3 HP flywheel input

Lkerley

Member
Wanting some input on changing to a 3 HP flywheel on a unrestricted build. I know I need coil adapter.Benefits?Good or Bad?Total Waste of Time?
Ive heard it has its benefits.
If you have any part #'s on a Briggs stk wheel let me know.thks
 
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flattop1

Dawg 89
I had good luck with the 3 hp flywheel.
Spins up faster then the stock 5 hp .
Heavier then the arc 3 hp .
 

OVALTECH1

Site Supporter
It is a noticeable seat of your pants difference, especially on a track that puts the motor in a lot of bind and you have big rpm drops. It will pick up quicker off the starts and off corner. If you were racing a momentum track you will notice it off the starts but I feel on that track type the whole heavier flywheel and inertia thing are a bigger plus. Just be sure to use the factory cast iron/steel wheel and not the factory aluminum and give it a good looking over and the ring test. I bet it’s worth 200 on the tach.
 

OVALTECH1

Site Supporter
The factory cast works perfect... I’d like to know it’s background a bit tho. Look for 2 jaw puller marks, broken or chipped fins and hammer marks...that makes it a big no no! I’ve run mine to 8,000 plus
 

Lkerley

Member
The factory cast works perfect... I’d like to know it’s background a bit tho. Look for 2 jaw puller marks, broken or chipped fins and hammer marks...that makes it a big no no! I’ve run mine to 8,000 plus
Can the flywheel be from any Flathead 3 HP or is there a specific model or part # that is better used on raptor style motors.thks.
 

alvin l nunley

Site Supporter
Wouldn't it be nice to see some real numbers? I can see the 3 HP being a little quicker accelerating from low RPM to engagement RPM on the starts, but once it's engaged, you're accelerating the whole kart driver, how much difference could that little bit of weight on the fly will help. And you're accelerating very slowly. Now I can see some benefits when you're decelerating, but again, very little. After all, you're trying to stop a 360 pound kart! A course, I'm just guessing, but my guessing is based on some relevant theory. Read my sig. lol. Any calculation of acceleration includes "time". I.e. how long does it take to accelerate from X RPM to Y RPM. If the time allotted is one second, yes, then the lighter flywheel would show improvement, but if the time allotted is 4 seconds, the difference between the light and the heavy flywheel becomes significantly less. Especially when you consider that your accelerating the whole kart, so the difference in flywheel weight becomes less significant. More data would be helpful. And then there is always the "I'm pretty sure this is going to be faster" factor to consider. lol
 

flattop1

Dawg 89
as they said the cast iron one is the only one you can use .
the arc for 100 dollars is pretty nice as shipping cost will bring it right up there any way .
your situation is a little different the cast wheel might be a benefit.
the inertia for standing starts could help.
I'm not sure what the cast wheel weighs.
 

CarlsonMotorsports

Site Supporter
Yea, we've got them in stock -- but not at 2001 prices. LOL
If you're going to go with the oem flywheel, get a new one. It's not worth the risk of not knowing how the previous person removed it from it's donor engine.
We've spun them over 8000 rpm often back in the day. Not that I am recommending that in any way, but use it at your own risk.
Keep in mind that there are aluminum 3 HP Briggs flywheels made for vertical shaft mowers -- DO NOT try to use them!!! They are cast aluminum and WILL come apart. I see them for sale often on ebay and advertised as a direct replacement for kart engines -- this guy/seller ought to be castrated for making such a claim!
The cast iron flywheel weighs just over 3 pounds if I remember correctly. The only ones I have here are still in the box so I can't get you an accurate weight on them.
They do help on acceleration, but will hurt momentum due to their lack of kinetic energy (rotating mass under deceleration.)

-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 

pitpal

Member
HI I have about 20 of them, I sell you one for 24+ shipping (cast iron) used and take offs
 
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Yea, we've got them in stock -- but not at 2001 prices. LOL
If you're going to go with the oem flywheel, get a new one. It's not worth the risk of not knowing how the previous person removed it from it's donor engine.
We've spun them over 8000 rpm often back in the day. Not that I am recommending that in any way, but use it at your own risk.
Keep in mind that there are aluminum 3 HP Briggs flywheels made for vertical shaft mowers -- DO NOT try to use them!!! They are cast aluminum and WILL come apart. I see them for sale often on ebay and advertised as a direct replacement for kart engines -- this guy/seller ought to be castrated for making such a claim!
The cast iron flywheel weighs just over 3 pounds if I remember correctly. The only ones I have here are still in the box so I can't get you an accurate weight on them.
They do help on acceleration, but will hurt momentum due to their lack of kinetic energy (rotating mass under deceleration.)

-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
I'm more than guilty when it comes to using those aluminum wheels back in the 90's . Luckly i never had one fail ..the only reason i never kept one on for any length of time was the difficulty in pull starting the as i did not own an electric starter.
 

welder60

Member
its the old spint car thing verses the mod thing. your going to gain in some areas and lose in others. you will acc quickerand decel quicker but if you have the idle to low its going to stall on decel. cure give it a little higher idle to avoid stalling.
 
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