SW 240A Fuel Pumps

[601HP]

Here's a diagram Hi-Tech provided for the tank and pumps plumbing.

David

[dcdoug]

Originally Posted by computerworks

They were plumbed as a secondary pump set up from a pickup lower in the tank.

The mechanical draws fuel from a higher point; the 240's are normally off during normal operation.

The purpose was, when the tank ran low and the mechanical pump starved, the racer could throw a toggle on the dash to turn on the electrics and make it back to the pits.

The plate that has the fittings on the fuel tank would have two fittings, with one drawing fuel lower than the other.

For what it's worth, CSX6022 came set-up exactly like this. There are parallel lines with a T-fitting on the outflow side of the mechanical pump. The mechanical pickup is lower than the pickup for the twin electrics. They are off during normal driving and even at WOT I have never had a fuel starvation issue on just the mechanical.

It works exactly as designed, by the way. Given the inaccuracy of my fuel level gauge, I ran out of gas once. Sat there for a minute pissed at myself and then remembered the story of why racers had it set up this way, flipped the switch to turn on the electrics, fired back up and drove to the nearest gas station.

[FatBoy]

Originally Posted by 1985 CCX

That's one of the pictures I was referring to.

[Bernica]

Here you go. This is CSX4250, unmolested or altered....

[FatBoy]

Originally Posted by Bernica

Here you go. This is CSX4250, unmolested or altered....

That doesn't count I'm afraid, we need CSX30** serial number cars.

[rsk289]

Originally Posted by Bernica

Here you go. This is CSX4250, unmolested or altered....

Interesting. Bye, SW - step forward, Facet!

[FatBoy]

Originally Posted by rsk289

Interesting. Bye, SW - step forward, Facet!

Yes, but the SW 240A pumps were no longer available when the 4000 series cars were produced, so an alternative was required.

[FatBoy]

Okay, I sent an email to Mike McCluskey and he replied straight back with the following:

Paul;
All the Comp.s and SC's had the 42gal. alloy gas tanks from AC Cars. It was a baffled sump with two pick-up tubes. A main and reserve. The electric pumps were only hooked up to the reserve pick-up tube and then ran up the chassis along with the main fuel supply hose to the engine mechanical pump which all the engines had. It tee'd into the output port on the Carter or AC engine fuel pump. It was primarily a system to get back to the pits when you started to run dry on the main circuit, not to boost performance or flow.
Mike

Does anyone know if there is a "reserve" pickup on the standard Kirkham fuel tank?

Paul

[computerworks]

Originally Posted by FatBoy

Okay, I sent an email to Mike McCluskey and he replied straight back with the following:

Paul;
All the Comp.s and SC's had the 42gal. alloy gas tanks from AC Cars. It was a baffled sump with two pick-up tubes. A main and reserve. The electric pumps were only hooked up to the reserve pick-up tube and then ran up the chassis along with the main fuel supply hose to the engine mechanical pump which all the engines had. It tee'd into the output port on the Carter or AC engine fuel pump. It was primarily a system to get back to the pits when you started to run dry on the main circuit, not to boost performance or flow.
Mike

Where have I heard that before?

[FatBoy]

Yes, I know. I could already hear the "I told you so" coming.

Paul

[computerworks]

..............

[Mongoose930]

Hi Paul,

Thanks for your diligence in going to reputable source to get these details. Mickmate will be installing my 42 gallon Comp tank over the next few weeks which was originally a Mike McCluskey fuel cell that Mickmate converted to baffled tank for me. It came with two pick-ups that were clearly marked “Main” & “Reserve” and the reserve pickup was lower in the tank.

[ERA Chas]

Interesting discussion. I wondered further; with gas at ~6.2 pounds per gallon (ambient temp. dependent), a full 42 gallon tank puts 260+ pounds behind the rear axle.
Think OVERSTEER.

Then consider the change in handling as the load burns off. Put this on 8.5" wide F'stones or G'years of the day and Bondo, Miles, Gurney et al look like genuine he-men to wrestle that. Especially like in the Targa or other endurance races.

#3170-Bruce, can you give some insight?

[FatBoy]

Okay, another update.

I've just had a reply from Thomas Kirkham. Their standard tanks are fitted with dual pickups. By default, the lower pickup is connected and the upper pickup is blanked off, which can be used as a return feed if fuel injection is used. However, if the fuel pipe is connected to the blanked off connection and the free connection is then connected to an electric pump, you have a reserve fuel capacity at the throw of a switch.

Paul

[rsk289]

Originally Posted by ERA Chas

... with gas at ~6.2 pounds per gallon...

Do you know, when I first read that, I assumed you were in the UK - but of course you don't mean 6.2 pounds per gallon, as in £6.2 per gallon. Which is pretty much exactly what we pay, $9.50.
Sorry - as you were...

[ERA Chas]

I used to buy race gas for $7.50 US per gallon-you poor guys are getting killed at the pump...

[FatBoy]

Another update from Mike McCluskey. Both pumps ran together rather than separately, although he did say that a BBF would run on a single pump.

Paul

[601HP]

Originally Posted by FatBoy

Another update from Mike McCluskey. Both pumps ran together rather than separately, although he did say that a BBF would run on a single pump.

Paul

Dang it! Now I've gotta re-plumb the trunk.

Not!

David

[mickmate]

David interesting to note your drawing shows a street tank albeit with a cell flange on top. That also shows a single line to the front as in street cars.
Hey Ron shall we sing together in two part harmony ;-)

[computerworks]

Originally Posted by mickmate

Hey Ron shall we sing together in two part harmony ;-)

Always....