Swapping pulleys >>> Go faster?

[Automobilist]

We're doing a lawn tractor race in a couple months. Neighborhood get together, meet folks, etc.. More of a party than an actual "race". We'll have a small car show, catered BBQ lunch, a little stand up comedy, etc. Third time we've done this event, and I want to play around with it a little.

My understanding is that on a NON-Hydrostatic drive riding mower, you can swap the front & rear pulleys to make it faster. (I've only had hydro drive mowers) True?
Fairly simple to do? Any advice? I'm looking locally for a cheap riding mower to take the deck off, swap pulleys, and put a big fake Nascar wing on it. Just for fun, of course... Any other thoughts/advice/questions on this idea? Last couple years I ran my Gravely ZT60 zero turn mower and beat my neighbor with his Toro.

 

[bertsmobile1]

Yes hydros have an input speed limit, vari drives & manual boxes dont
Manual boxes can not be shifted while moving or you rip the shift keys apart as they are constant mesh but you can reprofile the keys but you have to get the revs right to shift on the move
Vari drives have unlimited shifting because you just change the pulley diameters
In the latter case both will work well with a much larger drive pulley and the easy way is to turn the stack pully upside down
Better way is to get a cast iron engine pulley
Next thing that needs to be done is to lock the diff .
Most tracks are speedway / grass track style so an oval
In which case you lock the diff so that only the inside wheel is driving
The governor can be adjusted to 4000-4500 rpm but anything over that and you will throw the piston so you are then into the big $$$$$ competition zone of forged crankshafts and forged conrods , ball & roller bearings on the crank, the amount of money that can be spent is limited only by the thickness of your wallet and size of your ego.
On the cheap if the engine has a counter balance weight, that can go which will up the acceleration but of course increase the vibrations.

 

[Automobilist]

Yes hydros have an input speed limit, vari drives & manual boxes dont
Manual boxes can not be shifted while moving or you rip the shift keys apart as they are constant mesh but you can reprofile the keys but you have to get the revs right to shift on the move
Vari drives have unlimited shifting because you just change the pulley diameters
In the latter case both will work well with a much larger drive pulley and the easy way is to turn the stack pully upside down
Better way is to get a cast iron engine pulley
Next thing that needs to be done is to lock the diff .
Most tracks are speedway / grass track style so an oval
In which case you lock the diff so that only the inside wheel is driving
The governor can be adjusted to 4000-4500 rpm but anything over that and you will throw the piston so you are then into the big $$$$$ competition zone of forged crankshafts and forged conrods , ball & roller bearings on the crank, the amount of money that can be spent is limited only by the thickness of your wallet and size of your ego.
On the cheap if the engine has a counter balance weight, that can go which will up the acceleration but of course increase the vibrations.

Yes hydros have an input speed limit,

Thanks, good stuff...
I think I'll limit it to swapping pulleys.
We've done years of vintage auto racing, and are quite familiar with speed versus cash input ratios.

This is more of a non-serious event. We design a good road course type of track, kind of modeled after West Coast road courses we've raced such as Willow Springs, etc.
I get trophy's / awards for a few classes and the car show. Stuff like that.
Lots of fun....

 

[smhardesty]

It's been a while since I've been on here. I'll not even try to explain everything that has happened this year.

I logged in just while ago and happened to run across this thread. I'm interested in doing a similar thing, but not for racing. I'm hoping to turn some type of lawn tractor into a 10 to 15 mph, non-mowing, display piece for my business. I don't have a mower on hand, so part of what I'm asking on here is what mower you guys would buy to use for this type of project. I'm going to strip whatever I buy and then paint it a red, white, and blue color scheme. I'd also like to do a really simple pulley swap, or pulley replacement, then an aftermarket air filter system, some type of free breathing exhaust, and then increase the RPMs a bit.

I guess my first question is what I already asked. Which mower, or mowers, are the easiest to do a pulley swap/replacement on as well as having a larger HP engine from the factory?

 

[PTmowerMech]

It's been a while since I've been on here. I'll not even try to explain everything that has happened this year.

I logged in just while ago and happened to run across this thread. I'm interested in doing a similar thing, but not for racing. I'm hoping to turn some type of lawn tractor into a 10 to 15 mph, non-mowing, display piece for my business. I don't have a mower on hand, so part of what I'm asking on here is what mower you guys would buy to use for this type of project. I'm going to strip whatever I buy and then paint it a red, white, and blue color scheme. I'd also like to do a really simple pulley swap, or pulley replacement, then an aftermarket air filter system, some type of free breathing exhaust, and then increase the RPMs a bit.

I guess my first question is what I already asked. Which mower, or mowers, are the easiest to do a pulley swap/replacement on as well as having a larger HP engine from the factory?

They're all about the same.

 

[bertsmobile1]

Get any one that has either a manual gearbox or a varidrive
Flip the stack pulley over
On most MTD's you will need to cut off the tabs they bend down to act as a belt keeper
You can not increase the speed of a hydro without damaging the drive