Compressors - Is this right

VP Thankfully it was the little green magnetic microswitchy thing that failed. It seems to be designed to leave the compressor on if it fails, my guess is that at least you can get on to the plane and not chug around at 6 or 7 knots.

I can also confirm the one that Peanuts made up (NBBZ-V3-E1-V5 part no 67716 from RS) does actually work

My KAD32s have (gulp) an aftermarket mod so I can switch the compressors off anyway. I hope that will not count against me when I sell the boat - The mod was made by a Volvo dealer though

Done that job a few times now for river based boats that want to run at higher rpm but without the chargers in.
 
Well, I did not expect this to become such an interesting post.

Noting all of the comments so far and I understand why some of them have been made I feel I must add my side to them.

First of all the switch, we spoke with the manufactures directly and they confirmed that the original part number is a VP one and is made solely for them so could not supply them directly, however part number NBB2-V3-E1-V5 is electronically the same but with 4.8mm spade terminals, not the flylead as on the VP one.

This switch is not available in the RS catologue so had to be obtained through another dealer. The manufacture would not deal directly either, I can understand that though.

Regarding the engine survey and requesting an original item fitted, yes I understand where you are coming from, but by the time the lead from the old switch had been transfered over, heat shrinked and fitted it would hardly noticeable, although I have no reason to doubt a 'trained eye' would notice it.

At the end of the day the saving made is over £100, would I fit one to my engine/s, yes I would.
 
And me, flyleads and connection blocks make things easier for assembly as they can't be put together the wrong way round but they always go slack and play up in later life.
 
If the boat behaves exactly as it should, is an engine expert going to be brought in. I cannot see a surveyor looking into the jungle of an engine and saying that is the wrong sensor
 
Surely all engines should be treated kindly if you want them to look after you. Ramming the speed control to maximum before the the engine has picked up enough speed to bring in the supercharger does not seem very kind. I always bring the the speed up steadily, so why not bypass the WOT switch by connecting the appropriate wires before they reach the switch. Ah, but there are three, so which ones? Does any body know?
 
That's not what the switch is there for.

If you start to slow down and come off the plane, the engine has no way of "knowing" whether this is what you intended or not.

Without the switch, you'd continue to decelerate until you were back down in the normal supercharger engagement zone, with a cloud of smoke coming out of the back and 10 less kts than you started with. Engaging full throttle wouldn't do much other than produce more smoke until the compressor eventually kicked in, then you'd have all the palaver of getting planing again.

With the switch, a burst of full throttle on slowdown enables the compressor to engage sooner (at higher rpm), and gets you planing again with less of a delay.

dv.
 
Engaging the supercharger at a lower rpm than volvo designed it to cut in at can put excess strain on the pistons, crank and conrods as the torque curve is altered beyond its designed limit, on the black box is a potentiometer screw this can slighty vary the cut in and out rpm, its there for a reason, altering the cut in rpm is not adviseable, as is allowing the charger to stay boosting when the turbo cuts in.

You have been warned!
 
Top