nova26

How much does it shorten the life of a engine with modest boost? Like a wipple or procharger. What percent?

RJBBC

Interesting question. We are looking to supercharge our engine and that question has come to mind. In my novice opinion there are too many variables. Is the engine setup to be supercharged? What is the static compression? How kind of rotating assembly and valvetrain does the engine currently have? How much load will be put on the engine? How much boost is the supercharger producing? I started a blower upgrade thread recently was sent a very informative technical detail on superchargers. Take a look at this. To answer your question in general terms I am going to say 30%.

hoozeyurdaddy

If done properly, I think 350 to 400 hr's is reachable, if it is built modistly, 3-5 psi boost, proper carburation, and max timing of 28 deg. and all the reg. stuff in the motor, forged pistons, steel crank, good valve train assy. and the best head gaskets money can buy.

Chris Sunkin

Depends entirely on the engine. 6lbs of boost is going to dramatically shorten the lifespan of a stock Merc 330. If you build an engine specifically for supercharging, there's no reason it won't live just as long as an equivalent NA motor.

This is a common dilemma faced by guys who are looking for another hundred horses or so. They're confronted by many barriers. Let's take our Merc 330. To make another hundred horses, it's going to take exhaust, cam, manifold and carburetor and probably a set of heads- at a bare minimum it's going to take some headwork. That's all going to cost some bucks. Bolting on something like a B&M looks pretty attractive. The issue then becomes whther or not the bottom end and such can handle it. Once this person has their new toy, it's going to be hard to resist using it and we all know where that leads.

Now, take a fairly robust engine like a Merc 465/500. It already has some good stuff inside of it. Swapping the cam, adding inconel exhaust valves and good head gaskets will allow this motor to live a good long time with 5 psi.

Once you take the next step up into a hand-built blower motor, you end up in that blower vs. big cubes discussion and the blower then seems to be more economical, but now you're talking a bushel full of $$.

Smitty

iTrader: (1)

Also remember that you only hit max boost at WOT and how often are you going to be at WOT?? I have run supercharged boats for many years and they have all been fine for many hundreds of hours. As matter of fact they are all still going with their new owners with no issues. As long as you have changed head gaskets and done a few small mods everything will be fine. That is as long as you are not wanting to have 900 HP each

articfriends

iTrader: (1)

I would say at the 10-12 lbs boost level it shortens a engines life by 75% (rebuild every 100-125hrs vs 400-500hrs),Smitty

Chris Sunkin

10+ lbs of boost into a 9:1 Merc 330 engine would probably add 200+ horsepower. You'd need 108 octane race gas and I don't see it lasting more than a couple weekends... if that. Putting that same boost into a $20K longblock? Sure- 125-150 hours between rebuilds.

ZXXX Donzi

I am no engine builder but would say that it depends on the engine. It also depends on the setup and how rich/lean you run it. It also depends on how much boost you run. You can do 7 but I am told that if you run much more than 5 you are asking for it. I ran mine at 5 for a couple of years. It had 288 hours when I put on the blower (procharger M-3). I ran it good but did not do anything too stupid and paid attention to a few things.

Not all factory engines are set to the exact same tolerances. That is why Merc rebuilds then before calling them Blue engines.

As far as the 496's go...I have no knowledge of those. I hear that they hate boost. I know that they don't have true forged internals. That does not mean that they will fall apart but they will not like detonation.

A regular 502 mag...Well if it is setup right should run a solid 350 hours or so if squeezed on occasion. That is really pretty good considering the cost/HP. On the other hand, one wrong move and Bam!

I rolled the dice and it worked well.

kennyo

I'm getting tired of rolling dice....... Good to see ya yesterday Bill.

ZXXX Donzi

No joke. I am ready to ride. That is why I want most of the kinks worked out before I hit the water. It is good to have an auxillery boat.

Let me know the next time you come down to Center Hill. I am always up for a few beers.