Supercharging a 496...
#11
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Whipple makes a complete kit that will bolt on. It includes everything you need plus reprogramming of the PCM. With that said, no one can tell you how long the pistons will hold up. They are the weak link. The 496 pistons are weaker than cast 454 pistons. The reason being is they were designed with a very high top ring land to help with emissions(as I understand it). That leaves them weak when subjected to higher than normal loads. I just rebuilt 2 Whipplecharged 496's, upgrading them to forged internals. My recommendation would be to upgrade the pistons and then add the whipple. Tyler Crockett sells some forged factory replacement pistons made by Diamond. Use them and keep the rpm below 5400 and it should live ok. The engines I just rebuilt had been running for 2 years before a piston failed. They had maybe 60-70 hrs on them.
Bob Lloyd
Full Throttle Marine
Bob Lloyd
Full Throttle Marine
#12
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The problem is not with the internals it is with the setup of the internal for n/a. Yes the top ring is set high on the hyper pistons. For these to work in a blower app you must open the compression ring end gaps a lot. If you don't they will butt and it will lift the ring land. This of course is not a piston failure but a setup failure. Beyond ring gaps, you need better head gaskets, head studs, better fuel management to ensure rich a/f and less timing. What would stop me from supercharging a 496ho is the ring end gaps and computer. Put on a carb/tbolt ignition and open the ring gaps and a few other odds and ends and it will run great for as long as a forged assembly.
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Blower motors
I have a 2008 277 Islander with a 496 HO, wanting more power but I really don't want to change the motor. I would really like to go with a whipple charger but all i've heard is that a 496 cant be supercharged. There has to be someone that has had good luck with one. I know the 496 has cast internals but there are other engines that can be supercharged without forged guts. What has to be done to make it work?
One of the first boats I supercharged
Last edited by ElimiNordic; 02-15-2011 at 05:23 AM. Reason: spelling
#14
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If you don't want to build it to last (spend money on what you currently have), then by far the best way to handle your desire for more power would be to sell your entire engine as a take out and start over.
You can spend a lot doing it correctly. Or you can spend even more dealing with it after you went cheap (or cheaper).
You can spend a lot doing it correctly. Or you can spend even more dealing with it after you went cheap (or cheaper).
Eddie