Help Sizing a DC Motor for a 1958 Corvette

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Discussion Overview

The discussion revolves around selecting a suitable DC motor for powering a high-pressure fuel pump in a modified 1958 Corvette. Participants explore the requirements for torque, power, and temperature tolerance, as well as the feasibility of using electric pumps versus the existing gear pump system.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Dan seeks guidance on finding a 12VDC motor capable of reaching 3000 RPM to power a gear pump originally driven mechanically.
  • Some participants suggest that temperature may not be a significant issue for the motor's operation.
  • There is uncertainty regarding the power requirements to drive the gear pump, with suggestions to consult experts on old fuel injection systems.
  • One participant mentions the possibility of using modern electric fuel pumps, describing a small electric motor found in a Ford in-tank pump.
  • Dan clarifies that the existing gear pump is integral to the fuel system and expresses a need to focus on a motor that can drive this specific pump.
  • Concerns are raised about the pressure requirements, with Dan noting that the original gear pump can generate up to 200 PSI, while suggested inline pumps typically provide less than 60 PSI.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach to powering the pump, with multiple competing views on the suitability of electric pumps versus the existing gear pump system. The discussion remains unresolved regarding the exact power and torque requirements for the motor.

Contextual Notes

Participants express uncertainty about the specific pressure requirements and the power needed to operate the gear pump effectively. There is also a lack of clarity on the temperature tolerance of the proposed motor options.

Who May Find This Useful

Individuals interested in automotive modifications, particularly those working with vintage vehicles or fuel injection systems, may find this discussion relevant.

Dynodan
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I am new here and don't know if this is appropriate so let me know. I am not an engineer and no formal training other than a few Physics classes in college many years ago. I do however have a high mechanical aptitude and have always done some personalization of machines. Eg. I put a lawn mower engine on my bicycle at age 10. etc.

I am now attempting to modify a 1958 Corvette Rochester Ramjet fuel injection to run on a different engine. The item I need help with is the means of powering the high pressure pump. Originally it it mechanically driven via a flex cable attached to a special distributor.

Since the engine is not going to exceed 6000 RPM and the cam speed is 1/2 the speed of the crankshaft, I will need to find a suitable 12VDC motor that is capable of up to 3000 RPM.

I do not know how much torque/power it will take to turn the gear pump that it will attach to but a greater concern it that it will operate in an environment that consistently exceeds 200° F. It does not need to be variable speed as the flow is controlled by a mechanical bypass value in the fuel reservoir.

I would appreciate any help on pointing me in the right direction, who I might talk to etc.
Thanks for your time.

Dan
 
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I don't think the temperature will be too much of an issue. Figuring out the power requirement may be the biggest hurdle -- I would ask some experts on the old FI systems.

For a start, you might try http://www.hotrodders.com/forum/

Here's a list of other automotive forums:
http://www.crankshaftcoalition.com/wiki/List_of_hotrodding_forums

Have you considered just using an electric pump?
 
Pantaz-

I wish I could just use an electric pump but the existing gear pump sits inside a reservoir of fuel and the output channel is cast into the reservoir then to a flow control valve and then "spilled" back into the reservoir of fuel.

Thanks for the other ideas. I have spoken to several "experts" and they sent me here!
 
you might look into modern fuel pumps.

Not long ago I disassembled a Ford in-the-tank pump and found it to be a remarkably small electric motor similar to those in electric RC cars, driving a simple impeller type pump that's more tangential than centrifugal. It's surrounded by filters and structure, but the heart of it is size of a computer mouse..

Clearances are necessarily small to create required pressure in absence of positive displacement mechanism, so an input strainer is a MUST.

but it's a possible approach for you.

myself i'd look into the inline pumps from hot-rod sites like Summit Racing.
 
Jim,

Thanks for the reply. I do not know how much pressure the in the tank pump can generate. I have been told by the experts that the original gear pump can generate up to 200 PSI although it generally would need at least 100PSI to operate correctly.

The Summit inline pumps have good volume but generally less than 60 PSI.

I need to focus on a motor that can drive the existing pump as I mentioned to Pantaz earlier. Thanks for the good thoughts!
Dan
 

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