Down on rpm and speed 454mag F/I 385 hp
+ Reply to Thread
Results 1 to 6 of 6

Thread:
Down on rpm and speed 454mag F/I 385 hp

  1. #1
    Senior Member Mrs.HLB's Avatar
    Join Date
    Dec 2007
    Location
    Corona, Ca
    Posts
    308

    Default Down on rpm and speed 454mag F/I 385 hp

    Hey greg

    what do you think about this problem 1996 26 cloe boat weight 4900 lbs with the 454mag 385 with a performance yune that requires 89 octaine leak down was done be fore install and all was ok per GT performance.

    So I went for my sea worthy test today and everything accept the top end was as good as my genesis 236. However max RPM 4500 to 4600 and speed was 54 to 55 with a 21 3 blade.

    Is the boat just to heavey for my motor application as is and the exhaust along with a prop change by the formula of boat speed taht would get me to 4800-5000 per the formula Or maybe I have a motor down on power it is a 365 hp with carburator I had them retrofit a F/I for the 385 hp mag and a performance tune was done on it. The #'s above reguarding speed and RPM 4500 4600 @55MPH is a 10% slip factor witch is a great # for a boat built in 96


    *******would you raise the drive an inch I have done this before and it gave me 200 more RPM's. Theway it was explained to me we will put on a 23 wich will loose 200rpm not sure that change is a good one and the other deal that was talked about is some Imco exhaust toraise the rpm 300 rpm's and one up or more prop size depending what the exhaust do what is your tak on this situation. The boat is to heavey to run a single 454 385 hp in the mid 60 to 70 mph???????????????????????????????????????



    Mark

    HLB

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Senior Member Mrs.HLB's Avatar
    Join Date
    Dec 2007
    Location
    Corona, Ca
    Posts
    308

    Default

    Anyone run into this before with a cole 26' and yes it is a 26' not a 25 they made this boat 94, 95, and 96 in advance thanks for your input

    MR HLB

  4. #3
    Senior Member Mrs.HLB's Avatar
    Join Date
    Dec 2007
    Location
    Corona, Ca
    Posts
    308

    Default

    also keep in mind that elsinore was completely flat for our test could it be possable to pick up 2to 4 hundred rpms if it wher churned up a bit

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    HLB
    HLB is offline
    Member
    Join Date
    Nov 2010
    Posts
    93

    Default

    BTW I did not do my homework on the engine that was beeing put in. It's a 454 mag carburated 365 hp I thought that if i had them add the F/I to the motor that would compencate for the additional 20hp of the 454 385 hp F/I.

    Well as you know that is not gonna do it. I was told that the 365 hp version has a flat tappet cam and the 385 HP versin has a hydraulic roller for the extra 20 hp. Do you think that putting on an after market flame arrester and a performance tune symilar to what arizona speed does will that get me back into the 385 hp range? they are re tunning the original to have more timing and fuel and I will have to run 89 octain witch is fine with me. Also is it safe to say I can pick up 200 to 400 rpm with imco aftermarket exhaust

    If the water was not like glass we should have picked up 200 rpm's is that statement true also. I think it is with my other boats it did exzactly that just want to confirm with you since you test out there all the time in the GREEN MONSTER LOL

    Mark

  7. #5
    Senior Member
    Join Date
    Dec 2007
    Location
    corona calif
    Posts
    1,119

    Default 365

    I've been out of town in Colo. so I will gather my thoughts and get in touch with you.

  8. #6
    HLB
    HLB is offline
    Member
    Join Date
    Nov 2010
    Posts
    93

    Default

    ok thanks I look forward to your reply. Thanks again Greg

    Mark
    Last edited by HLB; 11-24-2010 at 02:57 AM.

+ Reply to Thread

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

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