Port Injection Explained and Guide

JohnnyTightlips

JohnnyTightlips

Motorhead
The OEM fuel system with e30 is good to about 370whp or so before you start to see some wild IDC "injector duty cycle" To fix this people will run port injection on top of the direct injection system. This provides fuel when you need it the most "higher boost" and supplements the OEM system.

This thread is to clear up some confusion on port injection and the multiple ways to do it. There are already some threads on it which I will be referencing. This will not cover the split second controller which is needed to control the PI "port injection" injectors. All of these are e85 safe "most people do e30 - e50 blends" I recommend checking out these threads as well for some more info.

***Added some good info form PurpleDrank "Will" and Freektune "Justin" to the bottom.

https://mazdaspeeds.org/index.php?threads/how-to-returnless-port-injection-setup.9707/
https://www.mazdaspeeds.org/index.php?threads/diy-port-injection-set-up.2579/


I will be going through Return-less PI, Return PI, Surge Tank PI, Fuel Cell PI

Return-less Port Injection:
Goal < 500whp

Returnless works well if you want to stay around 500whp, it is pretty simple. After 500whp you will need more fuel flow and the stock regulator will get wonky. This is when you would move to a Return style. This is how I would do it, it is not super fancy but it is cost effective and will work just as well as the PTFE or other ways. This uses the factor in basket fuel pressure regulator. This is the same for 6th port as it would be for doing a PI rail.

Items Needed:
  1. In Tank: Upgraded Drop in Pump
    1. AEM E85 High Flow In-Tank Fuel Pump - 340LPH
      PART# AEM 50-1220
  2. Fittings
    1. Firewall - OEM Feed - 6AN Male Flare to 5/16
    2. Firewall - 6an to 6an 90 - Female 6AN To 3/8
    3. Hose - Gates 27349 Barricade Fuel Injection Hose-15' Length, Inner Diameter 3/8"
    4. HPFP - Female 6AN AN6 To 3/8 Barb
    5. HPFP - Black Aluminum -6 AN Male Thread Flare Tee Union T
    6. HPFP - Hard Fuel Tubing Fitting for hardline tube 5/16" to AN6 female thread
    7. HPFP - to PI rail - Female 6AN AN6 To 3/8 Barb
    8. Hose - Gates
    9. PI Rail End 1 - 6AN 45 Degree Push Lock Hose Fitting End Black
    10. PI Rail End 1- ICT Billet -6AN Flare to 6 Oring ORB Male
    11. PI Rail End 2 - Aluminum -6 AN Male Hex Head Socket ORB
    12. #16 Stainless Steel 3/8" Fuel Injection Hose Clamps 10pc Pack (14mm - 16mm) (FIC-14x10)
Diagram:
upload_2021-10-14_13-23-47.png


Return Port Injection:
Goal > 500whp

Once you get into the higher power levels you will need regulated fuel pressure "more than the oem can handle" At high boost levels you will want a boost refence fuel regulator. This will cover that. Fuel is fed through the system and regulated in the engine bay then returned to the fuel basket in the tank. You will be running a line back to the tank for return.

Items Needed:

  1. In Tank: Upgraded Drop in Pump
    1. AEM E85 High Flow In-Tank Fuel Pump - 340LPH
      PART# AEM 50-1220       "good for 600+ish"
    2. Hellcat "good for 700+ish" Will need an adapter or make your own bracket
      1. WALBRO HELLCAT 525LPH F90000285 FUEL PUMP (UNIVERSAL E85)
        1. Hellcat Fuel pump basket
        2. DIY Hellcat Pump
        3. HOW TO: Mazdaspeed Hellcat Fuel Pump Swap!

