Walbro 525 "Hellcat" LPFP Upgrade

[nitemare]

This conversation is mainly for the x50i guys that live close to E85 stations. To start off I have been doing several hours of research on realoem.com, Walbro, Dodge Hellcat forums, and even searching on here in the X5M section.

The F10 535 guys have a direct swap option for the Walbro 39/50 style pumps i.e. 267/274/525 pumps. So I compared the F10 pump setup to the F15. They are different (obviously) as the F10 does not really have a bucket style system per say vs the F70/F15.

The F70/F15 in fact has a bucket style system, Item# 1 below:

http://www.realoem.com/bmw/enUS/show...diagId=16_0659

The F10 550 is a little different:

http://www.realoem.com/bmw/enUS/show...diagId=16_0779

The F10 535 looks exactly like the 550 except for the ending BMW part number is: 1301 unlike the 550: 1303

http://www.realoem.com/bmw/enUS/show...diagId=16_0779

I'm assuming the F10 550 has a higher flowing fuel pump vs the 535, for obvious reasons.

Now this is where it gets interesting apparently NO ONE has done any LPFP upgrade to the F10 550i/550xi to try and run full E85, I asked BPC and Sergey. Sergey told me the HPFP and injectors can't keep rail pressure. Obviously if the LPFP can't keep up with the required 30% more fuel demand required for E85 then yes you can't run high boost and full E85 on a Stage 2 or Stage 3 tune.

I come from the N54 world and the N54 on factory turbos with a single 450 Walbro can make 450-470whp on E85 before having to either overdrive the HPFP or adding in secondary fueling i.e. meth or port injection. This horsepower level is obtained from custom fuel scalars via TunerPro.

Going off of this doing simple math with 6 injectors vs 8 injectors.

N54 on E85 making 450whp / 6 = 75whp per cylinder/injector

on N63TU with E85 making 600whp / 8 = 75whp per cylinder/injector

Now comparing the Walbro 450 vs 525 "Hellcat" pump it flows 10-12% more across the board from 60-90psi. I do not know the flow figures of the factory BMW X70/F15 pump but what I did find out is interesting.

The F10 550 does not share the same pump as the M5.

The E70/F15 x50i in fact does share the exact same BMW pump part number as the X5M/X6M. Does this mean the x50i has a higher flowing factory pump than the F10 550i I can alsmost guarantee it does! As the X5M/X6M come with the more powerful S63.

The 550 does though share the same HPFP and same injectors as the X5M/X6M. So the limiting factor to me is not the injectors or HPFPs it's the intank LPFP.

So now we get into how much power can the factory X50i handle? I found two X5Ms that ran these:

11.42@122 JB4 and pump gas
11.34@123 custom tune and pump gas

Doing the online calculator for trap speed to horsepower at a race weight of 5460# and 123 trap = 685whp

https://robrobinette.com/et.htm

So going off this we can assess the factory x50i LPFP can supply enough fuel for roughly 700whp MAX on E10 pump gas. Which would equate to about 490awhp before running lean on E85 with a custom tune. Remember E85 demands 30% more fuel to maintain stoich/lambda.

I was on the Dodge Charger forums as the Walbro 525 is sometimes dubbed the "Hellcat" pump as this comes factory on the Hellcats. There are guys making in the high 600s low 700s on E85 with the single factory pump.

Math time for E85 Brake Specific Fuel Consumption at max effort assuming 850 brake horsepower (flywheel):

850bhp x 0.70 = 595lbs/hr

595lbs/hr / 6.2 lbs/gal = 96GPH or 364LPH of fuel required

Looking at the specs of the Walbro F90000285 @ 70psi pressure and @ 13.5volts the pump flow = 101GPH

So this tells me the Walbro will be able to handle 850 flywheel horespower on full E85 if low pressure stays at 70psi.....obviously if low pressure drops then flow will increase a little. Now this won't be a bad thing until it gets to the point where it gets too low and crashes the high pressure side. If you base this off of a 20% drivetrain loss it will roughly equal 680awhp.

I think if you can maintain above 55-60psi on the low pressure side your high pressure should be happy.

Cliff notes: I'm going to try and retro fit a Walbro F90000285 once I find the F15 M-Sport I'm looking for. This will need a custom tune to adjust the fuel scalar tables to account for the 30% more fuel demand with E85. Other mods I plan on doing:

- Secondary air box lid cut/modified to fit the Dinan filters
- Custom homemade behind kidney grille scoops to direct more air to box
- ARM catless DPs. Hi-Temp ceramic coated and wrapped
- Custom David Shoup tune with BM3 targeting 21.5psi. I'm trying my best to avoid the temptation of getting the 3.5bar TMAPs and kill the turbos at 25-26psi.

