*THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.
Welcome to the updated THT!
If you are having trouble signing in, please email feedback@thehulltruth.com with your username and we will help you. We thank you for your patience as we help you access the new site!
Seacat, are you kidding? I have to agree with Harry. Buy your self a book about engines. Study hard, and then make your statement again. Do you even know the principles of the diesel. Have you seen many Gas Semis? You know, the big truck thingys that are good for about a million miles?
Seacat, are you kidding? I have to agree with Harry. Buy your self a book about engines. Study hard, and then make your statement again. Do you even know the principles of the diesel. Have you seen many Gas Semis? You know, the big truck thingys that are good for about a million miles?
You really have no clue as to what I know about engines do you? Apparently you are well versed in trucks. Do you know anything about boats?
Are you saying a gas engine cannot be made as strong as a diesel?
Or are you saying it hasn't been done yet?
In any case the Verado does not need to be built like a MAN or CAT to be reliable with a supercharger does it?
I also maintain that there is nothing simpler or inherently more reliable about a diesel like Yanmar comparable to a Verado.
It was not a personal attack. If you had an engineering background, you'd understand what my point was. Sorry you are so insecure you felt attacked...now that was a personal attack :-)
Also, yes, you probably could build a gasser as srong as a diesel, but then it would get even heavier than that overbloated black anchor called the Verado...Spanish for self-destruct, if I remember correctly from high school.
Also, let's just look at HP to displacement. A 250 HP motor with 3.6L has a lower volumetric efficiency than a 250 with 2.6L displacement. That means it doesn't make as many HPs per cubic inch...basically, it doesn't work as hard. But since it doesn't work as hard, it also doesn't make as much heat, require as high compression, require higher octane gas to prevent pre-ignition, etc.
Finally, please remember that something has to drive that supercharger, and it's the engine. A fairly large amount of HP goes into driving the supercharger. That means even more heat, friction, etc.
It was not a personal attack. If you had an engineering background, you'd understand what my point was. Sorry you are so insecure you felt attacked...now that was a personal attack :-)
Also, yes, you probably could build a gasser as srong as a diesel, but then it would get even heavier than that overbloated black anchor called the Verado...Spanish for self-destruct, I believe.
Harry
Don't like having your assumptions challenged huh?
I thoroughly understand diesel and gas engines and the differences between them. My point was that gas engines can be built as strong as necessary. Apparently you missed that.
A comparable Yanmar diesel has no edge in simplicity or inherent reliablity over a design like the Verado if the Verado's design is executed properly. In fact the Verado installation is simpler in some ways than the Yanmar since it requires a lot less plumbing in the boat and a lot less gear to get the power.
A turbo charged diesel is built to be more durable than a n/a gasser. No doubt. But when mercury designed verado, I am sure they built the crank, con rods, pistons, wrist pins, block, etc. stout enough to handle the added pressures of forced induction. They have oil jets spraying the backs of the pistons for additional cooling. If the supercharger and after cooler were removed, I bet the verado would weight about as much as the competition.
As far as exhaust driven vs. gear/belt driven forced induction.
A belt/gear driven supercharger will require as much as a 30-40hp parasitic drag to make 100 hp. So your net hp is only a 60-70 hp gain.
An exhaust turbo will only use 10-15% drag to make the same 100 hp.
The big draw back to turbos is turbo lag and the issue of plumbing. It would be a bitch to stuff a turbo under an outboard cowling. I bet the Verado would be a bad ass with a turbo, but a bit slow out of the hole. Maybe not though. I bet the heat issues were one of the big negatives of a turbo on an outboard. Having the exhaust routed through a turbo. Special castings, water cooling, etc. Easier to strap on a supercharger.
Have you ever seen a big rig running a super charger? NO! Well maybe the old detroits, but they needed one to even run because of the fact they were 2 stroke diesels. To make real power they added turbos.
As far as Yanmar being built tougher than a typical gasser yes it is.
Modern day marine diesels are the result of years of experience on big rig deisel and heavy machinery equip.
Modern day marine gassers are the result of chevies 454 BB and 350 sb, etc.
Gassers aint gonna match up against diesels. Sorry.
Yes the gassers are alot more stout than years past, but they will not give you 5000 hours of continous use.
RE: Mercury Verado.......run Forest, run........ 
