AZ Speed's L-18 intake coversion pkg for 496HO
12-03-2003, 05:58 PM
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I too am extremely interested in this upgrade. I was quoted 538 HP @5200 and 575 ft/lbs @ 4500, with dyno headers. They also recommended CMI headers, but I don't know if it's E-Top or Sport tube.
I don't believe you can directly compare the 425 HP of the stock engine with the 538 HP of the modified engine because the 425 HP is the propshaft rating and the 538 HP is measured at the crankshaft. If we assume the same 30 HP drop as the HP500EFI (500 HP crank, 470 propshaft) the 425 translates into about 455 at the crank. You're still getting a healthy 83 HP increase, but not the 113 they referenced. I'd love to be wrong!
I don't believe you can directly compare the 425 HP of the stock engine with the 538 HP of the modified engine because the 425 HP is the propshaft rating and the 538 HP is measured at the crankshaft. If we assume the same 30 HP drop as the HP500EFI (500 HP crank, 470 propshaft) the 425 translates into about 455 at the crank. You're still getting a healthy 83 HP increase, but not the 113 they referenced. I'd love to be wrong!
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12-04-2003, 08:44 PM
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My "Mercruiser 496 Mag Bravo Models" Operation, Maintenance & Warranty Manual (black cover), on page 40 has a table with engine specifications. It states the propshaft horsepower for the 496 Mag HO is 425 with the following footnote "Power Rated in Accordance with NMMA rating procedures."
I couldn't find any reference to horsepower in the installation manual.
Confusing that Merc is publishing a different rating somewhere else.
I couldn't find any reference to horsepower in the installation manual.
Confusing that Merc is publishing a different rating somewhere else.
12-05-2003, 01:21 AM
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I've dyno'd a lot of Mercruiser motors and they have always made the "propshaft" horsepower at the crankshaft. The 496's make 415-430 at the flywheel. Although quoted as propshaft, this is not the case. Nor was the 6.2, 454, 502. All of Mercury Racing's motors have always tested higher than whats published.
Just to let you know, in order to use the Az. setup, you have to change the harness and computer system to the MEFI4, therefore, if you have Smartcraft, it will no longer work.
Our 525 packages will be available in Jan. and use the stock exhaust.
Thanks,
Dustin
Just to let you know, in order to use the Az. setup, you have to change the harness and computer system to the MEFI4, therefore, if you have Smartcraft, it will no longer work.
Our 525 packages will be available in Jan. and use the stock exhaust.
Thanks,
Dustin
12-05-2003, 06:27 AM
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Dustin,
Do you have the billet covers and the other polished engine parts ready now. Or if your using stock exhaust, are you going to change the engine look like you were planning on earlier.
Don
Do you have the billet covers and the other polished engine parts ready now. Or if your using stock exhaust, are you going to change the engine look like you were planning on earlier.
Don
