echappe
Well-Known Member
Can a fuel injection head be modified to use a mechanical fuel pump or is it easier to just install an electric fuel pump?
Thanks for your help
echappe
Thanks for your help
echappe
FI head with carburetors
- Thread starter echappe
- Start date
Later Heads
Generally yes. If it has the boss where the pump mounts. The second consideration is cam with provision for the pump.
If you're using the 78 head. Should be a piece of cake. Take the head to the machinist to drill out for the push rod and for the studs. Look at the head carefully or post a picture. I run an 81 head with mech. pump.
FYI- If you use a Motronic head (later FI) and want the distributer- you'll have to buy a conversion nut to drive it and use the old cam cover with the hole.
Electric pumps are pretty cheap now- $30-40. mechanical pumps are generally more now- low side $60 Ebay or a whole lot more from the usual sources.
It all depends on what you have to use at hand and how you want it to look.
If you don't have access to a machinist- electric will be cheaper.
Generally yes. If it has the boss where the pump mounts. The second consideration is cam with provision for the pump.
If you're using the 78 head. Should be a piece of cake. Take the head to the machinist to drill out for the push rod and for the studs. Look at the head carefully or post a picture. I run an 81 head with mech. pump.
FYI- If you use a Motronic head (later FI) and want the distributer- you'll have to buy a conversion nut to drive it and use the old cam cover with the hole.
Electric pumps are pretty cheap now- $30-40. mechanical pumps are generally more now- low side $60 Ebay or a whole lot more from the usual sources.
It all depends on what you have to use at hand and how you want it to look.
If you don't have access to a machinist- electric will be cheaper.
x_atlas0
Well-Known Member
Indeed, most people switch to the electric.
echappe
Well-Known Member
it does have a boss where the mechanical fuel pump would attach but there are no automotive machine shops near. Elestric sounds like the way to go.....now would it just go in the fuel line just upstream of the sending unit at the tank?
Electric pump
Location- near the tank is best. If you search this site there are very good recent pictures. Takes a little time, but pump will thank you for it as it has less to prime.
Second best- on the firewall by using one of the clips/ studs already there or by the wiper motor. (They actually used to mount them inside the firewall- don't do that!)
Some pumps are pushers than pullers. You want the puller type and for carbs. ( No more than 4-5 psi.) If you can spend the extra for a rotary- buy it. It's the same as the factory design and cools itself.( Mostly.) Probably about $60.
Don't buy the hot rod pumps though- you'll end up spending more on regulators, etc.
Location- near the tank is best. If you search this site there are very good recent pictures. Takes a little time, but pump will thank you for it as it has less to prime.
Second best- on the firewall by using one of the clips/ studs already there or by the wiper motor. (They actually used to mount them inside the firewall- don't do that!)
Some pumps are pushers than pullers. You want the puller type and for carbs. ( No more than 4-5 psi.) If you can spend the extra for a rotary- buy it. It's the same as the factory design and cools itself.( Mostly.) Probably about $60.
Don't buy the hot rod pumps though- you'll end up spending more on regulators, etc.
84E24
Well-Known Member
What electric pump would you use ?
My first elec. pump for my 3.0 with triple DCOE 40's was a AC Delco EP12S it pumped about 5 psi at 30 GPH. It was a pluse type, and quiet, it failed. I now have a Carter at 5 psi and 70/80 GPH. Redline/Webber recomends this pump without a regulator. So far it works but it is loud.
Has anyone used a in tank pump from a 85-86 E30 325e with a regulator and no return line?
What other electric pumps are being used ?
Steve
My first elec. pump for my 3.0 with triple DCOE 40's was a AC Delco EP12S it pumped about 5 psi at 30 GPH. It was a pluse type, and quiet, it failed. I now have a Carter at 5 psi and 70/80 GPH. Redline/Webber recomends this pump without a regulator. So far it works but it is loud.
Has anyone used a in tank pump from a 85-86 E30 325e with a regulator and no return line?
What other electric pumps are being used ?
Steve
x_atlas0
Well-Known Member
I'd be concerned about running a FI-based pump without some manner of adjustable pressure regulator, as the FI systems typically operate around 3 bar (~45 psi) compared to the very low pressures of carb systems.
Pumps
Steve,
Your Carter is known for noise. A rotory pump would be the type pump which BMW used then and still today. Even Carter professes it's quieter. They've recently come down in price and available just about anywhere.
I would aslo suggest that anyone who has or recently had a pump failure amp the circuit. It should not draw more than 1.5 amps. Since it's just a dc motor, I can readily see how many could chase down issues unrelated if the pump hasn't failed completely.
Steve,
Your Carter is known for noise. A rotory pump would be the type pump which BMW used then and still today. Even Carter professes it's quieter. They've recently come down in price and available just about anywhere.
