Safety margins LPFP and HPFP

[Tommix]

I have some issues with custom E85 map. I look at the log and I wonder what is the minimum pressure for LPFP and HPFP?

From my log
LPFP min 78 psi
HPFP mean 3200 psi
HPFP target 3500 psi

Thanks for advice.

[TopJimmy]

As long as your LPFP doesn't dip into the 50s under load you're good. When I ran short the LPFP dipped under 50 and then the HPFP pressure dropped.

If your HPFP seems short then try the Original setting. Some seem to need that set in BM3 for HPFPs to hit high pressure.

[Tommix]

Originally Posted by TopJimmy

As long as your LPFP doesn't dip into the 50s under load you're good. When I ran short the LPFP dipped under 50 and then the HPFP pressure dropped.

If your HPFP seems short then try the Original setting. Some seem to need that set in BM3 for HPFPs to hit high pressure.

Thanks for this info. I'm little bit confused, for some reason my car runs perfectly untill 6500 rpm and after that it misfires every time. Typically fault codes are: "cyl 1 or cyl 6 Fuel injection is switched off" and "Combustion misfires, several cylinders: Fuel injection is switched off." So I assumed the fuel system is the problem?
Here is last log:

https://datazap.me/u/tommix/e85-cust...og=0&data=4-24
My tuner is also confused.

car and mods:
BMW M4 2015. ~41 500 miles, DCT, Catles DP:s, MHD Custom E85 map, xHP Stage3, NGK F8S (cap 0,020"), Drop in K&N Air filters, aftermarket CP:s.
Coils and Injectors EU6 BOSCH.

Car runs perfectly when I use stage 2 93 ron OTS or E85 OTS maps...

[TopJimmy]

Sorry, I don't know MHD.
(meaning: hard to read DataZap)

[luchocamp]

stock fuel system has limits that is most of S55 users add Meth Injection or use less E85 content.

if you know how to use an HP calculator you will still know how to use a CASIO even though the keys are in different places, they are just tools

[Tommix]

Originally Posted by luchocamp

stock fuel system has limits that is most of S55 users add Meth Injection or use less E85 content.

if you know how to use an HP calculator you will still know how to use a CASIO even though the keys are in different places, they are just tools

S55 should work perfectly with full e85 custom map (for example Gary Jordan tune) and with stock fuel system and turbos. Jordan tune makes ~580 whp (26-27 psi). And I'm way under that level now (only 22 - 23 psi). So I'm just wondering if there's an problem in fuel sopply (?) or is the tune just bad?
I can change the tuner but I don't want to do it until I know there's nothing wrong with the engine.


I'm sorry about my poor English but I hope You got the picture.

Thanks for the advice

[TopJimmy]

Originally Posted by Tommix

S55 should work perfectly with full e85 custom map (for example Gary Jordan tune) and with stock fuel system and turbos. Jordan tune makes ~580 whp (26-27 psi). And I'm way under that level now (only 22 - 23 psi). So I'm just wondering if there's an problem in fuel sopply (?) or is the tune just bad?
I can change the tuner but I don't want to do it until I know there's nothing wrong with the engine.


I'm sorry about my poor English but I hope You got the picture.

Thanks for the advice

Fuel supply looks fine to me:
6300RPM
76PSI LPFP
3480PSI HPFP Requested
3255PSI HPFP Actual

It's hard to see on my phone but STFTs might be running different. If that's so then maybe an injector isn't happy. I'm not sure.

Did your tuner review your logs?

[hellokitty]

Originally Posted by luchocamp

stock fuel system has limits that is most of S55 users add Meth Injection or use less E85 content.

if you know how to use an HP calculator you will still know how to use a CASIO even though the keys are in different places, they are just tools

S55 can run full e85 on stock turbos with no issues.

OP: When was the last time you changed spark plugs and coils? What spark plugs?

I would start there then go down the path of whether it's an injector issue.

[Tommix]

Originally Posted by TopJimmy

Fuel supply looks fine to me:
6300RPM
76PSI LPFP
3480PSI HPFP Requested
3255PSI HPFP

I agree, I think both values seem to be at an acceptable level.

Originally Posted by TopJimmy

hard to see on my phone but STFTs might be running different. If that's so then maybe an injector isn't happy. I'm not sure.

This is possible. I am turning to this issue. I have heard several cases where new Bosch injectors have proven to be faulty (tuned engines)...

Originally Posted by TopJimmy

your tuner review your logs?

Yes, but I do not think he has a clear idea/solution to this problem.
I thought there would be an expert on this forum who could suggest what is wrong with the engine? Or is the engine OK but there might be some issues in tune?
It's always guesseing about these things, but guesses are better than nothing.
Let's speculate guys

Originally Posted by hellokitty

S55 can run full e85 on stock turbos with no issues.

OP: When was the last time you changed spark plugs and coils? What spark plugs?

I would start there then go down the path of whether it's an injector issue.

Sparks are brand new NGK F8S, gapped 0.02"
Coils (OEM) have been driven ~4,000 miles
Injectors (Bosch EU6) have been driven ~2,500 miles

Thank you in advance

[TopJimmy]

Perhaps you've run Boostane or another booster and partly clogged an O2 sensor with powder (Boostane does that)?

Maybe turned up burbles and AG, and cooked an 02?

Only the upper O2sensors detect Lambda for AFR… maybe look there.

[Tommix]

Originally Posted by TopJimmy

Perhaps you've run Boostane or another booster and partly clogged an O2 sensor with powder (Boostane does that)?

Maybe turned up burbles and AG, and cooked an 02?

Only the upper O2sensors detect Lambda for AFR… maybe look there.

I've never run Boostane or nothing else booster. But this Lambda hint is good. I have to monitor live data and compare bank 1 and 2 O2 sensors values.