Fuel Pump Mechanical or Electric ?

[Pav 5]

Hey Guys as you know I've built a 347 Stroker with a 750 double pumper carb , I just wand opinions weather I should go Mechanical or Electric fuel pump, from what I understand the Mechanical is better suited because its a lower psi 4-6 , where as the electric runs the risk of flooding the carb and is better suited to efi unless i put a regulator on it , is this correct ?  It's getting dynoed over the next 3 weeks so then I'll know exactly what hp it will have .

 

Cheers Josh

[Pav 5]

For your viewing plesure here's a pic of my baby[attachment=1160:347

[NZXD 2,328]

I believe there's pro and cons for both. <br /><br />Personally I went with mechanical on my Windsor to keep it simple. <br /><br />Great looking engine, what is it going into?

[slydog 7,873]

A mechanical pump on a performance engine should have a reg too.How ever in most case alot of guys get away with it. Prime example Tony Spazenoski who won this year NAT ASP 6cyl dyno comp ran a mechanical pump on his 265 to supply his webbers. No biggey issue was that @ idle the carbs were copping 5 plus PSI of fuel pressure where as webbers want under 3PSI at most.

 

You could find a HV mechanical pump to push 7-8 PSI which is too much.So back to original question I base the answer on use v's HP.If a daily mechanical with dead head reg if a more performance weekend warrior Id use a electric and return reg set up.

 

P.S Dig the little Windsor and thread moved to Windsor section Interested to see how it goe's on the the dyno.

[Thom 6,650]

Definitely run a fuel pressure reg on either setup as fuel being pushed past the needle and seats can cause it's own tuning issues, mechanical v electronic fuel pumps basically comes down to how much you want to spend and can you put up with the noise of an electronic pump?

[wagoon 2,429]

Can't help with which is better but I'm using the weekend warrior setup Sly mentioned, its an electric fuel pump with fuel reg and a pressure relief valve with return to tank line between fuel pump and pressure reg. The relief is actually attached to the engine side of the fuel pump and sends fuel back to the tank once fuel pressure raises above relief valve pressure rating. Doing it this way I am told it saves the pump as apparently pumps die due to making excessive heat or something like that when they have to constantly use their internal reliefs.

This is the fuel pump and reg combo I'm using (they come together as one "kit")

 

here's a link to their website http://www.trickflow.com/parts/tfs-25013  One thing I don't understand is why it says its for drag racing applications only?

 

 

[hendrixhc 10,918]

I got a mechanical on my 351 clevo with a 750 and it works fine.

[ando76 4,354]

Provided the electric pump has an external relief, I would run it over a mechanical pump - all day every day. Why? Because a mechanical pump is a constant drag load on the camshaft as it runs off the fuel pump eccentric. It's method of operation also induces harmonics into the engine, something I try my hardest to eliminate, especially in a crossflow.

 

I have only recently swung around to this way of thinking and this has occurred for a couple of reasons.

 

1. Electric pump tech has come along way and most top line pumps now feature an external relief. What does this mean? It means a significant reduction in pump noise and extended pump life. Why? Because when there is no demand for fuel the excess goes out of the pump (thru the ext. relief) back to tank, instead of being relieved internally. When it is relieved internally it super heats and aerates the fuel. That is bad.

 

2. mechanical fuel pump induced harmonics.

 

3. Reduced load on the camshaft. Yes the fuel pump takes amps to drive, you don't get something for nothing, and there is more load on the alternator, but it's the lesser of to evils.

 

4. I've found a way to make even the cheapest pump relieve externally. The set up the Wagoon is talking about above is my cure.

 

Put simply we reg fuel to the carb at 6.5psi, but the pump is capable of pushing 14psi and wants to do that. When there is no demand the fuel pressure raises until such time as the pump reaches its internal relief setting (14psi) then the unused fuel goes around and around inside the pump.

When we fit the hydraulic check valve (1/2 bar or 7.5psi) between the outboard side of the pump and the regulator, it senses when the fuel pressure goes above the reg setting and returns the excess fuel to tank. Basically eliminating the chance of fuel ever going over the fuel pumps internal relief. In doing that we improve fuel quality and reduce pump noise.

I've used this system on streeters, drag cars, burnout cars and meth speedway cars without issue. Even used cheap shit eBay fuel pumps on methanol with this set up and got 2 years and counting out if the pumps. Take the load off them and they last a damn site longer.

 

So short answer, electric pump with external relief for the win.

[ESPSIX 143]

Got a name, or link for the pressure relief valve?

[slydog 7,873]

Got a name, or link for the pressure relief valve?

 

Go to your local Pirtek or who ever and ask for a - hydraulic check valve (1/2 bar or 7.5psi)

[ando76 4,354]

Yep, Rob's all over it.

[Pav 5]

I can get a  brand new holley blue with the regulator shipped from the USA for $195.00  https://www.holley.com/store/viewcart/ heres the link , any thoughts , they have a newer model but's its around the $320.00 mark heres the link , http://www.rocketind...#.VtvW0-anxjI,� any feed back on the comparison?

[ando76 4,354]

I found a proflow one with reg on eBay for $138 delivered from Victoria to cairns. 110gph. Looks the goods as well. I'll be fitting it with my check valve external relief.

[Pav 5]

Thanks for all the input guys I ended up going with a Holley Electric Gerotor 125 GPH  , I have a mate who has an XY and he fitted one to it and says it works a treat , some mods are needed to fit the existing tank but went with 1/2" aluminum pipe gonna P clamp it to the chazzie rail and 1/2" braided lines .