Landracing Forum
Tech Information => EFI Questions => Topic started by: Boostedballs on August 20, 2014, 02:42:24 PM
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I haven't found much info on the topic of fabricating my own fuel cell for LSR and I have couple of questions.
I would like to build a fuel cell to install in place of the factory 18 gallon stock tank in my Chevy Monza coupe. I plan on running twin 340lph internal pumps mounted to a Fuel Safe fuel plate with screw-on filler cap. I want to cut a hole in the sheet metal of the car to access the filler plate. This will be covered with another piece of sheet metal with gasket, hinge and possibly dzus fasteners or wing nuts.
1. I plan on running gas at Bonneville with a 700 HP turbocharged small block. How many gallons should I design it to hold???
2. Can I use the cell without a bladder?
3. Does it need a second layer of material outside of the cell or will an angle iron "cage" around it suffice?
also- how do you guys feel about aluminum vs. stainless for the cell and fuel lines?
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Either will work but stay away from butt welds on a square corner.
Note the joints.
FREUD
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Stainless.
Lots of people know more about this than me here which partly explains why I have an Al one. Use the right grade and it's way easier.
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Either will work but stay away from butt welds on a square corner.
Note the joints.
FREUD
Nice looking cell and props to the oxy/cet approach!
Most every aluminum cell I have seen has the welds on the corners. I assume it is more likely to crack with corner welds? I do plan on rubber mounting this thing. I don't have a sheet metal brake to make the bends. Is it a big enough deal that I should invest in one?
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I've used both, aluminum & stainless, no issues with either except I empty the aluminum take when traveling. The humps & bumps will accelerate the potential to crack an aluminum tank.
My current tank is stainless & holds 3.5 gallons. I also make a bit more power than you so you might do yourself a favor. Leave the stock fuel tank in the car and fill it with water.... for weight over the tires. Then build a small tank for fuel, less fuel = less fire danger in a mishap.
Photo of current fuel tank added
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Boosted;
If the container contains a flexible bladder, it is a fuel cell. If it is just a container with no internal bladder it is a fuel tank. The word "fuel cell" continues to be misunderstood and misused.
A fuel cell has the ability to deform considerably without rupture and the reticulated (open-pore) foam inside the bladder quenches the flame front, making it less prone to ignite the fuel. The foam also acts as a damper on the fuel, keeping it from sloshing around in the bladder.
Tanks are fine but they should not be confused with fuel cells.
Regards, Neil Tucson, AZ
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3.5 gallons!? How much fuel do you use on a 5-mile pass? I was thinking that I should go with at least 5 gallons. I want my fuel "tank" to be as small as possible. I want to ditch the stock tank because it is huge and it sticks out under the car and is not mounted on center. It may also interfere with the parachute attachment. ( that's a whole different thread) :roll:
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3.5 gallons!? How much fuel do you use on a 5-mile pass? I was thinking that I should go with at least 5 gallons. I want my fuel "tank" to be as small as possible. I want to ditch the stock tank because it is huge and it sticks out under the car and is not mounted on center. It may also interfere with the parachute attachment. ( that's a whole different thread) :roll:
How much fuel on a 5 mile pass?
Well, this is my take... it all depends........... :-P
Kidding aside, it depends on how long you idle the engine on line, how much power you make, & how far/long you run at WOT. We already have some idea of the distance, 5 miles, even though you won't be a maximum power the moment you leave the push truck. A simple (I mean basic as other factors can change this) formula for what you need is (BSFC x HP) divided 6.1 for gasoline. This will get you GPH (gallons of fuel per hour) then divide by 60 to get GPM (you guessed it, gallons per minute). Keep in mind that the faster you are the less time on course, the average run at Bonneville is 60 to 90 seconds for 5 miles.
So lets start with BSFC (brake specific fuel consumption) with racing gas. A real good N/A motor can be at .40 or better, for my calcs I use .50 for N/A race motors, .55-.60 for blown gas & .60-.65 turbo gas. So, lets use your 700 hp turbo engine. (.60 x 700 hp) = 420 divided by 6.1 = 68.85 GPH. Now 68.85 divided by 60 = 1.147 or 1.147 gallons per minute. Not much fuel used so not much need for a 5+ gallon tank, unless it makes you feel good.....
Again, this is just a estimate as other factors contribute to how much fuel is used during a run.
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3.5 gallons!? How much fuel do you use on a 5-mile pass? I was thinking that I should go with at least 5 gallons. I want my fuel "tank" to be as small as possible. I want to ditch the stock tank because it is huge and it sticks out under the car and is not mounted on center. It may also interfere with the parachute attachment. ( that's a whole different thread) :roll:
How much fuel on a 5 mile pass?
Well, this is my take... it all depends........... :-P
Kidding aside, it depends on how long you idle the engine on line, how much power you make, & how far/long you run at WOT. We already have some idea of the distance, 5 miles, even though you won't be a maximum power the moment you leave the push truck. A simple (I mean basic as other factors can change this) formula for what you need is (BSFC x HP) divided 6.1 for gasoline. This will get you GPH (gallons of fuel per hour) then divide by 60 to get GPM (you guessed it, gallons per minute). Keep in mind that the faster you are the less time on course, the average run at Bonneville is 60 to 90 seconds for 5 miles.
