Cummins QSC500 Turbo Color

[ttmott]

Dual purpose. Keep heat in the turbine housing to keep gas velocity up through the turbine and also to stop heating up everything else around it.

On a QSC 540 probably good idea to remove during inspection to see if the waste gate shaft seal is leaking as evidenced by black soot around the shaft. Not a cheap repair.

I ceramic coated the turbine housing and used a turbo blanket on my 400 rwhp 2 litre 4 cylinder. Stops the paint on the hood blistering too, but still didn't save the nearby ABS system.

On a turbo race car, the turbine housing can glow cherry red.

But - isn't all QSC8.3 engine's turbochargers water jacketed on the turbine housing?
I believe the QSM11 like mine below are the only Cummins dry turbos for marine use.

 

[juggernaut1]

I'm not sure what you are asking Tom?

The QSC540's in the 48DA's I've looked at in recent times had turbo blankets.

 

[ttmott]

I'm not sure what you are asking Tom?

The QSC540's in the 48DA's I've looked at in recent times had turbo blankets.

sorry - Trying to understand why there are blankets on water jacketed turbine housings... Doesn't seem to make sense to me.

 

[Chief Ed]

Well, Sea-trials went very well today. Fuel burn numbers are within spec in the high RPMs and low RPMs. There is a range in the middle where the reported burn is a little higher than spec. Burn rate was displayed on SmartCraft Diesel View. Here’s a chart...

RPM Spec (GPH per engine) Port Stbd

800 1.3 1.2 1.2
1000 2.1 2.2 2.2
1200 3.3 3.8 3.8
1400 5.0 6.4 6.5
1600 7.0 8.6 8.7
1800 9.4 12.2 12.4
2000 12.2 15.2 15.2
2200 15.7 17.6 18.0
2400 20.1 19.9 19.9
2600 25.4 23.4 23.5

We were full of fuel (335 Gallons) and water (100 Gallons) with three adults on board. Seas were light with no measurable wind.

WOT was 2665 RPM doing 34.9 MPH. Did this for 10 minutes. Temps stayed right around 175.

Overall was very pleased. What do you all think about the fuel burn in the mid range being a little high? It’s also a little low at the high end. Props need tuning? Or is that close enough given the load?

Cruising at 2200, by the way, made 25.5 MPH burning 35 GPH (.7 MPG). SmartCraft showed load at 66%. Very satisfied with those numbers compared to my old 330 with 5.7s!

 

[Blueone]

Well, Sea-trials went very well today. Fuel burn numbers are within spec in the high RPMs and low RPMs. There is a range in the middle where the reported burn is a little higher than spec. Burn rate was displayed on SmartCraft Diesel View. Here’s a chart...

RPM Spec (GPH per engine) Port Stbd

800 1.3 1.2 1.2
1000 2.1 2.2 2.2
1200 3.3 3.8 3.8
1400 5.0 6.4 6.5
1600 7.0 8.6 8.7
1800 9.4 12.2 12.4
2000 12.2 15.2 15.2
2200 15.7 17.6 18.0
2400 20.1 19.9 19.9
2600 25.4 23.4 23.5

We were full of fuel (335 Gallons) and water (100 Gallons) with three adults on board. Seas were light with no measurable wind.

WOT was 2665 RPM doing 34.9 MPH. Did this for 10 minutes. Temps stayed right around 175.

Overall was very pleased. What do you all think about the fuel burn in the mid range being a little high? It’s also a little low at the high end. Props need tuning? Or is that close enough given the load?

Cruising at 2200, by the way, made 25.5 MPH burning 35 GPH (.7 MPG). SmartCraft showed load at 66%. Very satisfied with those numbers compared to my old 330 with 5.7s!

At 2200 I cruise at 26.1 mph and burn 1 mpg

 

[brewster16]

1 mpg vs. .7 mpg? That is a huge disparity for a miles per gallon figure. Could the difference be one of you is quoting statute mpg vs. nautical mpg?

 

[Chief Ed]

What is your load with those numbers, Blueone? I know you have the CTAs and mine are the QSCs, but that is a pretty big difference...

 

[swaterhouse]

What is your load with those numbers, Blueone? I know you have the CTAs and mine are the QSCs, but that is a pretty big difference...

You cant compare CTA and QSC fuel burn at specific RPM's the curves are very different.

Your numbers at survey are close to where I started when I purchased my boat. I initially removed some cupping and it didn't help much. I ended up removing 1" of pitch and got within spec and only lost 0.75 knot at 2300 RPM which is what I did my fast cruise at.