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Half-Lean fix possibly??
- Thread starter dotson90
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Bankrupter
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I tried it and it didn't work bud. the best bet is to get the bottom of the tank to be at Carb height. Mine is slightly above the carb and once primed it will gravity feed or siphon which ever you wish to call it. (Wont die with no preasure line)
That tank is the same shape as the stock tank so would also suffer with half tank lean, I would recomend the new-era 125cc tank as it gets rid of the half tank lean issue and also would likley cost half of what that tank would..
http://www.neweramodels.com/item.cgi?session_id=mwdvqtvagmogbxkryoxrogwpkqrhhuiq&part_id=1704
http://www.neweramodels.com/item.cgi?session_id=mwdvqtvagmogbxkryoxrogwpkqrhhuiq&part_id=1704
Mickey
just me
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i cant wait for my ofna tank to get here i just ordered it
- Thread starter
- #5
hmm well i thought it was a little different the bottom sticks out and the top goes in toward the engine but i thought the top and bottom looked to be the same size just off set from each other?? :dunno: Just trying to find something that will not cut down my run time
The main problem is that it has a shelf which when the fuel drops below the pressure changes which causes the half tank lean issue,,you need a tank without a shelf to solve the leaning issue, the 125cc run time works for me as I don't race so I don't have a problem with filling the tank with fuel every 10 or so mins...hope I have helped explain what causes half tank lean, otherwise there are plents of threads which go into more detail...😱)
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the one that Livewire gave you would do the trick, also check out this one here---> Rear Mount Fuel Tank
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Raises up the height of the tank pretty good, but you may have to adjust your gearing a little to keep the front tires on the ground..fj
You are welcome, Happy bashing :resp:
Bankrupter
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It's not so much the self as it is the position of the shelf as it sits on the truck. The top of the shelf is at or above the carb which takes less pressure to move the fuel to the carb. A full tank can supply fuel with little to no preasure at all with just a gravity feed (syphon). Once it is below the shelf it has to be pushed harder and the preasure tap cant do it. Do to the volume of the air space in the tank as it increases. Its all about gravity and preasure. The shelf just happens to mark the point where this occurs. you could move the stock tank above the carb and you would never have a issue
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Bankrupter
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Its too big and odd shaped. I just said it could be done. Not to try and do it.
But if you want to go for it!!!
Lift it by better than 2 inches and it will work. It will look bad and raise the CG of the truck so keep these factors in mind. The easiest way to do it is with the new era tank. For best overall performance mid tank but that is more costly. but in doing so you can add up to 250cc of nitro = max bash time. Mine will run at to just over 16mins per a fill.
But if you want to go for it!!!
Lift it by better than 2 inches and it will work. It will look bad and raise the CG of the truck so keep these factors in mind. The easiest way to do it is with the new era tank. For best overall performance mid tank but that is more costly. but in doing so you can add up to 250cc of nitro = max bash time. Mine will run at to just over 16mins per a fill.
lorinlewis23
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I'm curious, If it is true that having the bottom of the fuel tank lower than the carb contributes to the half tank lean then why is it that most truggies and buggies have the bottom of the tank way lower than the carb.
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If someone can answer Lorins question, then maybe you would know why my truck would barely start or stay running with stocker tank & 1/2 tank lean & 2 of the guys we bashed with that Saturday ran stocker tanks that had no noticeable 1/2 tank lean at all. :thinking:
Bankrupter
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What buggy or truggy ? the ones I have are far from as low as the savage. They are all on the same plane and the tank has no part above the carb. Read more... I said do to the preasure and the position not one or the other. The two together make the issue. The low tank in a savage takes more of a preasure head than a pipe can supply. and half of it (the upper tank) is level with the carb giving it too much. They are narrow and short on buggies and truggys giving more of a preasure head. Also not above the carb keeping the gravity swing at bay.
Siphon a gas can move the hose above the tank what happens.. it stops simple physics.
Now beach run a mill no truck. Holding the tank in your hand move the tank above the mill it will get fat now move it below it will lean out and that is within a second not half a tank. Also no measurable loss of fuel in the tank. So no preasure change. All simple physics. I did this test with a ofna tank and a Novarossi.
The same apply to all fluid dynamics The more empty the tank gets the more pressure to push the fuel and the less it gets do to the preasure head. You can tune a savage tank to run just fine on the bottom of the tank. But it will be fat on top. Its a poor tank design and position. But if you raise it it will work fine. there is less of a change in gravity on the tank.
Also for bashing there is no real reason to race tune a mill to the point this issue will hurt it.
Also for freddy some mills are much worse than others. I cant explain this. You may have had a leak in your tank(Oring in cap or a line). That is the only reason I can think of that you could not run it at all. it should have held a tune for at least half a tank top or bottom.
Long story short this is Off topic.
Why does not even matter. Some savages have it and bad, some do not, and some have a mild case of it. If you have it lose the stock tank any way you can afford to. If you don't be happy you don't and run it till the cows come home! I prefer the mid tank conversion do to the central and forward weight it gives the truck. But in the end lose it anyway you can and get bashing !
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lorinlewis23
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After reading your response about three times I under stand what you are saying. The problem the stock tank has is one of maintaining the consistency
of the fuel pressure. The engine is normally tuned at the upper level of the tank at high pressure. When the shape of the inside of the tank changes due to the fuel level. The engine receives less fuel pressure causing the mill to run lean; due to the position of the odd shaped tank having the shelf in the tank about level to the carb. What happens is when the tank is full gravitational pressure is high but, when the level goes below the shelf the gravitational pressure drops. This is how the position of the stock tank adds to the half tank lean. In a truck like the hellfire, the tank that has a consistent vertical shape. The half tank lean will never be an issue, especially because the fuel level will always be below the carb. that way gravity will not affect the change in pressure. If the bottom of tank is raised above the carb for example the pressure in the tank will raise yes but, the engine will hold a consistent tune due to the gravitational pressure remaining consistent at all fuel levels.
Also I do not think this is off topic because in order to understand why the tank will not work discussion about it is necessary.
Mickey
just me
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there is a tread in the mid tank mod section of this forum that explains half tank lean in plain english MotoPsycho's Meager Mod's - Tank 1/2 lean EXPLAINED
Bankrupter
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Only off topic caz the thread starter is not asking why. Just how to fix it.. people keep blaming its shape. Its shape would and does have no effect if mounted in a different location. I was just putting out the fact that it is not the shelf (shape) that is the main cause but is playing a role.
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lorinlewis23
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No problem Bank it's all good:resp:
