Thread: fuel pump selection

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Originally Posted by Bug

Jesus Christ, "Lighten up francis". Don't take much to get your panties in a bunch does it.

Your first post basicaly stated that you wanted to know what was best for for your STREET application. You were given some very good advise. We on this forum try to help people make the right decisions, not just answer their questions. You dont have to get on a forum just to get a basic question asked. Pick up a book and read it. That is the trouble with you young kids these days, you think that it is your right for us old guys to tell you everything that we know. Not with me, you have to EARN that right in my house.

since im a "young kid" i learn by hands on, i tought myself how to build motors and do bodywork. im sorry that i dont have all the money in the world to own everybook i can learn everything from. i dont know all this psi stuff that well so its a simple question to know what kind of psi im looking for. and my truck is mainly street with the occasional strip race. and ya us young kids are so troubled these days. i only built my own truck from the ground up with less than $1000 so i should read a book to learn one simple little fuel pump question huh? let me know how many other 17 year olds you know that built a truck and got 2nd place in a carshow. all i needed to know was what the first guy posted saying 7psi is stock and he thinks the mallory pump is good. i dont need to know that my trucks gonna overheat or use the alternator more. thanks everyone for the concerns but i do know what im doing

Well there youngin, good luck on your project.

7 PSI is too much, you'll need the regulator to cut the pressure back to 4-5 psi as Glenn mentioned. With your engine 110-130 gph is plenty of volume. With the increased volume and pressure with an electric pump you'll also want to use a 1/2" fuel line, available in aluminum also at Sumitt. No reason to have the hi pressure and hi volume if you restrict it through the stock 5/16" fuel line....

No one here is putting you down or saying you don't know what you're doing, just trying to save you a few $$$$$$ from lessons we've all learned along the way......

Originally Posted by Dave Severson

7 PSI is too much, you'll need the regulator to cut the pressure back to 4-5 psi as Glenn mentioned. With your engine 110-130 gph is plenty of volume. With the increased volume and pressure with an electric pump you'll also want to use a 1/2" fuel line, available in aluminum also at Sumitt. No reason to have the hi pressure and hi volume if you restrict it through the stock 5/16" fuel line....

No one here is putting you down or saying you don't know what you're doing, just trying to save you a few $$$$$$ from lessons we've all learned along the way......

thats all i needed to know so thank you

is the tank behind the seat in your truck?

Well – this thread has taken some interesting turns – I would again underscore the stock systems are best for cooling and fuel delivery in most vehicles with even serious engine modifications -especially those like your pickup –as GM has really done a great job of engineering. Electric fans can be fine if they are designed as an integral part of the car or if the modifications under the hood preclude the stock equipment due to clearance issues.

As mentioned above, electric fuel pumps can be expensive as they typically require different fuel lines, a regulator, fused circuit, etc. I have most of what Jerry detailed and $500 is real close. I also have an aluminum radiator and a very specialized electric fan setup that is in the $500 range as well. Look at this thread for some additional information on the radiator and electric fans - Radiator Replacement Bear in mind this is not my daily driver – rather a toy car that provides therapy for my “body-and-soul”.

I know you are young – all of us 60 plus guys were once and speaking for myself, I was pretty cock-sure of my car knowledge. Looking back, I didn’t know that much, but could talk a good line and would never have admitted (at the time) that the dual Holley quads on my ’57 Corvette did not perform as well as the single (stock) AFB! While some of what I’ll share may be real basic, please know that like all the other “old guys” here, I/we have your best interest at heart and would like you consider the hundreds of years of combined experience and hot rod knowledge we bring to the party. Many are long time racers, many have built more engines than we can remember and several of us have had PhDs in pure technical disciplines since before you were born. I commend you on your efforts to date on your truck and would enjoy seeing your handiwork! So please accept the following with the intent in which it is expressed:

Cooling 101 tells us that the cooling systems in most automotive engines have five basic hard parts:
1. Engine block
2. Water pump
3. Radiator
4. fan (including the shroud), and
5. The thermostat.

Water passages inside the engine are usually filled with an ethylene glycol (antifreeze) and water mixture (coolant). These passages (sometimes called water jackets) allow the heat from the block and heads to be transferred to the coolant. The coolant is circulated throughout the engine and the radiator by means of a water pump, which is driven from a belt from the crankshaft pulley. The stock fan clutch assembly mounts on the front of the water pump, and by default is driven by the engine as well. The water pumps only purpose is to move coolant however; it’s a real good place to mount the fan clutch as it’s in the center of the engine bay allowing alignment with radiator in a manner that positions the shroud to most effectively “funnel” air through the radiator and across the engine. Obviously, air flowing past the radiator cools the coolant, and transfers heat away from the engine. The thermostat is used to open or close flow of coolant to the radiator and helps to maintain the engine at a constant temperature. Most SBC run well between 170-190 degreed Fahrenheit. Common misconception number one is that the fan controls the engine temperature – not true, the thermostat controls the temperature. The engineering behind the thermostat is what allows your car to heat up in the winter (stays closed) and run cool in the winter (opens up). Thermostats stuck open or closed can cause engines to run too cool or too hot.