  1. Fittings
    1. Firewall - OEM Feed - 6AN Male Flare to 5/16
    2. Firewall - 6an to 6an 90 - Female 6AN To 3/8
    3. Hose - Gates 27349 Barricade Fuel Injection Hose-15' Length, Inner Diameter 3/8"
    4. HPFP - Female 6AN AN6 To 3/8 Barb
    5. HPFP - Black Aluminum -6 AN Male Thread Flare Tee Union T
    6. HPFP - Hard Fuel Tubing Fitting for hardline tube 5/16" to AN6 female thread
    7. HPFP - to PI rail - Female 6AN AN6 To 3/8 Barb
    8. Hose - Gates
    9. PI Rail End 1 - 6AN 45 Degree Push Lock Hose Fitting End Black
    10. PI Rail End 1- ICT Billet -6AN Flare to 6 Oring ORB Male
    11. PI Rail End 2 - 6AN 180 Degree AN-06 Female Swivel Push
    12. Hose - Gates
    13. FPR - Hyperfuel Tight-Fit Fuel Pressure Regulator -06AN 30-70PSI EFI Part Number: 493-44120
    14. FPR - 2 @ Female 6AN AN6 To 3/8 barb
    15. FPR - EVIL ENERGY AN6 Flare Cap
    16. Hose - Gates
    17. Fuel Basket Return - In Tank - 6an to 6an 90 - Female 6AN To 3/8
    18. Fuel Basket Return - ICT Billet -6AN Male Straight to 5/16" Barb Bulkhead Adapter
    19. Fuel Basket Return - Corrugated Fuel Hose 5/16" ID x 10" Long with Stainless Steel Vapor Clamps for In-Tank Use
    20. #16 Stainless Steel 3/8" Fuel Injection Hose Clamps 10pc Pack (14mm - 16mm) (FIC-14x10)
Diagram:
upload_2021-10-14_14-17-22.png

To be continued. If anyone notices any errors let me know.


FROM FREEKTUNE FACEBOOK:

FREEK:
Justin Brasil
Next up on this weeks episode on fueling. Let’s talk port injection, and how much fuel you need on your PI side. To recap on your DI side, you have 400whp worth of fueling headroom on 91/93 octane, 300whp on e85.
These next numbers are a close estimate based on running a return style fuel system. I prefer injector dynamics since they can run a very low pulse width and not just drown the motor in fuel when they start to fire. These numbers are also on FULL e85. They will flow a lot more on pump gas but let’s face it. You’ll be running at least some sort of e85 blend or
Full e85 if you want to make power.
Id1050 400whp
ID1300 550whp
ID1700 700whp
ID2000 (2200cc) 900whp
ID2600 1100whp
These are power levels that can be achieved on the secondary side alone. Now add in the 300whp on e85 on the DI side. Adding 300 plus the 400 on 1050s gives you 700whp worth of fuel on straight e85.
Don’t skip putting a return line on your car and a fuel pressure regulator. While returnless
Seems appealing, you lose a ridiculous amount of fueling headroom.
But Justin that doesn’t make sense. You said this injector will do this, that and, the other thing. Well buckle up. An injector works on differential fuel pressure. With a return line and a fuel pressure regulator. Your fuel
Pressure will increase 1:1 with boost. You set your fuel pressure to 43psi. As boost increases above 0 it will increase your fuel pressure. So at 40psi of boost you have 83psi of fuel pressure which is the desired 43psi of differential pressure. The injector needs to overcome boost pressure to fire.
If you had 43psi of fuel pressure. Without a fuel pressure regulator, and 40psi of boost you would only have 3psi of differential pressure and the injector would be a little tinkle like the last drop of a pee break.
This is why returnless is terrible in my opinion. Let’s talk mazdaspeed now. If you simply tee off at your hpfp using your intank pressure The mazdaspeed is 60-65psi of low side fuel pressure. It does not rise with boost. So now you throw 30psi of boost at the car cause you want over 500whp and now your fuel
Pressure differential is only 30-35psi and your injector flow is dropping dramatically. You just spent all this money on a port injection setup to skip about a couple hundred bucks on a fuel Pressure regulator, a return line and a top hat fitting. Makes no sense to me lol. Returnless is good for 500-550whp. That’s a lot of money for a sub par fuel system. Could have just went with 6th port and got the same
Amount of fueling headroom.
A setup I really like if you don’t want to run a return line back to the tank is a fuel cell setup. cs makes this really easy. I have been doing this on my silver car since about 2014. You can run your full e85 in the fuel cell. Pump gas in your stock tank for DI side. Viola. You have 400hp of fuel on your DI side and another 400whp worth of fuel with ID1050s. Thts 800hp worth of fuel with readily availible
Parts.
Keep in mind. You need proper fuel pump to achieve the numbers as well. We can get into that another day lol.
Ps. I didn’t proof read any punctuation and really DGAF. The info is there if you want it
1f602.png
Click to expand...

