Taking back control

[New Boater]

So I have decided to go a bit “MadMax” with my superchargers and have fitted switches.

I know a few people have fitted a bypass switch that can deactivate but I have gone a stage further due to my Speed Control Box lunching itself.

I have bypassed the speed control box and the kickdown proximity sensors on both engines and will operate the chargers manually.

Switches are in and operate well.

I plan to engage the S/C’s to get up on plane and then drop them out once up (much the same as the controller does) but then not re-engage on the way down or when I am cruising along at a slow speed and don’t want them on.

Will take her out for a run asap and report back.

Will try and post pic of the switches.

 

[New Boater]

 

[New Boater]

Ooh I did it. Result.

Port and Starboard.

 

[jaminb]

see bacon and egg pie thread

 

[DavidJ]

I’m pleased that it worked, I take it you have a non electronic engines.
You may have problems when you come to sell the boat. It’s likely not to impress the surveyor and to get a sale you may have to revert to replacing the control boxes again.

 

[Seastoke]

I say good job , and you control the noise. A nice install as well .

 

[Grubble]

I’m pleased that it worked, I take it you have a non electronic engines.
You may have problems when you come to sell the boat. It’s likely not to impress the surveyor and to get a sale you may have to revert to replacing the control boxes again.

And then he can just label the switches, torpedo launchers, or similar.

 

[New Boater]

see bacon and egg pie thread

I don’t get it. It seems to be about funerals. What am I missing?

 

[New Boater]

I’m pleased that it worked, I take it you have a non electronic engines.
You may have problems when you come to sell the boat. It’s likely not to impress the surveyor and to get a sale you may have to revert to replacing the control boxes again.

Hi David,

Yes they are thankfully non electronic. Not a sensor or complicated ecu in sight thankfully.

Noted regarding resale but I have just got her and will be holding on to her for a good while yet.

 

[Momac]

I quite like the idea of manual control of the superchargers . It certainly beats the ridiculous cost of the speed relays.
Perhaps there should be an inline fuse in case the clutch should become faulty and demands too many amps . Maybe you did this.
I do also like the Mad Max switches

 

[New Boater]

Have put a 10amp inline fuse in just incase as I think the clutch will pull more than it’s 3.something when it goes wrong.

What I am looking forward to is seeing how the boats reacts whilst leaving the S/C engaged from 1600RPM to WOT.

Not that I am a speed freak with the boat but it should be fun all the same.

Will let you know.

 

[New Boater]

Sorry, I meant 5amp fuse and it has a relay circuit too.

Had both engines running today and the superchargers were kicking in and out quite happily up and down the rev range with no smoke.

Didn’t go out as it was blowing 6&7 in the channel.

 

[DavidJ]

Have put a 10amp inline fuse in just incase as I think the clutch will pull more than it’s 3.something when it goes wrong.

What I am looking forward to is seeing how the boats reacts whilst leaving the S/C engaged from 1600RPM to WOT.

Not that I am a speed freak with the boat but it should be fun all the same.

Will let you know.

As you know the supercharger circuit is designed to drop out at say 2250 rpm (or so I don’t remember the exact figure) when the turbo has fully spooled up. Can you have too much pressure if you take it to WOT with both on the go. More”sophisticated” engines have a waste gate valve (from the turbo) which I believe is to prevent problems of excess pressure.
Await further input from others.

 

[New Boater]

As you know the supercharger circuit is designed to drop out at say 2250 rpm (or so I don’t remember the exact figure) when the turbo has fully spooled up. Can you have too much pressure if you take it to WOT with both on the go. More”sophisticated” engines have a waste gate valve (from the turbo) which I believe is to prevent problems of excess pressure.
Await further input from others.

Hi David,

I did wonder that too but thought that considering the Superchargers originally cut back in at WOT throttle anyway it would be ok.

I took the boat out yesterday for a good test and the switches are a game changer. I hadn’t had the boat long and really didn’t like the way the chargers behaved (although I did like their effect)

So far I have found this to be the most effective and pleasant way to use them.

