It is currently Thu Mar 28, 2024 8:05 am




Reply to topic  [ 23 posts ] 
 dont have a dyno, can you estimate HP 
Author Message
MMT Pro Member

Joined: Wed Sep 16, 2015 11:50 am
Posts: 284
Post dont have a dyno, can you estimate HP
modded my GT 35hp with, decked heads, 308 cam, mikuni, BPS crossover exhaust, and all other pieces that go with making that setup. rev limited to 4400. stock rods and pistons. What should she be putting out? 55? 60?


Wed Aug 16, 2017 1:27 pm
Profile
MMT Elite Member
User avatar

Joined: Wed Jan 14, 2009 7:23 am
Posts: 6233
Location: Tarkington, TX
Post Re: dont have a dyno, can you estimate HP
You need higher rev coils to get full potential, Your motor will be able to pull past 4350. Without a dyno its hard to say, But an accurate guess is upper 40's. Without knowing the porting and camshaft specs other than lift, I cant assume its better than upper 40's

_________________
Bayou Surface Drive
337-351-0362
Tarkington, TX 77327


Wed Aug 16, 2017 1:48 pm
Profile
MMT Sponsor

Joined: Fri Jan 10, 2014 1:16 pm
Posts: 2107
Location: Gladewater TX
Post Re: dont have a dyno, can you estimate HP
Agreed ^^ just bolting parts together is not the same as taking the time to do all the little things that add hp


Wed Aug 16, 2017 2:21 pm
Profile
MMT 1000 Club

Joined: Sun Sep 01, 2013 2:53 pm
Posts: 3480
Location: Hardin County, Tx
Post Re: dont have a dyno, can you estimate HP
Don't listen to these guys, that should be 70 at the PTO pretty easy.

_________________
#CFFITR

-Custom pool noodle
-stage 4 water wings


Wed Aug 16, 2017 4:21 pm
Profile
MMT Super Elite Member

Joined: Fri Dec 18, 2009 8:10 pm
Posts: 16915
Location: Rowlett, TX
Post Re: dont have a dyno, can you estimate HP
^^^^^^

Sent from my SM-T710 using Tapatalk


Wed Aug 16, 2017 6:34 pm
Profile
MMT Pro Member

Joined: Wed Sep 16, 2015 11:50 am
Posts: 284
Post Re: dont have a dyno, can you estimate HP
we went with the 4400 rev limited bc the motor is a 2008 and the stock rods weren't built to handle higher RPM's.

what other little things are you talking about? Iron mountain decked heads, Pelletier cam, Mikuni carb, high flow exhaust, tuned the valves and all the other little things so it doesn't blow up.

I see guys saying Lvl 3 mods on FB showing them run 35-6 on facebook all day on an 1854. just trying to figure mine. I certainty hope its more than mid 40's.


Thu Aug 17, 2017 10:02 am
Profile
MMT Sponsor

Joined: Fri Jan 10, 2014 1:16 pm
Posts: 2107
Location: Gladewater TX
Post Re: dont have a dyno, can you estimate HP
On boats with excellent bottoms, not too heavy , the right prop etc. ive got customers with new ones running delta motors that dont run 30. Still very strong motors and happy customers. Dont get too caught up in mph. If yours runs 30 now it was probably 25mph stock


Thu Aug 17, 2017 10:18 am
Profile
MMT 1000 Club
User avatar

Joined: Fri Jan 23, 2009 1:27 pm
Posts: 1095
Location: SW Michigan
Post Re: dont have a dyno, can you estimate HP
If you saw it on book face it's gotta be true. :roll:

Wanna go fast buy an outboard, there more reliable too.

If you bought a mud motor for the reason you should have bought a mud motor, you should be wondering how much of a load it will carry and what speeds you can run with a heavy load.

_________________
1854 Prodigy Open
HDR/Stage 3 mods
Prodigy Boats Pro Staff
BPS Swamp Staff Member
Blackwater Marine LLC.


Quote classic by rangerp: "Red seemed to be enjoying herself, and I assume by the look on her face was about to hit the high-note and throw a locate as she treed the possum."


Thu Aug 17, 2017 1:35 pm
Profile
MMT Elite Member
User avatar

Joined: Wed Jan 14, 2009 7:23 am
Posts: 6233
Location: Tarkington, TX
Post Re: dont have a dyno, can you estimate HP
Stock rods can handle 5k ish... IF you have oil in the motor... That's the key. I hate to say it but Iron mountain heads are probably the most available heads, BUT the worst in flow. The short turn is hogged out there hindering the port velocity.
Making a port bigger isn't always better. Id get a 4800 ish rev limit and let that motor sing.

_________________
Bayou Surface Drive
337-351-0362
Tarkington, TX 77327


Fri Aug 18, 2017 6:15 am
Profile
MMT F.E.
User avatar

Joined: Tue Aug 26, 2014 10:36 am
Posts: 822
Location: Jefferson TX
Post Re: dont have a dyno, can you estimate HP
I've seen 35.+mph but it was straight mud, new Hammer, tail wind, and only 2 adults, 1 small dog,and 1 48 qt. cooler. My boat gains speed in the right mud(hit rev limiter and had to back off WFO).
But that being said, with about the same load 29-31 mph(4350-4500rpms) but mostly 29, in "deep water". Cruising at 3600rpm @ 24-28mph turning and twisting on the river (chill mode).

