Reply With QuoteSounds like DM25CITATION just finished his Raylar kit and was out testing this past weekend.
The CMI's are supposed to be the best exhaust on this motor.
Whipple has some of the best upgrades available for that motor. They have 4 or 5 different packages ranging from ECU reprogramming, to full blown whipple supercharger. They are on of the few aftermarket company's authorized by Merc to do ECU reprogramming on the 555 unit.
There is no need to reprogram the ECU,The stock ECU already has the capability of making the adjustments and relearning itself,The ECU is just a processor it takes the inpiut data from various sensors and adjusts as nessacary.The fuel pressure on the 496 is externally adjustable.Making the engine breathe is the key,but just adding an intake won't do the trick.The stock exhaust has a restrictor plate between the manifold and riser that chokes down the exhaust,this must be removed,the stock cast iron cylinder heads don't even fit the block properly,the combustion chamber is larger than the cylinder bore.Part of the reason 496 supercharged engines have head gasket issues,not to mention piston issues.So porting the stock heads,you still wind up with the same combustion chamber.AZ speed & Marine does offer an intake but what good is an intake with poor flowing cylinder heads and exhaust,not to mention no cam change.the AZ speed&marine claim of 625 is a complete rebuild different crank and pistons as well.Along with your motor as a core plus $16,000.00.
Sounds like DM25CITATION just finished his Raylar kit and was out testing this past weekend.
hey guys,
the results on a advantage 25citation.
i had to stay a extra day in havasu. it was too nice to leave (talking about the boat perforance, of course). i am soo happy with the kit. the torque is there when u need it. i feels like iam driving a new boat. i gain about 12 mph on a tester aliumion 28 pitch prop. i think when i dial in on a stainless steel prop and right pitch. i would gain a few more mph. i should be at 75 mph on a old 496 mag. i use be be at 55mph with 6 people abroad. now with the same people and cruising at 65 mph. top speed this weekend was 70 at 4900rpm. getting on plane at half the time.
hey guys,
the results on a advantage 25citation.
i had to stay a extra day in havasu. it was too nice to leave (talking about the boat perforance, of course). i am soo happy with the kit. the torque is there when u need it. i feels like iam driving a new boat. i gain about 12 mph on a tester aliumion 28 pitch prop. i think when i dial in on a stainless steel prop and right pitch. i would gain a few more mph. i should be at 75 mph on a old 496 mag. i use be be at 55mph with 6 people abroad. now with the same people and cruising at 65 mph. top speed this weekend was 70 at 4900rpm. getting on plane at half the time.
I feel like I am in the movie Groundhog Day!! I have read this same post updated several times over the last two days. I'm glad your happy.
can you elaborate?
did you change the exhaust yet? or if your gonna with what?
thanks
The stock exhaust has a restrictor plate between the manifold and riser that chokes down the exhaust,this must be removed,the stock cast iron cylinder heads don't even fit the block properly,the combustion chamber is larger than the cylinder bore.
Shadow can elaborate more on this, but I know he removed the restrictor plate, and ported and matched the exhaust manifold to the heads.
If everybody and his brother can make a programmer for a auot gas or diesel engine and gain 25%+ horsepower, why can't somebody do that for this engine. Cgange the air intake and exhaust to let it breath and change the computer program. We all know these motors are detuned at the factory. my .02 and ?
Whipple has the rights from Merc to reprogram the Motorola 555 ECU. There are gains to be had with reprogramming either a stock or modified motor by going that route.
Most aftermarket reprogrammers are done WITHOUT the permission of the OEM.
The process involves "hacking" into the code of the vehicles computer then changing the code from results obtained by dyno testing.
That is why it takes almost 1 year to get a new programmer for new vehicles.
So just because someone has the rights doesn't mean other cannot develop a programmer. It just means those with rights have the code already and can do it quicker.
I surmise that once the programmers figure out practicall every HP boat made nowadays comes with a 496 they will get on it.
can you elaborate?
did you change the exhaust yet? or if your gonna with what?
thanks
AS Phebus said,i'm running stock exhaust,there is a restrictor plate between the top of the manifold and the riser,i removed that plate and ported out the exhaust.As far as the computer,keep in mind they already have the paramiters set in them and will adjust as the inputs to the computer change.
no need to send your ecu out to have it reprogramed if you don't open it up so it can breathe.
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