[TampaF87]

I'm currently waiting on delivery for my MY18 M2 (October), and I've read quite a bit about much of the common issues, quirks and things to pay attention to. I'm noticing that a lot of the limitations come down to fueling, and potentially the HPFP not being up to snuff for anything much beyond the limitations of the factory turbo. As with other platforms that have HPFP limitations, the aftermarket has come with revised/upgraded units to fill the gap. Has any of the major companies, especially the tuners, looked into exactly which part of the fuel system is the weak link? If in fact it is the HPFP, are there any plans in the works for an upgraded unit?

I know that I don't even have the car yet, and this is purely from a point of looking at the tuning headroom to work with later on down the road should I decide to go that route, but I like to know what I'm working with a little bit. It's a fairly new platform, but I feel ~2 years is an adequate amount of time to be able to find common mechanical limitations on ancillary parts. Thanks in advance guys.

[rwalker]

HPFP is pretty well known to be the bottleneck for fueling on the N55. The only real solutions on offer today are supplemental fueling via meth, throttle body injection, or port injection. No one offers an upgraded HPFP worth considering.

The S55 uses a double, parallel HPFP setup, but no one is working on adapting that to the N55, because port injection is cheaper (for the end user) and more profitable (for the tuners).

[SeanWRT]

To my knowledge, for n55 nobody has ever provided a HPFP upgrade yet, nor is anyone working on it. Most likely nobody ever will. Because of the cost in developing such a thing and selling price being far more than market agrees. These day everybody is chasing cheap horsepower.

[switlikbob]

I know this is a bit off topic, but I'd like to see an aftermarket intake manifold developed with a second set of fuel injectors, ran to a Walbro in tank pump. That would likely solve fueling issues. Managing it though, is a whole different issue.

[rwalker]

Originally Posted by switlikbob

I know this is a bit off topic, but I'd like to see an aftermarket intake manifold developed with a second set of fuel injectors, ran to a Walbro in tank pump. That would likely solve fueling issues. Managing it though, is a whole different issue.

That is essentially exactly what you get with a port injection (PI) setup. An upgraded LPFP is a prerequisite to PI.

[FSociety]

Originally Posted by switlikbob

I know this is a bit off topic, but I'd like to see an aftermarket intake manifold developed with a second set of fuel injectors, ran to a Walbro in tank pump. That would likely solve fueling issues. Managing it though, is a whole different issue.

https://www.eospeed.com/ is working on this

[TampaF87]

That's disappointing to hear. Part of the appeal of using DI is because of it's in-cylinder cooling benefits. Resorting to using older, albeit familiar, tech like PI is just a bandaid, not really much of a solution.

In other platforms I have seen development for HPFP internals that handle higher loads and are simple internal swap kits for a very fair price point, not exactly an entire replacement. I figured that something would be available considering BMW's in general are more up market anyways, and certainly a healthy enthusiast market. Ah well, gotta work with what you got. Are these entire fuel systems, or are we just talking larger injectors and a higher volume LPFP?

[switlikbob]

Originally Posted by rwalker

That is essentially exactly what you get with a port injection (PI) setup. An upgraded LPFP is a prerequisite to PI.

I thought the PI kits usually shoot meth, not gasoline? maybe I'm a bit behind on the times, LOL.

[rwalker]

Originally Posted by switlikbob

I thought the PI kits usually shoot meth, not gasoline? maybe I'm a bit behind on the times, LOL.

http://www.fuel-it.biz/f-series-fuel-system-upgrades/

[FSociety]

Originally Posted by switlikbob

I thought the PI kits usually shoot meth, not gasoline? maybe I'm a bit behind on the times, LOL.

for BMW PI shoot E85 but there's also Direct Meth Injection

[stefan]

Is it really that problematic? I am surprised dinan didn't see this as an issue in their p2 kit. I agree hpfp always seems to be a bottleneck. But I am surprised dinan felt the need to not address.

[TampaF87]

Originally Posted by stefan

Is it really that problematic? I am surprised dinan didn't see this as an issue in their p2 kit. I agree hpfp always seems to be a bottleneck. But I am surprised dinan felt the need to not address.