WILL:
Will Dawson
Everything here is complete fax machine
Justin and I hit on the same cylinders however we both have different preferences in small things that is just a difference in experiences.
Personally I do not advocate for 6 port over returnless pi because typically the customers that want a 6 port setup are still on stock intake manifold.
Whatever is sprayed pre throttle body will always balance as well as the manifold distributes.
Also cost for the 6 port kits that are on the market lands around 1200-1300 with fuel pump.
Returnless fuel kits with adapter for stock manifold is usually 1400-1600.
Personally balanced fuel (pi) vs an imbalance in air & fuel (6port) is what I would prefer.
This argument changes if we are talking about pump load or if you are introducing a balanced intake manifold in the mix.
To note: I am not disagreeing I am just of a different mindset
Click to expand...
 
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JohnnyTightlips said:
The OEM fuel system with e30 is good to about 370whp or so before you start to see some wild IDC "injector duty cycle" To fix this people will run port injection on top of the direct injection system. This provides fuel when you need it the most "higher boost" and supplements the OEM system.

This thread is to clear up some confusion on port injection and the multiple ways to do it. There are already some threads on it which I will be referencing. This will not cover the split second controller which is needed to control the PI "port injection" injectors. All of these are e85 safe "most people do e30 - e50 blends" I recommend checking out these threads as well for some more info.

***Added some good info form PurpleDrank "Will" and Freektune "Justin" to the bottom.

https://mazdaspeeds.org/index.php?threads/how-to-returnless-port-injection-setup.9707/
https://www.mazdaspeeds.org/index.php?threads/diy-port-injection-set-up.2579/


I will be going through Return-less PI, Return PI, Surge Tank PI, Fuel Cell PI

Return-less Port Injection:
Goal < 500whp

Returnless works well if you want to stay around 500whp, it is pretty simple. After 500whp you will need more fuel flow and the stock regulator will get wonky. This is when you would move to a Return style. This is how I would do it, it is not super fancy but it is cost effective and will work just as well as the PTFE or other ways. This uses the factor in basket fuel pressure regulator. This is the same for 6th port as it would be for doing a PI rail.

Items Needed:
  1. In Tank: Upgraded Drop in Pump
    1. AEM E85 High Flow In-Tank Fuel Pump - 340LPH
      PART# AEM 50-1220
  2. Fittings
    1. Firewall - OEM Feed - 6AN Male Flare to 5/16
    2. Firewall - 6an to 6an 90 - Female 6AN To 3/8
    3. Hose - Gates 27349 Barricade Fuel Injection Hose-15' Length, Inner Diameter 3/8"
    4. HPFP - Female 6AN AN6 To 3/8 Barb
    5. HPFP - Black Aluminum -6 AN Male Thread Flare Tee Union T
    6. HPFP - Hard Fuel Tubing Fitting for hardline tube 5/16" to AN6 female thread
    7. HPFP - to PI rail - Female 6AN AN6 To 3/8 Barb
    8. Hose - Gates
    9. PI Rail End 1 - 6AN 45 Degree Push Lock Hose Fitting End Black
    10. PI Rail End 1- ICT Billet -6AN Flare to 6 Oring ORB Male
    11. PI Rail End 2 - Aluminum -6 AN Male Hex Head Socket ORB
    12. #16 Stainless Steel 3/8" Fuel Injection Hose Clamps 10pc Pack (14mm - 16mm) (FIC-14x10)
Diagram:
View attachment 20379


Return Port Injection:
Goal > 500whp

Once you get into the higher power levels you will need regulated fuel pressure "more than the oem can handle" At high boost levels you will want a boost refence fuel regulator. This will cover that. Fuel is fed through the system and regulated in the engine bay then returned to the fuel basket in the tank. You will be running a line back to the tank for return.

Items Needed:

  1. In Tank: Upgraded Drop in Pump
    1. AEM E85 High Flow In-Tank Fuel Pump - 340LPH
      PART# AEM 50-1220       "good for 600+ish"
    2. Hellcat "good for 700+ish" Will need an adapter or make your own bracket
      1. WALBRO HELLCAT 525LPH F90000285 FUEL PUMP (UNIVERSAL E85)
        1. Hellcat Fuel pump basket
        2. DIY Hellcat Pump
        3. HOW TO: Mazdaspeed Hellcat Fuel Pump Swap!

