bentwings2
Mechanical
- Aug 29, 2006
- 47
I wasn't sure where to post this but here goes.
Fuel tank baffles. The application is a dirt/sand hotrod. 140 hp 650 pounds wet...one fast over sized go kart. This thing has a 950 cc MC motor and trans plus about 5:1 gear reduction so it can really accellerate. Live axel independent rear end. It will go up or down about anything normally found very quickly. out run most dirt bikes. Burn the tires on pavement.
The tank in question is about 4.5 gallons rather tall narrow and a little long. The bad part is that the intank fuel pump had to be mounted in the front of the tank. It is still the lowest part of the tank however by several inches. picture a flattened wedge with the point in the rear and about 1/2 way up the max height.
This motor on a bad day in the crotch rocket is supposed to get better than 20 mpg going very fast. So figure 60 mph 20 mpg 3 gallons per hour.
Even at 2.5 gallons in the tank there is over 7 inches of fuel over the pickup point.
Even if the kart could maintain 1/2 g for a length of time there would still be fuel over the pickup assuming the fuel surface would be 45 deg to level. Verified with SW design picture. Now if the kart goes up a steep hill say about 35 degrees and the acceleration is very small ...it would take say 30 to 60 seconds to get up the hill, the fuel will be at something like level to the ground or about 40 degrees maybe 45 to the bottom of the tank. At this point there is a question as to whether the fuel will still be over the pickup. So install a baffle. Not hard when building a tank. The question is...how big should the baffle openings be.??? Keep in mind how fast you could empty a 2 gallon can with unlimited venting through the standard gas can opening. 30 seconds ?? maybe. I haven't tested it yet. The point being that only a small hole is really necessary at the bottom of the baffle with a larger hole say 1/2 way up and another right at the top to aid in filling to the full mark. You don't want much flow thru the baffle.. right??
A simple solution is a trap door over a little larger hole or holes. This would be closed going up and open going down. More or less closed on the level. Even if this leaks some going up hill, it still will not pass gass (you know what I mean) very fast so the pickup will remain covered for the time required. right???
whattaya think.???
Fuel tank baffles. The application is a dirt/sand hotrod. 140 hp 650 pounds wet...one fast over sized go kart. This thing has a 950 cc MC motor and trans plus about 5:1 gear reduction so it can really accellerate. Live axel independent rear end. It will go up or down about anything normally found very quickly. out run most dirt bikes. Burn the tires on pavement.
The tank in question is about 4.5 gallons rather tall narrow and a little long. The bad part is that the intank fuel pump had to be mounted in the front of the tank. It is still the lowest part of the tank however by several inches. picture a flattened wedge with the point in the rear and about 1/2 way up the max height.
This motor on a bad day in the crotch rocket is supposed to get better than 20 mpg going very fast. So figure 60 mph 20 mpg 3 gallons per hour.
Even at 2.5 gallons in the tank there is over 7 inches of fuel over the pickup point.
Even if the kart could maintain 1/2 g for a length of time there would still be fuel over the pickup assuming the fuel surface would be 45 deg to level. Verified with SW design picture. Now if the kart goes up a steep hill say about 35 degrees and the acceleration is very small ...it would take say 30 to 60 seconds to get up the hill, the fuel will be at something like level to the ground or about 40 degrees maybe 45 to the bottom of the tank. At this point there is a question as to whether the fuel will still be over the pickup. So install a baffle. Not hard when building a tank. The question is...how big should the baffle openings be.??? Keep in mind how fast you could empty a 2 gallon can with unlimited venting through the standard gas can opening. 30 seconds ?? maybe. I haven't tested it yet. The point being that only a small hole is really necessary at the bottom of the baffle with a larger hole say 1/2 way up and another right at the top to aid in filling to the full mark. You don't want much flow thru the baffle.. right??
A simple solution is a trap door over a little larger hole or holes. This would be closed going up and open going down. More or less closed on the level. Even if this leaks some going up hill, it still will not pass gass (you know what I mean) very fast so the pickup will remain covered for the time required. right???
whattaya think.???
