Modifying ERA fuel tank

[HSSS427]

Not like I've got enough projects on my hands, but am now looking at a improved fuel system. With 566 HP it occurs to me that the FE is going to need better fuel flow.

So, my design is as follows:
1. Install Clay Smith high volume (140gpm) mechanical fuel pump
2. -8 braided lines to fuel filter - Fram HPG1
3. Holley 2 port fuel pressure regulator
4. -8 line to Barry Grant Mighty Demon 750

That I think addresses the fuel pump to carb set up. Now the challenge - fuel tank to fuel pump.

Apparently the ERA aluminum tank has a top mounted pickup that is a 3/8" hose barb threaded into a 1/4" npt boss. This becomes the restriction in the system as I'd like at least a -8 AN line to the fuel pump with a similar sized pickup outlet on the tank.

Has anyone modified an ERA tank to change the pick-up to a larger, higher flowing size? What was invovled?

Who are the sources for fuel cells that would bolt in place of the ERA tank and round numbers on price?

Other ideas?
Thanks!
Scott

[Jerry Clayton]

Scott

You can probably drill out the tank bung from 1/4 pipe to 3/8 pipe thread and drill that fitting out a little for the -8 line

DO NOT pressurize a fram hpg filter--they are meant to be in non-presurized supply line--they are almost impossible to keep from leaking under just a few pounds of pressure.

Jerry

[cobred]

I would drive it 1st with the new motor. How long will you be driving at full throttle? Thats alot of work and money if not needed.

[Excaliber]

I'm not sure there will be a problem. I was running 667 horse power out of the stock tank fittings (and running it HARD)!

[Carnut427]

I don't know if you've got a baffled tank or not, but mine was built in '94, was roadracing at the time and it would starve for fuel on left turns because the pickup was on the left side and the fuel was on the right side of the tank because of centrifugal force. I solved the problem by installng a second pickup on the right side with a separate filter and electric pump for each, installed just behind the cockpit, ahead of the rear end. From there they converge into a 1/2" dia aluminum line up to another filter on the front of the engine. As mentioned by others, I'm not sure if the large size is really needed, I did what I did for another reason (other than the 1/2" dia aluminum line) and it works. By the way, any air picked up by the fuel pump that's uncovered comes out the carb vents. No problems whatsoever.
Dan

[strictlypersonl]

Carnut...

I'm looking at a CAD drawing of the tank right now, dated 2/94 with the pickup in the center. Yours must have come just before.

All ERA tanks have two longitudinal baffles. One-way doors were also added in '94. A third transverse baffle was added a few years ago.
__________________________________________________

HSSS,

Another possibility for a new fitting:

Use a bulkhead fitting that's been modified to a barb on one end to take a hose. Drill a new hole in the top of the tank.

Somehow feed the fitting and hose in through the fuel sender hole and out the new hole. Secure with a nut on the outside. I would use an O-ring to seal the inside surface, a nylon washer and some serious goop on the outside. You will be left with a male AN thread on the outside to connect with your new feed hose.

[Mike Simard]

I second Jerry on the Fram filter, I was going to use one but changed my mind once I saw it, I have no confidence in it. If you're going to modify your tank, you could cut a big hole in it and use a fill plate from ATL or Fuel Safe. There are advantages aside from being able to use big supply and return fittings, you could then fit a surge tank in it or some foam. It would be nice to at least have some baffeling if you didn't use a proper surge tank but if you're using a mechanical pump and carb, fuel starvation isn't nearly the threat it would be if you had fuel injection. You could also order a custom fuel cell, ATL or Fuel Safe has probably already done some for ERA's and I would guess about $1500 or so. If you go with a fuel cell, call ATL and give them dimensions, then place the order thru a dealer, I used Racecar Engineering, it was easy but takes some weeks to make a custom. There's one aspect of a fuel supply that has benefits well beyond the biggest line, pump or filter. That's having a return line. With a return line you can use a pump that puts out 15 psi, the regulator (actully a relief valve) is always sending excess fuel back to the tank. Since fuel is always moving thru the lines, it's less likely to have have a problem pulling fuel from the tank during cornering and engine requirement changes. A good place to put the regulator is at the rear of a fuel log, that way fuel is always flowing thru the log. If you start making brackets for 2 -8 lines side by side, remember to leave enough space to fit a wrench. I used -8 metal lines along the bottom of my car mounted to brackets cut from aluminum angle stock. Let me know if you want pictures and I'll put some in my gallery.

