Chipping Volvo D6 330

[rubberduck]

Going forward it looks like eldest son is going to be using boat without me a fair bit, as I get tired a little too quickly these days, & he has asked if its possible to chip the engines up to say 375 ish. Not letting him out solo till his girlfriend has learnt the ropes (literally) & he has got the hang of planning, but doesn't seem to be a silly request. We have done it to a few vans with great success.

 

[wipe_out]

Apart from the reliability implications, you can't really compare it to a car/van engine that runs at very low load levels nearly all the time compared to the boat engine that runs at very high load levels all the time, wouldn't the extra power require you to change the props as well so your WOT revs get to the right place making it quite an expensive exercise once all is done and setup correctly?

 

[rubberduck]

Don't know but very good question, lets see what answers we get.

 

[aquapower]

this has been talked about a few times before

www.ybw.com/forums/showthread.php?412885-Re-mapping&highlight=Chipping+d6

 

[z1ppy]

i believe it can be done and has been done with great success but mostly on lighter boats.

I think the 330 D6 330 block was basically the same for the 350 and 370 variants.

My biggest concern would be the knock on effect on the other components. can the drives take the extra grunt and will the existing cooling systems be able to cope. New props to make use of the extra power....

In reality tho, what extra is it going to give you? its not going to move you from 35 kts to 45 kts top end unless you make some very serious changes.

 

[rubberduck]

Probably not worth the effort, she makes 37 fully loaded with a clean bum, but I can tell him I looked into it.

 

[jfm]

Even if it were a good idea on all other counts, which is questionable, you'd have to buy coarser props. So it is an expensive way to go, unless you want to run at 35kts+ lots

 

[Richard.C]

I've been reading a few threads that have discussed changing props, getting my head around all the technicalities has been a challenge.

Would I be correct that changing props for better top end would negatively affect the low end? Coarser props would be higher speed for same rpm?

 

[Latestarter1]

I've been reading a few threads that have discussed changing props, getting my head around all the technicalities has been a challenge.

Would I be correct that changing props for better top end would negatively affect the low end? Coarser props would be higher speed for same rpm?

Richard,

Provided one remembers that 'propellers move boats engines merely turn them' the concept is super simple....

If we have a theoretical 25 ft 4tonne vessel, simple spec, direct drive spinning a 17 inch wheel, 243kW Volvo D6330 to ISO 8665 3,500 rpm rated engine. 12 inches of pitch on our 17inch prop would absorb 100% of engine power and achieve 35 knots at WOT.

If we recalibrate our D330 to 272kW D6 370 it would take an extra 2 inches of pitch on our 17 inch propeller, 17X14 to absorb 100% of increased engine power giving us an extra two knots,

The only issue would be a slightly higher, perhaps half a knot at idle speed if that is what you mean by negative effect on 'low end'.

I have never really understood how one accurately does a propeller calculation of an engine which has had aftermarket up-rate, so called dyno data from chip tuners can be totally Mickey Mouse. I once asked chip tuner what altitude correction factor they were using on their dyno and was met with complete waffle.

 

[Richard.C]

Richard,

Provided one remembers that 'propellers move boats engines merely turn them' the concept is super simple....

If we have a theoretical 25 ft 4tonne vessel, simple spec, direct drive spinning a 17 inch wheel, 243kW Volvo D6330 to ISO 8665 3,500 rpm rated engine. 12 inches of pitch on our 17inch prop would absorb 100% of engine power and achieve 35 knots at WOT.

If we recalibrate our D330 to 272kW D6 370 it would take an extra 2 inches of pitch on our 17 inch propeller, 17X14 to absorb 100% of increased engine power giving us an extra two knots,

The only issue would be a slightly higher, perhaps half a knot at idle speed if that is what you mean by negative effect on 'low end'.

I have never really understood how one accurately does a propeller calculation of an engine which has had aftermarket up-rate, so called dyno data from chip tuners can be totally Mickey Mouse. I once asked chip tuner what altitude correction factor they were using on their dyno and was met with complete waffle.

Thanks Latestarter, that was my thoughts when referring to low end, I guess I thought it may have more effect at idle rpm though.

 

[Latestarter1]

Thanks Latestarter, that was my thoughts when referring to low end, I guess I thought it may have more effect at idle rpm though.

Richard if you take a look at V.P spec sheets you will see that although they do not go down to idle propeller demand low speed does not vary greatly.