Volvo...what to do, what to do?


M

mljjjj

New member
I have a 260SS with an 8.1L Volvo GXi DP and would like to know what I can do to increase my speed. I have not been able to find anything on the web about superchargers for Volvo.
 
Seeing that you have an SS, you guys may follow different ideas, but in my boating circles, the only way to really increase spped (& HP lol) is repowering.

For what I use my boat for, superchargers/dramatic "performance add-ons" have no business on my boat, as all they do is decrease reliability.

But as I said, being an "SS" guy you guys probably do this stuff all the time LOL.... ;) ;D
 
I've never seen a blower set up for a Volvo. All the ones I've seen a based on a Merc induction system.
 
Do You have a 375hp or 425hp motor? There is a company called Raymar (I think) that specializes in the 496 Mercruiser engines. They have deeloped a whole performance upgrade package for them. I e-mailed back and forth with them earlier this year. Mechanically Volvo and Mecruiser 496's are the same. Volvos have worse stock exhaust manifolds though, according to them. The only difference between the 375 and 425 motors are the cam and the computer program. They offer a reprogram for it to make it a 425 hp. So all you would need is a cam swap. Not too expensive if you can do it yourself. And no one would know at that point that your engine is anything other than stock. Also CMI makes a header package that supposedly adds 60hp to the 425hp motor. It will fit our Volvo's. It is even suppossed to be eaiser because Volvo does not bolt as much junk to their manifolds and risers as Mercruiser does. Any or all of these would make a pretty big difference on a 375hp for not much cash compared to a supercharger and if the quality of the workmanship is up to snuff should not affect reliability at all. I have decided to wait on doing my engines for now because all that times two and then two new propsets, because I can hit rev limiter now with a light load, is too much money for me right now. It was the only time I wished I had a single since I got my twins!
 
Unfortuanately Volvo is the only company that makes props for V/P Duoprops. And there is not a huge selection. Basically if your redline rating on your engine roughly matches what your boat redlines at with an average load than you have the best prop Volvo has for that application. There may be some custom prop shops that can do some fancy stuff to them to eek out a bit more but it would be expensive and probably make your props very fragile.

The other thing you could do is the exhaust. Volvo's are supposed to have very restrictive exhaust manifolds according to the performace guy I spoke with (Raymar Marine) That is why the same engine for Merc is rated at 425hp and ours is 420, there is at least 50-70 hp to be found with cmi's exhaust kit. Which is a pretty good increase for the money. Horsepower is expensive on a boat and it takes a fair amount to see an actual increase in usable speed.
 
Macjazzy is right. Horsepower in a boat does cost money. If the CMI exhaust does give 50-70 HP increase that is definitely the most bang for the buck. Using a rule of thumb of 1 mph gain for an increase of 20hp you should pick up about 3 mph. If you plan to do any more engine mods, get them done first before doing anything with the props. This should be the last thing you do. There are two places That I have seen on other boating sites, Throttle-up.com in FL and Bblades.com in Wisconson. Either one should be able to help you.
 
"We are in the final stages of development for a 496 Sport Tube Performance package for the Volvo application. The bracket relocation kit is different than the Mercury application, but the headers are the same. We anticipate release to the public in April.
Thanks for your interest in CMI products."

Just got that this morninig from CMI. This is probably going to be my first step, but I have to wait awhile. Still less money then a supercharger! ;D
 
Great news on the exhaust kit. April is right around the corner. You can have it and be faster before the first day of summer!
 
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