Like Tree0Likes

Help me prop my Thunder

Reply
Old 05-10-2002, 11:32 AM
  #1
Registered
Thread Starter
 
Tantrum's Avatar
 
Join Date: Oct 2000
Location: USR, NJ
My Boats: Stray Cat Statement Marine
Posts: 4,000
Default Help me prop my Thunder

Ok heres the deal
Boat is a 25' Active Thunder spinning a 26p Bravo I

PitchxRPM 26x5000
------------- = Theo Speed ------------ = 82.07
Gearx1056 1.5x1056

TheoxASpeed 82.07x74
------------------ = Slip ------------- = 9.16
Actual Speed 74

Actual speed is a guess but I think the prop slip sounds about right using that number......Yes or No
Here's the Dyno info;
Max Torque; [email protected]
Max HP; [email protected]
This is where I need to look for prop;
RPM Torque HP
4900 549 513
5000 545 519
5100 525 510
5200 523 518
5300 515 520
5400 499 513

Rev Limiter is set at 5300 or 5400 I need to double check.
What props should I be trying? What RPM should I be shooting for? Escape Velocity and BigWaves both have props that may work. One is a 26p lab finished and the other has added cup. There are several other 25' AT's that claim to be running considerably faster with less HP/Torque, where could I be losing.
Any help would be great.
Tantrum is offline  
Reply With Quote
Old 05-10-2002, 12:34 PM
  #2
Charter Member #94
Charter Member
 
Gordo's Avatar
 
Join Date: Oct 2000
Location: New Port Richey, FL
My Boats: 1999 Active Thunder 25' Factory 1 Race Edition
Posts: 2,646
Default

Not sure if this helps, but the One Vision Thunder runs a 28 Labbed bravo. Funhome & I tested quite a few props and found the 26 Hydromotive to be VERY close, but handled a litle better. For some reason, the boat didn't like the stock 26 Bravo at all. Lost speed and rpm's. We then sent a box stock, (new) 28 Bravo 4 blade to a place in Wisconsin, (GAWD I wish I could remember the name of that place). They lab finished the prop much like Mercury did, but we asked to have some of the bow lift taken out. (The 25 already has a buttload of bow lift). This gave us .2 mph faster top speed and handled as good as the Hydromotive and improved accelleration.
final numbers were 81.7 @ 5200rpm w/ two people at approx 800' elevation, hot day running low on fuel.

Hope this helps.
__________________
Abby-someone
Gordo is offline  
Reply With Quote
Old 05-10-2002, 12:34 PM
  #3
Registered
 
Join Date: Feb 2001
Location: EGG HARBOR TOWNSHIP, NJ
My Boats: 2004 PANTERA SURVIVOR
Posts: 513
Default

you need to get a 24 bravo. dropping two sizes will give you that 400 rpm your looking for. hence more speed. if your motor is new give it 40 hrs . then try the 26 bravo and see what your max rpms are then.

Treadewll
Treadwellmotorsports is offline  
Reply With Quote
Old 05-10-2002, 12:56 PM
  #4
Registered
Thread Starter
 
Tantrum's Avatar
 
Join Date: Oct 2000
Location: USR, NJ
My Boats: Stray Cat Statement Marine
Posts: 4,000
Default

Gordo,
It all helps, thank you. I bought my boat used from Pat so Im not sure how agressive it was intended to be. It was biult as a pleasure boat not F1. Although the X-Dimmension does not seem aggressive I dont have anything to compare it to. Could I lose that much speed in the X and additional wieght. Im assuming you are running an HP500 @ 470hp. Do you have a stand-off box or anything else?

Treadwell, do you think I should run it up 400rpm to be up on the rev limiter or is that how your looking at the power curve?
Motor has more than 60hrs on it.

Thank you for your input. Im learning a little more every day.

Last edited by Tantrum; 05-10-2002 at 01:01 PM.
Tantrum is offline  
Reply With Quote
Old 05-10-2002, 01:13 PM
  #5
Registered
 
thunderdan's Avatar
 
Join Date: Oct 2000
Location: medford, nj usa
My Boats: 37 Active Thunder
Posts: 2,185
Default

Tantrum,

I wish i still had my 25, I would lend you the hydromotive 26 that i ran on my thunder. I know the previous owner had his"racing prop" worked on. The best I saw was 78-79 mph, very light on fuel and alone. My boat did have a racing layup and extention boxes, but I would guess you are a few hundered (400 to 600?)pounds more in weight.