If you really wanna go fast get a Hoss 75 come give me ride to see if I want one too! Nothing like an oversized mailbox with a bunch of wire and stuff sticking out hanging on the back of a boat.

_________________
SEAARK FX 2472 CC Merc 150HP 4Stroke(CypressCadillac)
Uncle J Custom - 19x54 CC Skiff w/40XD GTR


Fri Aug 18, 2017 8:07 am
Profile
MMT Pro Member

Joined: Sun Feb 20, 2011 4:14 pm
Posts: 95
Post Re: dont have a dyno, can you estimate HP
bottom of that boat is toast!!! Ive seen it.


Fri Aug 18, 2017 12:19 pm
Profile
MMT Sponsor

Joined: Fri Jan 10, 2014 1:16 pm
Posts: 2107
Location: Gladewater TX
Post Re: dont have a dyno, can you estimate HP
That will do it!


Fri Aug 18, 2017 1:06 pm
Profile
MMT Pro Member

Joined: Sun Feb 20, 2011 4:14 pm
Posts: 95
Post Re: dont have a dyno, can you estimate HP
don't know size of boat but it is a beavertail boat with pods that has hooks like a mofo at the transom, bottom is pretty rough, and where the rake meets the bottom looks like someone took a sledgehammer to it being pushed by a older short transom gator tail with wat looked like an 11' prop and the older 45 gearing in the lower. he had a bow fishing platform built on it then had mods done to motor to try n push it. don't believe it would even turn a big blade. he took of bowfishing deck then got some decent speeds now he wants to go even faster lol.


Fri Aug 18, 2017 3:54 pm
Profile
MMT Member

Joined: Mon Sep 16, 2013 6:34 pm
Posts: 20
Post Re: dont have a dyno, can you estimate HP
Following


Tue Aug 22, 2017 10:28 am
Profile
MMT Pro Member

Joined: Wed Sep 16, 2015 11:50 am
Posts: 284
Post Re: dont have a dyno, can you estimate HP
^who even is this guy.

I wanted to know about the HP, not talking about the boat. I know its a little rough


Tue Aug 22, 2017 10:28 am
Profile
MMT Sponsor

Joined: Fri Jan 10, 2014 1:16 pm
Posts: 2107
Location: Gladewater TX
Post Re: dont have a dyno, can you estimate HP
Back to the best guess answer from Maxxis, upper 40s hp is my guess too


Tue Aug 22, 2017 11:25 am
Profile
MMT Pro Member

Joined: Sun Feb 20, 2011 4:14 pm
Posts: 95
Post Re: dont have a dyno, can you estimate HP
You brought up seeing other peoples "speeds" on facebook. Sounds to me like you dont believe your motor is putting out enough HP to achieve speeds of other people. Boat has a lot to do with performance or speed. Your motor is deff making more power with the parts you have on it. All im sayin is your boat is deff not helping your situation. P.S. wasnt trying to sound like an ass, just dont believe you have said much about boat condition in other posts. Boat makes big diff


Tue Aug 22, 2017 3:15 pm
Profile
MMT Pro Member

Joined: Sat Dec 11, 2010 6:25 am
Posts: 493
Location: SWGA
Post Re: dont have a dyno, can you estimate HP
Is this the boat with that expensive poly sprayed on the bottom? Do you wish you just would have acquired a new hull?


Wed Aug 23, 2017 4:46 am
Profile
MMT Addict

Joined: Sun Aug 09, 2009 12:50 pm
Posts: 574
Location: Muscatine, Iowa
Post Re: dont have a dyno, can you estimate HP
I have about the same mods in my motor, It started out as a 45BD MB with 38/46 gears. I assumed it came from factory at 44 hp as advertised. With mods I would guess 47/49 HP. On my old Alumacraft riveted 1648 jon I can hit 35 mph pretty easily at 4700 RPM with a Hammer prop. But then again my rig weighs just under 1000# with Battery, 12 gal of gas and me in it. Weigh your rig, might surprise you.


You do not have the required permissions to view the files attached to this post.


Wed Aug 23, 2017 8:51 am
Profile
MMT Pro Member

Joined: Wed Sep 16, 2015 11:50 am
Posts: 284
Post Re: dont have a dyno, can you estimate HP


Wed Aug 23, 2017 10:40 am
Profile
MMT Pro Member

Joined: Wed Sep 16, 2015 11:50 am
Posts: 284
Post Re: dont have a dyno, can you estimate HP


Wed Aug 23, 2017 10:46 am
Profile
MMT Addict

Joined: Sun Aug 09, 2009 12:50 pm
Posts: 574
Location: Muscatine, Iowa
Post Re: dont have a dyno, can you estimate HP


Wed Aug 23, 2017 4:15 pm
Profile
MMT Pro Member

Joined: Sun Feb 20, 2011 4:14 pm
Posts: 95
Post Re: dont have a dyno, can you estimate HP
sorry if I was bashing your willingness to learn. didn't mean to. I have learned tons off this site over the years. now that u have it running better have you tried any other props besides the gtr 3 blade you bought? I just found out that the shop I had my valve seats recut at has a dyno. He works mostly on powersports motors. he said dyno isn't set up for these briggs motors but he could get it that way if I wanted. shop is only half hr away from henry


Wed Aug 23, 2017 8:10 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 23 posts ] 

Who is online

Users browsing this forum: No registered users and 263 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron