Volvo D4's Rev Limiter?

[Vagabond]

Volvo D4\'s Rev Limiter?

Hi all,

Anyone know if the D4's have a rev limiter?

If they do I think I may be under propped as she jumps onto the plane quicker than a scoulded cat and easily reached the 3,500 - 3,600 Limit.

These are great engines, smooth, quiet and powerful.

 

[Whitelighter]

Re: Volvo D4\'s Rev Limiter?

er, yes. as you say 3500-3600rpm

Doesnt mean shes under propped, a boat should acheive max rpm without struggling. The fact she hops ontot he plane means you will burn less fuel in the transition.

I almost posted on you pics thread, but I think the Cruisers have a fairly shallow V (deadrise) at the stern, I think around 12 degrees from emory and this will give aflatter planing surface and make the transition quiker than you might expect too.

Builder usually get it right. If its reachin max revs and speed is ok I wouldnt bugger about with it and just enjoy your boat.

 

[Vagabond]

Re: Volvo D4\'s Rev Limiter?

Ah I was wondering if it was an electronic rev limiter ...

Yes true she has an 18 Deg deadrise at the stern ... she also has the chines like the old Taga 33's. I was expecting a slower and less responsive boat coming from Legs to Shafts but she is really nimble and has a tight turning circle.

 

[Whitelighter]

Re: Volvo D4\'s Rev Limiter?

18 degrees isnt so flat. Its better than I thought it was. I am sure I was told by the UK dealer that the 330 was much shallower than that. Maybe they changed the model.

Nice looking boat all the same...

 

[Vagabond]

Re: Volvo D4\'s Rev Limiter?

The spec sheet says it's 17 and the Volvo report says it's 18 ... I expect it's 17.

She's still good in the rough which is good.

 

[mlthomas]

Re: Volvo D4\'s Rev Limiter?

I think there are two rev limiters, one in drive - about 3500/600 and the other with the drive dissengaged which will be about 1500

 

[Vagabond]

Re: Volvo D4\'s Rev Limiter?

Ah cool ... thanks for the tip. If she does hit the limiters that quick then I may be able to adjust the props a little.

 

[Latestarter1]

Re: Volvo D4\'s Rev Limiter?

Clive,

No that is not the answer!

Your engines are electronically goverened diesels. Remember it is a governor NOT a rev limiter.

The Volvo D4/6 are rated at 3,500 rpm, in other words they stop making power at 3,500, however they have governor 'droop'. Instead if hitting a brick wall the engine continues to rev but the fuelling is reduced. On an electronic engine this is about 5% of rated speed, so you are out on the droop at about 3,600 rpm or so. This is referred to as 'High Idle'

You always need to be able to make rated rpm plus a bit of the droop to prevent engine being overloaded when you have added weed growth an weight.

Your boat sounds spot on, do not mess with the props.

 

[Vagabond]

Re: Volvo D4\'s Rev Limiter?

Thanks for that.

I just wanted to make sure that I was not hitting an electronic rev limiter as I am really surprised at how easily she jumps onto the plane with no tab and a full fuel tank. She is quicker onto the plane than allmost all the other planing boats I have been on and she is shaft drive so I was wanting to make sure.

Cheers,

Clive.

 

[Geoffs]

Re: Volvo D4\'s Rev Limiter?

I have to agree with you about the excellent performance of the D4. I've got 475 hrs on mine and, touch wood, never missed a beat, or given a puff of smoke.

Mine tops out at 3450, according to Volvo rev counter, which may not be totally accurate. Don't think I'm over propped, like you,it accelerates well. If it is revving slightly low, this may be electronic, but I'm happy as it touches 36knots.

 

[Vagabond]

Re: Volvo D4\'s Rev Limiter?

They are quite something ... having had boats with 'Old Smokies' AD41's, KAD32's etc the D4's are brilliant.

Loads of low down power and no smoke!! Also the ancillaries are more an integrial part of the engine and not bolt on's like the older engines.