129 MAX Speed

Rob Ach · #1 08-26-2016, 11:02 PM

Tomorrow is the annual neighborhood tractor race [all stock - I think] and was curious if there is anything easy that could be done to eek a little more speed out of the old 129. Granted the max speed of the tractor is controlled by the hydrostatic trans and maybe this is more so psychological, but was looking for any edge I could find. [the one neighbor has a big ol' JD] I've seen posts to remove the sponge around the air cleaner and have since put some additional air in the tires and removed the deck, hanger and wheel weights. Was considering buying higher octane gas but thought I would throw it out to the experts here. Any suggestions, ideas, ro comments would be greatly appreciated.

thanks in advance
Rob

Jeff in Pa · #2 08-26-2016, 11:21 PM

The tallest tires you have will increase speed.

have fun

J-Mech · #3 08-26-2016, 11:24 PM

Speed up the engine to 3800RPM

Sievert456 · #4 08-27-2016, 12:59 AM

I had 26x12x12 ag tires on my 147 for a tractor pull and they made it a little faster then the stock 23x10.50x12.

prlwpod · #5 08-27-2016, 08:58 AM

should make a worthwhile improvement in the way the motor runs (Higher Octane = better combustion ). You can usually buy Av gas (Aviation Fuel ) at the airport or Racing gas from a station that carries the premium stuff. Google is your friend. Good Luck.

cubs-n-bxrs · #6 08-27-2016, 09:54 AM

Quote:

Originally Posted by prlwpod

should make a worthwhile improvement in the way the motor runs (Higher Octane = better combustion ). You can usually buy Av gas (Aviation Fuel ) at the airport or Racing gas from a station that carries the premium stuff. Google is your friend. Good Luck.

You can basically run any grade gas you want it's not gonna change engine RPM's . Gov is set at 3600 RPM's and that's all there is. You can change Gov settings but I wouldn't go more than 2 or 3 hundred RPM.

Sam Mac · #7 08-27-2016, 10:18 AM

Quote:

Originally Posted by prlwpod

should make a worthwhile improvement in the way the motor runs (Higher Octane = better combustion ). You can usually buy Av gas (Aviation Fuel ) at the airport or Racing gas from a station that carries the premium stuff. Google is your friend. Good Luck.

Sorry, but I have to disagree with this. Higher Octane in a low compression engine like you have in a Cub will actually give you less power. High Octane is used to control detonation in high compression engines.

Bo185 · #8 08-27-2016, 01:00 PM

Quote:

Originally Posted by prlwpod

should make a worthwhile improvement in the way the motor runs (Higher Octane = better combustion ).

Not really better combustion in this application. Avg gas is 100-110 low lead which is most common by far. Its not really better at combustion or has more energy content one vs the other, it depends on the use IE what motor it is burned in that's the difference.. Gas burns either way. The lead has a higher octane rating which is more resistance to detonation on high compression or boosted engines of which aircraft have. This higher CR or boost give more performance no really the gas persay.

The by product of the lead is it created a layer of lead on the valve seats to cushion the valves and it retains its octane for years IE it doesn't go bad. I have left avg as in a motor unstarted for 2 years and it started right up.

The bad is avg gas is expensive now $5-7 a gal normally some times cheaper. Oh and lead will kill you well over time.

EDIT: Any one ever put some spray or a small turbo on one of these motors? I guess it wouldn't matter on a hydrostat as it only spins x speed to get X pressure?