I would aslo suggest that anyone who has or recently had a pump failure amp the circuit. It should not draw more than 1.5 amps. Since it's just a dc motor, I can readily see how many could chase down issues unrelated if the pump hasn't failed completely.
84E24
Well-Known Member
Would you have a model or part number for those pumps ?
Steve
Steve
Rotory pump
Steve,
Summit has them but only shows one- 4psi, 72GPH, 3/8ths. I know others have them now- bg shows them in the catalog, which is the normal replacement available at the auto parts. ( O'Reilly by me.) Carter has a slightly different spin on what they call it. You can see from the picture below what the design looks like. It's not a pulse type pump which is fine for two carbs; not your triples. Check out the repair manual for the FI and you'll see the fuel passes around the outside of the case.
Carter Carotor design
Carter Carotor universal pump applications range from carburetor to TBI & MFI systems. They are also used in many OE-type hanger and module assemblies. The gerotor is unquestionably the most versatile pump design today. It utilizes a unique gear and rotor eccentric mechanism that squeezes the fuel within the pump to create high pressure with very little pulsation. Compact, lightweight and fuel-cooled, it is a current favorite of many OE manufacturers. EFI marine manufacturers are also installing these robust gerotors to meet their fuel delivery demands.
Steve,
Summit has them but only shows one- 4psi, 72GPH, 3/8ths. I know others have them now- bg shows them in the catalog, which is the normal replacement available at the auto parts. ( O'Reilly by me.) Carter has a slightly different spin on what they call it. You can see from the picture below what the design looks like. It's not a pulse type pump which is fine for two carbs; not your triples. Check out the repair manual for the FI and you'll see the fuel passes around the outside of the case.
Carter Carotor design
echappe
Well-Known Member
where would one obtain 12V to run the electric fuel pump in the trunk.
Thanks for all the help
Thanks for all the help
recovering this thread for a detailed info
hi
i am in a similar situation, i am trying to build my future engine like a hobby, not really need it but, it will be nice to do
i bought an engine from a 75 cs car, and then i will bought a head from a FI 1985 e24
i can go either ways or drill the hole for the mech pump or go for an electric pump
while considering all the possibilities this is my question on the latter
i have been advised to use a carter P4070 pump, but considerations on the noise and so on had made me search for alternatives
if you go to the carter online catalog, they directly propose for a 3000cs bmw the pump P60504 DP
here are the differences
ROTARY VANE PUMP P4070
flow 72 GPH
pressure 4-8 PSI
Gerotor CAROTOR PUMP P60504
flow. 30 GPH
presure. 2-4 PSI
gerotor CAROTOR PUMP P60430
flow. 30. GPH
pressure. 4-6 PSI
so, now the questions, provided CARTER is recomending the CAROTOR P60504, will the flow and pressure be enough considering that some of you are installing the P4070 (roughly speaking double flow and pressure) ?
thanks for your attention
hi
i am in a similar situation, i am trying to build my future engine like a hobby, not really need it but, it will be nice to do
i bought an engine from a 75 cs car, and then i will bought a head from a FI 1985 e24
i can go either ways or drill the hole for the mech pump or go for an electric pump
while considering all the possibilities this is my question on the latter
i have been advised to use a carter P4070 pump, but considerations on the noise and so on had made me search for alternatives
if you go to the carter online catalog, they directly propose for a 3000cs bmw the pump P60504 DP
here are the differences
ROTARY VANE PUMP P4070
flow 72 GPH
pressure 4-8 PSI
Gerotor CAROTOR PUMP P60504
flow. 30 GPH
presure. 2-4 PSI
gerotor CAROTOR PUMP P60430
flow. 30. GPH
pressure. 4-6 PSI
so, now the questions, provided CARTER is recomending the CAROTOR P60504, will the flow and pressure be enough considering that some of you are installing the P4070 (roughly speaking double flow and pressure) ?
thanks for your attention
Mike Goble
Well-Known Member
I'm using the lift pump from an 80's BMW as the fuel pump for my carbureted M30B35. I found that the pump/sender ass'y from an E24 was real close in length to my stock Bav unit, and it puts out about 3psi, great for the Webers. It's pretty quiet, and real easy to come by.
I have the 4070 because triple webers need high volume/low pressure. I have a rubber isolator mounting kit for between it and the bracket and I put a piece of rubber between the frame of the car and the bracket. I can barely hear it whir with the engine off, definitely no noise when the engine on. It's all in the mounting.
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Polariscsl
Well-Known Member
I ran a single facet red top with a standard 3.0 and webers. Well mounted in the boot it was very quiet. Currently running two red tops in series and they are very quiet due to their mountings.