The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support JNZ Tuning
Please Support STM Tuned

2G custom mechanical fuel pump help!

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

TheFlashDSM

Supporting Member
1,082
312
Feb 18, 2010
stony brook, New_York
I'm going mechanical for my fuel pump, I don't want to spend the money for the fancy Magnus set up, my fuel cell will be in the trunk, what pump do I need, does it come with the coupling?

How to set up the pulley version, I can make my own custom bracket, so I can save the $750, I just would like to get everything I need for the set up.

800+ hp build, my build, http://www.dsmtuners.com/threads/my-2g-dsm-second-build-this-ones-going-smoother.499369/

What do I need to do this?

You must be logged in to view this image or video.

You must be logged in to view this image or video.
 
The pump in the pictured is the Aeromotive hex drive.

https://www.aeromotiveinc.com/product/billet-hex-drive-fuel-pump/

The regulator is the associated one for the big mechanical drive pumps.

https://www.aeromotiveinc.com/product/belt-drive-pump-efi-regulator/

The coupling insert comes from Lovejoy I believe, though I may be wrong.

You may have to have the timing gear side coupling made. If you have access to a machine shop they wouldn't be too difficult to make. You can either bolt it to the cam gear center like Hal's was done. His is the belt drive picture you posted and he did build that himself.

Others use a long dowel that runs through the cam gear and engages the pump drive. The pump drive bolts onto the cam gear using the cam center bolt.

You also have to maintain the specified alignment between the pump and cam if you direct drive. The belt drive will give you a tad more wiggle room on alignment.

I had priming issues with the pump pulling from the tank in the rear of the car, it was actually vapor lock in a high spot causing the pump to lose prime after hot shutdown. I ended up using a stock pump and a check valve on the mechanical feed. This pressurized the feed line to the mechanical while the engine is being cranked to push any bubbles through the pump. I had initially primed through a port on the regulator but this wouldn't let the bubble pass through the mech and the car would stall.

After the change mentioned I've never had another problem.

All that stated, there's something to be said for the Magnus parts. It comes with the coupling pieces and they'll machine the cam drive for proper fitment with your cam gear. If you're going to follow through with the mechanical drive pump, it's money well spent.
 
If you have an engine that's built enough to need a mechanical pump, then the $750 drive setup shouldn't be a huge deal. Unless you only want the pump for the "Bling" status, in which case I would highly recommend against installing a $800 pump for looks.

As stated it won't self prime, meaning that you would have to squirt some type of flammable liquid into the intake every time you want to drive your car etc. Plus you would need some type of surge tank on top of it, simply not worth it!

This is coming from someone that has the Aeromotive belt drive pump setup and the Garrett GT4202R to back it up.
 
If you have an engine that's built enough to need a mechanical pump, then the $750 drive setup shouldn't be a huge deal. Unless you only want the pump for the "Bling" status, in which case I would highly recommend against installing a $800 pump for looks.

As stated it won't self prime, meaning that you would have to squirt some type of flammable liquid into the intake every time you want to drive your car etc. Plus you would need some type of surge tank on top of it, simply not worth it!

This is coming from someone that has the Aeromotive belt drive pump setup and the Garrett GT4202R to back it up.
Thanks for the info. I'm shooting for 1000hp and I don't want the issue of the electrical fuel pump dropping pressure, or have a circuit fail and blowing my motor due to lack of fuel, any way you can get some pics or your setup so i do it right the first time?

The pump in the pictured is the Aeromotive hex drive.

https://www.aeromotiveinc.com/product/billet-hex-drive-fuel-pump/

The regulator is the associated one for the big mechanical drive pumps.

https://www.aeromotiveinc.com/product/belt-drive-pump-efi-regulator/

The coupling insert comes from Lovejoy I believe, though I may be wrong.

You may have to have the timing gear side coupling made. If you have access to a machine shop they wouldn't be too difficult to make. You can either bolt it to the cam gear center like Hal's was done. His is the belt drive picture you posted and he did build that himself.

Others use a long dowel that runs through the cam gear and engages the pump drive. The pump drive bolts onto the cam gear using the cam center bolt.

You also have to maintain the specified alignment between the pump and cam if you direct drive. The belt drive will give you a tad more wiggle room on alignment.