I think with the above mods with some good fine tuning hitting 21psi to like an 18 taper it should make 575-600whp on E85. Which is all I need for a fun daily/tow rig.....the 535 is the fast car.

Nick

[HydroStream6]

FYI, running BM3 and JB4 at 21.5lbs on E30 with no issues (stock hardware) . I have 3.5bar maps sitting on the counter, just haven't gotten around to it yet. You may not need to do any hardware upgrades for what you want. Dragy shows solid 11s with my setup.

[nitemare]

Originally Posted by HydroStream6

FYI, running BM3 and JB4 at 21.5lbs on E30 with no issues (stock hardware) . I have 3.5bar maps sitting on the counter, just haven't gotten around to it yet. You may not need to do any hardware upgrades for what you want. Dragy shows solid 11s with my setup.

Can't compare E30 and E85 at same boost level. The fuel demand is going to be far greater. I already knew several guys were running E30 at your current boost level, as the DME is able to adjust without going lean. The limit would be to find how far your can take a custom tune with various ethanol mixes before being capped out at boost and horsepower. At which point will need to upgrade the LPFP to help supply enough volume and pressure to both HPFPs.

Do you have catless DPs on as well?

[HydroStream6]

Originally Posted by nitemare

Can't compare E30 and E85 at same boost level. The fuel demand is going to be far greater. I already knew several guys were running E30 at your current boost level, as the DME is able to adjust without going lean. The limit would be to find how far your can take a custom tune with various ethanol mixes before being capped out at boost and horsepower. At which point will need to upgrade the LPFP to help supply enough volume and pressure to both HPFPs.

Do you have catless DPs on as well?

I understand this. I'm just saying, if you're only planning on running ~22lbs, you may not need the octane of E85, unless you're really trying to maximize timing/hp. If you're going all out high boost / timing, then sure.

No catless DPs here. Maybe someday, but I'm enjoying no smell haha.

[nitemare]

Originally Posted by HydroStream6

I understand this. I'm just saying, if you're only planning on running ~22lbs, you may not need the octane of E85, unless you're really trying to maximize timing/hp. If you're going all out high boost / timing, then sure.

No catless DPs here. Maybe someday, but I'm enjoying no smell haha.

Maximize hp with timing....plus it adds convenience with filling up, burns cleaner, and doesn't smell bad without cats.

[IRG006]

Originally Posted by nitemare

This conversation is mainly for the x50i guys that live close to E85 stations. To start off I have been doing several hours of research on realoem.com, Walbro, Dodge Hellcat forums, and even searching on here in the X5M section.

The F10 535 guys have a direct swap option for the Walbro 39/50 style pumps i.e. 267/274/525 pumps. So I compared the F10 pump setup to the F15. They are different (obviously) as the F10 does not really have a bucket style system per say vs the F70/F15.

The F70/F15 in fact has a bucket style system, Item# 1 below:

http://www.realoem.com/bmw/enUS/show...diagId=16_0659

The F10 550 is a little different:

http://www.realoem.com/bmw/enUS/show...diagId=16_0779

The F10 535 looks exactly like the 550 except for the ending BMW part number is: 1301 unlike the 550: 1303

http://www.realoem.com/bmw/enUS/show...diagId=16_0779

I'm assuming the F10 550 has a higher flowing fuel pump vs the 535, for obvious reasons.

Now this is where it gets interesting apparently NO ONE has done any LPFP upgrade to the F10 550i/550xi to try and run full E85, I asked BPC and Sergey. Sergey told me the HPFP and injectors can't keep rail pressure. Obviously if the LPFP can't keep up with the required 30% more fuel demand required for E85 then yes you can't run high boost and full E85 on a Stage 2 or Stage 3 tune.

I come from the N54 world and the N54 on factory turbos with a single 450 Walbro can make 450-470whp on E85 before having to either overdrive the HPFP or adding in secondary fueling i.e. meth or port injection. This horsepower level is obtained from custom fuel scalars via TunerPro.

Going off of this doing simple math with 6 injectors vs 8 injectors.

N54 on E85 making 450whp / 6 = 75whp per cylinder/injector

on N63TU with E85 making 600whp / 8 = 75whp per cylinder/injector

Now comparing the Walbro 450 vs 525 "Hellcat" pump it flows 10-12% more across the board from 60-90psi. I do not know the flow figures of the factory BMW X70/F15 pump but what I did find out is interesting.

The F10 550 does not share the same pump as the M5.