Let the rpm’s come up to about the 1800/2000 range, then switch the chargers on. You can hear them kick in and feel a little gentle extra shove. Then bring the throttle up slowly to about 2500rpm which see’s the boat easily up on plane. Then switch them off. The boats stay up and is much quieter.

Dropping back down I leave them completely off.

I did do one full power run with the chargers left on the whole way up and it was very effective way to get to full speed. She flew up and got to max speed very quickly.

Very happy with the result.

 

[DavidJ]

Hi David,

I did wonder that too but thought that considering the Superchargers originally cut back in at WOT throttle anyway it would be ok.

I’m interested in the source of this information

Assuming you have KAD43’s or similar WOT is about 3800rpm, well above the supercharger drop out.
Go carefully I would hate for your very interesting project to end up with a “bang”

I do like the idea of a switch though and yours is a particularly good installation. There are occasions with the S37 where I would like to travel at a relaxing displacement speed of say 12 knots without the supercharger howling away and producing belt dust.

Suggest researching the reasons for waste gate valves

ps
I found this:
The wastegate valve's purpose is to:

• Protect the engine and turbocharger
  By preventing the boost pressure from rising indefinitely, the wastegate protects the engine and turbocharger from damage.

 

[Alicatt]

It is one of the things with the old Perkins on our boat, up to about 1100rpm the turbo has no effect or anyway very minimal, once you go above that at about 1500rpm the turbos can be heard and the boat is up on the plane about 1700-1800rpm and maxes out at 2600rpm at 16 knots.
It makes for easy cruising on the canals with their speed limits of 14 - 18km/h, at 15km/h the boat is doing about 1100rpm, and at tick over at about 500-600rpm she is doing around 8km/h on both engines, and 7km/h on one engine.

The boost gauges have been disconnected - it was a weakness in the system as the capillary tube that operates the gauge can split putting oil onto the hot turbo causing a fire (anecdotally) so thinking on replacing them with electronic sensors during the winter lay up. plus there is no turbo pressure gauge on the upper helm where you operate the boat from 99% of the time.

On our trip back from Volkerak Sluis I think I spent about 10minutes operating the boat from the lower helm as that is where the control for the searchlight is and coming into the unlit dock in the dark I needed a little light

 

[New Boater]

I’m interested in the source of this information

Assuming you have KAD43’s or similar WOT is about 3800rpm, well above the supercharger drop out.
Go carefully I would hate for your very interesting project to end up with a “bang”

I do like the idea of a switch though and yours is a particularly good installation. There are occasions with the S37 where I would like to travel at a relaxing displacement speed of say 12 knots without the supercharger howling away and producing belt dust.

Suggest researching the reasons for waste gate valves

ps
I found this:
The wastegate valve's purpose is to:

• Protect the engine and turbocharger
  By preventing the boost pressure from rising indefinitely, the wastegate protects the engine and turbocharger from damage.

Hi David,

The engines I am running are KAD32P’s

As far as I know they cut in circa 1600rpm

Cut out at 2600rpm

Cut in at WOT by way pf a proximity sensor on the throttle linkage

Then off when coming off WOT

And then back in on the way down at (if I remember correctly) at a out 2500/2400rpm then drop out completely back under 1600.

I don’t know what the max rpm of my 32’s are but I have yet to get them over 3000 (maybe 3200) rpm.

I do know that there is some sort of flap valve involved somewhere and you can hear that dump some air (or it sounds like it does) when the chargers disengage.

I will hunt down my max rpm info and maybe install a couple of boost gauges to get better info.

As long as these switches and having manual control aren’t doing any harm they are a really nice thing to have. I went out again today and was plodding along at a very comfy and quiet 10/12 knots.

 

[New Boater]

Found this.

 

[New Boater]

She is shifting along at 3200rpm. Seems I have a bit more to go.