So our chump car has suffered fuel starvation issues from nearly day one. It's an '86 Escort, originally a 1.9L carbureted car, now a turbo 2.0L Zetec powered car. We had the stock carb tank with a pick up and external fuel pump, and it starved badly under 3/4 tank. My suggestion was to get a stock EFI tank ('87-'90 Escort) and use the stock pickup with a high flow pump, but my team likes to do thing the hard way. We've now got a fuel cell, and the plan is to use an internal pump that will feed an external high pressure pump. I've got a nice VW MKII pump with the accumulator and built in surge tank that I think will reduce starvation a bunch by itself, but I want to make sure the feeder pump starves as little as possible. So the pump will pretty much be straight down from the lid piece, and I thought about making a wall around it with aluminum and putting a couple trap doors in it, but I also just thought about filling it with foam. What would you suggest?
16vCorey wrote:
So our chump car has suffered fuel starvation issues from nearly day one. It's an '86 Escort, originally a 1.9L carbureted car, now a turbo 2.0L Zetec powered car. We had the stock carb tank with a pick up and external fuel pump, and it starved badly under 3/4 tank. My suggestion was to get a stock EFI tank ('87-'90 Escort) and use the stock pickup with a high flow pump, but my team likes to do thing the hard way. We've now got a fuel cell, and the plan is to use an internal pump that will feed an external high pressure pump. I've got a nice VW MKII pump with the accumulator and built in surge tank that I think will reduce starvation a bunch by itself, but I want to make sure the feeder pump starves as little as possible. So the pump will pretty much be straight down from the lid piece, and I thought about making a wall around it with aluminum and putting a couple trap doors in it, but I also just thought about filling it with foam. What would you suggest?
We used a foam filled one like the drag racers use (from a drag car) and it worked fabulously.
Ours is something like this, but not as deep.
It did not come with foam in it, and I've heard horror stories about the foam breaking up and clogging everything. Is there a preferred foam to use? I don't want to do this again. I'd also really like to complete the 24 hour race without incident.
16vCorey wrote:
Ours is something like this, but not as deep.
It did not come with foam in it, and I've heard horror stories about the foam breaking up and clogging everything. Is there a preferred foam to use? I don't want to do this again. I'd also really like to complete the 24 hour race without incident.
This foam came stock with the tank. I am pretty sure it's fine, my Dad's cars sit with race gas in them for weeks between races sometimes and it doesn't break up at all, ours (for Lemons) has had gas in it all of the time for years and it's fine. Call RCI or some other normal fuel cell maker and see if they'll sell you some foam.
Speedway sell the foam. Most racers replace it every year...it's cheap.
ncjay
Reader
4/19/11 8:08 p.m.
I've had a fuel cell with the same foam in it for over 15 years, but I don't use race fuel in it, just regular street fuel. I don't see the need for two fuel pumps. One good fuel pump should be more than enough. Just make sure the fuel pressure is where the system needs it to be. No sense having 70 psi if the system was designed to run at 30 psi. With two fuel pumps, one will just be extra weight and in the way. It sounds like the original tank wasn't vented properly. As the fuel runs out, it creates a vauum and the pump doesn't work as well. Proper ventilation is a necessity for a fuel tank. I've even seen people put a non vented fuel cap on a tank designed to run a vented cap and create similar problems.
44Dwarf wrote:
Speedway sell the foam. Most racers replace it every year...it's cheap.
The plastic tanks are not disassembleable, so you can't get the foam out.
Bull E36 M3. Stick your hand in the hole and pull it out.
Ya it's not fun and the cap ring digs in your hands but it comes out.
These guys just started advertising in GRM:
http://www.intengineering.com/Fueling/Surge-Tanks/sc458226-1-2/
Among other things they make surge tanks to alleviate fuel starvation. Their products may push your LeMons budget, but checking out how they do it may give you an idea or two.
Super nice guys too. You may want to call them to pick their brains. Let them know you are a GRM reader for extra style points!
The foam sold for fuel cells will last years before it needs to be replaced. I have heard that 10 years is about the most you can expect.
As for the number of fuel pumps: A low pressure pump to feed the high pressure pump is the way to go. VW uses that method on the Mk I & Mk II cars. The low pressure inside the fuel cell or below it if external.
The foam will slow the movement of the fuel inside the cell but not eliminate it.
A sump like you described is what is used in some fuel cells. I had one come stock in the Fuel Safe cell I used on my Mustang. It was a direct replacememt for the OEM tank.
44Dwarf wrote:
Speedway sell the foam. Most racers replace it every year...it's cheap.
It's not THAT cheap. Our tank is 24"x18"x11" so I'll need 14 pieces to completely fill it, at $8 a piece that's $112 plus shipping. Although I definitely appreciate the tip! Speedway is the cheapest so far!
I know in the volvo they also used a dual pump system... but I think that was more of a practicality thing due to fuel pump technology at the time... the stock in tank pump is a high volume low pressure and the inline pump is a high pressure pump... but flows about 1/2 the volume (at least on the volvo)
I think they did that largely because of finding a pump back in the 70's/early 80's that flowed enough and had enough working pressure was a problem...
then again I suppose the fuel filter/fuel line does act as a very small surge tank...
