Like Tree1Likes

what is the fuel consumption for 496 ho

Reply
Old 10-24-2008, 09:38 PM
  #21
Registered
 
Join Date: Jan 2004
Location: San Diego, California
Posts: 2,777
Wink 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
Raylar is offline  
Reply With Quote
Old 10-24-2008, 10:12 PM
  #22
Registered
 
Join Date: Jan 2007
Posts: 1,656
Default

Quote:
Originally Posted by SDFever View Post
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!!!!
I meant to say 2.9 & 3.3. Huge difference. Have a saved Diacom file to prove it also.
SDFever is offline  
Reply With Quote
Old 10-25-2008, 09:49 PM
  #23
Charter Member #1055/Moderator
Charter Member
Trade Score: (1)
 
GO4BROKE's Avatar
 
Join Date: Feb 2001
Location: CNY
My Boats: Sonic 386
Posts: 4,579
Default

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.
__________________
[img][/img]
GO4BROKE is offline  
Reply With Quote
Old 10-25-2008, 10:02 PM
  #24
Registered
 
jeff32's Avatar
 
Join Date: Jun 2004
Location: St-Hyacinthe, quebec, canada
My Boats: 2000 triple 500 efi Sonic 45
Posts: 6,254
Default

Quote:
Originally Posted by GO4BROKE View Post
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...
jeff32 is offline  
Reply With Quote
Old 10-26-2008, 09:32 PM
  #25
Charter Member #1055/Moderator
Charter Member
Trade Score: (1)
 
GO4BROKE's Avatar
 
Join Date: Feb 2001
Location: CNY
My Boats: Sonic 386
Posts: 4,579
Default

Twin 496's. I was surprised myself. Quite a bit of idle time though, lots of channels into the bays here.
__________________
[img][/img]
GO4BROKE is offline  
Reply With Quote
Reply

Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ciaoderhead
General Q & A
18
11-11-2008 11:55 PM
buggyride
Baja
15
09-26-2007 11:54 AM
Twin-Kyle
General Q & A
10
09-11-2006 02:38 PM
fastrrrr
General Q & A
0
04-25-2004 02:26 AM
later
General Boating Discussion
5
06-17-2003 09:00 AM



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 04:10 PM.


Copyright 2011 OffShoreOnly. All rights reserved.