engine ??s
 

i have a 94502mag,efi.i belive the h/p rating is 415.toying w/putting decent,double plane intake on it and a 800-850 holly double pumper on the engine and keeping the same heads and cam.how do you thank the engine will perform....more or less h/p,and how reliable,fuel consumption.the boat is a 27fever,1994.thanks.

You definately won't gain anything and will probably increase fuel consumption.

If I had that engine, I'd bolt on a set of AFR 305 heads, a new slightly larger cam to make peak power at 5,500rpm, a Edelbrock RPM Air-Gap intake and a 850 cfm carb. Then upgrade exhaust to some 496HO take-offs. Total upgrade $3000. Should be good for 550hp.

Put a crane 731 cam and headers remap the ecu and leave it the hell alone.

Air gap dual plane is nice.

What parts are you stealing to come up with 3K????

More like 5k by the time you are done and you can't run a lot of cam with the 496 exhaust.

$2000 for heads (JEGS)
$300 for exhaust (same as I paid for mine)
$250 for intake
$200 for cam
$250 (maybe more) for carb (ebay or swap meet)

I don't steal, I shop! :drink:

WHY would you want to get rid of the efi? That's crazy unless you just like working on sh*t all the time.

:ernaehrung004::p:p I don't think it has a hdy roller cam on the 94 so thats some big bucks to change, I spent 6000 on my 1st upgrade in 95 on my 93 502. to get 585 hp and 580tq switch to hdy roller cam, 1500, head work 700, dart intake 400,bg carb 850 700,exh dry 2700, flame ar 200,msd full 1000 so over $7200 plus labor:p latest rebuild to a 509 9.5 to 1 added merlin heads isky cam nickerson 1050 dom, dart intake which netted me 650 hp with a stock 1050 so with the nickerson they fell another 20hp so 670hp and over 640tq.that work was another 7200. art

because i have alot of engine stuff left over from my drag-racing days,plus a carberated motor would be easy and cheap to fix,trouble shoot,etc.parts this i have ,efi i do not.do not get me wrong,efi is better as far as fuel consumption goes,but parts cost more and you have to go to mercury to get them....some of them.besides,dont carberated motors make more h/p?thanks for all the input.

????
My motors are carbed and I've never even had a hiccup. 120hrs and going strong. I can't say that for the EFI boats I've towed in.


Darrell.

:Whatever:

I did it, never happier. Not to mention 300 extra hp.

Carbed these days is a little more for the low dollar shade tree mechanic type who wants to make excellent hp. To make excellent hp with EFI you need to be the puzzy rich guy that wants his boat to run the same as his PT cruiser. The lack of tech ability and knowledge with the PT cruiser crowd is annoying. But they compensate for that with $$ which is really funny when us low dollar shade tree guys are rompin past them :ernaehrung004:

BT :cool:

In my opinion you will spend more time working on an EFI setup than a carbed setup.

carbed these days are for the shade tree guys that aren't smart enough to run a lap top and a programable efi set up.

there is no carb on the planet that will make the precise fuel curve that an efi system will throughout the range that the motor makes power in.

none

zero.

carb guys like to say " well at least when it stops out on the water, i can still fix it"

thats from years and years of practice. efi guys like to turn the key... have it start without pouring raw fuel into the oil... and if they want to hot rod the motor, they simply do what everyone else does that does it intelligently...

go to the dyno, put in the right fuel curve, and go home.

the motor then makes the max power it can make from the mechanicals and gets superior fuel milage as well.

there are 8 to 10 of these boats here. all the carbed ones seldom run well if at all.... and all those guys have two or three spares. all the injected boats run all the time. perfectly.

they are , without exception, faster, than the carbed boats ... even those that they shouldn't be on paper but are because the carbed boats are either blowing black smoke or fouling plugs or some such thing...

when the injected boats have a prroblem, the guy comes out with the scanner. prob is identified in minutes, ( no guesswork) sometimes its a connection... sometimes its a part... fix it and away they go....

couldn't be more straight forward.

as for making power ... my position ( and long experience in engine building/dyno work is:

no motor i have ever seen on a dyno with a carb, that was then converted to efi , EVER made more power than the efi set up did. not once. if the intake flowed the same then just the ability to make the fuel curve perfect EVERYWHERE always paid big dividends.

stick with carbs if thats all you can understand... but efi is better in every single aspect of engine function. by a lot

It really depends on if you prefer analog or digital control of your fuel system. I find analog superior albiet somewhat more restrictive that digital. I don't really think a guys preference for carb setups is an indicator of them not being smart enough for efi setup. I in fact have been trained in and can write code in fortran, basic, rslogics, and CTC. I'm sure I could handle programing a fuel curve. Yet I chose to run carb. Do you drive a PT cruiser stevesxm?

BT :cool-smiley-011:

Isn't that kind of obvious...........


Perfectly all the time.......You BS like a politician............



Except repairs..............


EFI greatest benefit to the everyday boater is the easy starting and I'm not that lazy.

EFI greatest benefit to the everyday boater is the easy starting and I'm not that lazy.[/QUOTE]



Hence the PT cruiser jab. I think you and I are on the same page Pismo :cool-smiley-027:

Putting all the EFI/Carb BS asside. The 502 Mag efi system makes tons of low end torque, but doesn't flow well enough to support a lot of HP at higher RPM. So, you really have to look at the application. For a mild engine built to turn around 5000-5200 RPM max at 500+/- HP the Merc EFI will perform better. Beyond that the carb will surpass it. You will notice a significant loss of torque below about 3800 RPM when switching to a carb.

Bob