Cummins QSC 8.3 500hp

[plowin]

Is anyone here running the QSC 8.3 500hp. If so what are your toughts so far. Any suggestions prior to installation? How are your fuel burn numbers?

 

[cb34]

Gear

What gear ratio are you going with? shaft size, and what size prop do you hope to swing?

 

[plowin]

2:1 with a 27" wheel and a 2" shaft.

 

[cb34]

8.3

Seems to be agreat choice, although 500lbs heavyer than the 5.9. I am sure you can loose the weigtht somewhere else. The specs on the 6.7 make the engine look like a bit of a dog with higher fuel burn at equal hp and torque compared to both the 5.9 and 8.3. What will be the step height for the wheel house in order to fit the engine? Very interested in the 33 myself.....thanks

 

[plowin]

The step is anticipated to be around 3-4 inches. We will not know for sure until the engine arrives. As far as the weight goes, I am willing to sacrifice that in order to have an engine that is sleaved and has been around in boats for a while.The weight should be offset with composite construction and if it is not at least the weight is going to be down low in the bilge where it belongs. The 6.7 has some impressive stats on paper for sure but has seen little operation in the marine marketplace. If it is as sucessful in boats as it is in trucks it should be great.Good luck and thanks for your response.

 

[petrel]

There's a guy down here w/ a pair of QSC's in a charter boat. He runs as many trips as anyone and I'm guessing he might have 8000 hours or so by now in the course of six years. I can call him and find out how they are holding up and exactly how many hours. I agree that a C series would be a far batter choice than a hotrod B series if you have the room for it.

 

[BillD]

There's a guy down here w/ a pair of QSC's in a charter boat. He runs as many trips as anyone and I'm guessing he might have 8000 hours or so by now in the course of six years. I can call him and find out how they are holding up and exactly how many hours. I agree that a C series would be a far batter choice than a hotrod B series if you have the room for it.

Petrol,
The new 6.7 has its roots as an industrial engine.
I would not call it a hotrod B
I too am looking forward to the 33F/QSC 500 package

 

[petrel]

Bill,

It's PETREL; I was talking about a 5.9, not a 6.7, which I know nothing about. I know you have a pair of 370's, but it seems to me a QSC would be better than a QSB 5.9. That's all I've got to say.

 

[plowin]

Petrel I appreciate the reply. You have been one of a very few with any real info about the engines.There is no need for you to make a special trip over to that charter boat to get any info for me, but if you are there I will take anything you can get. I do not want to inconvenience anyone. Thanks Mike

 

[tunaorlater]

My buddy has the 540 qsc in his 37 Duffy. He gets a 23 knot cruise at 21gph. It's his 5th season and he can't say enough about how much he likes the engine. Very quiet and smooth, fully loaded canyon trip is under 200 gallons, 200 mile trip plus trolling for two days.

 

[cb34]

6.7 vs 8.3

6.7 at 350 hp burns 17.6 gph vs 8.3 at 390 hp burns 7.0 gph. The 6.7 specs are not impressive at all.

 

[plowin]

I am hoping that I will see those same kinds of fuel burn numbers! God knows fuel is going to be $5.00 before its ever going to be be $2.50 again

 

[cb34]

fuel

Only thing worse than 5 bucks a gal is a boat loan:shock:

 

[petrel]

I talked to the guy w/ the two QSC's in his 50 some foot Carolina boat. He runs them real easy, more so than I thought, like 700 to 800 turns off the top, and he has about 9000 hours so far. Fuel prices like they are, he's only cruising like 17 or 18 knots, but the boat will do low to mid 20's easily. Anyhow, he's not had the heads off or any problems.

 

[plowin]

Thanks for the info. Fuel prices are killing everybody!!

 

[pointblank1]

cb34 --- "6.7 at 350 hp burns 17.6 gph vs 8.3 at 390 hp burns 7.0 gph. The 6.7 specs are not impressive at all."

I am not sure these quoted figures are accurate. I am researching the Qsc and have found the GPH:HP as with most ALL engines to be quite similar (At least concerning HP).

There is a lot of data on many websites and I am collecting opinions and data. Are you quoting from personal experience, cummins websites, or ?

Respectfully - Thanx

 

[Nighthawk]

Agree, that comparison is out to lunch. I don't care what Quantum engine you run, the fuel burn at a specific HP will be scarily similar as long as you aren't comparing HP at a level where the smaller engine is being pushed too hard. At 250-350 HP a QSB or QSC engine will be very close...........

 

[cb34]

#'s

6.7 #'s are right off cummins site

 

[pointblank1]

Where did you find "8.3 at 390 hp burns 7.0 gph"?

 

[cb34]

#'s

Just realized the performance charts are not apples for apples. 6.7 1900rpm 340hp 940flbs 6.4 gph, 8.3 1600rpm 390hp 1280flbs 7.0gph