Fuel Pump Thoughts...

[engine24355]

As some of you know, I have been fighting a fuel pressure gremlin for weeks now. As I have been working through this pressure issue, I have been thinking about electric vs. mechanical pumps and would like your thoughts. I like electrical for some reasons, but it seems mechanical is more efficient and consistent. What are your thoughts?

 

[RPM]

I run 1 of each. A Holley Blue pump in the back pushing and a Holley mechanical on the motor. Then the regulator before the carbs.

 

[FOX FABRICATION]

I have to run an electric own my current project due to I use MOTOR PLATES and no room to run a mechanical pump off the block....so I run an electric....Would have perfered a nice "performance" mechanical one...but just would not fit..

My next couple projects (buckets) will be mechanical fuel pumps.

I found thru the years of building many projects...we all get stuck in the "GOTTA HAVE RACE PARTS" on our builds.....sometimes the simple way the factory did it is more than what we need...but they sure do look cool!

Sometimes "DESIGN and PLACEMENT" of certain components on our projects may justify the use of an electric pump.....but I bet 9 out of 10 "STREET" cars would function just fine with the proper mechanical pump on their engine.

 

[Screaming Metal]

Engine.....whichever way you go, just remember this......a electric CAN push fuel thru a mechanical pump......but a mechanical cannot PULL fuel thru a electric...........

 

[engine24355]

[quote name='Screamin' Metal']Engine.....whichever way you go, just remember this......a electric CAN push fuel thru a mechanical pump......but a mechanical cannot PULL fuel thru a electric...........[/quote]


Thanks for the information Screamin.

 

[RPM]

[quote name='Screamin' Metal']Engine.....whichever way you go, just remember this......a electric CAN push fuel thru a mechanical pump......but a mechanical cannot PULL fuel thru a electric...........[/quote]

Oh but it will, I hardly ever run the electric pump. The mechanical pump does just fine for just cruising up and down the roads. Now it won't maintain good pressure if I run it hard, fuel pressure will drop. That is when I use the electric to run it hard. I don't want it to lean out.

 

[Hotrod46]

I like electric pumps on my "toys", because they don't get driven as often as I would like. My poor old 46 sits way too long between drivings, especially since my T has been on the road. New formulations of gas seem to evaporate faster than the old stuff did.

It's nice to be able to prime the carbs before starting. Saves a lot of grinding. It's surprising how much priming it takes to "top off" the float bowls in my T, even if it only sits for a week. You learn real quick not to get "heavy footed" on pumping a 3x2 setup. They can flood in a heartbeat if you're not careful (6 barrel, mechanical secondary triple-pumper!!).

Also. changing a mechanical fuel pump on my 46 would be a bear on the side of the road or in a parking lot. The electric Holley is right in back on the rear crossmember, easy to get to. This wouldn't be a problem on most T's, though.

In the past (way back before EFI took over), I used mechanical pumps on my daily drivers.

Mike

 

[engine24355]

Thanks for the information guys. I picked up a Holley red earlier in the week and plan to try it out this evening. I have always liked electric pumps for the main advantage Hotrod46 mentioned. I will try this one last electric and if no luck, it will be mechanical time. That said, I would like some examples of how you mounted your electric fuel pump. Currently I have a carter bracket (top only) welded to the right frame rail just before the kick up. Hence the reason I kept trying to make Carters work. Since I have changed over to Holley (or at least trying) I need to figure out if I should cut the old bracket off or just mount the Holley another place. Ideally, I think where the Carter was mounted was the best place as it was close to the tank and low so it got good fuel feed. However, I may have to try another Carter or similar type pump in the future and it would be nice to just bolt it up. Just thinking out loud here guys. Send some pics of your mounting expertise.

Thanks!

 

[Screaming Metal]

Oh but it will, I hardly ever run the electric pump. The mechanical pump does just fine for just cruising up and down the roads. Now it won't maintain good pressure if I run it hard, fuel pressure will drop. That is when I use the electric to run it hard. I don't want it to lean out.

Let me rephrase that statement I made...........UNDER Most Conditions, A manual fuel pump won't pull thru a pulsed type fuel pump, but will pull thru a rotaryvane pump. It will still allow fuel flow past.......but, enough for what you want?????? Maybe, maybe not, depends on what your doing......like what RPM says......If ya got a blown double carbed engine that won't tolerate anything below5.0 PSI without falling on its face.....I'd say no.........you can read between the lines here I hope............

If you gonna run both, match them close to the same flows, etc. I've been building race stuff for well over 25 years, and alot of folks forget about fluid dynamics and the physical laws that apply to that science................they pull all the thought into traction, the engine, the suspension, the trans, and the fuel system......they put a big pump on there with a filter and call it good, then call me when when the engine leans out mid track and oils everthing down within about a 200 yard radius............

On the street, it isn't critical, unless your at really high altitudes, then things change slightly...............
Under most circumstances....a stock pump is plenty. A stock mech. pump with a elect.booster, great.................

ME? I don't like mech. fuel pumps......there's a metal arm rubbing on a dawm cam lobe in there rubbing.........no roller, OR, a metal pushrod riding on a camlobe pushing on that metal arm.................they're mounted down there by the exhaust where they can be nice and toasty on those 100 Degree days when your trying to cruz, getting even more heat thrown to em, hey, whats not to like.........

they're durable, they're great, they're fine and they work, mostly trouble free, are a great asset to the human race.................but I don't like them...........just my preference on the matter..........I'll take a crank driven pump anyday!.......:lol::lol::lol:

Gotta go......a big Tractor with about 4 or5 motors on it needs someone that can do the blower belt boogie.......its sick and running a fever.......and I gotta go catch a plane.............I'm outta here.............