[speed220mph]

My 575 hp big block doesn't have any problem sucking gas from the unmodified fuel tank with the mechanical pump. I would say check it out first. Remember, "If it ain't broke, don't fix it."

[ack fia]

While you are at it, you may want to put a fuel shut off valve as close to the tank as you can. It would be ideal to have the shut off accessable to the driver.
If you have a filter it makes the changing lots easier.

[HSSS427]

Thanks for all the input.

So, what filter would you guys recommend? The tech guy at Clay Smith was pretty confident in the Fram filter. Also, what's defined as "under pressure"? If it's installed before the fuel pump is it still under pressure that would cause a leak?

Mike, would love to see some pictures of your setup.

My approach right now is to deal with the fuel pump to carb first and see how that works before dealing with the fuel tank to pump.
Thanks!
Scott

[Mike Simard]

Scott, I was just under my car wiring the alternator directly to the battery and took some pics of the fuel lines and filter, they're in my gallery. I ran -8 aluminum lines along the inside of the frame rails, the rails are 4" tall. The aluminum brackets holds bulkhead fittings. If you need more info or part numbers let me know. BTW, it sounds nice that your tank has flap door traps, that's the way to go.

[HSSS427]

Thanks Mike,
Couple of questions:
1. What kind of filter is that with the cooling fins? Looks expensive

2. Is the ATL fuel cell shaped to fit a cobra or is it a standard square shaped tank that you fit in to the car? They advertise that they make a tank that will fit an ERA but I sure have a hard time getting any response out of them when I inquire about it.

3. What type of pump do you have and what type of bypass?

Thanks!
Scott

[strictlypersonl]

ATL and Fuel Safe will make a custom tank to your specs. They do not stock "shaped" cells. Our tank is 4.5" deep at the back and 8" deep at the front. I haven't found any standard tank that would replace it and still have adequate ground clearance.

[Mike Simard]

Scott, the filter is a Professional Products #10300. It uses the same replacable element as the Fram but the body is higher quality. I like the finned body because my fuel circulates constantly and some cooling is good. It has 3/8 NPT holes, look on page 21:http://www.professional-products.com...alproducts.pdf. I bought mine from Lawrenceville Auto parts for $45, they have one in stock as well as alot of fittings, their# is 770-963-2491 and Jeff is the best guy to talk to.
Aside from the filter and lines, there might not be more on my car that would interest you. I use a Walbro pump mounted inside a surge tank in the fuel cell. The surge tank is a box with 3 flap doors mounted at the rear of the cell, it's more critical on a fuel injected car that the pressure never fall whereas a mechanical pump and carb are more tolerant. For fuel cells, there are only 2 companies that make proper cells, ATL and Fuel Safe. I gave up on Fuel Safe after leaving voicemails that were never returned, I don't know what the deal is with companies that don't return sales calls. Anyway, after much fretting over whether to have my cell slope or be square, I went with square because the fuel pickup wants to be at the rear. I used a SU117 which is 17.5 x 7 x 32, it's modified to have the fill plate in the center so it was actually a custom but with a steel body. Customs are generally done in aluminum. I have reservations about mine just because it looks hideous with a big red box jutting out from a green car. I would recommend a fuel cell on your car given it's probable use. The thing that bothered me most about the SPF tank was the fill hose came into the bottom outside of the tank and was exposed to possible damage from an off road excursion, if that hose was breached, all the fuel would come out, scary to think about.

[HSSS427]

Thanks Mike - Been exchanging emails with ATL today to see what a fuel cell will cost that is the same size and shape as the ERA tank. I'll take a look at that filter.
Thx
Scott

[Richard Hudgins]

Scott,

At full output of your engine you are going to need 39 gpm.

Why would you buy anything outside of that parameter?

Note: 566hp X .45 lbs per HP = 254.7 lbs of fuel per hour.

254.7 lbs divided by 6.5 lbs (Premium) = 39.18 gpm.

When are you folks going to stop listening to the hype?

Holley and Barry Grant make money selling these pumps that no one here needs.

NASCAR NEXTEL cars run a standard mechanical pump that delivers 38GPM.

Does your 566 hp COBRA suck in more fuel than a 875hp Cup car?

[decooney]

Maybe its because complicated solutions to basic problems are more interesting

I'm still trying to figure out why my basic Carter mechanical fuel pump keeps working and I still don't have to replace it. This really has me stumped.

