496 H.O Mag Fuel Type
03-04-2021 | 02:22 PM
#11
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From: Western Pennsylvanoa
There was a dyno a while back that tests stock and modified 496/8.1. (Below) There is only a 1/2 to 1 horsepower difference between 87 and 93. Thats it! Lets be honest, in stock form the 496 is a low compression, iron head truck engine. Its basically designed for 87. Even modified or highly modified, I see no difference in speed or power, matter of fact, I think the soot on the transom is worse with 93. Now, 87 marine is better IMHO than street 87 gas station fuel, but thats another topic.
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03-08-2021 | 10:46 AM
#14
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From: Pasadena, MD
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03-08-2021 | 10:59 AM
#15
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Hey,
Just wondering what everyone's running for gas in their 496 Mag HO, I like always run 93 in my stuff, but I have seen multiple forums saying that the computers programmed to run 87 because it burns faster, and that 93 burns slower due to the higher octane, so you lose out on HP. 93 is a cleaner burning fuel though, so will that add longevity to the motor?
Just wondering what everyone's running for gas in their 496 Mag HO, I like always run 93 in my stuff, but I have seen multiple forums saying that the computers programmed to run 87 because it burns faster, and that 93 burns slower due to the higher octane, so you lose out on HP. 93 is a cleaner burning fuel though, so will that add longevity to the motor?
03-08-2021 | 11:15 AM
#16
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Another vote for 87. I can vouch that anything over 87 just soots up your transom and lightens your wallet unnecessarily. Take the $$ saved on 93 and use it to stay current on preventive maintenance. Coolant, plugs, sea water pumps etc are all things that are easy to let go past their window but will cause problems eventually. Oh and not a PM item exactly, but if you own a 496 long enough, you'll replace an IAC or two eventually.
But putting 93 octane in a low compression engine like the 496 does nothing except make XOM shareholders happy.
But putting 93 octane in a low compression engine like the 496 does nothing except make XOM shareholders happy.
03-08-2021 | 01:26 PM
#17
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Watchout! - I put 93 in a new boat with a stock 496 while on the lake. It had so much soot that it stained the back of the hatch black spots all over the brand new interior. Not like I could drain it and put 87 back in for the weekend. I was able to scrub it all off with Ajax but it took a lot of work and I learned the hard way that these engines are setup stock for 87.
03-08-2021 | 05:09 PM
#18
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Posts: 583
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From: Portland OR
Keep in mind the 496 is fuel injected but it's a very basic system. It's not like a car where it will re-tune itself when higher octane is being run and thus put out more power. It has a tune that was created to run reliably considering all the fuels throughout the world, some very poor.
