he went this way.

Any thoughts? Anybody familiar with a blower application for a late-model small block Volvo?

mattyboy
06-05-2009, 03:02 PM
he needs more than 100 hp to jump up 10 mph


I was under the impression all newer volvo stuff was chevy stuff so wouldn't a warmed up 383 bolt right up
I think that would be the way to go with out having to worry about going to a big block and the issues it comes up with exhaust outlets and the like

Ghost
06-05-2009, 03:07 PM
Well, it's not Donzi performance talk, but it is performance talk.

On the phone today with a prop shop I use a lot and when he heard I was just finishing up the procharger he got really interested. Seems he has a 22' Cobalt with a Volvo 5.7 and duo-prop drive and he wants more out of it. Right now, he's pushing it to about 58-59 GPS, but he's re-worked the props several times to find the perfect fit so he's pretty much getting everything he can out of the stock set-up. I believe he's got about 250 hrs.

He'd like to do push it up around 70 mph and thinks he could do it with another 100 hp or so. (I'm not sure about that...) I don't think he'd have a drive problem putting that kind of power down since they run the same unit behind the 8.1s, but there's just not much of an aftermarket for Volvo motors. He thought about trying to convert a Merc Procharger application to fit his Volvo, but I don't think he realizes what a PITA that could turn into.

My thinking is his best bang for the buck might be swapping in a low-hours take-out 8.1. He wouldn't get 70 mph out of it, but it should offer a decent improvement over the 5.7. Or would it? He'd be picking up a fair bit of weight if he went this way.

Any thoughts? Anybody familiar with a blower application for a late-model small block Volvo?

Interesting. First, is it a 1999- vintage 22' Cobalt, or the more recent 2000+ vintage 22 with the reverse chine hull that creates more lift?

My 22 had a Volvo 310 HP 7.4 GiDP, and was a 54-55mph boat, speedo, but I think that was actually correct based various factors. Published tests of the same boat with a 300 HP small block Merc showed 57-58 on radar. I was bummed mine didn't go a hair faster, but I think this was due to the extra couple hundred pounds of the big block.

With the '99 and earlier hull, I doubt 100HP gets all the way to 70MPH. But MAYBE, if the weight stays down in small block range.

The reverse chine hull, which generates more lift, I don't know. It's a substantially heavier hull I think and the lift gave it a lot more speed per pound than the previous generation. (Of course, it is butt ugly by comparison to the older model. I think it goes faster so people can't see that.) :)

I openly admit almost anyone here will know VOLUMES more about the motors and weight consequences, but since I may have had some experience with this hull, I chimed in on this for a change, when usually I just read and try to learn.

FWIW,

Mike

MOP
06-05-2009, 03:23 PM
There should be no major issues putting a procharger because it is a Volvo that has no bearing it is a Chevy plain and simple.

zelatore
06-05-2009, 06:28 PM
I believe the boat is an '03 or there about.

While I'm sure the procharger would work with the motor, a small block being a small block, the concern is how much custom fabrication would you have to do to get it to actually fit? All the brackets are made to accomodate Merc accessories.

Now that I think about it, I like Mattyboy's idea of building a stroker. Keep the weight down; heck, with good exhaust he could even reduce the weight a bit. No alignment issues. And all the accessories will bolt right back in place.

Realistically, what's an achievable number from a 383? And would the stock injection have any issues dealing with the needs of the bigger motor?

BigGrizzly
06-06-2009, 08:38 AM
Zel, I have my M1 procharger for sale it is a bbc one but he may be able to adapt it.