They may not have mentioned it, but I'm fairly sure that with their revised turbine can flow 500. We all know they tend to be more conservative for reliability reasons, but maybe they reached the upper safe limit of fuel. You'd think that with a "big turbo" upgrade you'd be getting more than 80-100hp, but that's just my opinion.

[goodstuff448]

I saw this on the Dinan website. Thinking it maybe the solution. There is also a hose kit. I took a road trip to la and found that at a certain speed with jb4 and upgrades the hpfp is definitely the issue. It was disappointing.

[SeanWRT]

Originally Posted by goodstuff448

I saw this on the Dinan website. Thinking it maybe the solution. There is also a hose kit. I took a road trip to la and found that at a certain speed with jb4 and upgrades the hpfp is definitely the issue. It was disappointing.

Dinan pump is a lpfp.

BTW on what JB4 map did you see fueling issue? And your hardware mods?

A few of us long term tested different JB4 maps including custom ones, and pushed as hard as we can, but fueling seemed not an issue with piggyback that tends to run lean.

[goodstuff448]

JB4 maps 1 and 2. Akra exhaust, vrsf intercooler, vrsf catless **, removed intake due to pcv code 120E20. The hpfp kept crashing. Logs were checked out by bms.

[FSociety]

Originally Posted by SeanWRT

Dinan pump is a lpfp.

BTW on what JB4 map did you see fueling issue? And your hardware mods?

A few of us long term tested different JB4 maps including custom ones, and pushed as hard as we can, but fueling seemed not an issue with piggyback that tends to run lean.

Any dynos or logs or threads on JB4 not crashing HPFP ?
As far as my research goes, all my M2 friends were crashing until EWG11 came out that means a full year of unable to run higher than map1.

Originally Posted by goodstuff448

JB4 maps 1 and 2. Akra exhaust, vrsf intercooler, vrsf catless **, removed intake due to pcv code 120E20. The hpfp kept crashing. Logs were checked out by bms.

What firmware are you on? FOL settings?

[SeanWRT]

Originally Posted by FSociety

Any dynos or logs or threads on JB4 not crashing HPFP ?
As far as my research goes, all my M2 friends were crashing until EWG11 came out that means a full year of unable to run higher than map1.

Not my car, but this is a 5th gear run on map6.

[FSociety]

Originally Posted by SeanWRT

Not my car, but this is a 5th gear run on map6.

Trims that low & AFR that low, and AVG_IGN , means there's a Backend Flash involved.

Fuel Pressure looks stable

[SeanWRT]

Originally Posted by FSociety

Trims that low & AFR that low, and AVG_IGN , means there's a Backend Flash involved.

Fuel Pressure looks stable

No BEF actually, stock flash with JB4.

I tend to believe m2 stock flash itself would be a good BEF if it wasn't for its top end throttle closure strategy...At least in stock tune, it runs extremely rich at higher rpms as a safety measure - kill power big time while is good for piggyback to lean it up a little bit.

And I thought timing isn't bad either, except for the rpms of throttle closure on overboost, which is normal with stock flash.

Your thoughts?

[FSociety]

Originally Posted by SeanWRT

No BEF actually, stock flash with JB4.

I tend to believe m2 stock flash itself would be a good BEF if it wasn't for its top end throttle closure strategy...At least in stock tune, it runs extremely rich at higher rpms as a safety measure - kill power big time while is good for piggyback to lean it up a little bit.

And I thought timing isn't bad either, except for the rpms of throttle closure on overboost, which is normal with stock flash.

Your thoughts?

Never seen avg_ign at 0, trims/AFR that low on stock flash in M2. Maybe they have racegas ?

Otherwise you're right

[blackholescion]

The real main issue on fueling until you get to stupid levels of power is the saddle tank. If you run the car below half a tank with prolonged periods of acceleration, the pump that feeds the saddle (where the pump to send fuel to the motor resides) can't keep up and so you get fuel cuts.

People have ran 500WHP without too much issue until you get up to roughly 6500RPM. If your goal is 500WHP, look into a different solution (PI, lpfp, meth, e85, etc.). Otherwise, you should be fine.

[TT1351]

On the Dinan site, they offer a complete pump or just the hose kit for $600 less, which allows you to modify existing HPFP. Looks like bigger hoses and some other connectors that from the photos looks like they may flow better, IDK