The fan is really important at slow speeds or when idling. As mentioned above, the clutch fan is attached to the water pump shaft and is belt driven from the crankshaft. The fan is not directly attached to the water pump’s shaft; it is actually bolted to a viscous clutch. The clutch then sits between the fan and the shaft. The clutch keeps the fan at a consistent speed when idling, and engages the fan when it is needed. There is an impeller inside the clutch that is connected directly to the input shaft. This impeller is suspended on a bearing allowing the fan and impeller to rotate independently of each other. The housing has a clutch plate mounted opposite of the impeller. The clutch is controlled by a bimetal spring (acts like a thermostat). If the air flowing over the clutch heats up, the thermostat moves the clutch into the impeller and “engages”. The housing is filled with fluid (gear oil). As the clutch moves closer to the impeller, they become coupled by the swirling of this fluid (like a torque converter). The clutch is splined to the housing so the housing rotates and thus the fan (which is bolted to the housing) spins. Conversely, when cool air prevails, the spring relaxes and the clutch disengages. This allows the clutch to slip and the fan “freewheels”. Also at high RPM there is not enough friction to couple the impeller to the clutch so it slips to keep the fan operating at a constant speed and to prevent the fan from taking unnecessary power from the engine. It is important to note is that the fan is only required at idle or when moving slowly when there is not enough airflow through the radiator to provide adequate cooling.

By far, the most common misconception is that the big honking electric fan cools better then the stock metal fan. The fan to cool a 400HP engine is the same size fan as would be used to cool a stock 200HP engine since both engines are producing approximately the same amount of heat during idle and slow speeds. Also mistakenly believed is that an electric fan will cure freeway overheating problems. Remember that the fan is not used at freeway speeds - the natural flow of air through the radiator is more than sufficient (much more than a fan, in fact) to keep the engine at proper temperature. If you’re running hot at freeway speeds, it’s almost always a radiator blockage or coolant flow issue.

Another misconception is “horsepower savings” – they’re just not there. To adequately duplicate the stock mechanical fan, one typically needs a motor that draws between 35 and 50 amps at startup. My fans will blow a 20 amp fuse instantly when they start. When running, my fans draw almost 20 amps. To make this happen, I am converting mechanical energy, to electrical energy, to mechanical again to run the fan. This is very inefficient, much less then just driving the fan directly via the mechanical energy of the rotating shaft.

Also mentioned above - The stock clutch fan can have two failures: the clutch will fail, or the fan will physically break. Electric fan introduces several additional failure points: fuse and fuse holder, all wiring connections (I’d recommend #10 wires), physical failure of the fan, failure of the motor, failure of the thermostat controlling the fan…

So – if you’ve read this far, thank you! Do what you want (we already know you will) but consider and weigh the total cost and risks against a stock setup. You can spend two hundred bucks or a grand – with no noticeable difference in performance. You've done a commendable job on your truck - maybe we can help ya keep a few more of those hard earned dollars (I know they were hard for me when I was 17!! Still are!)


Edelbrock 1721 - Edelbrock Performer RPM Street Fuel Pumps - $95.00
Edelbrock 1721 - Edelbrock Performer RPM Street Fuel Pumps - Overview - SummitRacing.com

A new Flex-a-lite 5555 - Flex-a-lite Fan Clutch -$47.00
Flex-a-lite 5560 - Flex-a-lite Fan Clutches - Overview - SummitRacing.com

A new Flex-a-lite 5718 - Flex-a-lite Standard Rotation Clutch Fan - $41.00
Flex-a-lite 5718 - Flex-a-lite Standard Rotation Clutch Fans - Overview - SummitRacing.com

Regards,
Glenn

so I went and read all your posts----it appears you have a chev 305, ford fe 352 and now a chev 327?????????

Originally Posted by jerry clayton

so I went and read all your posts----it appears you have a chev 305, ford fe 352 and now a chev 327?????????

my old motor was a 305, i replaced it with a 357. and the ford motor is my one of my friends. and my tank is behind the seat

Originally Posted by glennsexton

Well – this thread has taken some interesting turns – I would again underscore the stock systems are best for cooling and fuel delivery in most vehicles with even serious engine modifications -especially those like your pickup –as GM has really done a great job of engineering. Electric fans can be fine if they are designed as an integral part of the car or if the modifications under the hood preclude the stock equipment due to clearance issues.

