Getting a few more RPM out of a 496
+ Reply to Thread
Page 1 of 3 1 2 3 LastLast
Results 1 to 14 of 29

Thread:
Getting a few more RPM out of a 496

  1. #1
    Senior Member
    Join Date
    Sep 2009
    Location
    Calimesa CA
    Posts
    195

    Default Getting a few more RPM out of a 496

    Just bought it and sure as hell don't have the money for it now, but I would really like to know the best way to get a few hundred rpm out of a stock 496 mag w/o killing reliability? Basically I have a 78 mph boat, I want 80+!!! Thanks guys
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	shockwave.jpg 
Views:	37 
Size:	24.2 KB 
ID:	348497  

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Member D Johnson's Avatar
    Join Date
    Jun 2013
    Location
    Yorba Linda/ Willow Valley
    Posts
    50

    Default

    Pulling out the Turbolators increased approx. 100 RPM in my friends boat. The turbolators are sandwiched between the exhaust manifold and the elbow. Be careful removing it try not to tear the gaskets. Simply remove it and bolt the elbows back on. Other then that adding new exhaust should get you 2 MPH

  4. #3
    Senior Member
    Join Date
    Sep 2009
    Location
    Calimesa CA
    Posts
    195

    Default nice and easy!

    First ever boat diagnosis I have ever seen that didn't cost me a bunch of money!! Any opinions on the chances of getting water in the motor by removing these? I looked it up and that seems to be the only possible hitch with removing turbolators. As much as I would like to bump her up a mph or 2, don't know about the risk of getting water in the motor. I have owned enough jets with bassetts! Been there done that with milky oil and rebuilds!

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    New here Beer:30's Avatar
    Join Date
    Feb 2008
    Location
    Bakersfield, CA
    Posts
    4,219

    Default

    Several lengthy threads on this subject already. Just search here about "496HO headers" Or, "496 HO roller rockers" any of those keywords should get you there.
    Quote Originally Posted by gn7 View Post
    EFI is the wave of the future. There can be no denying it. Electronics have been on the leading edge of our entire lives. Not only os the magneto dead, but the standard issue CDI is wavering. Its all about total fuel, air AND spark control. Anybody that thinks its not has their head up their ass.


    2001 SleekCraft 30' Heritage SSB, open-bow mid-cuddy. 496HO / Bravo-I.

  7. #5
    Senior Member 74Bonneville's Avatar
    Join Date
    Jan 2013
    Location
    Magic Mountain CA
    Posts
    542

    Default

    Change the prop, will suffer on take off

    Buy a Procharger, run 5 psi

    The only way I would mess with your exhaust is by replacing it, not cheap

    Procharger & Exhaust, Can you say 90

  8. #6
    Senior Member 74Bonneville's Avatar
    Join Date
    Jan 2013
    Location
    Magic Mountain CA
    Posts
    542

    Default

    Quote Originally Posted by One More Year View Post
    Just bought it and sure as hell don't have the money for it now, but I would really like to know the best way to get a few hundred rpm out of a stock 496 mag w/o killing reliability? Basically I have a 78 mph boat, I want 80+!!! Thanks guys
    Hey dude, I have the same trailer my Cobra sits on. WATCH those oil filled wheel bearings. I sprung a leak on the road, had only a few minutes to total destruction of everything on that wheel. I just finished changing everything out to grease.

    The caps looked sealed to me, I thought they were black, turns out they are clear and you watch the oil level from the front. Lay down under and check for tell tail signs of leakage. Mine lasted 9 years before any problems and 4 or 5 of those years sitting in the Parker heat.

    If those are bearing buddies ignore the above

    Enjoy
    Last edited by 74Bonneville; 08-10-2013 at 07:09 AM.

  9. #7
    New here Beer:30's Avatar
    Join Date
    Feb 2008
    Location
    Bakersfield, CA
    Posts
    4,219

    Default

    Quote Originally Posted by 74Bonneville View Post
    Change the prop, will suffer on take off

    Buy a Procharger, run 5 psi

    The only way I would mess with your exhaust is by replacing it, not cheap

    Procharger & Exhaust, Can you say 90
    CORRECTION.....Run 3.5 psi. The top ring land is VERY CLOSE to the top of the piston. Any detonation at all will knock a small chunk out. That small chunk rattles around for awhile and......well......you get the picture (I hope). Catastrophic failure.
    Quote Originally Posted by gn7 View Post
    EFI is the wave of the future. There can be no denying it. Electronics have been on the leading edge of our entire lives. Not only os the magneto dead, but the standard issue CDI is wavering. Its all about total fuel, air AND spark control. Anybody that thinks its not has their head up their ass.


    2001 SleekCraft 30' Heritage SSB, open-bow mid-cuddy. 496HO / Bravo-I.

  10. #8
    Senior Member
    Join Date
    Sep 2009
    Location
    Calimesa CA
    Posts
    195

    Default Prop question?

    Quote Originally Posted by 74Bonneville View Post
    Change the prop, will suffer on take off

    Buy a Procharger, run 5 psi

    The only way I would mess with your exhaust is by replacing it, not cheap

    Procharger & Exhaust, Can you say 90
    I have a 24 pitch 4 blade on there now that runs it to max rpm 48-4900. I am prop ignorant. Have been told a 3 blade same pitch is gonna get me a little more top end and a little less out of the hole. You agree with this one? Thanks! 78 mph on glass coming south out of the sand bar Lake Havasu about 8 pm Saturday! Lovin this boat!
    Last edited by One More Year; 08-12-2013 at 07:35 AM.

