First 2.5 mods

[Chaz]

Chaz, it's a TRI-TOON!!! He can leave it where it is and hang two more on the outriggers!!!

Hey ... lets not get carried away Besides, it'll never work

[FMP]

Originally posted by Tony Brucato

John Tiger tested a lightweight 40 amp flywheel made by Hydro-Dynamics (6 1/2 lbs lighter than stock) and published the results in "Bass & Walleye Boats" magazine.

The test boat was a Blazer bass boat with a 225 ProMax clone. Prop was 14 1/2 X 26 Mercury chopper. The motor retained the stock 40 amp charging system for both tests.

0 to 30 acceleration with the stock flywheel was 6.56 seconds.
0 to 30 with the lightweight flywheel dropped to 6.13 seconds, a significant improvement! No major improvement in midrange acceleration or top speed was noted in this test.

An improvement of .43 seconds for 0-30 would be huge for a race boat. On a lighter boat with a smaller prop the engine would be capable of a faster rise in RPM. Results should be more dramatic.

I witnessed this test myself along with Matt Riddle, and Sean Hill.

https://www.screamandfly.com/showthr...ight-Flywheel&

[FORBESAUTO]

Thats with an overhub chopper prop that allows the rpm to jump into the engines power range quickly before hooks up, therefore removing the load factor down low. Do the same test with a nice tight through hub prop and see what the results are.

[FMP]

Tell John

[nitro_rat]

Hey ... lets not get carried away Besides, it'll never work

Brings this to mind:

https://m.youtube.com/watch?v=_e7qVlrHbYE

Maybe a trailer hitch for the van is in order...

[FMP]

Thats with an overhub chopper prop that allows the rpm to jump into the engines power range quickly before hooks up, therefore removing the load factor down low. Do the same test with a nice tight through hub prop and see what the results are.

In that case with a slipping venting prop, the heavier wheel should hold the rpm more as it bit, if it could hit the same slip rpm, is that what you're saying?

[Chaz]

Thats with an overhub chopper prop that allows the rpm to jump into the engines power range quickly before hooks up, therefore removing the load factor down low. Do the same test with a nice tight through hub prop and see what the results are.

It just sounds like they found the right combination that picked up the bottom a bunch. He said no improvement in the middle, but I would suspect an over-hub on a V hull would kill off some gas mileage and drivability thru our lovely sacred cow 30 mph zones here in Florida. When I had a 21 Superboat, a 4 blade O/T Trophy seemed the best compromise for holeshot, cruise and top end.
And I'll bet I've got a cleaver you can put on your 2.5L that you'd have a hard time getting on top, let alone whistle Dixie with. I'm finding cord length of the blade from the case diameter to each inch outward, has as much to do with overall characteristics as pitch, diameter and rake.

[nitro_rat]

Here's a few more flywheel threads from the archive:

https://www.screamandfly.com/archive.../t-245494.html

https://www.screamandfly.com/archive...hp/t-2856.html

Now, let's discuss what reeds and tuner will be best for this combination....

[Chaz]

Well I was able to find my third round bye run from 2009 Citrus Nats. Only perfect run I made in my life .. LOL .000 Trip zip on the tree and on with egg as they say 7.650 on a 7.65

I read a lot of this does this , and that is a big waste of money bla,bla,bla, in those threads. Honestly, if you you don't have a modern dyno that takes operator error out of the equation. Or do back to back testing at a race track with a real timing system, the best you can hope for is to think you know what you see or feel. Or be the best out of who's happens to be there on that particular day.

I like what multi time world champion builder George Bryce of Star Racing say's about his knowledge of Pro Stock Motorcycle engines ...

" Everything I know about winning P/S is good for one week "

[FMP]

Here's a few more flywheel threads from the archive:

https://www.screamandfly.com/archive.../t-245494.html

https://www.screamandfly.com/archive...hp/t-2856.html

Now, let's discuss what reeds and tuner will be best for this combination....

Ask Al Stoker. Test or experiment with results which raise more questions are great. Better if you can duplicate the results. The post was the heavier wheel had an advantage and it lead to a good discussion.

[90 5.0]

Originally posted by Tony Brucato

John Tiger tested a lightweight 40 amp flywheel made by Hydro-Dynamics (6 1/2 lbs lighter than stock) and published the results in "Bass & Walleye Boats" magazine.

The test boat was a Blazer bass boat with a 225 ProMax clone. Prop was 14 1/2 X 26 Mercury chopper. The motor retained the stock 40 amp charging system for both tests.

0 to 30 acceleration with the stock flywheel was 6.56 seconds.
0 to 30 with the lightweight flywheel dropped to 6.13 seconds, a significant improvement! No major improvement in midrange acceleration or top speed was noted in this test.

An improvement of .43 seconds for 0-30 would be huge for a race boat. On a lighter boat with a smaller prop the engine would be capable of a faster rise in RPM. Results should be more dramatic.

I witnessed this test myself along with Matt Riddle, and Sean Hill.

https://www.screamandfly.com/showthr...ight-Flywheel&

now throw a 30 on and a heavy fishing load , with a 300lb draw passenger and a limit of bass in each livewell and post the results.

[FMP]

Again what you're saying is if you put increased resistance on the output shaft this will make the already lesser available hp due to additional wheel resistance to acceleration out accelerate the more available hp from reduced wheel mass.

[FORBESAUTO]

So the raggedy idling mota with the light flywheel is making more hp than the smother not struggling mota with heavier flywheel at idle and right off idle?

[nitro_rat]

I think the bottom line may be that the motor with the heavier flywheel has more inertia built up at the point where the prop stops sliiping and hooks up. Instead of lugging the motor there is enough stored energy to keep pulling through. Who knows, I'm no physicist...

[FORBESAUTO]

I think the bottom line may be that the motor with the heavier flywheel has more inertia built up at the point where the prop stops sliiping and hooks up. Instead of lugging the motor there is enough stored energy to keep pulling through. Who knows, I'm no physicist...

Bingo! That’s what I am saying. This don’t apply to the setups that allow the rpm to jump up 3k or better when ya slam the throttle down, we’re talking about that heavy weight with a setup that is digging off idle and rpm don’t even jump over 2 k when the trotlle is slammed open. It this situation I have to believe the added momentum of the heavier flywheel is a better option to get it movin. Ya can’t deny the fact of more momentum at idle, it’s the whole reason they idle much better with heavier flywheel.