Low Boost Issue

NoelPR

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Strange. It seems that the logical explanation for this is that Honda stock ECU programming has a maximum amount of fuel that can be used.
Since is colder and the air is way more dense it requires more fuel than usual. So the ceiling of that max fuel value is reached at lower boost levels.
Since the stock ECU programming dont allow more fuel than the maximum limit, the ECU reduces boost.

That is how I see it from my programmer point of view.
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boosted180sx

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Strange. It seems that the logical explanation for this is that Honda stock ECU programming has a maximum amount of fuel that can be used.
Since is colder and the air is way more dense it requires more fuel than usual. So the ceiling of that max fuel value is reached at lower boost levels.
Since the stock ECU programming dont allow more fuel than the maximum limit, the ECU reduces boost.

That is how I see it from my programmer point of view.
I'm pretty sure it has nothing to do with the max amount of fuel that can be used.
Ktuner (or was it Hondata? I forgot) has said that the factory tune targets TORQUE and not boost. If that is true, Colder Air = ability to run more timing = less boost required to hit the torque target.
Which is why you have less boost in colder weather.
 

tapakidney

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I'm pretty sure it has nothing to do with the max amount of fuel that can be used.
Ktuner (or was it Hondata? I forgot) has said that the factory tune targets TORQUE and not boost. If that is true, Colder Air = ability to run more timing = less boost required to hit the torque target.
Which is why you have less boost in colder weather.
I've been sort of agonizing over this, and your explanation makes sense to me. These lower boost numbers I'm seeing during the cold, they're not necessarily a problem, because I may just be hitting my torque numbers without the full boost (cause the boost I have is better in the cold, due to air density). Is that roughly correct?
 

charleswrivers

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You're spot on. More dense air = more O2 content per volume of air. You need less pressure above atmosphere worth of boost because the density is so much higher.

That's also, on the flip side where those of us running more boost are getting a *lot* more power. I'm only running 21 psi. By my reckoning, I'm probably making more power in the winter at 21 psi than I'd make in the summer at 23 psi and I just wanted a bump in power with better throttle response while remaining on the stock clutch and 21 is doing exactly what I want.
 

jaydubz79

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So to add to this thread.

Ambient air temps were around 54 degrees when I did the test. The car is bone stock with just shy of 8000 mi on the clock. I did a pull in 2nd and in 3rd, the highest I ever saw was about 13-14 psi I believe. Does this sound normal?
 


tehSteve

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So to add to this thread.

Ambient air temps were around 54 degrees when I did the test. The car is bone stock with just shy of 8000 mi on the clock. I did a pull in 2nd and in 3rd, the highest I ever saw was about 13-14 psi I believe. Does this sound normal?
Resurrecting thread. I decided to flash my car to stock this morning. 50 degrees in jersey. Didn’t see more than 13psi on 93oct. Unless they still have a winter blend at the gas stations, no idea what the problem is. I was about 3krpm in 3rd and went WOT. Then 4th gear same thing. Maybe I should try 2nd?

Vacuum was also @ -11 idle , no mods

Or am I just reaching all my target levels with less boost?
 
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odinist

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Mid 80's here in OK. Noticed yesterday or day before I saw 21 on my boost gauge when I got on it hard. Not tuned. When it was in the 50s/60s a lot last month I rarely saw 18.

It's making the boost it needs to make, to make the power numbers it's supposed to be hitting. Simple as that.
 

tehSteve

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Is -11 on the vacuum normal? Should I be at -10,-9,-8?
 

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Is -11 on the vacuum normal? Should I be at -10,-9,-8?
I think the best way to gauge this, is to take your car to the track. If you are in the 14.5-15.0 range in the 1/4 mile, on a stock tune, then you are fine. You might be stuck down a rabbit hole on this one. Boost pressure can differ greatly based on the ambient air temperature and humidity. Sounds like the car is doing what it should, unless you notice a significant change in performance.
 
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Akalawur77

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As temps have been slowly rising I've been noticing some increase in boost. It's been hovering in the 60's here in PA and I'm seeing about 15-16psi vs 12-14psi in the winter. I understand that this is intentional on the stock map, but I've never seen a stock tune vary so greatly and run considerably under advertised boost
 


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Resurrecting thread. I decided to flash my car to stock this morning. 50 degrees in jersey. Didn’t see more than 13psi on 93oct. Unless they still have a winter blend at the gas stations, no idea what the problem is. I was about 3krpm in 3rd and went WOT. Then 4th gear same thing. Maybe I should try 2nd?

Vacuum was also @ -11 idle , no mods

Or am I just reaching all my target levels with less boost?
FWIW - also in NJ. Flashed with Hondata +9 map. Bone stock. See 25-26 psi in sport mode anytime. Back when I was stock I would see 16-18 psi, and actually seemed to build boost easier in "normal" vs "stock" which was annoying (as was not seeing the 20 psi they advertise).
 

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FWIW - also in NJ. Flashed with Hondata +9 map. Bone stock. See 25-26 psi in sport mode anytime. Back when I was stock I would see 16-18 psi, and actually seemed to build boost easier in "normal" vs "stock" which was annoying (as was not seeing the 20 psi they advertise).
I'll try a 2nd gear pull today. Should be 70 degrees. I have limited areas to do pulls where I live lol. And go figure rush hour traffic. What gear should I do?
 

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If its anything like the Focus ST and Fiesta ST that I had prior to the SI then there is a set power number the ECU is trying to hit, thus causing your turbo pressure to vary. In other words its normal.

Is our boost gauge an accurate gauge? I had something similar in the Mazdaspeed 3 and it was just a fake gauge. Boost was limited in 1st and 2nd gear (I think both or just 1st) and it would show erroneously that those gears were at the same boost as 3rd gear.
 

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I'll try a 2nd gear pull today. Should be 70 degrees. I have limited areas to do pulls where I live lol. And go figure rush hour traffic. What gear should I do?
I hit the target boost in 1-4 for sure, probably the overdriven gears too, but I would never WOT in those. Scramble boost lets me hit up to 15psi on the parkway in cruise control in 6th, I've learned to turn off sport mode on the parkway.
 

Micah

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If its anything like the Focus ST and Fiesta ST that I had prior to the SI then there is a set power number the ECU is trying to hit, thus causing your turbo pressure to vary. In other words its normal.

Is our boost gauge an accurate gauge? I had something similar in the Mazdaspeed 3 and it was just a fake gauge. Boost was limited in 1st and 2nd gear (I think both or just 1st) and it would show erroneously that those gears were at the same boost as 3rd gear.
Only way to know for sure is to connect a known good accurate gauge. I can say that what I am seeing on the dash matches what I see in Hondata..... so it's not purposefully misleading us. I sure as hell hope the other readings are accurate(IAT, IAT2, AFR, MAP, 12V, etc....).
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