My Experience Installing PR Stage 3+ LPFP and PR/MMP Port Injection

suspenceful

700 HP Club (N54)
Aug 1, 2017
542
551
0
Ride
2015 M3, 2008 135i, 2009 335i
After installing MMP Stage 3 turbos on my 135i (write-up coming soon), I needed an upgraded fuel system to get the most power out of the car. I was filling up with an E40 mix of 93 and E85 , but my HPFP couldn't keep up and my old stage 1 inline LPFP was inadequate. I needed something that could handle straight E85 fuel and not run out of pressure at 700+whp.

Having good experiences with Robert at Precision Raceworks, I decided to go with his Stage 3+ Modular Fuel Pump Kit and opted for the upgraded fuel feed line and PNP harness. This would take care of my LPFP issues. I also purchased the PR/MMP Port Injection Kit at the same time to help my HPFP.

The products arrived quickly and were packaged nicely. I've always been satisfied with the quality from Precision Raceworks for the price. Upgraded fuel feed line not pictured.

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The first step was to install the upgraded Stage 3+ bucket that had two Walbro 450s stuffed inside. Robert was nice enough to assemble the fuel pumps in a core bucket for me to swap out. Usually you have to modify your stock bucket while mounting and wiring up the pump yourself. I jumped in the back seat and got to work.

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After fiddling around in the gas tank for a bit, I got the stock bucket out. New Precision Raceworks Stage 3+ bucket on the left, old OEM bucket on the right (with my old Stage 1 inline pump still attached). Note the additional terminals on the top of the new bucket for the secondary pump.

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Installation was basically the reversal of disassembly. Fairly straightforward, more gas on the hands. A plug-and-play harness is included in the kit to activate the 2nd pump under boost. I routed it from the battery to the two terminals on the top of the bucket, then up under the hood to a Hobb's switch (also included) that screws right into the meth port my charge pipe. The PNP harness is very nice quality and makes installation a breeze. The 2nd pump is set to kick on anytime the car sees more than 15PSI of boost.

NOTE: I made the mistake of cutting the Hobb's switch off because I planned on using JB4 to trigger the pump, but later resorted to the Hobb's switch for various reasons. Those two blue crimps are my doing, the harness does not come this way.

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Next up was installing the port injection kit and upgraded fuel line. I reconnected the battery right before this to test that the LPFP bucket installation worked as it should (and it did). However, for those of you who are aren't familiar with these cars, they run/prime the fuel pump every time a door opens after the car is "asleep". Well, I disconnected the OEM fuel feed line and then opened the door so I could route the upgraded line to the tank. As soon as I opened the door, the pump kicked on and fuel sprayed everywhere out of the open port. I'd assume a gallon of gas was on the garage floor before I quickly plugged the OEM line back in. Whoops!

Battery disconnected, OEM fuel line out, new fuel line routed and plugged in.

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I ran the larger fuel feed line up to the front of the car and started removing parts so I could install the port injection kit.

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Intake manifold removed, port injection plate installed. I added a dab of gasket sealer to the o-rings just to make sure they stayed on. The manifold studs have to be replaced with longer bolts, but it's best to leave two studs in, just hand tight. That way the port injection plate stayed aligned while I re-installed the intake manifold and tightened things down with five of the new longer bolts. Then remove the two studs and insert the two remaining bolts.

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I connected the upgraded fuel line to the HPFP and port injection plate with the included T adapter. Then I plugged all of the injectors into the BMS port injection controller that I purchased ala-carte since I am using JB4. It took less than an hour to wire up the controller to my JB4 using the instructions at the top of this post. I forgot to take a picture of this, but I managed to fit everything in the DME box for a stealthy installation. Everything went back together smoothly and you can't even tell the port injection is in there unless you look for it.

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After everything was back together, I connected the battery so I could test that the port injection worked. As soon as I did, the fuel pumps primed and I heard fuel spraying under the car. Not just a small leak, it was dumping fuel - another gallon or two on the floor. I quickly disconnected the battery and investigated.

Well, I forgot to plug this port on the plate! The kit comes with a proper plug and o-ring... make sure to use it. Another whoops!

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I screwed in the plug and wrapped things up, then went out for my first full tank of pure E85. No more mixing!

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The car runs great and pulls strong on 28PSI. I'm thrilled! Shoutout to Robert at Precision Raceworks. This installation isn't that hard but he promptly answered any questions I had. Not to mention the awesome pricing and quality of these products. I plan on getting his Precison Raceworks Ignition System Upgrade to go with this fuel system as well. I've already ordered a VRSF 7.5" race intercooler and colder spark plugs.
 
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Mellow Yellow

Specialist
Jan 22, 2017
53
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Putting together the pump is a pain (luckily you avoided that) and I still had no idea how to add the 3rd pump on properly. There should be an option when purchasing to have the pumps pre assembled. I'd pay a bit extra for that. I bought their elite kit and had to get in contact with them on how to route all the new Fuel lines because there were no instructions.
 
