GMPP Ram Jet 502 vs Merc HP500/525 EFI
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GMPP Ram Jet 502 vs Merc HP500/525 EFI
http://www.gmperformanceparts.com/En...9121&engCat=bb
Other than some obvious issues with marinizing the crate Ram Jet, just how far apart is this motor from a Merc blue motor? Is a "GM" MEFI 4 easier to get access to than a "Merc" MEFI 4, for custom programming? Is the Merc HP EFI intake a GM part?
Other than some obvious issues with marinizing the crate Ram Jet, just how far apart is this motor from a Merc blue motor? Is a "GM" MEFI 4 easier to get access to than a "Merc" MEFI 4, for custom programming? Is the Merc HP EFI intake a GM part?
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It's got a high compression ratio...perhaps a head gasket change would help. A good marine cam would replace any HP lost by lowering CR. Still cheaper than Merc blue?
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http://www.gmperformanceparts.com/En...9121&engCat=bb
Other than some obvious issues with marinizing the crate Ram Jet, just how far apart is this motor from a Merc blue motor? Is a "GM" MEFI 4 easier to get access to than a "Merc" MEFI 4, for custom programming? Is the Merc HP EFI intake a GM part?
Other than some obvious issues with marinizing the crate Ram Jet, just how far apart is this motor from a Merc blue motor? Is a "GM" MEFI 4 easier to get access to than a "Merc" MEFI 4, for custom programming? Is the Merc HP EFI intake a GM part?
The electronics and computer are not that different, in fact Volvo and others used the GM stuff on marine engines. The computer would need to be reprogrammed from scratch.
The intake on Merc Racing is from AZ Speed and Marine.
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Thanks Pat for chiming in. I wonder if the lower intake is a GM piece, and just the upper is different between the AS&M versus the GM Ram Jet? Now that I've found these Marine Power brand engines, I see they're also using the AS&M intake/upper.
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I have a buddy running a completely stock 502/502 with a Demon 850 and MSD ignition. He has run the hell out of it for 4 seasons with no problems at all. It turns 5800 rpm all day in a 23 foot Wellcraft Nova. The boat runs an honest 70mph. The old motor ran about 55 or so. I think the cam in the EFI motor is the same. I would not be afraid to run the ram jet out of the crate.
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I have a buddy running a completely stock 502/502 with a Demon 850 and MSD ignition. He has run the hell out of it for 4 seasons with no problems at all. It turns 5800 rpm all day in a 23 foot Wellcraft Nova. The boat runs an honest 70mph. The old motor ran about 55 or so. I think the cam in the EFI motor is the same. I would not be afraid to run the ram jet out of the crate.
The cam in the EFI and Carb engine is most likely different. The EFI engine would not idle worth a crap with a ZZ502 cam.
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