So lets start with BSFC (brake specific fuel consumption) with racing gas. A real good N/A motor can be at .40 or better, for my calcs I use .50 for N/A race motors, .55-.60 for blown gas & .60-.65 turbo gas. So, lets use your 700 hp turbo engine. (.60 x 700 hp) = 420 divided by 6.1 = 68.85 GPH. Now 68.85 divided by 60 = 1.147 or 1.147 gallons per minute. Not much fuel used so not much need for a 5+ gallon tank, unless it makes you feel good.....
Again, this is just a estimate as other factors contribute to how much fuel is used during a run.
Wow, thanks for the calculation; it really puts it into perspective. I think 3.5 gal should be plenty! I'll see how it comes out with the available space. I just have to make sure my pump pickups don't run dry.
On a side note: what gas should I use for dyno tuning? I know that elevation will play a big part but I want to start with something close to what I will get at Bonneville.
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One other thing I'd consider is do you want to go to the fuel truck every run if you are running in the gas class?
You are planning on qualifying for a record aren't you :-). If so make sure you have enough for a return run or that you can take a bottle to the fuel truck and get your gas and get it sealed and make sure you have Dan or one of the guys from impound there when you re-fuel in impound so that all of the seals can be broken and re-applied in the correct manner.
I'd like to have enough for 3 runs myself but it is your call. You sure can waste a lot of time and endure embarrassment when you run out on a run after sitting in line for a couple hours. We hope not to repeat that :cry:,
Sum
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I agree with Sumner, my tank was SS and held 20 gallons. I usually bought 10 gallons, at $15.00 a gal that is $150. Only once did I have to go get some more gas. Is the price higher now????
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I would go with enough fuel to make 3 runs, you will be happier not waiting in the gas line every run...
and if you decide you need to run alcohol or E85 you will have enough capacity for a run.
YMMV :-D
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The above points are well taken, as I said before it depends.....
Now add this to the thought process. I want fresh fuel for my engine every run. ERC A8D racing gas is pushing $20 a gallon, if you break on your run do you want to go home with $200 worth of fuel for your lawn mower? It sure shouldn't be run next year. If we qualify and go to impound we wander on down to the ERC trailer and get Rick Gold (Thanks Rick!) to fill our fuel jug and seal it. Back at impound I ask Mr. Warner (Thanks Dan) to watch as I open sealed fuel jug and add some to my sealed fuel tank. Works for me. But I understand the other opinion. Let me add one more point; we also run at El Mirage, same fuel, same price. We don't need nearly as much running 1.3 miles so like I said it depends..... 8-)
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Thanks everyone for the insight!
I think I will shoot for 3-4 gallons, maybe more if I have room. I will run dual internal pumps so I need a little extra to cover the pickups.
How long should I expect use aluminum hard lines on the salt before they need replacement?
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Our vent line is aluminum.... it has lasted about 20 years... however I would use stainless for hardlines and braided on the ends if the run seems too long for all braided
Just my opinion
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Use Aluminum if your to heavy, or Stainless Steel if your to lite.
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When you build the tank make it small in plan view and tall in side view, make a sump at the bottom for the fuel pump inlet and if you are using EFI make sure that the return from the fuel pressure regulator dumps the return fuel below the fuel level and as far away from the pump inlet as possible and maybe even put a small baffle between the return area and the pump inlet sump. Use only stainless lines, a little bit more of a pain in the a$$ but much more reliable especially at the salt. When you build the tank you don't really need a break you can bend up the sides with a pipe or angle "iron" clamped to a good table. Heed Freud's comment about the corners not being a sharp edge, very difficult to weld and they like to fail. You need to buy (or make one yourself) a tee dolly which you use to radius the edges before you weld them, then the weld becomes a butt weld much easier to weld and much stronger. That is probably how Jason in Freud's pic put the radius on the tank he is welding ( he may also have an edge radius rollers for his bead roller). If you happen to make the tank from aluminum, back weld as many of the joints from the inside of the tank as you can (I am assuming that you will TIG weld the tank) as it will reduce the number of leaks that you will have. If you plan the tank out right you can do all of the side welds and the bottom welds from both sides (i.e. back weld) then weld the top on, again radiusing the corners. I have built a number of aluminum gas tanks and have never had one that didn't leak (maybe that is a statement on my TIG welding ability!) so when you are done fill the tank with water and mark the leaks then weld them closed and check again. I have an aluminum gas tank in my little lakes roadster and have put probably 15,000 miles on it without problem but I check it alot.
Rex
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I have lot of 1/8" thick stainless that I would like to use for the tank. At this thickness, do I really need to bend the corners and butt weld? I'll bet I can set the car on top of the tank and not break a corner weld. I can bend it up if absolutely necessary; but it will be a lot more work to make a tight fitment. This will have twin 360lph pumps setup similar to the Stealth series.
