Originally Posted by Whipple Charged

You have some good points here, but I disagree with just a few items. What Mercury Racing did is incredible and I'm always the first to say, job well done. But, turbo motors in OEM and in many other applications have been proven to get poor mileage once the customers get them. If you go off OEM and CARB driving cycles, they look great. But the fact is, there just awful on gas engines for mid to heavy vehicles or vessels with variable loads. Do a search on the F150 Ecoboost engine, 3.5L turbo charged. While its claimed to have excellent mileage, almost nobody is happy with the mileage. In fact, the 5.0L, NA gets significantly better and the supercharged 5.0L (aftermarket) gets identical highway mileage as the Ecoboost, but 2-3mpg better in the city, with significantly more power across the board. The turbo engine is just always in boost where the supercharged engine rarely goes over 1-2 psi in any normal driving cycle. In fact you can cruise at 90mph, 6th gear at 5" of vacuum. While that's not apples for apples, its a nice example.

As for boost all the time? Do you know how much boost the 1350's run at lower RPM to get the boats on plane, cruise and accelerate? 28psi. Does that sound like low boost? How about the 1650, 40psi! While that's not needed for all boats, it shows what has to be done with that setup to meet the torque curve they wanted, which is certainly impressive. But, do you know how much power can be made with a supercharger at that boost level?

So the harder on the engine theory is not really accurate. What major advantage the turbo has is that they don't typically require as an aggressive camshafts. Therefore, valve train life can be extended in theory. But turbo's always have higher exhaust temps, especially with backpressure. The high temps is no friend to engine components and exhaust. But Mercury's extended life on the 1350's is due to the overhead cam cylinder heads, not the turbos. I think we all know the benefits of the DOHC concept, smaller, mild camshafts and basic valve train.

It really doesn't matter what engine you have, if you have a 12,000lb boat running 100mph, it takes a certain amount of power to go a certain speed. Therefore, its about engine efficiency at that point, something the superchargers (modern SC's) do quite well. Turbo's really shine at very high boost levels, 20+psi. But because the turbo's are water cooled, they lose significant energy, thus lower efficiency. If anyone actually thinks that we can't supercharge the 1350 long block and make the exact same power with same reliability is extremely in accurate. Of course, cams would ideally be changed to open the exhaust valve some, but 1350 is easily attainable. Also, to note, if you've ever been in a boat with 1.21 gears with 40 pitch props, the amount of torque required at 1500rpm is extremely significant.

Originally Posted by Whipple Charged

The only way you can make 1350trq at 2500rpm is massive cubic inch, nitrous or boost

Originally Posted by boostbros

Ok i,ll bite here and jump off the nice nice bit i go to a poker run to see big blowers vibrating the dock and blower rolling now its called old school but thats what i want to see and hear we walk right by the shiny, looks like it belongs under the hood of a toyota, purring while idling mercs as they make martinis in cockpits so big a leather couch for a back seat might be more approiate! i want to see the ratty old V bottom with big cube,s with massive blowers and carbs big enough to run an aircraft carrier! anyone here remember the engines in sorcerior? or the echo of inxs as it went by? any one here ever play reggies 177 speed run thru a big sound system? i want the hair on the neck to stand up! I don,t want civil in a bad ass boat i want to always know were playing with fire! Old school maybe but rat rods are the rage these days. Now for a bit of fun if Duck dynasity goes poker running what boat can you picture Si in?

Originally Posted by cougarman

Dustin,

What do you feel is Massive Cubic Inch?

Thanks
Jon

Originally Posted by boostbros

lets post some boost numbers of various sports i know many tractor pullers running way north of 300 pounds with compounding i know nitro in NHRA runs 50-60pounds alky runs much more but i not sure of the number artic cat 660 ran 24pounds yanmar marine diesel 60psi

Originally Posted by Whipple Charged

Sorry, that may have been to general. In my head, I always associate 5" bore spacing or larger as "massive" LOL. The Goodwin Competition motors, which I feel are the best motors to date (for marine) when money is not an issue, are conservatively built to 650ci. They made 1850hp on 87 octane and idle at 1000rpm and currently have one season on them. I think we will see some more of these soon, they are quite incredible.

Originally Posted by Whipple Charged

Sorry, that may have been to general. In my head, I always associate 5" bore spacing or larger as "massive" LOL. The Goodwin Competition motors, which I feel are the best motors to date (for marine) when money is not an issue, are conservatively built to 650ci. They made 1850hp on 87 octane and idle at 1000rpm and currently have one season on them. I think we will see some more of these soon, they are quite incredible.