[Bee Pee]

TTFS - OE S55 dual HPFP setup - will require tune/coding to get S55 secondary pump to work

https://www.facebook.com/TuningTechF...18218138223616

XDI - non OE PnP HPFP upgrade also due out soon too

http://www.xtreme-di.com/index_files/HPFP35.htm

[Bt12]

Interesting sub’d

[BMWPWR18]

Nice, XDI is located in Michigan. I may contact them in the near future.

[lax01]

Subed for more...wish their website didn't look like 1997...

[Bee Pee]

Originally Posted by BMWPWR18

Nice, XDI is located in Michigan. I may contact them in the near future.

Nice one - keep us posted ??

[mike@x-ph.com]

Sub'd

[Endeav]

Sub'd. Curious to see how the price of this compares to the port-injection alternative.

Originally Posted by brooke1972

Fuel-It already has an option for our cars.
http://www.fuel-it.biz/f-series-n55-...-lpfp-upgrade/

Unfortunately this is the LPFP which isn't the #1 culprit when it comes to the fueling problem for the N55. It's the HPFP that's the problem and upgrading the LPFP alone doesn't solve that issue.

However, Fuel-It does have an "indirect" solution - port injection. Should run you about $1700 - $2000 for the LPFP and port injection kit and that'll solve the crashing HPFP issue.

[Daleb]

Looking at the current XDI options on the market the 35 retails at $1850 and the 60 at $2850.

[UltraMagneticAL]

Originally Posted by brooke1972

I thought the LPFP would be needed for volume so wouldn't both be needed ?

LPFP doesn't crash like the HPFP does. maybe an upgraded LPFP would be required when going beyond the stock turbo, but the HPFP seems to be the weak link right now to making big, reliable power. look at how the HPFP pressure dips by over 1000psi, but LPFP remains constant in my datalog

[ZM2]

Originally Posted by brooke1972

I thought the LPFP would be needed for volume so wouldn't both be needed ?

LPFP upgrade is needed only on track to fix fuel pick up issues in the fuel tank. The $230 Dinan kit lets me run down to 1/8 tank on track. Before that I would get limp mode below 1/3 tank left.

This is a completly different issue, tho, than the HPFP crashing under heavy boost and fuel load.

[NO_USER_]

LPFP upgrade also helps with port injection too right?

[ZM2]

Originally Posted by tehboost

LPFP upgrade also helps with port injection too right?

I think that’s a different type of LPFP “upgrade” than the Dinan fuel pick up fix. I’m not sure, though.

[Endeav]

Originally Posted by tehboost

LPFP upgrade also helps with port injection too right?

Correct. Fuel-It recommends a "Stage 2" LPFP if you plan on running Port Injection with a bigger turbo. A bigger LPFP helps supply the demands of the HPFP while still being able to supply the port-injectors with their fuel demand.

[ZM2]

Originally Posted by Endeav

Correct. Fuel-It recommends a "Stage 2" LPFP if you plan on running Port Injection with a bigger turbo. A bigger LPFP helps supply the demands of the HPFP while still being able to supply the port-injectors with their fuel demand.

Got it.

[Bt12]

Originally Posted by UltraMagneticAL

LPFP doesn't crash like the HPFP does. maybe an upgraded LPFP would be required when going beyond the stock turbo, but the HPFP seems to be the weak link right now to making big, reliable power. look at how the HPFP pressure dips by over 1000psi, but LPFP remains constant in my datalog

It’s interesting that it just falls off. It definitely seems like failure... Surpised it drops that much. Is it normal for the fuel pressure to drop and just stay there if it’s the hpfp failing?

[DrKevM5]

Subscribed!

[PiK]

Originally Posted by ZM2

LPFP upgrade is needed only on track to fix fuel pick up issues in the fuel tank. The $230 Dinan kit lets me run down to 1/8 tank on track. Before that I would get limp mode below 1/3 tank left.

This is a completly different issue, tho, than the HPFP crashing under heavy boost and fuel load.

I had or have the same issue. The car was going in a limp mode when there was 1/4 tank left. Street driving. My dealer had replaced the tank. After that the same issue was happening when 1/8 tank left. The dealer reported it to the BMW, and they replied it is a known issue, and it will be fixed by the firmware upgrade.
It took a couple of weeks, but now the firmware is available, and now is running on my car. Not sure if the issue has been fixed - still have more than 1/4 and below 1/2 tank, but we will see.
The I-Step version with the fix is F020-17-11-540.

[ZM2]

Originally Posted by PiK

I had or have the same issue. The car was going in a limp mode when there was 1/4 tank left. Street driving. My dealer had replaced the tank. After that the same issue was happening when 1/8 tank left. The dealer reported it to the BMW, and they replied it is a known issue, and it will be fixed by the firmware upgrade.
It took a couple of weeks, but now the firmware is available, and now is running on my car. Not sure if the issue has been fixed - still have more than 1/4 and below 1/2 tank, but we will see.
The I-Step version with the fix is F020-17-11-540.

Interesting. Dinan and others state the issue happens because the LPFP cannot fill the saddle tank quickly enough under extreme load. Their fix essentially routes more fuel to the saddle tank so there is not a fuel pick up problem.

Dinan’s “hardware” fix cured my issue, so I question if BMW’s “software” fix would. I guess we’ll hear soon enough.

[SeanWRT]

Originally Posted by PiK

I had or have the same issue. The car was going in a limp mode when there was 1/4 tank left. Street driving. My dealer had replaced the tank. After that the same issue was happening when 1/8 tank left. The dealer reported it to the BMW, and they replied it is a known issue, and it will be fixed by the firmware upgrade.
It took a couple of weeks, but now the firmware is available, and now is running on my car. Not sure if the issue has been fixed - still have more than 1/4 and below 1/2 tank, but we will see.
The I-Step version with the fix is F020-17-11-540.
[IMG]http://i65.tinypic.com/s40w8h.png[/IMG]

LPFP issue is exaggerated, as least as it looks to me.

I had two HPDE last year on SH F1 circuit, a very horsepower demanding track - you'll reach factory speed limit point on straight no problem if you have 500+hp.

On FBO + STG1 turbo, I was making no less power than most of stock turbo build that I assume. Pretty sure I was below 1/2 tank all the time (lowest being 1/4~1/5?). I am not a pro racer but I was hard on throttle. No issues whatsoever.

[ZM2]

Originally Posted by SeanWRT

LPFP issue is exaggerated, as least as it looks to me.

I had two HPDE last year on SH F1 circuit, a very horsepower demanding track - you'll reach factory speed limit point on straight no problem if you have 500+hp.

On FBO + STG1 turbo, I was making no less power than most of stock turbo build that I assume. Pretty sure I was below 1/2 tank all the time (lowest being 1/4~1/5?). I am not a pro racer but I was hard on throttle. No issues whatsoever.

It’s a very real issue. Many in the forums have experienced it. It also depends on the track and driver.

I found tracks with more on/off throttle application make the issue worse. The SH F1 circuit is a very wide track relative to most HPDE tracks and has more WOT throttle application vs shorter bursts of on/off throttle.

The more aggressive the driver also makes the issue worse.

[harkes]

Then N55 does not have a LPFP sensor so I dont know what that value being logged is...

I have seen 900psi in my logs without any CEL or hiccups.

[nomade30]

Like all other similar ecus (MEx17’s) it’s calculated LPFP (very bad way of determining problems). I can tell you from my experience in the VAG world, when the lpfp starts to run out of juice the HPFP falls straight on its face. When this happens the ecu will still show lpfp has having enough pressure, due to no sensor.