The E70/F15 x50i in fact does share the exact same BMW pump part number as the X5M/X6M. Does this mean the x50i has a higher flowing factory pump than the F10 550i I can alsmost guarantee it does! As the X5M/X6M come with the more powerful S63.

The 550 does though share the same HPFP and same injectors as the X5M/X6M. So the limiting factor to me is not the injectors or HPFPs it's the intank LPFP.

So now we get into how much power can the factory X50i handle? I found two X5Ms that ran these:

11.42@122 JB4 and pump gas
11.34@123 custom tune and pump gas

Doing the online calculator for trap speed to horsepower at a race weight of 5460# and 123 trap = 685whp

https://robrobinette.com/et.htm

So going off this we can assess the factory x50i LPFP can supply enough fuel for roughly 700whp MAX on E10 pump gas. Which would equate to about 490awhp before running lean on E85 with a custom tune. Remember E85 demands 30% more fuel to maintain stoich/lambda.

I was on the Dodge Charger forums as the Walbro 525 is sometimes dubbed the "Hellcat" pump as this comes factory on the Hellcats. There are guys making in the high 600s low 700s on E85 with the single factory pump.

Math time for E85 Brake Specific Fuel Consumption at max effort assuming 850 brake horsepower (flywheel):

850bhp x 0.70 = 595lbs/hr

595lbs/hr / 6.2 lbs/gal = 96GPH or 364LPH of fuel required

Looking at the specs of the Walbro F90000285 @ 70psi pressure and @ 13.5volts the pump flow = 101GPH

So this tells me the Walbro will be able to handle 850 flywheel horespower on full E85 if low pressure stays at 70psi.....obviously if low pressure drops then flow will increase a little. Now this won't be a bad thing until it gets to the point where it gets too low and crashes the high pressure side. If you base this off of a 20% drivetrain loss it will roughly equal 680awhp.

I think if you can maintain above 55-60psi on the low pressure side your high pressure should be happy.

Cliff notes: I'm going to try and retro fit a Walbro F90000285 once I find the F15 M-Sport I'm looking for. This will need a custom tune to adjust the fuel scalar tables to account for the 30% more fuel demand with E85. Other mods I plan on doing:

- Secondary air box lid cut/modified to fit the Dinan filters
- Custom homemade behind kidney grille scoops to direct more air to box
- ARM catless DPs. Hi-Temp ceramic coated and wrapped
- Custom David Shoup tune with BM3 targeting 21.5psi. I'm trying my best to avoid the temptation of getting the 3.5bar TMAPs and kill the turbos at 25-26psi.

I think with the above mods with some good fine tuning hitting 21psi to like an 18 taper it should make 575-600whp on E85. Which is all I need for a fun daily/tow rig.....the 535 is the fast car.

Nick

Originally Posted by nitemare

This conversation is mainly for the x50i guys that live close to E85 stations. To start off I have been doing several hours of research on realoem.com, Walbro, Dodge Hellcat forums, and even searching on here in the X5M section.

The F10 535 guys have a direct swap option for the Walbro 39/50 style pumps i.e. 267/274/525 pumps. So I compared the F10 pump setup to the F15. They are different (obviously) as the F10 does not really have a bucket style system per say vs the F70/F15.

The F70/F15 in fact has a bucket style system, Item# 1 below:

http://www.realoem.com/bmw/enUS/show...diagId=16_0659

The F10 550 is a little different:

http://www.realoem.com/bmw/enUS/show...diagId=16_0779

The F10 535 looks exactly like the 550 except for the ending BMW part number is: 1301 unlike the 550: 1303

http://www.realoem.com/bmw/enUS/show...diagId=16_0779

I'm assuming the F10 550 has a higher flowing fuel pump vs the 535, for obvious reasons.

Now this is where it gets interesting apparently NO ONE has done any LPFP upgrade to the F10 550i/550xi to try and run full E85, I asked BPC and Sergey. Sergey told me the HPFP and injectors can't keep rail pressure. Obviously if the LPFP can't keep up with the required 30% more fuel demand required for E85 then yes you can't run high boost and full E85 on a Stage 2 or Stage 3 tune.

I come from the N54 world and the N54 on factory turbos with a single 450 Walbro can make 450-470whp on E85 before having to either overdrive the HPFP or adding in secondary fueling i.e. meth or port injection. This horsepower level is obtained from custom fuel scalars via TunerPro.

Going off of this doing simple math with 6 injectors vs 8 injectors.

N54 on E85 making 450whp / 6 = 75whp per cylinder/injector

on N63TU with E85 making 600whp / 8 = 75whp per cylinder/injector

Now comparing the Walbro 450 vs 525 "Hellcat" pump it flows 10-12% more across the board from 60-90psi. I do not know the flow figures of the factory BMW X70/F15 pump but what I did find out is interesting.