Should I rubber mount or use straps and leather between tank and body???
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I have lot of 1/8" thick stainless that I would like to use for the tank. At this thickness, do I really need to bend the corners and butt weld? I'll bet I can set the car on top of the tank and not break a corner weld. I can bend it up if absolutely necessary; but it will be a lot more work to make a tight fitment. This will have twin 360lph pumps setup similar to the Stealth series.
Should I rubber mount or use straps and leather between tank and body???
Some rubber strips will keep the tank from chafing on the body. A couple of heavy-duty steel straps with T-bolt fasteners over the tank is a good strong restraint. Think tractor-trailer fuel tank mounts.
Regards, Neil Tucson, AZ
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So I decided to go with the 1/8" thick stainless for the tank material and I will attempt to bend the corners and butt weld them. If I can't get a good bend, I might try corner welds for the sake of an easy weld and install triangular gussets inside to hold the sides together. Thoughts on this?
I am having trouble finding a fuel plate that will integrate the twin internal fuel pumps, filler cap, vent, supply and return lines and most importantly... the electrical feed-throughs for the fuel pumps. I could use a couple of large nylon bolts / nuts and just tread brass all-thread through them, but there must be something out there that I can slap on there and move on with the project without breaking the bank in the process. (?)
To those who have bent and flared stainless tubing: Should I run two AN-6 supply lines or a single AN-8? My fuel rails have AN-6 fittings and I already have a bunch of 3/8" stainless tubing. Also, I plan on running a braided rubber return line back to the tank located as low as possible in the tank and as far away from the pickup as possible. (as suggested here) :cheers:
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.......If I can't get a good bend, I might try corner welds for the sake of an easy weld and install triangular gussets inside to hold the sides together. Thoughts on this?...
I wouldn't worry about that and in fact....
(http://purplesagetradingpost.com/sumner/Hooley%202013/Ice-Water-Tank-86.jpg)
http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20construction%20menu.html
.... have a lot of corner welds on the intercooler tank above and...
(http://purplesagetradingpost.com/sumner/Hooley%202013/rad-in-box-76.jpg)
http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20construction%20menu.html
....the rad-in-a-box.
So far no problems. These cars don't go hundreds of miles,
Sumner
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I corner welded my 16 ga. stainless steel fuel tank and used it 10 years without any problems, and Sumner, I still sharpen the tungsten with the belt sander and I am still alive. hahaha
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... and Sumner, I still sharpen the tungsten with the belt sander and I am still alive. hahaha
Private joke since I was trying to get the "old set in his way's man" to try Chen Sharp vs. the grinder.
If anyone is interested a video......
https://www.youtube.com/watch?v=SSSaJ-Ke7as (https://www.youtube.com/watch?v=SSSaJ-Ke7as)
.... and I don't use the torch but short it out but might try the torch. I also use a small HF dedicated grinder at times :-D,
Sumner
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I'm with you Gary, I still do exactly the same.
My welder is old school too and doesn't have square wave or any of the fancy settings, just amperage, high feq., post flow and a pedal. It still turns out good old fashioned quality work and I can weld the bottom of two pop cans together with it. :-D :-D :-D
Pete
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GH, that's sharp. :-D
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BB...Let us know bending .125 stainless without a press brake works out for you.
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It's not going to work at all.
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I will be in the same situation at the OP with fabricating my own fuel tank. I thought about going aluminum for the corrosion resistance but seems SS would be a better way to go. A few questions regarding custom tanks:
1) what should be the thickness of metal (aluminum and ss)?
2) could you build 2 or even 3 tanks and have them filled then swap tanks out for runs? (this will be for a motorcycle with limited space for a large fuel tank)
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For a very small tank, 18ga should be fine but 16ga is probably going to be easier to weld.
Regards, Neil Tucson, AZ
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I've always built tanks with aluminum & made corner welds & never had a failure. I leave the ends of the sheets exposed at the corner with a thin gap on the back side, that gives a 90 deg "V" to get a full width weld. If the tank has a large volume, build some center support into the mount base for it. I usually use 1/8 but have never used any less that .090.
Sid.
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I have a general materials question. Are there any corrosion concerns with aluminum or stainless if you run fuel? I am running run gas class now but also want to be able to switch to methanol or E85 in the future. In my case it's for a fuel rail but I figure it applies to fuel tanks as well.
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Methanol is corrosive to aluminum. Hard anodizing is used to protect aluminum parts from methanol. I know nothing about E85.
Regards, Neil Tucson, AZ
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Good to know. Thanks Neil.
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Methanol is corrosive to aluminum. Hard anodizing is used to protect aluminum parts from methanol. I know nothing about E85.
Regards, Neil Tucson, AZ
When I was a kid I put a dent in my dirt bikes tank so I borrowed my uncle's spray gun, had the paint shop mix up the Suzuki yellow
and bought new factory decals.
I spent about a week polishing out the orange peel. When done the tank looked like new.
We go to the races and I gassed up with Methanol but I spilled some on the paint.
New paint job. :x :x :x :x :x