I had priming issues with the pump pulling from the tank in the rear of the car, it was actually vapor lock in a high spot causing the pump to lose prime after hot shutdown. I ended up using a stock pump and a check valve on the mechanical feed. This pressurized the feed line to the mechanical while the engine is being cranked to push any bubbles through the pump. I had initially primed through a port on the regulator but this wouldn't let the bubble pass through the mech and the car would stall.

After the change mentioned I've never had another problem.

All that stated, there's something to be said for the Magnus parts. It comes with the coupling pieces and they'll machine the cam drive for proper fitment with your cam gear. If you're going to follow through with the mechanical drive pump, it's money well spent.

I'm most likely going to do the belt drive setup but please tell me more about using a stock pump to help prime the mechanical pump, like draw some kind of diagram of your pump set up, from cell to rail.
 
I have more but this gives you an idea of clearance etc.

You must be logged in to view this image or video.

You must be logged in to view this image or video.
 
I have more but this gives you an idea of clearance etc.

Seeing that is not mounted to the motor or motor mount, when the motor torques back, will it tighten and loosen the belt causing it to slip or come off?

It makes sense to mount it to the motor mount like the pictures I posted above just keep that in mind but where did you get that pulley from and what bolt do I use to mount the pulley to the cam shaft?

I have more but this gives you an idea of clearance etc.
hahaahh i take back my mounting thoughts, i see you mounted it to the power steering bracket LOL :D
 
The cog was bought from Summit Racing, I made the coupler to adapt it, the bolt is a standard DSM 6 bolt headbolt, runs through the cog and into the cam to mount both the pump cog and the cam gear.
 
The cog was bought from Summit Racing, I made the coupler to adapt it, the bolt is a standard Dsm 6 bolt headbolt, runs through the cog and into the cam to mount both the pump cog and the cam gear.

Awesome, I'll start buying things for this, I really like your set up, and if you have the link for the parts that will be great!!!

The pump in the pictured is the Aeromotive hex drive.

https://www.aeromotiveinc.com/product/billet-hex-drive-fuel-pump/

The regulator is the associated one for the big mechanical drive pumps.

https://www.aeromotiveinc.com/product/belt-drive-pump-efi-regulator/

Do I have to use that regulator or can I use a different type (cheaper)?
 
I use a regular 4 port regulator for efi engines from magnafuel. I also use their hex drive pump. We actually use it with a direct drive on a few cars right off the cam gear. One of the cars uses a tiny single port aeromotive efi regulator without issue with a bigger 7 gph pump.

We prime our cars with an inline walbro pump. We use a simple ball valve with two y's in the system before and after the valve to keep the pump from feeding back to the tank. Once the car is fired we open the valve and shut the primer pump off. Once primed and running it will perform flawlessly on its own until the tank runs dry or the ignition is killed.

I have been using a mechancal pump system since 2008 in a simple, yet successful fashion since then.
 
I use a regular 4 port regulator for efi engines from magnafuel. I also use their hex drive pump. We actually use it with a direct drive on a few cars right off the cam gear. One of the cars uses a tiny single port aeromotive efi regulator without issue with a bigger 7 gph pump.

We prime our cars with an inline walbro pump. We use a simple ball valve with two y's in the system before and after the valve to keep the pump from feeding back to the tank. Once the car is fired we open the valve and shut the primer pump off. Once primed and running it will perform flawlessly on its own until the tank runs dry or the ignition is killed.

I have been using a mechancal pump system since 2008 in a simple, yet successful fashion since then.


does it matter the flow direction through the rail? (i dont think it does)
please view picture i drew and let me know if its right!
location for the check vales and Y connector


You must be logged in to view this image or video.
 
I have a Y fitting before the electric pump. It goes from a -10 to a -10 around the pump and a -6 through the pump to the manual ball valve(not check valve). After the pump and ball valve there is another Y fitting that joins the -6 and the -10 back to the -10 feed to the pump. I run the filter before the primer pump. I do not draw through only the primer pump. I do not run the primer pump other than to start the car. The valve is only shut to prime and start the car. It is opened once the car fires. Thus leaving it to draw through the primer pump and around it through the -10 line as to not starve the mechanical pump.

All our cars feed from the left(driver side of the rail). We have a small hole in the floor of our cars for access to the valve. On my rat rod it was under the driver door. This has worked well for us up to 1000whp and 840whp through the auto without nitrous at a moderate boost level. Doing it this way leaves no need for a surge tank or a electric pump constantly running and trying to feed the system.
 
