Boost Pressure Low

[Acraig3]

Hey all,

I've been running the @KTuner V1.2 for a while now and I am really enjoying it thus far. The issue I am having is that my target boost under WOT should be near 22.5PSI shown in the first picture below, although, it is nowhere near that value.

Now When i am running full throttle at 4500 RPM (above) it is only mapping a target PSI of 13.9. My datalog reads that target pressure is at 14.6 (Below) and I am only seeing 14.6PSI from the MAP.

The following Picture shows the boost target in "Normal mode" under the exact same conditions (all pulled from same point in datalog. So here it shows I should be targeting 21PSI. So why am I not seeing target pressures near the 21-22.5 range and am only seeing a target pressure of 14.6PSI?

Thanks a bunch everyone,

Alex

 

[KTuner]

If you're not at sea level you need to offset for your atmospheric pressure difference.

The highlighted points in the maps you're showing are where you have clicked, not a trace.

 

[Acraig3]

If you're not at sea level you need to offset for your atmospheric pressure difference.

The highlighted points in the maps you're showing are where you have clicked, not a trace.

So I tried a few things... I checked ignition timing, matches that of stock. I adjusted boost tables... The way ktuner has it laid out, the header is ambient air pressure, the first column is rpm... I adjusted ambient air pressure at -3.5psi (6000ft elevation) to 21 psi. I also adjusted fuel enrichment under WOT to 11.3 along with slightly adjusting the cylinder fill limitations.
By my calculations a 1.5 liter engine should have a cylinder fill of ~375mg/stk without boost. So running 14psi of boost should yeild a cylinder fill of ~750mg/stk. The way this table is laid out is that if knock retard is 4 deg then cylinder fill limits to ~650mg/stk. This would explain why I can't make more than 14.8psi and it slowly drops to ~13psi. I am afraid to adjust those tables though as they are most definitely a safety factor. Out here in Colorado all we get is 91 octane e10 or ethanol free 91. I started running ethanol free to see if that would help knock retard and so far, hasn't changed anything.
I think my best bet will be e30-e40 blend with a flex fuel converter.

 

[KTuner]

So I tried a few things... I checked ignition timing, matches that of stock. I adjusted boost tables... The way ktuner has it laid out, the header is ambient air pressure, the first column is rpm... I adjusted ambient air pressure at -3.5psi (6000ft elevation) to 21 psi. I also adjusted fuel enrichment under WOT to 11.3 along with slightly adjusting the cylinder fill limitations.
By my calculations a 1.5 liter engine should have a cylinder fill of ~375mg/stk without boost. So running 14psi of boost should yeild a cylinder fill of ~750mg/stk. The way this table is laid out is that if knock retard is 4 deg then cylinder fill limits to ~650mg/stk. This would explain why I can't make more than 14.8psi and it slowly drops to ~13psi. I am afraid to adjust those tables though as they are most definitely a safety factor. Out here in Colorado all we get is 91 octane e10 or ethanol free 91. I started running ethanol free to see if that would help knock retard and so far, hasn't changed anything.
I think my best bet will be e30-e40 blend with a flex fuel converter.

mg/stk is calculated from airflow, not boost pressure.

Download the version from the website as it adds tracing to the boost target tables.

 

[Acraig3]

mg/stk is calculated from airflow, not boost pressure.

Download the version from the website as it adds tracing to the boost target tables.

The latest version adds tracing to Target boost tables? I'll get right on that.

And the cylinder fill limitation would limit boost though, correct? Airflow is a function of boost pressure .

 

[KTuner]

The latest version adds tracing to Target boost tables? I'll get right on that.

And the cylinder fill limitation would limit boost though, correct? Airflow is a function of boost pressure .

It would pull back throttle, which would lower boost, but you'd notice throttle pullback in datalogging.

 

[Acraig3]

So after some discussion with ktuner, it seems as though I may be hitting a limiter set by Honda in order to protect the turbo from overspinning. If anyone has had any issues with this please feel free to comment .

 

[bgutierrezx]

So after some discussion with ktuner, it seems as though I may be hitting a limiter set by Honda in order to protect the turbo from overspinning. If anyone has had any issues with this please feel free to comment .

Did you ever fix this ?What part of Colorado? I’m on the same boat. I want to say it’s a lack of knowledge of tuning??. I had my car pushing 21psi with some good pull. Anyways I achieved that by switching all sorts of tabs & what not. I thought I could get more and I ended switching my tune & totally forgetting what I had done before & of course I didn’t save it either. Now I’m stuck at 17psi and I don’t have the same torque. Feels like I have a stage 0 with 17psi.....

 

[Acraig3]

Did you ever fix this ?What part of Colorado? I’m on the same boat. I want to say it’s a lack of knowledge of tuning??. I had my car pushing 21psi with some good pull. Anyways I achieved that by switching all sorts of tabs & what not. I thought I could get more and I ended switching my tune & totally forgetting what I had done before & of course I didn’t save it either. Now I’m stuck at 17psi and I don’t have the same torque. Feels like I have a stage 0 with 17psi.....

No, ktuner wrote it off to being a hard limit set by Honda. I would like to know what you had switched to get 21 lbs! I decided to tune for straight e85 and increase timing a bit to get some power that way. Ended up back to stock for a while as I have developed a strange noise in my CV axle and need to take it to the dealer. I would love to get 21 lbs and get back to my e85 tune though .If you'd like, I could send you my tune, it pulled hard, 14s at the drag strip running stock tires. PM me with your email if you wish! It was a really nice tune, fuelling handled it nicely at the 16ish lbs that I was getting.

I'm in Colorado springs btw

 

[bgutierrezx]

No, ktuner wrote it off to being a hard limit set by Honda. I would like to know what you had switched to get 21 lbs! I decided to tune for straight e85 and increase timing a bit to get some power that way. Ended up back to stock for a while as I have developed a strange noise in my CV axle and need to take it to the dealer. I would love to get 21 lbs and get back to my e85 tune though .If you'd like, I could send you my tune, it pulled hard, 14s at the drag strip running stock tires. PM me with your email if you wish! It was a really nice tune, fuelling handled it nicely at the 16ish lbs that I was getting.

I'm in Colorado springs btw

May explain why I only got it once ? & I couldn’t tell you, i forgot. (Sadly!) & shoot me your number in a pm. I’m over at ft Carson but I live Pueblo with my girl. I’d love to see those pulls in person. & idk how you’d feel about sharing your tune now since we’re in the same city ha but I’d definitely take you on that offer. Do you go to the 719 street scene meets ?

 

[Diegooosiso]

No, ktuner wrote it off to being a hard limit set by Honda. I would like to know what you had switched to get 21 lbs! I decided to tune for straight e85 and increase timing a bit to get some power that way. Ended up back to stock for a while as I have developed a strange noise in my CV axle and need to take it to the dealer. I would love to get 21 lbs and get back to my e85 tune though .If you'd like, I could send you my tune, it pulled hard, 14s at the drag strip running stock tires. PM me with your email if you wish! It was a really nice tune, fuelling handled it nicely at the 16ish lbs that I was getting.

I'm in Colorado springs btw

Can y’all share the time with me or the solution? I’m at 18psi only getting 14.5, I’m in Colorado centennial

 

[KTuner]

It's about absolute pressure, which is what you see in KTuner, and relative pressure, which factors in your elevation to offset that pressure.

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