  1. Fittings
    1. Firewall - OEM Feed - 6AN Male Flare to 5/16
    2. Firewall - 6an to 6an 90 - Female 6AN To 3/8
    3. Hose - Gates 27349 Barricade Fuel Injection Hose-15' Length, Inner Diameter 3/8"
    4. HPFP - Female 6AN AN6 To 3/8 Barb
    5. HPFP - Black Aluminum -6 AN Male Thread Flare Tee Union T
    6. HPFP - Hard Fuel Tubing Fitting for hardline tube 5/16" to AN6 female thread
    7. HPFP - to PI rail - Female 6AN AN6 To 3/8 Barb
    8. Hose - Gates
    9. PI Rail End 1 - 6AN 45 Degree Push Lock Hose Fitting End Black
    10. PI Rail End 1- ICT Billet -6AN Flare to 6 Oring ORB Male
    11. PI Rail End 2 - 6AN 180 Degree AN-06 Female Swivel Push
    12. Hose - Gates
    13. FPR - Hyperfuel Tight-Fit Fuel Pressure Regulator -06AN 30-70PSI EFI Part Number: 493-44120
    14. FPR - 2 @ Female 6AN AN6 To 3/8 barb
    15. FPR - EVIL ENERGY AN6 Flare Cap
    16. Hose - Gates
    17. Fuel Basket Return - In Tank - 6an to 6an 90 - Female 6AN To 3/8
    18. Fuel Basket Return - ICT Billet -6AN Male Straight to 5/16" Barb Bulkhead Adapter
    19. Fuel Basket Return - Corrugated Fuel Hose 5/16" ID x 10" Long with Stainless Steel Vapor Clamps for In-Tank Use
    20. #16 Stainless Steel 3/8" Fuel Injection Hose Clamps 10pc Pack (14mm - 16mm) (FIC-14x10)
Diagram:
View attachment 20381

To be continued. If anyone notices any errors let me know.


FROM FREEKTUNE FACEBOOK:
Click to expand...
I think the links for 10 and 11 on the list are wrong:
PI Rail End 1- ICT Billet -6AN Flare to 6 Oring ORB Male:
https://www.jegs.com/i/ICT-Billet/335/AN920-06-06A/10002/-1

PI Rail End 2 - 6AN 180 Degree AN-06 Female Swivel Push:
Template public:_media_site_embed_amazon not found. Try rebuilding or reinstalling the s9e/MediaSites add-on.
 
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squingy said:
I think the links for 10 and 11 on the list are wrong:
PI Rail End 1- ICT Billet -6AN Flare to 6 Oring ORB Male:
https://www.jegs.com/i/ICT-Billet/335/AN920-06-06A/10002/-1

PI Rail End 2 - 6AN 180 Degree AN-06 Female Swivel Push:
Template public:_media_site_embed_amazon not found. Try rebuilding or reinstalling the s9e/MediaSites add-on.
Click to expand...
I think just 10 is wrong it should point to
Template public:_media_site_embed_amazon not found. Try rebuilding or reinstalling the s9e/MediaSites add-on.
The text is right though. With return less you plug one side of the PI rail. There are other ways to do it. You could have all the fuel pass through the PI rail before it ends at the HPFP which also works. This would mean no split at the HPFP. I fixed the link for 10
 
So I was reading up on this and was thinking of other ways of running a port injection setup, wouldn’t we be able to put a fuel pressure regulator on the top hat at the tank, having a line coming out of the factory feed go into the fpr and then going out of the fpr back to the line that runs to the front. And finally using the return port on the fpr to dump right back into the basket because it would be mounted right on the top hat.

I thought of this because there could be people out there that are using a returnless setup where the line coming out the firewall goes to port rail then hpfp could keep that setup because there is already a fpr increasing 1:1 with boost and returning back at the tank.

Those are just my thoughts I thought I could add, if I could get some insight on that idea it would be great

IMG_2596.jpeg
This is how I’m thinking of running the setup, 60psi rail pressure then increasing 1:1 with boost, as long as you have enough fuel pressure, I think that you won’t have a restriction no matter where the fpr is located.
 
Last edited by a moderator:
So after using this and a few other threads to build a return setup, a couple things to note...