I never tried the bravo's but I heard the same thing that Gordo said, probably because he is the one who told me.

I would see if anyone has a 26 p hydromotive you could borrow.

I would also mesure your x dimension and see where it is in comparision to maybe Gordo's.

These two factors, weight and x dimesion could be where the speed is getting scrubbed.

Good Luck

Dan

Last edited by thunderdan; 05-10-2002 at 01:19 PM.
thunderdan is offline  
Reply With Quote
Old 05-10-2002, 01:15 PM
  #6
Charter Member #94
Charter Member
 
Gordo's Avatar
 
Join Date: Oct 2000
Location: New Port Richey, FL
My Boats: 1999 Active Thunder 25' Factory 1 Race Edition
Posts: 2,646
Default

Tantrum,
Not sure which boat you bought, but if it is the recreational version, then you do have a lower "X" cut in the transom which won't help speed any. It also means that your boat possibly weighs as much as 800-900 lbs more than mine which really doesn't help any. In fact, If all the above are true, then I'm pretty impressed with the speed you are now getting. On the other hand, I'll bet you plane off much better/faster than I do.
Getting a lab finished prop will gain you about 200rpm's, and gained us almost 2 mph ofer box stock stuff. I'm not sure what rpm's you are running at 74mph, but Eric may be closer to the right track for your application. Either way, I would start saving my Pepsi points and get a lab finished prop.
__________________
Abby-someone
Gordo is offline  
Reply With Quote
Old 05-10-2002, 01:24 PM
  #7
Charter Member #94
Charter Member
 
Gordo's Avatar
 
Join Date: Oct 2000
Location: New Port Richey, FL
My Boats: 1999 Active Thunder 25' Factory 1 Race Edition
Posts: 2,646
Default

Oh, by the way, We did have a Stellings box on for a while, but it added weight to the back of the boat which didn't help balance at all, and it created so much more bow lift that the boat was really out of control. Made for some great video, but was definately a higher pucker factor. Besides, we got back almost all the speed without the box after more testing.

Racing tip for the day...
Running 81 mph for a few miles in control will beat running 82 mph for a few seconds out of control any day!
__________________
Abby-someone
Gordo is offline  
Reply With Quote
Old 05-10-2002, 03:17 PM
  #8
Registered
 
FunHome's Avatar
 
Join Date: Oct 2000
Location: Kansas & LOTO
My Boats: 28ft Saber, 22 Velocity
Posts: 2,648
Default

I dido (ditto) what Gordo said!

Last edited by FunHome; 05-10-2002 at 07:46 PM.
FunHome is offline  
Reply With Quote
Old 05-10-2002, 05:59 PM
  #9
Charter Member #94
Charter Member
 
Gordo's Avatar
 
Join Date: Oct 2000
Location: New Port Richey, FL
My Boats: 1999 Active Thunder 25' Factory 1 Race Edition
Posts: 2,646
Default <GASP!!>

For a moment there, I thought you said "dildo"...
__________________
Abby-someone
Gordo is offline  
Reply With Quote
Old 05-10-2002, 06:02 PM
  #10
Registered
 
MissAmy's Avatar
 
Join Date: Sep 2001
Location: LOTO / O.P. KS
Posts: 813
Default

Yes Funhome...I believe the correct spelling of that would be "ditto".

Gordo....are you post hoin' this afternoon, or what?
MissAmy is offline  
Reply With Quote
Reply

Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
rssteiny
Active Thunder
6
10-16-2008 05:37 PM
awsomethunder
Prop Talk
7
08-01-2006 07:51 PM
Sydwayz
Prop Talk
5
06-06-2005 10:28 PM
ghaskell
General Q & A
2
05-22-2005 08:54 PM
CigDaze
General Boating Discussion
14
02-27-2003 01:38 PM



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 03:47 AM.


Copyright 2011 OffShoreOnly. All rights reserved.