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suspenceful

700 HP Club (N54)
Aug 1, 2017
542
551
0
Ride
2015 M3, 2008 135i, 2009 335i
Very nice man!

Thank you!
Putting together the pump is a pain (luckily you avoided that) and I still had no idea how to add the 3rd pump on properly. There should be an option when purchasing to have the pumps pre assembled. I'd pay a bit extra for that. I bought their elite kit and had to get in contact with them on how to route all the new Fuel lines because there were no instructions.

Yeah, I initially ordered it without it being assembled. I received it and was overwhelmed, sent it back and asked for it to be pre-assembled. :sweatsmile:

A lot of the N54 vendors don't include instructions with the products, but I found links for just about everything on their website under "installation guides".
Does your car have long crank during cold or warm start up?

Not a long crank, but it stumbles for a second after starting usually. I'm still trying to dial in my ignition setup/settings. Why?
 

Mellow Yellow

Specialist
Jan 22, 2017
53
37
0
Thank you!


Yeah, I initially ordered it without it being assembled. I received it and was overwhelmed, sent it back and asked for it to be pre-assembled. :sweatsmile:

A lot of the N54 vendors don't include instructions with the products, but I found links for just about everything on their website under "installation guides".


Not a long crank, but it stumbles for a second after starting usually. I'm still trying to dial in my ignition setup/settings. Why?
Yea that install instructions name includes the stage 4 but in the actual instructions, I don't think it covers it at all.

Does your car have long crank during cold or warm start up?
Mine stumbles a little on cold starts but I get long cranks on warm starts. I need to check to see if they're leaking
 

suspenceful

700 HP Club (N54)
Aug 1, 2017
542
551
0
Ride
2015 M3, 2008 135i, 2009 335i
Yea that install instructions name includes the stage 4 but in the actual instructions, I don't think it covers it at all.

Mine stumbles a little on cold starts but I get long cranks on warm starts. I need to check to see if they're leaking

Yeah, I also want to check. I've read some things about MMP PI injectors leaking. Time to take the manifold off and prime the fuel pump.
 

TWilly

Specialist
Jul 7, 2017
85
18
0
Ride
Tyler
good write up! I plan on going with their pi too someday in the future! looks great. I wonder why they cant have the 2nd pump run all the time? Can I ask the reasons why you didn't have the jb4 power the pump? man your car is beautiful!
 

suspenceful

700 HP Club (N54)
Aug 1, 2017
542
551
0
Ride
2015 M3, 2008 135i, 2009 335i
good write up! I plan on going with their pi too someday in the future! looks great. I wonder why they cant have the 2nd pump run all the time? Can I ask the reasons why you didn't have the jb4 power the pump? man your car is beautiful!

Thanks man! I don't think there is a need to run the 2nd pump all the time. It would be working hard for no reason and burn out much quicker. The primary Walbro 450 is enough to supplement fuel until the boost gets going.

I didn't have JB4 power the pump because I couldn't get it to work properly. I have the 2-step/NLS relay installed, which is where I wouldn't had to tap into for a signal. I tried wiring it to the orange trigger wire on my BMS PI controller, but that didn't work correctly. The pump was constantly on (even with the car off). So I just wired it to a Hobb's switch and it's working great.
 
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matreyia

Major
Apr 19, 2017
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335i e93
Thanks man! I don't think there is a need to run the 2nd pump all the time. It would be working hard for no reason and burn out much quicker. The primary Walbro 450 is enough to supplement fuel until the boost gets going.

I didn't have JB4 power the pump because I couldn't get it to work properly. I have the 2-step/NLS relay installed, which is where I wouldn't had to tap into for a signal. I tried wiring it to the orange trigger wire on my BMS PI controller, but that didn't work correctly. The pump was constantly on (even with the car off). So I just wired it to a Hobb's switch and it's working great.

I installed my Bmp PI kit and left the negative wire unplugged because I don't have a tune yet. There is a base map on the controller but I didn't want to damage the engine from running rich or anything like that.

Are you saying that it worked fine when you didn't have a customer tune and ran it temporarily with the base map? If so, did you got wot on the base map to test? I also have the flex fuel in my car. Next Saturday is the day I do a remote dyno tune with Twisted.
 

suspenceful

700 HP Club (N54)
Aug 1, 2017
542
551
0
Ride
2015 M3, 2008 135i, 2009 335i
I installed my Bmp PI kit and left the negative wire unplugged because I don't have a tune yet. There is a base map on the controller but I didn't want to damage the engine from running rich or anything like that.

Are you saying that it worked fine when you didn't have a customer tune and ran it temporarily with the base map? If so, did you got wot on the base map to test? I also have the flex fuel in my car. Next Saturday is the day I do a remote dyno tune with Twisted.

No, I never ran the car without the controller hooked up. I also had the BMS JB4 PI controller which doesn't require tuning. It auto-tunes itself. Sounds like you have an AIC6 which is a completely different system.
 

Maniac0908

Corporal
Mar 22, 2018
109
6
0
Ride
07 335xi
Did you notice the fuel line provided was a little long? I feel like it’s cocked on there because the line is long.