  11. #9
    Senior Member
    Join Date
    Sep 2009
    Location
    Calimesa CA
    Posts
    195

    Default Thanks!

    Quote Originally Posted by 74Bonneville View Post
    Hey dude, I have the same trailer my Cobra sits on. WATCH those oil filled wheel bearings. I sprung a leak on the road, had only a few minutes to total destruction of everything on that wheel. I just finished changing everything out to grease.

    The caps looked sealed to me, I thought they were black, turns out they are clear and you watch the oil level from the front. Lay down under and check for tell tail signs of leakage. Mine lasted 9 years before any problems and 4 or 5 of those years sitting in the Parker heat.

    If those are bearing buddies ignore the above

    Enjoy
    Thanks for the heads up! Man I hope they aren't oil filled wheel bearings? That just sounds like a bad idea! I will bearing buddy them for sure if that's the case.

  12. #10
    Senior Member
    Join Date
    Sep 2009
    Location
    Calimesa CA
    Posts
    195

    Default Would love to . . . one day!

    Quote Originally Posted by Beer:30 View Post
    CORRECTION.....Run 3.5 psi. The top ring land is VERY CLOSE to the top of the piston. Any detonation at all will knock a small chunk out. That small chunk rattles around for awhile and......well......you get the picture (I hope). Catastrophic failure.
    Would love the pro charger but after running this weekend at nearly 80 I'll be fine with her for a bit (lol if my wife found this she would print it out and show it to me every time I said we need a little more out of her!). Gotta make a few payments on it first before we spice it up too much!!!! Thanks for the info.!

  13. #11
    Platinum Member BigSteve's Avatar
    Join Date
    Feb 2008
    Location
    Close to the water...
    Posts
    2,014

    Default

    Quote Originally Posted by One More Year View Post
    I have a 24 pitch 4 blade on there now that runs it to max rpm 58-5900. I am prop ignorant. Have been told a 3 blade same pitch is gonna get me a little more top end and a little less out of the hole. You agree with this one? Thanks! 78 mph on glass coming south out of the sand bar Lake Havasu about 8 pm Saturday! Lovin this boat!
    Stay with a 4 blade

    A Bravo is good overall prop

    A Hydromotive is better and will have a little less slip
    giving you a mph or two

    The best thing you can do to 496 is leave it alone, headers are a plus

    And make sure you service the water pump. Most of the time you have to replace the whole thing.

  14. #12
    Senior Member 74Bonneville's Avatar
    Join Date
    Jan 2013
    Location
    Magic Mountain CA
    Posts
    542

    Default

    Quote Originally Posted by One More Year View Post
    I have a 24 pitch 4 blade on there now that runs it to max rpm 58-5900. I am prop ignorant. Have been told a 3 blade same pitch is gonna get me a little more top end and a little less out of the hole. You agree with this one? Thanks! 78 mph on glass coming south out of the sand bar Lake Havasu about 8 pm Saturday! Lovin this boat!
    Rpm's are in a good place, not sure you should change prop, but it is the logical place go if you want a change. Been a long time since I messed with props, strictly jets for the last 15 years or so. You should get some help here from guys who do this on a regular basis.

    Post in the outdrive section for specific help on this

    I just saw there is a prop section too
    Last edited by 74Bonneville; 08-12-2013 at 07:43 AM.

  15. #13
    Senior Member
    Join Date
    Sep 2009
    Location
    Calimesa CA
    Posts
    195

    Default Best advice so far!

    Quote Originally Posted by BigSteve View Post
    Stay with a 4 blade

    A Bravo is good overall prop

    A Hydromotive is better and will have a little less slip
    giving you a mph or two

    The best thing you can do to 496 is leave it alone, headers are a plus

    And make sure you service the water pump. Most of the time you have to replace the whole thing.
    I am with you on not doing a damn thing to it (outside of water pump and annuals)! If you remember any of my posts from the 86 Daytona in the outboard church that I never got fully operational this year, then you gotta understand how happy I was to put nearly 10 hours on the hour meter this weekend from the South end of Havasu to Needles and back a few times!! Mission accomplished! Do you ever boat in Buena Vista up there by Bakersfield? I haven't been there in many years.

  16. #14
    New here Beer:30's Avatar
    Join Date
    Feb 2008
    Location
    Bakersfield, CA
    Posts
    4,219

    Default

    Quote Originally Posted by One More Year View Post
    Would love the pro charger but after running this weekend at nearly 80 I'll be fine with her for a bit (lol if my wife found this she would print it out and show it to me every time I said we need a little more out of her!). Gotta make a few payments on it first before we spice it up too much!!!! Thanks for the info.!
    I call bullshit. First, you have JUST a 496MAG, right? NOT an HO? 78 mph with a 24P and 4900rpm equals MINUS-5 SLIP. There's no way your boat is going anything NEAR that speed. Hell, I am getting near the rev-limiter at 5100 with the same 24P and I am NEARING 70, but not quite there. 66, 67 on a good day. Besides, without full external hydraulic steering, you would be all over the lake over 70.

    So, download a GPS SPEEDOMETER app on your phone and go try it again.
    Last edited by Beer:30; 08-14-2013 at 07:30 PM.
    Quote Originally Posted by gn7 View Post
    EFI is the wave of the future. There can be no denying it. Electronics have been on the leading edge of our entire lives. Not only os the magneto dead, but the standard issue CDI is wavering. Its all about total fuel, air AND spark control. Anybody that thinks its not has their head up their ass.


    2001 SleekCraft 30' Heritage SSB, open-bow mid-cuddy. 496HO / Bravo-I.

+ Reply to Thread
Page 1 of 3 1 2 3 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in

Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95