Turbo 2.5 mercruiser possible

[achris]

Re: Turbo 2.5 mercruiser possible

To run a 350 in a boat that small you are going to need to run 1.32:1 drive ratio.... an they are as rare as rocking horse pooh...

350 in a 16 foot boat is not just scary, it's downright dangerous and ill-conceived... As the man said, put a 3 litre in there and you'll have all the fun you want...

I'm unsubscribing now... your boat, do as you like...

 

[dollarten]

Re: Turbo 2.5 mercruiser possible

I remember back in the day when a customer had a Mrecruiser 198 ( 305 CI ) a Starcraft tri hull boat. I am not sure of the length but it was short compared to all the other boats the were 305 powered . Everyone thought that this boat would be a rocket , not to mention unstable > Turned out that is was a slug for performance . The boat was so off balance with all the weight in that back it had a hard time getting on plane if any additional people were behind the windshield . This boat was brand new , mind you . The customer had to have a shorter hull so it would fit in his garage . This was before swing away tongues . The whole program was an all around bad decision at the time

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

I doubt it was no power. On that boat. And also putting 300 more pounds on back wont be issue cuz I put 2 people on back weigh 360 total plus motor and handles good. Lighter better. It should get on plane fast with v hull not tri hull

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

What about the 305 mercruiser

 

[QC]

Re: Turbo 2.5 mercruiser possible

Let's let this one die since you've started another thread, and decided to dump the turbo idea. I'm moving the other one to non-Repair I/O.

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

Ok sorry just have ideas lots to learn

 

[Kja4555]

Re: Turbo 2.5 mercruiser possible

When Merc changed those engines to MPI a couple of years ago, they managed to get about 170hp out of them, but not for very long. They would break the lower end.. That's why, even with MPI, they are still only rated at 135hp... Yes you can get more power, but the bottom end of the engine just isn't strong enough to withstand it....

If you need more power, pull the 2.5 litre out and put something bigger in....

Chris.....

As far as I've been taught the 2.5 is pretty stout, id say 175 is not at all too much for an engine that has a forged steel crank and 5 mains. That lower end can handle more rpm and power than rated by Merc. The pistons and rods could use something different sure... but for a lower comp. engine and let's say keep the boost at 5psi that would be a walk in the park for rods and pistons modeled after a small block v8. Midget racers have pushed this architecture to good power numbers for years and still continue to drool over this engine. After all its just a Nova 153 marine edition. So my question is where did you get your info on this engine? Have you boosted these before? Where's the pictures and info? How much boost? What was the engine condition? Boat size? Load %? Afr? Intercooler? Meth injection? Octane rating? Carb size? MPI? What intake? Exhaust? Turbo? Supercharger? Spray? There's so many different variable here. And with such a simple response it doesn't justify this engine and the possibilities of a new market idea. I can blow the guts out of any motor with poor execution and lack of experience. So my question is how did you blow yours up? Or was this a "freind of a friend" kind of response? It shows you come on here quite often so the first hand experience and statistics to verify how a 5 main forged lower is weak would be a nice response. What hp were you turning under what conditions proved to be a common 2.5 merc failing point and I'd like a number on how many of these engines you blew at that power level to be able to confidently say 175hp for not very long can permanently hurt these engines (before rebuild)