As mentioned above, electric fuel pumps can be expensive as they typically require different fuel lines, a regulator, fused circuit, etc. I have most of what Jerry detailed and $500 is real close. I also have an aluminum radiator and a very specialized electric fan setup that is in the $500 range as well. Look at this thread for some additional information on the radiator and electric fans - Radiator Replacement Bear in mind this is not my daily driver – rather a toy car that provides therapy for my “body-and-soul”.

I know you are young – all of us 60 plus guys were once and speaking for myself, I was pretty cock-sure of my car knowledge. Looking back, I didn’t know that much, but could talk a good line and would never have admitted (at the time) that the dual Holley quads on my ’57 Corvette did not perform as well as the single (stock) AFB! While some of what I’ll share may be real basic, please know that like all the other “old guys” here, I/we have your best interest at heart and would like you consider the hundreds of years of combined experience and hot rod knowledge we bring to the party. Many are long time racers, many have built more engines than we can remember and several of us have had PhDs in pure technical disciplines since before you were born. I commend you on your efforts to date on your truck and would enjoy seeing your handiwork! So please accept the following with the intent in which it is expressed:

Cooling 101 tells us that the cooling systems in most automotive engines have five basic hard parts:
1. Engine block
2. Water pump
3. Radiator
4. fan (including the shroud), and
5. The thermostat.

Water passages inside the engine are usually filled with an ethylene glycol (antifreeze) and water mixture (coolant). These passages (sometimes called water jackets) allow the heat from the block and heads to be transferred to the coolant. The coolant is circulated throughout the engine and the radiator by means of a water pump, which is driven from a belt from the crankshaft pulley. The stock fan clutch assembly mounts on the front of the water pump, and by default is driven by the engine as well. The water pumps only purpose is to move coolant however; it’s a real good place to mount the fan clutch as it’s in the center of the engine bay allowing alignment with radiator in a manner that positions the shroud to most effectively “funnel” air through the radiator and across the engine. Obviously, air flowing past the radiator cools the coolant, and transfers heat away from the engine. The thermostat is used to open or close flow of coolant to the radiator and helps to maintain the engine at a constant temperature. Most SBC run well between 170-190 degreed Fahrenheit. Common misconception number one is that the fan controls the engine temperature – not true, the thermostat controls the temperature. The engineering behind the thermostat is what allows your car to heat up in the winter (stays closed) and run cool in the winter (opens up). Thermostats stuck open or closed can cause engines to run too cool or too hot.

The fan is really important at slow speeds or when idling. As mentioned above, the clutch fan is attached to the water pump shaft and is belt driven from the crankshaft. The fan is not directly attached to the water pump’s shaft; it is actually bolted to a viscous clutch. The clutch then sits between the fan and the shaft. The clutch keeps the fan at a consistent speed when idling, and engages the fan when it is needed. There is an impeller inside the clutch that is connected directly to the input shaft. This impeller is suspended on a bearing allowing the fan and impeller to rotate independently of each other. The housing has a clutch plate mounted opposite of the impeller. The clutch is controlled by a bimetal spring (acts like a thermostat). If the air flowing over the clutch heats up, the thermostat moves the clutch into the impeller and “engages”. The housing is filled with fluid (gear oil). As the clutch moves closer to the impeller, they become coupled by the swirling of this fluid (like a torque converter). The clutch is splined to the housing so the housing rotates and thus the fan (which is bolted to the housing) spins. Conversely, when cool air prevails, the spring relaxes and the clutch disengages. This allows the clutch to slip and the fan “freewheels”. Also at high RPM there is not enough friction to couple the impeller to the clutch so it slips to keep the fan operating at a constant speed and to prevent the fan from taking unnecessary power from the engine. It is important to note is that the fan is only required at idle or when moving slowly when there is not enough airflow through the radiator to provide adequate cooling.

By far, the most common misconception is that the big honking electric fan cools better then the stock metal fan. The fan to cool a 400HP engine is the same size fan as would be used to cool a stock 200HP engine since both engines are producing approximately the same amount of heat during idle and slow speeds. Also mistakenly believed is that an electric fan will cure freeway overheating problems. Remember that the fan is not used at freeway speeds - the natural flow of air through the radiator is more than sufficient (much more than a fan, in fact) to keep the engine at proper temperature. If you’re running hot at freeway speeds, it’s almost always a radiator blockage or coolant flow issue.

