Diagnosing a weak hpfp

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Sergeant
Jul 27, 2017
330
134
0
Ride
335i
Hello guys,
for about 4 years now I've run meth injection on my 335i. I felt before I got the meth that my hpfp was quite weak but this was back before flash tunes and many other things. It wasn't possible to raise fuel scalars back then.

So asking for the advice of the forum members here. How much boost do you think a FBO car should be able to run without meth injection? Purely pump gas and no ethanol. I know ethanol will increase fuel demand in order to hit the lambda/AFR targets. I also know that pump gas will be knock limited. I couldn't expect to target 30 psi. Boost is just a useful value to use because as boost goes up, so does fuel demand. I have a stage 2 lpfp so the low pressure delivery shouldn't be a limiting factor.
However to complicate things I'm running GC turbos. So the volume of air at x psi wont be the same as x psi on stock turbos. Ultimately it should flow a much greater volume of air.

So a strong\healthy hpfp should maybe cope with 20 psi on hybrids? What do you think.
 

Rob09msport

Major
Oct 28, 2017
1,928
662
0
Monroe CT
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09 335i msport le mans 18 x5
You gave 2hrs for a response and you really need to post a log but on e85 I believe your only good for like 450 whp e50 you can go low 500s but even a healthy pump needs help to use gcs to potential I would think 20psi is right around edge
 
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martymil

Colonel
Sep 6, 2017
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Down Under @ madautodevelopments
madautodevelopments.com
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BMW 1 Series M
I'm testing this atm but running a double barrel and a stage 3 on gc 2.0 with a ff manifold and a monster ic by MAD.

It really depends a lot of factors and each car is different.

Im aming to hit around 550 to 570hp with no meth or octane booster.

Still a week or so from getting/posting some results.
 

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Sergeant
Jul 27, 2017
330
134
0
Ride
335i
You gave 2hrs for a response and you really need to post a log but on e85 I believe your only good for like 450 whp e50 you can go low 500s but even a healthy pump needs help to use gcs to potential I would think 20psi is right around edge

Whoops. Didn't realise it was only 2 hrs. Was up all night with my 2 month old. Lost track of the time.

I'm pretty sure I can do 20 psi. Had a blockage in my port injection once. So boosted to 23 psi before the hpfp pressure took a dive. I know I can't do 23 but I was wondering what kind of levels people do attain.
 

MoreBoost

Sergeant
Jul 27, 2017
330
134
0
Ride
335i
I'm testing this atm but running a double barrel and a stage 3 on gc 2.0 with a ff manifold and a monster ic by MAD.

It really depends a lot of factors and each car is different.

Im aming to hit around 550 to 570hp with no meth or octane booster.

Still a week or so from getting/posting some results.

Cool martymil,
Look forward to seeing what you find. I would like an uprated DI solution some day.
 

buster84

Corporal
Mar 24, 2018
240
91
0
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335 bmw xdrive
I will say that. On 93 I run 25psi on my GCs and my hpfp cant keep up. I need a little PI to not go lean. I wouldnt run anything more than 20psi on 93 and definitely no amount of e85 at that psi level.

These GCs put put alot of air and you will run out of fuel if you dont have alternate fuel sources. A log will tell alot more about what you can handle, but from my experience I'd not touch e85 with these turbos until you get upgraded fuel. 93 is plenty and at 20psi your at least at 450 or so hp. You might be able to squeeze 22psi but if you go lean your just taking a risk that's not needed. Go PI or Double barrel and never look back. You'll be so glad you did once you do it.
 

buster84

Corporal
Mar 24, 2018
240
91
0
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335 bmw xdrive
I took a log the other day after swapping back to 93 (from my e85 tune) I also updated my JB4 firmware and it messed up all my port injection settings. What worked before no longer worked now, i had to double/tripple my settings to get it back in line. Im guessing it had to do with scaling.

My port injection was way to low in this log and it caused my trims to max out, but my air fuel ratio was good. I actually was about to delete this log since its old, but i just remembered i had it and thought it would be a good log for you to see that my hpfp is maxed already and my port injection was barley keep it aflout at 25psi (with small spikes to 26), without the little bit of port injection fuel I would have been lean for sure. I would not take the GC's above 20psi on 93 without port injection. Your already running low because these turbos output alot of air. If you plan to run e85, dont. You are really risking it with 93 and any extra ethanol is not worth the risk. Youd need to drop it down to 12-15psi for maybe e40-e50. Stick to full gas until you can get alternate fueling.

https://datazap.me/u/buster84/gc-20-3rd-gear?log=0&data=1-4-7-10-14-17-18-24-33-35
 
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LessIsMore

Specialist
Aug 21, 2017
56
22
0
Ride
09 535i
Start low on boost, 13 psi or so, and log wot 3rd gear pulls to check the HPFP signal. If it is above 9 or so, try a nother psi or two. If HPFP starts to get too low (9 or below) in the log, dial the boost back. Settle on a good boost level.
Every car is different, and you think your hpfp is weak, so trial and error.
 
