what is the fuel consumption for 496 ho
 

hi guys
can somebody tell me the mpg over the rpm for a single 496 ho
thanks

not good...

not sure but better then a 525

It's going to be totally dependant on the boat, prop selection and drive ratios, etc. I could not begin to guess here without a lot of input.

Best Regards,
Ray @ Raylar

Most performance boats with twins will be between 1 mpg to 1.5 mpg. If fuel consumption is of any consideration.......buying a boat is not for you.

MPG will vary depending on the boat and efficiency of the hull.

Merc has charts that will show the GPH(gallons per hour) at various rpms though. At WOT, a 496 HO is probably about 35gph.

Exactly! I run my diacom software and record live data. I've determined that 3500 RPMs is my best bang for the buck. I'm burning around 14 GPH and running 55 MPH. That's nearly 4 MPG, not bad for a boat. Over many hours I average around 11 GPH. That's some idle, cruise, and WOT.

A friend of ours has a 41 Velocity we ran 178 nautical miles at a RPM 3200-3600 his average was about 1.6 mpg.:drink:

AT WOT 5,100 I get 1mpg @ 70 mph so at WOT my 496HO burns 51.4 gph. MY best bang for the buck is ~ 3,500 also, I get about 3mpg.

Sounds high. My 525 burns 42 GPH at WOT according to Smartcraft.

I agree, if I recall my 496 was running 34 GPH @ 5000 rpms.

How do to figure that???????? A 496 HO cannot burn that much fuel. Its not capable.

On my Nordic 28' Heat, open bow, I've calculated between 1.5 - 1.8 MPG running between 3500 - 4000 RPM.

Powerboat mag had an article a while back that had a 496 in a Sunsation and claimed between .8 mpg and 2.3 mpg. I made a run from Benton Harbor to Chicago 70 miles as the crow flies runnin 40-45 in 2-4's most likely put on about 80 miles fill up took 35 gallon. return trip 40-45 half way across then 55-65, second fill up 35 gallon again. 280 Velocity single 496 HO

Labbed 34 bravo I prop, 1.65 gears, single raylar 600 in 27' fountain single step with 3 people including driver

seeing 1.9 - 2.3mpg between 3200 & 3700 rpm's.

the reason i posted here is to make the reminder that the ho600 is based on the 496. It's working a lot less in my boat in terms of necessary output.

before with stock 496ho, had to run the boat 4000 plus cause it just wouldn't run much below without falling off or needing extreme trim which again, demanded heavy duty cycle. it was miserable much below 4000 r's.

sure if you open her up now, it'll burn more but cruise mpg has increased significantly with nearly 200 upgraded horsepower!!!!

1.21 gigawatts

WOW, thats crazy.

That much fuel ??!

In my raceboat , single ,lets say around 760 HP N/A i only burn a max. of 1.2 GPM.

The boat is 32 feet. Turning a heavy SSM on a tranny.

And thats at WOT.
Why do you all need that much fuel ?:eek:

Your number seems unbelievable to me but hey if you can get it that's way good.

The PCM555 is simply measuring open injector time so anybody using the SmartCraft fuel burn rate is getting there number from that.

I'd be curious to see what an actual flow meter would say in comparison but all claims are that the SmartCraft is very accurate.

Now my question is:

With that said, what if you have a malfunctioning injector but it's still responding to computer inquiries and pulse instructions? The computer knows what the open time is "supposed" to be so is it going by that very number or is it bi-directional to the point where the computer can actually monitor and compensate the measurement if the injector is dumping more fuel than necessary??

Ray?

But if you had 0/2 sensors in the exhaust you could then monitor what the fuel system is actually doing instead of going by what it's "supposed" to be. Took me a minute -

I failed to tie the burn rate to the whole rich/lean idea...

We have twin 496HO's in a 32 footer.

We average between 40 and 55 gallons to Avalon and back (depending on speed), which turns out to be roughly 1.1 - 1.5 MPG. I've seen higher other times when I cut the throttles back to 2800 or 3000. Throttle position makes a BIG difference :-)

John

I have twin 496/HOs in my Donzi 33ZX take in that the boat weighs 9200lbs at 3800 RPMs I burn 18 gallons and hour per engine running about 50MPH. at 5000 RPMs she burns 45 gallons per hour per engine running at 72mph. I have a Flo Scan.

How Do It know?
 

Obviously, the weight of the boat, the hull type and hull efficency will have a lot to do with fuel consumption figures for a 496HO. I can tell you that in dyno testing under sustained loads at wide open throttle making about 420-430 hp a good 496HO will use about 38-42 gph and that it will record BSFC's of about .51 to .53. I would think that in most good high performance hulls depending on cruise rpms and throttle position to make that cruise rpms that a single engine boat in light condtions will see about 1.6 to 2.5 mpg at about 14-16 gallons per hour with cruise rpms between 3500 and 4000 rpms.
One of the big determiners for any engine is its volumetric efficency at various rpms under loads.
A stock 496HO will deliver about 85% VE at 4000rpms which is its torque max on the stock 496HO.
SDFever, the reason your Raylar HO600 is delivering such good economy at 3500 rpms is that you are making more torque at that rpm and the volumetric efficency of the Raylar HO600 at between 3500 and 4000rpms is also up @ between 103 and 107% VE. (it breathes much better than a stock 496HO) and its BSFC at 4000rpms is about .48 which is a significant improvement over a stock 496HO
What this really means in simple terms is that a high torque marine engine can sometimes run a boat more efficently at given rpms with a situation like this where you have 20% better VE and the same or higher torque than you had with a stock 496HO that had to use more throttle to make the similar torque values at 4000rpms.
A more effiicient engine uses less fuel to make the same power and torque at given rpms, its as simple as that!
As for someone having a 496HO that uses over 50 gallons per hour at WOT, you have one of two problems:
1. a very poorly running 496HO! or 2. your measurement system or values are highly flawed!
Hope fuel efficency 101 helps here.

Best Regards,
Ray @ Raylar

I meant to say 2.9 & 3.3. Huge difference. Have a saved Diacom file to prove it also.

I would think that in most good high performance hulls depending on cruise rpms and throttle position to make that cruise rpms that a single engine boat in light condtions will see about 1.6 to 2.5 mpg at about 14-16 gallons per hour with cruise rpms between 3500 and 4000 rpms.


Right on the money. 15.2 gph average for the whole summer cruising at about 3500 a lot of the time.

are you running twins or triples? 15 is pretty good!

In my Formula, I averaged this summer with 19 gal / hour also at cruising rpm between 3400 and 3600 rpm, with no idle time except approaching docks or beaches...

Twin 496's. I was surprised myself. Quite a bit of idle time though, lots of channels into the bays here.

Is this per engine? or in total?