[HSSS427]

.... was the excerpt below from Don Gould's Demon Carburetor Tuning guide:

There lot's of thing's that determine fuel requirements, there’s some redundancy here but let’s review and let's analyze the whole system:
>>
1. You have a 1/2 line, that's very good, but what size are the inlets and outlets on your pump? The answer of course is 3/8" so your pump will only flow at the rate allowed by the smallest orifice in the system, remember electric pumps are gravity fed so although the outlet side will flow more volume due to the pressure the inlet which is gravity fed is the limiting factor. >>
>>
2. Let's use a 12 second flat car for an example. I would think we could all agree that this car would burn about 1/2 gallon of fuel to make a 1/4 mile pass. So if we do the simple math to determine GPH (Gallons Per Hour) 1/2 gallon x 5 (60 secs. / 12 sec pass = 5)= 2.5 gallons per minute x 60 minutes = 150 Gallons per hour, far beyond the capacity of a Holley Blue or most mechanical pumps.>>
>>
3. So we've determined how much fuel we need to make a pass and the capacity of the pump required. But what about the gear ratio in 1st of about 2.50:1? Does this have any affect? Of course, we all know from experience that a car will use way more fuel at 30 MPH in 1st than it will in at 30 MPH high gear so we need to make allowances for the huge consumption rate in 1st and 2nd gear. Some of this is built into a Demon with the larger float bowls creating a built in reserve, but if the pump can't keep up the floats will drop and the carb will not be able to maintain a flat fuel curve as demand increases. Do you think that maybe 20% more fuel would be a fair number to use? So we're now up to 150 + 20%= 180 GPH.>>
>>
4. Let's not forget G forces, does your fuel line run from the cell straight up the carb taking the shortest route possible? By running the fuel line in this manner you further complicate the G forces working against the pump, all the fuel in the line is pushing back against that pump and in extreme cases can actually stall the pump (Remember the main feed line from the tank to the pump (Gravity fed) it's going in the opposite direction also starving the pump of adequate supply)>>
>>
The correct way to plumb a car for optimum fuel delivery would be to have the main line come all the way to the front of the car, we run them through the radiator core support, a big 180* loop and back to the regulator. Now when the car launches G forces drive the fuel to the regulator giving it a supply while the pump recovers from the G forces of the launch. So if your running your lines in what is probably not the best location then I think a 10% increase in pump capacity should now be factored into the equation....180 + 10%= 200 GPH>>
>>

So how's your fuel system holding up so far?>>

>>
5. I'll bet you have your regulator mounted to the engine or chassis right? Another No-No....as the engine starts to wind up and the car builds speed that regulator is getting the ever loving ***** rattled out of it. In allot of cases so violently that the spring can't hold the ball on the seat so it releases fuel and can overflow the float bowls. You've all seen this at the track...a car gets about 300' out and it starts leaving a black haze behind it.>>
>>
6. Feeding the carb from the regulator is another consideration, if you running a dual feed line that uses a T and splits off to feed the bowls your probably OK to about 350-400 HP with a Mechanical Pump. After that, we recommend you consider an Electric Pump and 2 port regulator and supply each bowl with a -6 line from the 2 available ports on a good regulator like the BG 2 port or Aerospace 2 port. These lines need to be as short as possible we use a 7.5" line with a 45* on one end and a straight on the other with the either 2 port it works perfect. Too large of lines or too long of lines will cause the regulator to respond slowly as there's more fuel volume to drop in pressure and more volume to fill to get back to full pressure.>>

And, yes it's a hobby, and like any good hobby you have to spend money on shiny new toys that relate don't have that big an impact in the end ie do you really need that new driver with a head the size of a football when you play one round a month and can't break a 100? Absolutely!!

[strictlypersonl]

Originally Posted by HSSS427

.... 1. You have a 1/2 line, that's very good, but what size are the inlets and outlets on your pump? The answer of course is 3/8" so your pump will only flow at the rate allowed by the smallest orifice in the system, remember electric pumps are gravity fed so although the outlet side will flow more volume due to the pressure the inlet which is gravity fed is the limiting factor....

Ummm, not correct. Pressure drop is determined by the sum of all the restrictions. A single 3/8 orifice may be equivalent to 3 feet of 1/2" tube but it is not the limiting factor to flow.

I also suspect that their fuel consumption estimate is not very accurate.

[Mike Simard]

I conservativey calculated approximately.1 gallons used for 12 seconds full throttle on a 600hp car with 50 lb injectors.