Efficiency of H5 5.3L direct injection (355) vs ZR4 6.0L (409)

[NautiqueOasis]

Does anyone know of the estimated fuel savings on the H5 vs ZR4? Trying to justify a $3000 upgrade.

[Infinity]

Is it the ZR4 or the ZR409? They are a little different
I have the ZR409 in my 24ft boat and absolutely love it, I average 4.5GPH when surfing with full ballast which is very close to 5k lbs.I do have surf prop so bottom end hookup is great and it will still hit 40mph on top end. Have never had a power or reliability issue and have about 255hrs on the engine. The torque at 492ft lbs is pretty impressive IMO....I know the torque curve between this engine and the H5 are pretty similar and I like that the ZR409 is partial closed cooled so heater is part of the closed cooled system, and winterizing is pretty easy as well (tho I know it is easy on the H5 as well).
Not sure which boat you are looking at, to me the cost of upgrade would not be worth it. H5 may be equal, but not better and doubt you will get a return on that upgrade. Some people would also have the perception that less HP is bad and that could effect resale on less educated buyers even tho a few people on here have stated that the H5 pushed their larger boats (G21) without an issue.

[oldsmobiledriver]

Direct Injected is the new hot thing! The 6.0 has a traditional fuel pump. H5 has a high pressure pump factory on the rail to feed the injectors. Maintenance out of warranty is going to be more expensive on parts once out of warranty. Id roll the 6.0 if you’re not stepping up to the H6


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[DW SD]

At what point (hrs) does the direct injection engines have to have the valves decarbonized?
Seems like most automotive engines running direct injection have carbon buildup issues due to lack of fuel spray cleaning the intake valves.


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[NautiqueOasis]

I thought the ZR4 was the same engine as the 409 upgrade from the 343 prior to the release of the direct injection models. I think the current ZR4 no longer has the partial closed cooled system; the ZR4 is actually 400hp not the 409hp that I previously posted. I am interested in the GS20 and I know the ZR4 will provide all the power that I really need to surf and ski. I currently have a '13 200v 343hp with 600hrs and typically keep my boat on average for about 6-8 years before upgrading. I am interested in anyone's GPH experience with the H5 especially with the GS20 or possibly the GS22 to compare and estimate fuel efficiency over 800 hrs of use.

Nautique website: "The Super Air Nautique GS20 comes standard with the proven power of the PCM ZR4 engine. Upgrade to the groundbreaking PCM and GM Marine Engine Technology 5.3L H5 direct-injection engine and experience industry-leading precision, power, and torque." ZR4=6.0L; 400hp; torque 400ft/lb; H5=5.3L; 355hp; torque 405ft/lb.

[oldsmobiledriver]

We’ve been having some of the Tahoe’s and suburbans needing a carbon clean around 50k but some of the trucks are good over 100k. Could be a difference between women and men drivers. With it being a boat and wide open fairly often I would compare to the man status of driving.


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[DealsGapCobra]

I don't surf and don't pay attention to fuel burn rate but I'm stunned at 4.5 gal/hr!

To recoup your cost you would need to save $5/hr (ignoring interest). My advise is you can't have too much power, if you can afford the bigger motor, go for it!


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[charlesml3]

I don't surf and don't pay attention to fuel burn rate but I'm stunned at 4.5 gal/hr!

Are you stunned at how much or how little this is?

[DealsGapCobra]

It seems really low. But, like I said I don't have any idea. I do know that a 260 hp engine can burn around 25 gal/hr so that would mean that the boat is running at around 50 hp. I guess that makes sense now that I see the numbers. I'm sure that 4.5/hr adds up pretty quickly.


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[charlesml3]

OK, yea, gotcha. You're right. 4.5 gallon/hour for surfing is on the low side. My 230 has the 6.0L engine and I burn about 6 gallons/hour surfing.

-Charles