Another misconception is “horsepower savings” – they’re just not there. To adequately duplicate the stock mechanical fan, one typically needs a motor that draws between 35 and 50 amps at startup. My fans will blow a 20 amp fuse instantly when they start. When running, my fans draw almost 20 amps. To make this happen, I am converting mechanical energy, to electrical energy, to mechanical again to run the fan. This is very inefficient, much less then just driving the fan directly via the mechanical energy of the rotating shaft.

Also mentioned above - The stock clutch fan can have two failures: the clutch will fail, or the fan will physically break. Electric fan introduces several additional failure points: fuse and fuse holder, all wiring connections (I’d recommend #10 wires), physical failure of the fan, failure of the motor, failure of the thermostat controlling the fan…

So – if you’ve read this far, thank you! Do what you want (we already know you will) but consider and weigh the total cost and risks against a stock setup. You can spend two hundred bucks or a grand – with no noticeable difference in performance. You've done a commendable job on your truck - maybe we can help ya keep a few more of those hard earned dollars (I know they were hard for me when I was 17!! Still are!)


Edelbrock 1721 - Edelbrock Performer RPM Street Fuel Pumps - $95.00
Edelbrock 1721 - Edelbrock Performer RPM Street Fuel Pumps - Overview - SummitRacing.com

A new Flex-a-lite 5555 - Flex-a-lite Fan Clutch -$47.00
Flex-a-lite 5560 - Flex-a-lite Fan Clutches - Overview - SummitRacing.com

A new Flex-a-lite 5718 - Flex-a-lite Standard Rotation Clutch Fan - $41.00
Flex-a-lite 5718 - Flex-a-lite Standard Rotation Clutch Fans - Overview - SummitRacing.com

Regards,
Glenn

thank you for all this info here. ive never really considered running a clutch fan because i know of the failure rate which i do not like. im wanting to try electric fans just to see how well they do in my setup. i understand what you mean by it drawing more amperage and if it goes horribly wrong i do plan to stay with mechanical. im wanting to try these new era parts just to see if they perform better or worse.
thanks again

Originally Posted by RedMan16

....but thanks to all the people who actually helped me out with what to get instead of just talking smack on here. even with all the negative comments im still leaning towards electric so thanks anyways.

Glenn provided you with an excellent and very detailed explanation of both cooling and fuel systems design features. If you read back through all of the posts here without letting your emotions come into play I think you'll see that all of the information was provided with respect, and with an eye on trying to help you get to the right place without throwing your money away. No one here "talks smack" as you put it - probably not capable of keeping up in the "smack" department, and generally don't put up with it anyway. Bottom line, if you choose to stick around you'll find that to a large degree this is a bunch of guys old enough to be your grandpa, and there's a wealth of knowledge that you can pick up for free provided you really want answers and not just instant agreement with your ideas. Like your grandpa or grandma we'll tend to tell you if we believe you're screwing up or headed in the wrong direction, and that's just something that's not going to change. You always make your own choice in the end, right?

We really enjoy pictures of projects, and yours sounds like one that has lots going for it. If you decide to hang around with this bunch, maybe you can post up some pictures of your truck, and keep us in the loop as you continue to make changes. Continued good luck on your truck.

Try to keep in mind that the people who post answers and comments are attempting to help you based on many years of experience. Some guys post comments that are a little edgy sometimes but you just have to ignore that part of it. We all have different personalities. You should concentrate on the information itself and overlook the rest. You can learn a lot hanging around here.

OK---so now we know what engine you have--If you want to do electric fan--use a unit from Tauras or Mk 8 lincoln--take a look at this unit from guy known as GT_RECYCLER in Nashville, Tn its an Ebay item#221029845889 and also lots of info on fans at his site--I have gotten several from him----there is a guy in texas that sells a relay package fot 2 speed fans for the cobra guys that i will look up for you if you want---

On the fuel pump----For your application I would go with a engine mech pump from Holley, Edelbrock that is up around 80-100 gallons /hour---Pick the unit that has the size fittings you want ---and I would go to a 1/2 line from the tank or at least a 3/8--plumb in a good filter thats easy to get to and away from heat sources--

If you do the electric pump, be aware that you will need it near the tank----and since thats in the cab---noisy---you won't be able to hear your exhaust or radio-----

For info on wiring kit relays, etc for the high amp fans -------www.thehollisterroadcompany.com----------------lots of info on the different fans, types of wire and relay/fuses/switches, etc--

these Lincoln, Taurus/Sable fans are available almost everywhere but there are some differances so do a little research

another route is the earlier Viper fan assemblys

for fuel pump ideas---Southern Performance systems offer a kit for hot rod electric fuel pumps, braided hose, filter(no regulator) around $400--------

Jerry, thanks for supporting the "young whippersnapper".. lol..