Returnless/Return setup:
- You can use 6AN to 5/16" quick disconnect fittings to connect to HPFP, Firewall OEM hardline, tank side OEM hardline, and tank tophat OEM plastic nipple. I used these: female 6AN to male QD, male 6AN to male QD, male 6AN to female QD
- you can reuse stock lines or make new to connect to the hardline, I reused one but tried to cut the firewall side one and messed it up, so make a new one

Returnless setup:
- MAKE SURE YOU INCLUDE POST PUMP FUEL FILER (10 micron), I don't think you can used stock filter, (plastic piece that wraps around pump has a post pump filter inside)
- I went with a Walbro pump, those are 3/8" nipple outlet, so I had to use 3/8" line in pump basket. don't use the line in the kits (he shows 10" line, that's good), it's not long enough, you want a longer one that can loop and have room to move when the fuel baket is compressed in the tank: 3/8"x10" submersable hose
- 3/8 line WILL NOT clamp down to the 5/16" barbs, I had to get a 6AN to 6AN bulkhead and female 6AN to 3/8" barb, if you know a machinist, you can prob have them turn down the 6AN to a barb and remove one set of fittings: 6AN straight bulkhead, 6AN 90° bulkhead, female 6AN to 3/8" barb
- the seatpan does not have the room for some of the taller 90° fittings, so make sure you use a 90° bulkhead above or this: 6AN 90°
- don't use the cheapo clamps in the walbro kit,it might work but the fuel line hose clamps are made to distribute pressure a bit more evenly. Pretty sure I used 10-12mm clamps for in tank corrugated line, but they BARELY fit over when loosened all the way, here's 11-13mm clamps that will likely fit: 11mm-13mm stainless steel clamps
- I bought 20ft of line and prob have 5ft left, so 15ft would be cutting it close.
 
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Does anyone know if you have to take out the in tank fuel regulator when going the return style method or do you still just keep it in and regular what’s being sent back to the tank via the regulator on port system ? Looking to make my 6th port system return back to the tank but am stuck on this thought.
 
jesus said:
Does anyone know if you have to take out the in tank fuel regulator when going the return style method or do you still just keep it in and regular what’s being sent back to the tank via the regulator on port system ? Looking to make my 6th port system return back to the tank but am stuck on this thought.
Click to expand...
I'm also wondering this
 
jesus said:
Does anyone know if you have to take out the in tank fuel regulator when going the return style method or do you still just keep it in and regular what’s being sent back to the tank via the regulator on port system ? Looking to make my 6th port system return back to the tank but am stuck on this thought.
Click to expand...
Yes, you need to take the regulator & filter out of the basket for running a return setup. Then in-tank regulator regulates the pressure to [about] 40psi and dumps the excess back into the fuel basket.
For a return setup you run ALL your fuel to the engine bay and have a regulator there to regulate fuel pressure. From there the regulator dumps the excess fuel back to the fuel tank through a 2nd line. You can't reuse the in tank regulator OR the fuel filter, you need to add both of these to your new fuel line(s) (you need to add at least one fuel line, 2 if you don't reuse the stock hardline).
 
Pyrokid73 said:
Yes, you need to take the regulator & filter out of the basket for running a return setup. Then in-tank regulator regulates the pressure to [about] 40psi and dumps the excess back into the fuel basket.
For a return setup you run ALL your fuel to the engine bay and have a regulator there to regulate fuel pressure. From there the regulator dumps the excess fuel back to the fuel tank through a 2nd line. You can't reuse the in tank regulator OR the fuel filter, you need to add both of these to your new fuel line(s) (you need to add at least one fuel line, 2 if you don't reuse the stock hardline).
Click to expand...
I ran the in tank fuel filter and never did an external filter. The only time I did an external was when I ran the secondary PI system with a CS fuel cell and that was completely separate from the OEM system. I can't remember if you need the regulator or not, pretty sure with the hellcat pump you just remove it. The Miata uses a similar setup and they sell a block off for the regulator, I am not really sure the difference between their setup and the speeds setup for this and why they need this and we don't. I am sure you will want to keep it for any OEM pump replacement but a return setup will need to bypass it.

https://mazdaspeeds.org/index.php?t...build-maximum-carnage.7025/page-20#post-95481
https://fab9tuning.com/nc-mx-5-fuel-regulator-block-off/
 
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