Computer/Wiring questions.

94m5

94m5

Dmaup's Daddy
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allright, this is what I am wondering.


I am planning a build that requires wiring 2 VIII engines in to one vehicle.


Is there anyway to run 2 engines off of one ECM, or am I gonna need to wire the thing with 2? I'm guessing it won't work because of TPS inputs and what not, but if I can make it work from a simplicity standpoint, I will.


What do you guys think?
 
This sounds like a good plan.

Is this some sort of Lincoln Death-Wagon?
 
IN THEORY IF you had BOTH engines timed EXACTLY the same and were connected by their crankshafts, then yes you could do that. If they are independent, then no, you will need 2 pcms, although some of the wiring could be consolidated, such as vcrm, alternator control, fuel pump, accessories, and that's about all I could think of...interesting idea though.
 
Thats what I was assuming.


These will be working independent of each other............One on starboard, and the other on port.


Thanks for your insight.
 
Nothing too exciting really............


~560 HP in a cigar boat. I'm just looking for an older hull sans engines.

I'm trying to find info on what stern drives I need to stand up to them.
 
wouldn't it be much easier to get a big block ford w/ forced induction? Even with the fi, it'd be a damn sight easier to do than 2 4v engines and all that wire...but wouldn't be as interesting, so I kinda see your point. Now if you could transplant 2 conti drivetrains in a mark, that'd be interesting as well. Not really doable, but interesting.
 
Just run two PCMs, dont make it more difficult than it already is.
Boats that run EFI motors dont "share" PCM's between the TWO engines.

Keep it simple, your gonna have enough hurdles to overcome.

Stern drives are gonna be a STEEP hurdle...getting them mated to the 4.6
Unless you went with a 302 based "velvet drive"

There is a 4.6 block out there made of IRON that has a 302 bellhousing.
That would work with a mercrusier alpha drive set up for the 302 marine engine.
 
Well,

That is'nt gonna work for me. :D


I'm not "up" on outdrives/motor combinations here but I am thinking about doing a couple one off CNC, SBC -> Ford modular adapter plates. I want to keep the aluminum blocks to keep weight down.


Any chance of that working?
 
there is what about 100lbs combined difference in the weight of the two engines?
and your talking about a 8-10K lb boat?

seriously your worried about 1%?

I'd be more concerned about durability and corrosion control than I would about 1% weight difference with two different engine packages.
 
94m5 said:
Nothing too exciting really............


~560 HP in a cigar boat. I'm just looking for an older hull sans engines.

I'm trying to find info on what stern drives I need to stand up to them.
Click to expand...

The "older" boats are MUCH heavier, you would be better off getting a newer hull that is BUTTLOADS lighter.

and.. a pair of 280HP motors run thru bravo outdrives probably wont even PLANE a Cigarette boat.

if your going with itty bitty motors, dont use the HP ROBBING BRAVO DRIVES, they soak up an insane amount of HP.
your gonna WANT the smaller, easier to turn FORD compatible Alpha drive.

You talk about the difference between the iron block and the Alum block but dont know anything about outdrives?

you really need to get some research done sir.
 
If your gonna do this.. forget the mark 8 motor.
It simply doesnt have the "bottom end grunt" your gonna need to get a big heavy cigarette boat up "on the step".

if it were me.. I'd be looking for a pair of 03-04 cobra motors or some of the newer 5.4 four valve SC motors.

your gonna want a minimum of 1K HP for a 40 foot boat..and if it AINT 40 foot it AINT a cigarette boat...(lol)

we had two 500HP motors in a 74 Performer Cigarette boat, 1K HP would barely get it up on the step and it was only good for about 46MPH at WOT.

you need MORE umph than 3 mark 8 motors will give.

^ 74 performer, a very old heavy boat.
your gonna want a 90's year model boat to get away from "heavy".
 
Thank you for e-slapping some sense into me mang. Was'nt taking into account the sheer weight of the boat itself.


With a proper prop selection what kind of speed/economy should I expect given lets say 25-29 Foot V hull, and twin N/A DOHC fords?
 
well 560 HP minus about 30% lost thru the outdrives...
560 - 170ish = 390HP

too many variables to predict MPH honestly, it WONT do 60 which is quite fast.. it might do the low 50's.
Greatly depends on the actual boat it goes in...and alot of other factors.
 
Wow... that was informational if I were to ever build a boat! Thank god my addictions and pocket book have kept me confined to land!
 
I should just always remember that if it has pistons or can burn anything petroleum based Tommy knows more about it that I do...
 
gentlemen and ladies in my 60+ years i have found out that the person you are talking to is not a complete idot. it's up to YOU if you use the information with intellance or idotice. jd
 
kustomizingkid said:
WTF Tommy... since when did you know anything about boats??
Click to expand...


Boats were one of my addictions back when I had large amounts of disposable income.

From pleasure craft, to 80-100 MPH dragboats to 40+ ft multi engine off shore boats.
 
rayner601 said:
wouldn't it be much easier to get a big block ford w/ forced induction? Even with the fi, it'd be a damn sight easier to do than 2 4v engines and all that wire...but wouldn't be as interesting, so I kinda see your point. Now if you could transplant 2 conti drivetrains in a mark, that'd be interesting as well. Not really doable, but interesting.
Click to expand...


kinda like the hairy hurst olds.......2 toronado drivetrains in a 442....."the hairy mark viii
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