I have a Y fitting before the electric pump. It goes from a -10 to a -10 around the pump and a -6 through the pump to the manual ball valve (not check valve). After the pump and ball valve there is another Y fitting that joins the -6 and the -10 back to the -10 feed to the pump. I run the filter before the primer pump. I do not draw through only the primer pump. I do not run the primer pump other than to start the car. The valve is only shut to prime and start the car. It is opened once the car fires. Thus leaving it to draw through the primer pump and around it through the -10 line as to not starve the mechanical pump.

I revised the picture let me know if its correct and what size for the return line?

You must be logged in to view this image or video.
 
Sorry. Playing race cars all day. The regulator is in the wrong spot. Needs to be after the mechanical pump. The injectors need to be between the pump and regulator. Everything else is correct. You have to pressurize the injectors. The trade off is having a hole in the floor for the valve, figure out a longer handle in some way a pivot for the valve or a cable of some sort. We just mount the line and valve right under the floor behind the shifter (fwd car, no driveshaft) and cut a hole in the floor.
 
Sorry. Playing race cars all day. The regulator is in the wrong spot. Needs to be after the mechanical pump. The injectors need to be between the pump and regulator. Everything else is correct. You have to pressurize the injectors. The trade off is having a hole in the floor for the valve, figure out a longer handle in some way a pivot for the valve or a cable of some sort. We just mount the line and valve right under the floor behind the shifter (fwd car, no driveshaft) and cut a hole in the floor.


and yea i knew where the regulator was suppost to go but for some reason i had a brain fart during the making of the diagram, ill fix and post it with this... and what size return line


Sorry. Playing race cars all day. The regulator is in the wrong spot. Needs to be after the mechanical pump. The injectors need to be between the pump and regulator. Everything else is correct. You have to pressurize the injectors. The trade off is having a hole in the floor for the valve, figure out a longer handle in some way a pivot for the valve or a cable of some sort. We just mount the line and valve right under the floor behind the shifter (fwd car, no driveshaft) and cut a hole in the floor.

@biglady112 please find and post a link to a shut off vale @bling5tatus found one but is it big enough for a -6 line....
You must be logged in to view this image or video.
 
I think i have spoon fed you enough. You can run any valve you want. I guess unless you live in the middle I nowhere and don't have access to anything. I just went to my local hydraulic store (Parker store) and grabbed a small one off the shelf that was close to a -10 in size.

-8 return.

I buy local for 97% of the parts I need. I don't bother with online vendors except for summit racing.
 
Last edited:
I think inhave spoo. Yes you enough. You can run any valve you want. I guess unless you live in the middle I nowhere and don't have access to anything. I just went to my local hydraulic store (Parker store) and grabbed a small one off the shelf that was close to a -10 in size.

-8 return.

I buy local for 97% of the parts I need. I don't bother with online vendors except for summit racing.


awesome ill look now to see what i can find!!!!
 
I just posted the first electric ball valve I could find. I would use that so you could prime on a switch/relay instead of cutting the floor of your car. I'm sure you could find one larger that would work by letting your fingers do the walking.

The other thing worth noting is that the fuel prime line doesn't have to be huge, it just has to pass fuel long enough to fill the line going to the mechanical pump. Your ball valve and priming line could likely be pretty small because you're shutting it off when the car is started anyway.
 
Pic of my good friends setup. +1 on magnus parts! Hope this gives you a good look. I will run some questions by him for you.
 

Attachments

  • Screenshot_2017-04-04-05-37-16.png
    Screenshot_2017-04-04-05-37-16.png
    394.9 KB · Views: 320
I know it’s an old conversation but dose anyone run -12 line to the pump?? Also do you have to run an electric pump? Doesn’t the mechanical pump not draw vacuum?? Front fuel cell not rear. Thanks
 
Theres no need to run much bigger than -8 an lines to the pump, and the pump will only draw a few inches of fuel at cranking speed so if you have a fuel sub tank or a actual fuel tank up front close to the pump you should be ok, but it wont draw from the tank in the rear on its own at cranking speed.
 
All the cars I know run -10 not -8 and I heard -12 helps with the fuel cranking I guess more fuel going in the pump... that’s why I’m asking if anyone uses -12??

Also do people run stock of aftermarket cam gears??
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top