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Sergeant
Jul 27, 2017
330
134
0
Ride
335i
Start low on boost, 13 psi or so, and log wot 3rd gear pulls to check the HPFP signal. If it is above 9 or so, try a nother psi or two. If HPFP starts to get too low (9 or below) in the log, dial the boost back. Settle on a good boost level.
Every car is different, and you think your hpfp is weak, so trial and error.

Yes I get every car is different. Be it different revisions of the hpfp or greater amounts of wear and tear.
I was wondering what levels people hit.
As if my pump maxes out at 15 psi on pump gas then people might say a healthy pump should do 18 to 20 psi.
I run meth port injection but if I can be sure my hpfp is weak then I'm able to get it replaced now.
 

MoreBoost

Sergeant
Jul 27, 2017
330
134
0
Ride
335i
I took a log the other day after swapping back to 93 (from my e85 tune) I also updated my JB4 firmware and it messed up all my port injection settings. What worked before no longer worked now, i had to double/tripple my settings to get it back in line. Im guessing it had to do with scaling.

My port injection was way to low in this log and it caused my trims to max out, but my air fuel ratio was good. I actually was about to delete this log since its old, but i just remembered i had it and thought it would be a good log for you to see that my hpfp is maxed already and my port injection was barley keep it aflout at 25psi (with small spikes to 26), without the little bit of port injection fuel I would have been lean for sure. I would not take the GC's above 20psi on 93 without port injection. Your already running low because these turbos output alot of air. If you plan to run e85, dont. You are really risking it with 93 and any extra ethanol is not worth the risk. Youd need to drop it down to 12-15psi for maybe e40-e50. Stick to full gas until you can get alternate fueling.

https://datazap.me/u/buster84/gc-20-3rd-gear?log=0&data=1-4-7-10-14-17-18-24-33-35

My normal setup is port injected meth. With that I run about 25 psi typically. However I had a blockage and the hpfp just couldn't supply enough fuel. I'd never expect it to at such high boost. It reminded me though that before I fitted meth, my car really seemed to struggle on just pump gas. So I want to do some testing and if it's weak then slap in a new hpfp. In the future the double shotgun upgrade might be an option I go for.

I do like the GCs though. Running 25 but I'm sure with some other mods 30 psi would be possible.
 

LessIsMore

Specialist
Aug 21, 2017
56
22
0
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09 535i
Yes I get every car is different. Be it different revisions of the hpfp or greater amounts of wear and tear.
I was wondering what levels people hit.
As if my pump maxes out at 15 psi on pump gas then people might say a healthy pump should do 18 to 20 psi.

Nobody can actually truthfully say "a healthy pump can do XX psi" at all. Since cfm at a given boost depends on many things (turbo choice, other mods, ambient temp/conditions, elevation, etc.), boost level isnt a great comparison tool for what an HPFP can do. Dyno HP would be better. But it boils down to what YOUR particular car is showing for HPFP pressure based on your boost level.
 

dyezak

Major
May 4, 2017
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Plano TX
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335is
I can say this. A healthy HPFP will hold full 100% E85 on an FBO stock turbo car and put down about 500wtq and ~420whp. You will be limited by the HPFP at that point. You can make more power by dropping the ethanol percentage but for a statement on what a healthy HPFP can do...that's about the limit from a fueling perspective.
 
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Sergeant
Jul 27, 2017
330
134
0
Ride
335i
I can say this. A healthy HPFP will hold full 100% E85 on an FBO stock turbo car and put down about 500wtq and ~420whp. You will be limited by the HPFP at that point. You can make more power by dropping the ethanol percentage but for a statement on what a healthy HPFP can do...that's about the limit from a fueling perspective.

Unfortunately no E85 available in England so I'll be testing on the equivalent of 93 octane pump gas.

From what I recall I think my car struggled at 15 psi on stock turbos (and pump gas) but it's been a really long time. So I'll load a pump flash on and do some tests. If it's weak I'll look to get it replaced soon.