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MG Midget and Sprite Technical - Fuel pump query

I have measured the output of my SU fuel pump over exactly 1 minute. It pumped almost exactly 1 pint or 0.6 litres. Is that OK?

I have no other measuring equipment other than a stop watch and a glass measuring jug (don't tell my wife!).
Chris H (1970 Midget 1275)

Hi Chris,

the SU pump used on the 1275 (AUF 300/305) was rated for 18 US gal/hour (68.2 Liters/hr), at 2.8 ~ 3.8 psi. (0.2 ~ 0.27 kg/m2).

So, 0.6 liters / min = 36 liters / hr, it sounds like yours is not keeping up.

You might want to re-test it again, just in case of measurement error, and your target will be 1.1 ~ 1.2 Liters/min (68.2/60).

Norm
Norm Kerr

The OEM SU pump for the midget is the AUF 214, which pumps 8.4 GPH or 1.1 PPM. The AUF 300/AZX 1300 series pumps were an alternate pump and as Norm states provide 18 GPH or 2.4 PPM. See the chart, SU Fuel Pump Specs in the SU Fuel Pump Articles section of my web site at: http://homepages.donobi.net/sufuelpumps/ for pictures of the two pumps. If you have the AUF 214 pump, then it is working fine. If you have the AUF 300/AZX 1300 series pump, you have a problem - however, since the pump is putting out the original OEM stated volume, it is a problem you should be able to live with. Cheers - Dave
David DuBois

Norm

The standard Midget pump is AUF214 which is rated at 8.4 (US) gal/hr, which is 31.79 l/hr or 6.99 Imp gal/hr, or 0.932 Imp pints/minute.

Sounds about right.
Dave O'Neill2

Darn it, David beat me to it...although I was using his website for the flow rates ;o)
Dave O'Neill2

Is 1 pint a minute adequate? Use your brains gentlemen. If the engine needed 1 pint of petrol a minute you would use a gallon in 8 minutes and empty a 6 gallon tank in 48 minutes. I rather hope your engine can do considerably better than that, so yes, 1 pint per minute is plenty.
Mike Howlett

Mike,
I agree with you and also believe that 1 pint per minute would be adequate. But the theory behind you sums is faulty. There are clearly times when the engine uses far more fuel than the average consumption that it achieves over a tankfull. For those brief periods when it is in "open throat gulp mode" otherwise known as "dentist chair mode" the pump may well need to deliver all of 1 pint per minute, or even more!
Guy

I've found (through other peoples unfortunate experiences) that the SU pump is the only way to go.. The Solid State pumps deliver too much fuel at too high pressure.. You can get all the spares for the SU pumps and I would guess that Chris' pump has a stiff diaphragm making it awkward to pump.

The Electronic version of the SU pump works well..

Mark.
M T Boldry

Mark

Chris's pump is delivering the correct amount of fuel.
Dave O'Neill2

I've got an electronic Q&H pump it works fine

MG Midget Electronic Fuel Pump - QH QFP171E / AUF21412v ELECTRIC METAL BODIED FUEL PUMP, MADE BY QUINTON HAZELL (QFP171E)

This pump delivers 9 gallons per hour and has a 2.5 - 3 PSI delivery pressure. It is equivalent to O.E. part number AUF214 and is an underbody fitment pump. The Pump is Suitable For The Following Vehicles -
MG Midget 1098cc Mk.2 1964-1966
MG Midget 1275cc Mk.3 1966-1974

Price: £48.75

other suppliers are available - I got mine elsewhere about the same price

http://www.classicparts4cars.co.uk/mg-midget-electronic-fuel-pump---qh-qfp171e--auf214-133-p.asp

ETA: venting not required on this replacement pump
N Atkins

I've got the same pump as Nigel. It replaced a cheapo one I bought off eBay which turned out to be next to useless and didn't last all that long. According to what I've heard on here, the Q.H. pump is German and has a very good reputation. So far, so good.

Bernie.
b higginson

Here's a question for you.

Can a +ve earth, SU AUF214 pump, be used on, or converted to, a -ve earth car?
Lawrence Slater

Lawrence - e-mail me at SUfuelpumps@donobi.net I can help you with converting a positive ground pump to negative ground. Cheers - Dave
David DuBois

Done, thanks David.
Lawrence Slater

From what I've just been reading, the QH pump is good, but spares are not available. So seems better to go for an SU even though it is slightly more money.

If they last the same time, then in x number of years, at least you can service/repair the SU, whereas the QH will be a throw away.

And if they fail prematurely, then again the SU can be fixed, and the QH then gets to have been an expensive purchase, as it is throw away.
Lawrence Slater

But if the Q.H. doesn't fail, you're quids in LOL. Decisions, Decisions.

Bernie.
b higginson

Yup true Bernie, I've rechecked the prices and the SU seems to be about 35 quid more.
Lawrence Slater

This thread was discussed between 17/11/2011 and 20/11/2011

MG Midget and Sprite Technical index

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