The F10 550 does not share the same pump as the M5.

The E70/F15 x50i in fact does share the exact same BMW pump part number as the X5M/X6M. Does this mean the x50i has a higher flowing factory pump than the F10 550i I can alsmost guarantee it does! As the X5M/X6M come with the more powerful S63.

The 550 does though share the same HPFP and same injectors as the X5M/X6M. So the limiting factor to me is not the injectors or HPFPs it's the intank LPFP.

So now we get into how much power can the factory X50i handle? I found two X5Ms that ran these:

11.42@122 JB4 and pump gas
11.34@123 custom tune and pump gas

Doing the online calculator for trap speed to horsepower at a race weight of 5460# and 123 trap = 685whp

https://robrobinette.com/et.htm

So going off this we can assess the factory x50i LPFP can supply enough fuel for roughly 700whp MAX on E10 pump gas. Which would equate to about 490awhp before running lean on E85 with a custom tune. Remember E85 demands 30% more fuel to maintain stoich/lambda.

I was on the Dodge Charger forums as the Walbro 525 is sometimes dubbed the "Hellcat" pump as this comes factory on the Hellcats. There are guys making in the high 600s low 700s on E85 with the single factory pump.

Math time for E85 Brake Specific Fuel Consumption at max effort assuming 850 brake horsepower (flywheel):

850bhp x 0.70 = 595lbs/hr

595lbs/hr / 6.2 lbs/gal = 96GPH or 364LPH of fuel required

Looking at the specs of the Walbro F90000285 @ 70psi pressure and @ 13.5volts the pump flow = 101GPH

So this tells me the Walbro will be able to handle 850 flywheel horespower on full E85 if low pressure stays at 70psi.....obviously if low pressure drops then flow will increase a little. Now this won't be a bad thing until it gets to the point where it gets too low and crashes the high pressure side. If you base this off of a 20% drivetrain loss it will roughly equal 680awhp.

I think if you can maintain above 55-60psi on the low pressure side your high pressure should be happy.

Cliff notes: I'm going to try and retro fit a Walbro F90000285 once I find the F15 M-Sport I'm looking for. This will need a custom tune to adjust the fuel scalar tables to account for the 30% more fuel demand with E85. Other mods I plan on doing:

- Secondary air box lid cut/modified to fit the Dinan filters
- Custom homemade behind kidney grille scoops to direct more air to box
- ARM catless DPs. Hi-Temp ceramic coated and wrapped
- Custom David Shoup tune with BM3 targeting 21.5psi. I'm trying my best to avoid the temptation of getting the 3.5bar TMAPs and kill the turbos at 25-26psi.

I think with the above mods with some good fine tuning hitting 21psi to like an 18 taper it should make 575-600whp on E85. Which is all I need for a fun daily/tow rig.....the 535 is the fast car.

Nick

Question...
I'm doing this on e71 x6M I swapped in the pump and have an issue with the wiring car starts and isles for about 30 seconds then dies. I can keep doing it but will not stay running. I think I'm not getting enough power to it. Granted it's a 20 amp fuse and for the wiring harness the bmw pump had 5 wires the walbro pump has 2.

[NOTORIOUS VR]

Originally Posted by nitemare

The E70/F15 x50i in fact does share the exact same BMW pump part number as the X5M/X6M. Does this mean the x50i has a higher flowing factory pump than the F10 550i I can alsmost guarantee it does! As the X5M/X6M come with the more powerful S63.

It's not clear to me what you're attempting to do here or to what vehicle. Sounds like you're looking for a solution in a 35i vehicle.

What I can tell you is that the Twin turbo V8 (M and non-M 50i) X5/6's run the same BRUSHLESS Walbro fuel pump which is extremely capable of flowing huge amounts of fuel. However the controller and the programming and load capacity of it is another issue all together.

The 35i's use normal brushed fuel pumps (but are still speed controlled via PWM).

[IRG006]

Originally Posted by NOTORIOUS VR

It's not clear to me what you're attempting to do here or to what vehicle. Sounds like you're looking for a solution in a 35i vehicle.

What I can tell you is that the Twin turbo V8 (M and non-M 50i) X5/6's run the same BRUSHLESS Walbro fuel pump which is extremely capable of flowing huge amounts of fuel. However the controller and the programming and load capacity of it is another issue all together.

The 35i's use normal brushed fuel pumps (but are still speed controlled via PWM).

I'm trying to mount one in the x6M having a hard time with the wiring harness. This was a much simpler job with the n54s