Turbo 2.5 mercruiser possible

[Speed1v8]

Hi everyone I have a 2.5 mcm mated to alpha one. I want to turbo it with carb setup. My goal is no more than 8psi and motor running helthy. I done plenty of auto turbo kits but on this one what most worries me is the tubing connection. Also water runs threw exhaust is it suppose to exit the exhaust hot side of manifold with water is that normal or do you reroute a way for water to go around. Please help thanks

 

[dollarten]

Re: Turbo 2.5 mercruiser possible

A little to dangerous for an marine application . you will no longer have any water cooling to the manifold and way to hot of an item to have in a engine cowl where there is no air movement .The coast guard would nix the whole project after an install There are turbo kits installed on professional drag bots but their engine is out in the open and only run for 5 seconds or so

 

[dollarten]

Re: Turbo 2.5 mercruiser possible

a supercharger might be a little more realistic because you are not disturbing the exhaust program . Google them both and you will see

 

[Bondo]

Re: Turbo 2.5 mercruiser possible

Hi everyone I have a 2.5 mcm mated to alpha one. I want to turbo it with carb setup. My goal is no more than 8psi and motor running helthy. I done plenty of auto turbo kits but on this one what most worries me is the tubing connection. Also water runs threw exhaust is it suppose to exit the exhaust hot side of manifold with water is that normal or do you reroute a way for water to go around. Please help thanks

Ayuh,... It can be done,... With a water jacketed blower....

But,... Yer gonna be spinnin' yer wheels, 'n goin' nowhere with that idea....

I truly doubt that motor would take 8psi, on the stock cast components...

 

[Scott Danforth]

Re: Turbo 2.5 mercruiser possible

by the time you built up the 2.5 to be stout enough for forced induction to live in a boat, you could have bought a much bigger boat with a big motor.

a turbocharged car does not operate at full load most of the time like boats do.

can it be done - yes, should it be done - no.

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

My friends not Asking about safety here asking what I need for piping that's iron block it 8psi ain't nothing for that motor with small turbo. I understand how boat motors work or should I swap a v6 mercruiser carb

 

[achris]

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.....

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

Like a v6 I was thinking a 302 that be nice stock motor can I do that.

 

[dollarten]

Re: Turbo 2.5 mercruiser possible

A 302 will sound nicer and look better than the four banger but , the 4.3 GM engine would be a better choice for a marine application . They both have a 4.00 bore . The Ford engine has a 3.00 stroke , whereas the 4.3 engine has a 3.480 stroke , which is more suited to marine applications .

 

[achris]

Re: Turbo 2.5 mercruiser possible

Next problem... The drive you have for the 2.5 litre has a 1.98:1 ratio. If you put a higher horsepower engine in, then you might not find a prop taller enough (little/small boat, 'big' engine, short ratio means it'll need a lot of pitch on the prop).. You need to change the ratio in the drive, to 1.62:1... Or just get a new drive...

Chris.......

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

I would rather put 302 for torque will that motor fit the transome assembly I have. I know I have to change the bell housing and mounts on transome. On the boat two sides mounts I'll just custome make the bottom stronger

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

By finding a cheap boat for sale be best bet on getting all I need as long as motor running.

 

[achris]

Re: Turbo 2.5 mercruiser possible

What year is the 2.5? If it's any later than about 1980, then you will not find a Ford bell housing to fit the inner transom plate engine mounts... If you want torque, go for a GM 350 block... Merc stopped using Fords in 1977... They are still using the GMs and parts will be much easier to get and cheaper....

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

So will the 350 be a good fit. On my boat is a 16 ft open bow. I want it mostly for looks and cruise torque. Sure I'll punch it ones great while but mostly for pulling cruising looks and still have that speed just in case. So will that sucker connect to my transome assembly

 

[QC]

Re: Turbo 2.5 mercruiser possible

My friends not Asking about safety here

But we will always answer regarding safety here

So will the 350 be a good fit.

Yes. Now you're getting it. All the components are available. I would still look for a 4.3 though. 16 ft. and a small block is gonna be scary.

 

[Scott Danforth]

Re: Turbo 2.5 mercruiser possible

I would simply bolt in a 3.0 in place of the busted 2.5 and go boating in a few hours.

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

I want to feel scared like others out their lol some guy has a boat for sale with 351 Volvo winser for 500 can I buy that boat and transfer it to small 16

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

Please no 3.0 5.7

 

[Scott Danforth]

Re: Turbo 2.5 mercruiser possible

with a lot of work and money, anything is posible. the Volvo hole in the transom is different then the Mercruiser.

 

[Speed1v8]

Re: Turbo 2.5 mercruiser possible

If I get 350 mercruiser what do I need to connect to the drive and motor mounts. Also if I buy a boat with this motor in it can I swap those parts to my boat