FB + AWDDSM

Need some suggestions for new pumps.

Going with a Weber 48 DCO (E or /SP) so fuel is definatly needed .

mar3

iTrader: (8)

Mallory Comp70 if it's only a little thirstier than stock...Mallory Comp110 if it's really thirsty but isn't a race engine...self regulates at around 7 PSI....Mallory Comp140 if it won't spend any time below 7000 RPM but this will require a regulator. These are gerotor style pumps which means no pulsation of the fuel supply, just solid volume and pressure to the carbs.

Pele

iTrader: (28)

gerotor? There's other types of fuel pumps? I always thought they were all the same as the windshied washer pump. Centrifugal pumps with an impeller and all.

What's available? What is the Carter 7lb pump? (Pump type) What's the stock?

How do they work? Which is best for what application?

mar3

iTrader: (8)

A gerotor style pump utilizes two close-tolerance gears to build pressure. Think roots-supercharger only straight cut lobes. I've only seen the Carter in catalogs so I can't say what style that type of fuel pump that would be. The advantage of gerotor type pumps is such that Holley eventually was forced to make a copy-cat version in addition to their regular "blue" pump which had been a mainstay of racers for years. Everybody's on the bandwagon now but Mallory is still the most reasonably priced and field rebuildable if I remember right...

Pele

iTrader: (28)

What other kinds are there?

I know of the pluger one.

Taking a shot at that one, it's got check valves and a piston, right? Is that what the stocker is? I'd imagine so cause you all talk about it clicking. (I never heard it.)

mar3

iTrader: (8)

Think of a 3 leaf clover rotating. Now imagine another one rotating so that its petals mesh with the other one without ever actually touching each other. The space just outside of the petals meshing is the input and output of the pump. The space between the petals decreases as you follow the movement of one petal and that space differential creates the fuel pump pressure or "vaccum" depending on which side of the rotation you're looking at. There are no pistons in a gerotor pump. I'll do a drawing tonight or dig out one my Mallorys that has the exploded view of the pump. Other good pump mfgs are Granatelli, Aeromotive and SLP. Again, Ive never used or got literature on these other pumps, so I don't know what style they are.

Felix Wankel

The oil pump on a rotary is a gerotor type. You can look at those (if there are pics anywhere) to see how they work.

Pele

iTrader: (28)

I saw one off of an 86-88 type (Mechanical). Its a 5 point star rotating in a 6 point hole.

I was talking about stock pumps when I meant the plunger type. I know gerotor isn't the only type of pump.

By the first defenition of gerotor, I thought there were two things similar to gears that mesh together, bot not exactly touch. The oil sits between em.

mar3

iTrader: (8)

Exactly right. Gears can be wafer thin or they can be two feet thick like some mega diesel oil pumps. What matters is the space or volume outside of where the gears start to come together and the final clearances between the gears. Since a liquid won't compress, you're not looking at compression efficiency so much as the total amount of liquid "gulped" each time the gears mesh their lobes to spit out the precious juice on the other side. I'll skip on the diagrams since you did understand what I was trying to verbally paint into your mind's eye...

Pele

iTrader: (28)

I was wondering if there were other types of fuel pumps available other than gerotor. If so, what works best for what application? IE Carb, FI, etc.

Someone mentioned a plunger type fuel pump one time. I only remember the context vaguely though. It was before the hack. The thread had something to do with upgrading from stock to the carter 7lb and a non Nikki carb.