my imaginary motor

[John]

This should be fun:

but first here is the background:

this all started with a TX-19 for sale on FB, it got me to thinking, what realistically  is the top end on those boats before you run out of hull, so to speak, for instance, in the scarab hit a wall at 80 I could throw 300 more horses at it and it wouldn't do any good.

So it got me to thinking how much is too much on a TX? im not in to flying a kite

For conversations sake right now lets just talk a N/A motor, no juice, running on pump gas, OR possibly 100LL

I think a tunnel ram 540 should be fun in a lake boat.

Assume your starting from scratch.

Block: DART big M

Crank: Callies

Rods: carrillo

Pistons: forged CP

Heads: Dart Pro 1

Valve train: Hyd Roller Isky Lifters, and Comp hyd cam (it is a lake boat)

intake ?

now as you can tell money was no problem in this Fantasy land paper build

Now how about something just as good but much cheaper. ( I know find a boat with this already in it is the cheapest)

 

[TexasJet]

I have been told that anything over 125 mph in my CP is unwise. I would think the TX is about the same.

 

[TexasJet]

Also, the pump has to be able to handle that much H.P. $$$$$$$

 

[John]

Also, the pump has to be able to handle that much H.P. $$$$$$$

oh yeah, thats why i i quit looking at that TX 

 

[Patchman]

think.gif So are we building a motor for the TX? In theory, or is it any hull any power plant type of discussion? :smile21:

 

[John]

think.gif So are we building a motor for the TX? In theory, or is it any hull any power plant type of discussion? :smile21:

yes

 

[Michael Swindoll]

Well I can't speak for the TX19 but as far as my Nordic went when John had it with the little ol 496 it ran 90mph then I put a 750 hp 598 in and it ran 90! Then I did the pump intake set up and other work and paint etc then add a 565 900 hp pump gas motor and only ran 102-105 on motor and then sprayed it to 110, with the right water I've been the fastest of 112 all gps on nitrous! Basically I think regardless of the motor it's a easily 90 mph with a mild motor but to get it any faster takes a ton of power and a lot of other work so brake over point I say is 90 for the Nordic pickles!

If I had to guess,and talking to friends when I wanted one! I would guess the tx19 would be the same a decent motor would get you 90 pretty easy! Then it would take a high dollar motor with some real nice power to brake it past 100-110 and a lot of pump work! .02

 

[Devilman]

If I remember right, Esa was pretty close to the century mark with his TX19. Century mark being MPH not age, lol. 521 Ford & a blown out pump. Don't recall if that was with the single carb Victor set up or the tunnel ram set up (probably the tunnel ram). Some pump work & that thing would be brutal.

Too bad he don't post no more or he could tell you in better detail. :tongue:

So whats the deal, you get a TX or just fantasizing? Know you've talked about getting a little hotrod in the past.

 

[Patchman]

Well I would be curios as to what it would take to push a 25' ish sport boat 90 mph. Since I would love to get something in that range, and make it go fast! :grin:

 

[TexasJet]

Well I would be curios as to what it would take to push a 25' ish sport boat 90 mph. Since I would love to get something in that range, and make it go fast! :grin:

You would be talking IO not jet. V hull or pickle fork, makes a difference. V hull=700 HP, pickle fork=600HP, both are ball park.

 

[John]

Well I would be curios as to what it would take to push a 25' ish sport boat 90 mph. Since I would love to get something in that range, and make it go fast! :grin:

No TX i still want one though!

patch it all depends on weight, and a stepped hull will help on a V, easy way there is in a tunnel hull

For instance my motor and the motor in superboat were just about identical, mine would go 79-80 empty with a three blade, the scarab weighs 3000 pounds dry, the superboat weighs half that and had a black hawk prop, it would run 90, before you and i popped it at BC, that motor was about 550hp now with alum pro 1 heads off the eliminator and a victor and a 1050 4500 carb it dynos at 651 hp, its running 98-99, but needs a new prop set, it has 29's turned to 30p and needs 31p turned to 32p 

 

[Patchman]

Well I would be curios as to what it would take to push a 25' ish sport boat 90 mph. Since I would love to get something in that range, and make it go fast! :grin:

No TX i still want one though!

patch it all depends on weight, and a stepped hull will help on a V, easy way there is in a tunnel hull

For instance my motor and the motor in superboat were just about identical, mine would go 79-80 empty with a three blade, the scarab weighs 3000 pounds dry, the superboat weighs half that and had a black hawk prop, it would run 90, before you and i popped it at BC, that motor was about 550hp now with alum pro 1 heads off the eliminator and a victor and a 1050 4500 carb it dynos at 651 hp, its running 98-99, but needs a new prop set, it has 29's turned to 30p and needs 31p turned to 32p

Uh that was Devilman who helped you pop it! :evil: :smile30:

 

[Patchman]

So how long and what horsepower is your boat? :smile21:

 

[Devilman]

Uh that was Devilman who helped you pop it! :evil: :smile30:

Hey, I was just riding along, wasn't even telling him to mash on it. Figured with the puffing smoke that would have been a bad idea, lol...

 

[John]

So how long and what horsepower is your boat? :smile21:

its a 22 ft to the transom, and the motor wasnt ever dyno'ed so its 955hp  :smile16:

its probably around 550

heres whats in it

 

[Patchman]

Can you change a prop and get more out of it? I need this info so when I purchase, I can be faster than Sgayrab! :smile30:

 

[John]

me no, i mean maybe, i had a 25 pitch 3 blade, but now i have a 28 p four blade, i would like to try a 27p 3 blade, but the hull starts chine walking  a little to much for me at 80, so i just haven't tried, theres like 10 thousand dollar's worth of upgrades i could do and may be be at 85when i was done, so i put along with my 28p prop and cadilac around about 50 mph at 3000 rpm

 

[Patchman]

So maybe a 3 blade could be better than a 4 blade? Man it seems like pumps are way easier! :smile30:

 

[John]

there is way more efficiency in a prop so you can tailor it to you needs, it isnt as simple as deciding on an A or AA

Different boats like different props

a 3 blade prop has a higher top end capability (just like a two blade on a v drive is faster than a three)

Pros for a 3 blade
Faster top end
less stern lift, so you can air your nose a little higher

Cons
Slower holeshot
slower mid range acceleration
cruising speed is a little bit slower


Pros for a 4 blade
better holeshot
faster cruising speed
more mid range acceleration

cons
slower top end

now on pitch size, pitch is the theoretical distance a prop will move forward in one revolution, a 18 with 0% slip will move 18 inches, just like a 32 will move 32 inches

one inch of pitch is worth 200 rpms on your motor, stock merc motors are rev limited at 4850 rpms, to make the stock motors live, also when going from a 3 to a 4 blade prop also treat that as a pitch size (another 200 rpms) so.

i was at WOT at 5800 rpms with the 25 and a Slow time to plane, so i wanted to go up four inches in pitch, the problem is that a 29p mirage, according to mercury is like a 31p propeller  crazy.gif so i went to a 28p four blade and now my motor runs slower at WOT i gave up 2mph on the top end, but much better holeshot, mid range acceleration and a faster cruise, a trade ill make any day.

 

[John]

this thread went way off topic from a paper engine build thread, to propeller discussion

what bore and stroke do i need to make a 540?