Want to squeeze more power outta my 454

I have a Baja Boss Hammer with a 454 Mercruiser MPI and a Bravo one drive.

I would appreciate any suggestions on engine modifications that I could do to boost hp and performance.

Thanks!!

 

The 7.4 MPI / 454 MPI is probably one of the most commonly modified boat engines there is, and there's no shortage of suppliers for aftermarket gear.
There are a few questions you should ask yourself before you proceed, and that we will need to know the answers to before any of us can recommend specific equipment to you.
- How much are you willing to spend?
- How much power do you want to gain?
(These two points usually prove incompatible, in which case you must decide which is allowed to give way.)
- What kind of increase in operating costs are you willing to accept?
(Most power-increasing mods also increase your fuel and repair bills accordingly.)
- How much of a sacrifice in the engine's longevity will you tolerate?
(Again, coaxing more power out of the motor will wear it out faster- sometimes a lot faster.)
- At what speeds do you want the increased power? (Do you want it low down in the RPM range for fast starts at the expense of top end, or do you want killer speed at the expense of acceleration?)
Knowing ballpark answers to these questions, will make it a lot easier for us to recommend (and you to decide between) superchargers, exhaust systems, cams, etc.

 

old school math
1mph=$1000.00 today most likely more
think about a go reliable power plant that you have the about marshmat's questions

 

Keep in mind, First 100 additional HP equals about 5 mph increase and the next 100 HP, Less speed increase. Relationship between HP and Speed is Expodential not proportional. Significant speed increases will be expensive,

 

Its likely that if it was easy to make the boat go --just a little faster for a reasonable price then the boat manufacturers would have done so.

One of the best and easiest ways to make a boat go faster is reduce its wieght.

Or --and I am not trying to be negative--buy a more suitable boat.

It is quite likely you will throw a lot of money at this project and not be entirely satisfied.

 

Ever heard about banks Turbo?
You can dubble the power and get a 1/4 speed increase

 

You reckon you could just bolt on a turbo or 2 and double the HP then do you?

 

You could triple it too, but your copresion had to be reduced and octane rating increased and your crank would probartly be at the seafloor with the fish

 

Dont tell me your one of those guys who think bolting on a turbo is magical HP?

Your graph is an example of an engines Hp output not the same engine in different builds.

Hp comes from the drawing board, bolt on Hp is minimal.

 

It's not magical, but fysiks. More air presed into the cylinder means you also can increase the injected fuel and therfor more HP.

Don't tell me your one off those old guys thinking turbos are not worth the effort even they has ben around since 99% off the board members was still unboarn. I'm shure MTU, Cat, Volvo, B&WMan, Mak, Wartsila, Isota and all those other diesels use it because it's magical HP.

 

Yeah But they didnt wake up one day and say "oh lets put a turbo on it and double the HP.

Dont quote me here but I think the Ford lehman is 110 HP in natural aspiration and 130 in Turbo.

This engine was not designed to have a turbo but it will improve its breathing so you get a bit more. Not double!!!

 

That depends on how mutch bost you runn. There is tractor pulling engines designed for 130hp, but deliver mutch more after puting on 3 stage turbo.

A normal 2 valve 2 litre engine will develop around 180-190hp with a turbo and about 200 with a intercooler. With a normal I mean a vaxhuall or opel from the mid 80's running about 1bar bost. Hocking up a turbo on a diesel and expect twice the power won't work since all you get is more air, you nead to increase the fuel flow to if you want some serious hp

 

Nice pics.

I cant fathom out what the single long spring at the top of the picture is for.

I dont like waste gates--no need.

 

Do turbos boost power? If properly designed and matched to the engine being used, yes. Are they expensive? Yes. Do they increase fuel consumption? Yes. Do they reduce the engine's lifespan? Usually.
We can toss out suggestions all we want, but without knowing more about andrewhr's priorities in this project, we're just guessing. Turbos aren't the solution to everything. We need to know what he wants to gain from the modifications. More power- but where in the RPM band, and to what end? What are we optimizing the engine for, and what tradeoffs are acceptable?

 

I think what I wanted to point out with the turbo thing is that it can dubble the power, but only increase the speed by 1/4. hp and speed is not linjar.

If he bought a new cam it would probartly do no diference on speed. He would probartly have to go all the way with cam, pistons, a head job and upgraded fuel system to feel the diference.