DRAG

The electronic throttle is easy to control and i believe the throttle shifting is a separate control module that isn’t too complex. I could be wrong on that but that’s my understanding. I’m sure this is all easy to figure out if I had it sitting on the dyno. Im dead set on not messing with anything in the boat

articfriends

iTrader: (1)

merc uses SAE 1349, 99% of small shops (me included) use J607 so a stock merc engine is gonna show 3.8% more power from j607 alone. Then, most shops dont have a way to supply water to raw water pump and reclaim it as it comes out exhaust so again, that also pumps number up 20/30 hp on a 600 ish hp motor. Then, theres the shops that promise a "number"and will manipulate whatever it takes to show that corrected number. Ive had over achievers and Ive had turds on my dyno, some packages deliver, others are lame. Then, on top of all that, we got guys who think "bigger is better" and put in appropriate cams, cylinder heads, intakes etc on and make some beautiful number at a unrealistic rpm then the motors lack of average torque NEVER gets it there unless their spinning a tiny prop, compounded by fact the big power numbers generated by huge cams fall of face of earth on NA motors when entry level 3000$ exh manifolds or CMI sport tops are used. The fastest once in boat NA motors I built and dynoed almost always have a great torque curve, no one wants to spin a 23 pitch 6500 vs pulling some real prop!

Wildman_grafix

I need to clean up the excel file (some data that is not to be released yet.)

It is stock HP500EFI and HP525EFI results from the same dyno and ran full dress with wet exhaust. May be tomorrow. Just to see it, compared to the sort of new motors. Just from what I read here it obvious where Merc is spending the engineering dollars.

cheech

Just so I'm following you.
You say you run your Superflow. Are you an engine builder?
The 520 is just the old 502 based architecture right?
What's the price of a 520 longblock?
Couldn't you put some stout "base"engines of all aftermarket components together for way less and swap your accessories over?
Speaking of which, the 520 appear to have the 525 plenum. Weren't those handicaps once a certain threshold power wise was reached? The 565 I see has the flame arresters on top, so not sure what they have going on under that cover.

You get OEM Merc rods?

MMatt28

would be cool if someone took the 565 intake manifold and did some dyno testing to see if the dual throttle bodies help out with power at all.

Wildman_grafix

Years ago Tyler Crockett put the throttle body on the top of a 500EFI plenum. Said it was the only way to increase the power. Never seen any results.

KWright

stock 525 ran in complete boat trim. With wet exhaust.

MMatt28

wish he would have shared the results. Seems like a potential option if you wanted to stay NA.

SB

iTrader: (1)

There where results at some time.i know it’s been years but…..

302Sport

Dont want to throw this thread off topic but does anybody have any dyno numbers on 700SCi's?? Stock, Stage 1,2, etc....