Cons of large gas tank

[dannyd]

As the title says I would like to know some of the cons of having a large gas tank. I already know some of the pros, like longer run time I just want to know the downside of have a larger gas tank. At the end of the week I'm going to be ordering hpi hellfire 150cc gas tank
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXLZZ4&P=7

To mount it I'm going to use Ofna hyper 7 tank post.
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCVY4&P=7

If guys have a better suggestion on what to use to mount the tank please let me know.

 

[jon2]

What is this tank going on?

Only cons I can think of is weight and the imbalnce of weight distribution to the ride.

Oh yeah ... you use gas a little faster.

 

[Monkey Wrench]

You also may experience 1/2 tank leaning issues.

 

[supercharged]

i'v heard people say the engine may start to overheat because it running longer i don't think it will be a problem it its tuned right

 

[dannyd]

its going to be going in my hpi nitro rs4 mt. What is this half tank lean? IS there a way to avoid it.

 

[jon2]

its going to be going in my hpi nitro rs4 mt. What is this half tank lean? IS there a way to avoid it.

You can try doing a Uni-flow mod. Same that is done to the Savage.

 

[dannyd]

You can try doing a Uni-flow mod. Same that is done to the Savage.

I'm going to look in to that.

Does anyone know how many cc's is the Mugen Prospec's tank is? I was looking at how much space i have and the hell fire tank wont fit.

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJAP2&P=7

 

[vbgagnon]

Any 1/8 scale buggy tank is going to 125cc. Mugen tank included.

 

[NvNitro]

danny, I am running the 290cc tank on my Mammoth ST, and as of today have never had a 1/2 tank lean issue. Half tank lean is basicly the motor starts to lean more at half tank and start getting your temps going up in the hot range. If you feel you are getting half tank lean, Just set your temps at half tank instead of full tank. Might run alittle rich at full tank. You can also do the uniflow modification, pretty simple. Just look in the search for uniflow mod, it will come up. Its just how you want to take the issue on. Adjust it once, or twice. Btw...SD is running that same tank, and to my knowledge he isn't having that problem either. Keep us up to date.

 

[cavicatz24]

its going to be going in my hpi nitro rs4 mt. What is this half tank lean? IS there a way to avoid it.

Basically the carb is fed with fuel two ways: pressure from the exhaust through the pressure hose, and gravity. When you have a full tank, there is a large amount of fuel applying downward pressure over the bottom fuel feed nipple which increases fuel flow to the carb. As fuel is used up, the downward pressure slowly drops, also reducing the "gravity assist" on the fuel and thusly fuel to the carb is reduced, leaning the mixture. This is a HUGE problem on the T-MAXX - resolved by swapping in a smaller 75cc tank. The smaller tank has less pressure fluctuation from full to empty and reduces the leaning condition. You can also tune your truck for optimum performance with only a half tank. Unfortunately, this will cause your mixture to be rich at full, making your truck sluggish for a few laps. As the fuel is consumed the mixture will slowly lean until you are at optimum tune at just before and after a half tank while not running overly lean when you're nearly empty. Hope this helps!

 

[dannyd]

Thanks guys. I think I'm going to get the mugen tank then. Wow so much help in a short amount of time.

 

[sweetdiesel]

On my mammoth with it's huge 290cc tank versus the stock 125cc one, half tank lean is an issue. You can help compensate by running a very short fuel line from the tank to the engine.

 

[dannyd]

OK Sd. I dont think that will be a problem since I like to keep my lines as short as possible any way.

 

[olds97_lss]

From what I've dealt with, a tank that has a uniform shape from top to bottom and is a rectangle type shape seems to not have the 1/2 lean problem as much as others.

I've run the t-maxx tank, savage tank and revo tank (all weird shapes) and all of them had half lean issues. On my maxx and savage, I replaced the stock tanks with the OFNA buggy tank and I no longer had the half lean problem.

I'm still trying to find the time to figure out how to get that tank on my revo as it has the 1/2 tank leaning issue as well.

I also had a HB lightning and it would go 1/3 tank lean when 1/3 was left in the tank. The temps would rise about 15-20 degrees for the last 1/3, but that's about as bad as it got. It was much worse on the maxx and savage tanks.

 

[dannyd]

From what I've dealt with, a tank that has a uniform shape from top to bottom and is a rectangle type shape seems to not have the 1/2 lean problem as much as others.

I've run the t-maxx tank, savage tank and revo tank (all weird shapes) and all of them had half lean issues. On my maxx and savage, I replaced the stock tanks with the OFNA buggy tank and I no longer had the half lean problem.

I'm still trying to find the time to figure out how to get that tank on my revo as it has the 1/2 tank leaning issue as well.

I also had a HB lightning and it would go 1/3 tank lean when 1/3 was left in the tank. The temps would rise about 15-20 degrees for the last 1/3, but that's about as bad as it got. It was much worse on the maxx and savage tanks.

OK Olds. How many cc is that ofna tank and do you know the demension of it (L,H,W)?

Do you think the mugen tank i picked will haver the 1/2 lean problem?
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJAP2&P=7

 

[NvNitro]

Sorry SD, Should of not spoken for you....I was running short line already and did not have the lean problem. Sorry bro!

 

[sweetdiesel]

Sorry SD, Should of not spoken for you....I was running short line already and did not have the lean problem. Sorry bro!

No worries bro. I like to run an inline fuel filter even though the tank has a stone filter. I just like the added protection from dirt. I just won't be able to do that with the XLB tank.

 

[rocknbil]

As the title says I would like to know some of the cons of having a large gas tank.

Probably doesn't matter, you're probably just bashing, but if you race be sure the tank does not exceed the maximum allowable CC's for your class.

 

[sly2136]

also if you race where they don't have tank rules the other down side is when you need to do a pit stop if useing a fuel gun most guns only hold 180cc or so with bigger tanks like 220cc and larger it might be a problem, also takes a couple seconds longer to get a proper fill. and when racing sometimes a couple seconds here and there really add up.

 

[dannyd]

Thanks guys. I'm going with a 125 cc tank. I might be racing this summer. If I do i'll check to see if I have to swap it out for a smaller one.