575 sci power upgrades ?
 

I'm interestd to know what kind of power upgrades have been done to Merc 575 sci set-ups.

How much boost do they run in the stock / factory configuration ?

Your expereince or redirect to reference info appreciated.

I had a set 575 sci in my Top Gun, From what I understand the best upgrade is to actually reowork the motors a little, different cam, different valves, rockers, etc.. If I remember right the boost is only around 5 - 6 lbs or so, if you go any more you will blow the motor up. My motor was reworked and was getting around 650 - 675 HP with a mild cam.

Stock boost is about 4#. An innercooler, pulley change and ECM flash will get you to about 650HP.

Mine are at about 650 now with stock pully. Best was 715 or so on dyno I had him back down due to NO 93 in OK,
New heads punched out to 509 and just about everthing else.
Call Brad Smith you wont be sorry.

Ron Potter built mine up to 700+. They are awesome! New cam, massaged heads, roller cam, pulley, and ECM.

something like this?

http://www.youtube.com/watch?v=25XxQ2eiuYg

Now where is that smiley face!

I have done several of these and we put Dart heads, cam, innercooler, program the ecu and get 730HP.

If you don't mind working with an engine builder that is some distance away from you, Tyler Crockett in Michigan.
http://www.crockettmarineengines.com/

Hint: Who ever you choose, get several OSO member recommendations BEFORE you decide. Please don't become a member of the "Beware---Stolen Thread" club. We have enough of those already enlisted.

Dean Gellner supplied the stuff for mine
( heads, hr cams/lifters, ECM upgrades)

216-398-8500

They run great:drink:

Dean Gellner in Ohio is probably one of the foremost experts on squeezing power out of the 575 sci.

I would start by swap out the 256 Blower for an 8-71 @ 8psi. also maybe add a healthy roller cam to help out.

The question is: how much do you want to spend? If the boat has 200hrs on it you should change the head gaskets and rebuild the blower. You can only guess how I know. If you do the head gaskets with the motor out of the boat it would be a good time to do a cam change. Even if you dont have 200hrs on the boat, if you turn the boost up the stock head gaskets in that motor are a chance I wouldnt take. If the head gaskets have been replaced and you dont want to pull the motor apart, an intercooler, pulley and fuel adjustable fuel pressure regulator is a good place to start. That is basically teagues kit. If you are limited on hatch space the whipple cooler might fit but it is spendy. The superchiller is priced right but tall and you will get into adding scoops and losing you sun pad. Also modifying your covers. As mentioned earlier, you can upgrade to an 8:71 (which is an 1.5" taller) and pedal your 256 for some good cash...I found a good lightly used 8:71 with a low pro whipple cooler for about $3300 complete with carbs and linkages.

x2 on Dean Gellner
 

I also support the vote for Dean Gellner...

He did heads, custom rollercam, whipple low-pro intercooler, smaller pulley and custom tuning to hit 775hp on my 575SCi's and the best part is they idle like stock and pull like a rocket all the way to 5600.

Just my two cents. :drink:

Recently, when I start my port engine 575sci, the engine idles at around 2200 to 2500 rpm versus the starboard engine idling at roughly 1100 rpm.

After a few minutes the port engine idle slows down to match the starboard engine at 1100 rpm.

Is this a concern? What may be causing this and what to fix?

They idle at 1100rpms????? They should idle at about 750rpms.