Fuel Cell and Safety

Richard Broadhead

Richard Broadhead

Flag & Com
It happened this weekend and has had an extensive thread on Apexspeed about the 'need'.

When we first went through Jeff's FC preparing it for the track, I was rather surprised to find the cell breather routed UP into the roll bar shroud with NO one way check valve in it.

As I recall as far back as the earyl 60's the fuel tank or cell breather was required to have a check valve in it. Somewhere along the decades of racing, this requirement seems to have been overlooked or 'assumed' to be installed. But we see many, many cars today without this item or vent lines routed in such a way as to expose the driver to fuel spillage in a roll over situation.

It happened this weekend with the FF roll over. NO check valve and fuel flowed out of the breather line puddling under the driver. Fortunately, no source of ignition was present and the E-crew extracted him safely.

I encourage everyone to check for or INSTALL these one way valves in your breather lines. They are a CHEAP safety feature and very worth while. In addition, route your vent lines to take any spillage prior to the ball valve closing away from your cockpit area.

Per the SCCA GCR:

GCR 9.26.3 (9.3.27 second paragraph:)

blah, blah, blah..... and do not use an unchecked breather opening.


On the cheap side it's a $15 investment

http://www.pegasusautoracing.com/productdetails.asp?RecID=899

If your all AN stuff it's $40

http://www.pegasusautoracing.com/productdetails.asp?RecID=5568

And if you're in to a high dollar 'fix' it's $123

http://www.pegasusautoracing.com/productdetails.asp?RecID=5284

Yes, we went the cheap route and took the hose WAY back away from the cockpit.
 
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Wow.

Thanks for noticing, Rich.

I don't even like to think about roll-over fires. We've all seen the short track roundy-round version (every 4th lap) of that, especially with open wheel midget, sprint, and outlaw classes, and it looks like no fun at all.
 
A word on fuel cells. Over the course of this season I have been behind two cars that were leaking noticeable amounts of fuel during hard cornering (e.g., one did it consistently in T6 at PIR). In both cases, these cars had fuel cells. These were the only cars that I saw lose fuel on track. What's going on here?
 
Mike,

What kind of cars?

On open wheelers with fuel bladders or sedans with hard 'cells'? It could be from what I described above due to two things.

1.
NO check valve in the breather line with a FULL fuel cell like an ATL or other hard cased cell.
2.
When the driver sits in an open wheel car (with a really full bladder) the panel behind his back compresses the bladder and may eject some fuel out the breather.

As a worker, we OFTEN see fuel leakage on the first few laps. 99% of the time it's from a loose fuel filler cap or, a missing cap. We'll, usually, NOT give a mechanical flag for for this unless it lasts for a considerable amount of time (like 5 laps or more). On the other hand, if it's REALLY pouring out, then we'll meat-ball quick.

The reasoning is, fuel isn't real slippery like oil so it's not 'too much' of a hazard to the cars behind and it does usually stop. But if it's really bad or continues we become concerned for the safety of that driver and his car.
 
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If it was me, or another old stock car, it's because of a very full fuel cell, and the way the rollover protection is designed.

The fill plate on a typical stock car has a 2-1/4" or 2-1/2" filler neck, and a 1", 1-1/4" or 1-1/2" vent connection. On both of these, the rollover protection consists of a large steel ball hanging in a cage on the inside of the cell, for both the fill and vent part. The ball in the fill part for instance must be almost 3" in diameter, and probably weighs 5lbs. The system is designed to flow lots and lots of fuel and air in a pit stop, something on the order of 2-3 gallons per second.

So, it's an open system until the car is inverted, and then the heavy steel balls roll into place to cover the fill and vent openings. As we scrub tires with a full fuel load, the gas sloshes around and burps out the vent.

Here's a pic to illustrate; http://cgi.ebay.com/ebaymotors/NASC...a9eQQitemZ180405009054QQptZRaceQ5fCarQ5fParts
 
and an anti- spill system ('discriminator valve' etc)
in the breather works the same way, it's just a LOT smaller.

If I filled mine to the gills, it used to squirt a bit for about 5 laps.
Then I got smart(ish) and routed the hose UP from the cell a couple of feet
at first, THEN out the side AWAY from the exhaust (thanks Dave B)
That cured it.
On the few weekends it ran.

t
 
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