More power from a 3.0GL Volvo

[ontheplane]

Hiya,

Looking at "yet another" boat now - (just remembers to self, swmbo is lovely and is perfectly entitled to change mind at any time)...

This one powered by 3.0GL 130hp Volvo + SX drive. 19ft so should be kind of ok performance wise, and I suspect pretty decent on fuel.

However I remember when I had my old boat, the timing setting on the engine was for 92 octane petrol - well we don't have that over here (American regular I think) and I advanced the ignition a bit and got better performance.

That was an 80's engine - could you still do that with the late 90's engines? if so, what would the setting be for 95 octane compared to 92?

Also, would there be an easy, safe and reliable way to get a little more power out of the engine - as I hardly think 130hp from a 3.0 engine is stressing it at all (in fact only the yanks could get that little power out of that big an engine!)

 

[tinkicker0]

This motor needs to be kept fairly stock. They have a reputation for dieseling when hot as it is, increasing cylinder temps further and you may find yourself with an engine that you cannot shut down and spends minutes trying to jump off its mounts.

There are tuning kits available in the states but you run the risk of losing bottom end torque for top end. Water toys etc would be out as if done drastically, you may struggle to get on the step with a standard prop, lowering the pitch to compensate would give you less top speed anyway.

Fit a K&N filter and be content with 40 knots.

 

[ontheplane]

no, if it will do 40 knots that's more than adequate for us anyhow - I thought with "only" 130hp it would struggle to do more than mid twenties!

I don't want to risk any problems with reliability on that unit.

Other than "dieselling" - is there anything else to keep an eye out for with that motor? Does it have risers like the V6/V8's or being an in-line is it free from that corrosion problem?

It was for toys and stuff I fancied a bit more power - but I guess for fun I can just pitch it down an inch or so and get the pull that way?

 

[Spi D]

40 knots is a wild guess.

Lets us know the ready-to-go weight and make/model or hull type.

For 130 hp to push a V-hull at 40 knots the gross weight should be max. 900 kgs. with all else perfect (clean hull, intact prop etc.)

 

[tinkicker0]

no, if it will do 40 knots that's more than adequate for us anyhow - I thought with "only" 130hp it would struggle to do more than mid twenties!

I don't want to risk any problems with reliability on that unit.

Other than "dieselling" - is there anything else to keep an eye out for with that motor? Does it have risers like the V6/V8's or being an in-line is it free from that corrosion problem?

It was for toys and stuff I fancied a bit more power - but I guess for fun I can just pitch it down an inch or so and get the pull that way?

I have the same motor, only in mercruiser guise in a 20ft cuddy. Real world speed (gps) in freshwater (slower) is around 34 knots. All up weight is around 1200kgs + loads of gear for overnighting, plus house battery and loads of tools.
Brochure speed is 40kts but as spidi says, real world will always be slower.

I made the assumption that you were probably a bowrider type so maybe 1000kgs all in.


As for risers and manifolds, yes they are present and likely raw water cooled.

 

[Spi D]

The 4-cyl inline 3.0 is no different to other cast iron engines/heads/manifolds in regards to corrossion.

Unless a full FWC is fitted it will rust. Exhaust manifold, riser and elbow first..

 

[landlockedpirate]

In automotive terms, you are right, 130hp from a 3L block isnt much. But boat engines are used differently, they are more stressed,how often do you bury the throttle and keep it pressed to the carpet in your car ?.

Depending on boat and if its a bowrider the 3.0L will be fine, I wouldnt mess about trying to get more out of it, you could spend a great deal for very little gain and end up destroying your engine.

If you still arnt comfortable with the power, find a 4.3 or 5.0.

 

[rbcoomer]

Comparison...

Don't know if it helps, but a friend of mine has a 19' Fletcher GTO (Outboard) with a 115hp Yamaha, I believe he gets 30-35kts with a clean hull (anti-fouled). An inboard 4-stroke will be a bit heavier, but the extra 15hp would probably compensate that?

 

[Spi D]

Don't know if it helps, but a friend of mine has a 19' Fletcher GTO (Outboard) with a 115hp Yamaha, I believe he gets 30-35kts with a clean hull (anti-fouled). An inboard 4-stroke will be a bit heavier, but the extra 15hp would probably compensate that?

Maybe.

The last knots don't come easy and always at a cost.

For the enthusiast the outboard has other benefits when it comes to tweaking as the running height and setback can be altered 'easily'. Some fit brackets to allow adjustment while underway and when going fast, minimizing the drag from the gearhouse by lifting the engine provides more speed and less chine walking.
In combination with surface breaking propellers the potential is much better than i/o.

There's even a difference in weight distribution.

 

[ontheplane]

It's a 19ft cuddy - but to be honest even 34kts will be more than ok for what we need.

Thanks for all the replies