Whats your max Karman reading

[pickens]

I was wondering, since karmans translate into airflow, and airflow translates into horsepower, where are everybodies readings hovering around at? It seems to me that mine are maybe a little on the low side. But then I don't have many mods.

small 16g (17psi)
3" cat-back
No cat though
RC550s
AFC

The karman readings on my AFC are usually 1800-1850Hz w/ out boost spiking.

 

[yo2001]

I think mine is about that on 17 psi. I see 22xxhz at 20psi with 7500rpm redline

 

[98autogstspyder]

I have a evo316g at about 18- 20 psi (depends on what it feels like boosting) and my max reading so far has been around 2017. Something to that effect.

A friend of mine has the same turbo at 20 psi and got 2200 hz.

Tyler

 

[90AWDTalon]

I've hit 2802hz with my small 16g creeping to 24psi.

 

[Kevin Jewer]

Just for the sake of being "correct," Hz isnt airflow alone, baro pressure and intake temp must be combined with it for that number to mean anything. There has been a lot of good discussion on this subject in past years if anyone is interested in how it all relates. That being said, my max airflow is about 3800 Hz. I dont log it very often though. Its also worth noting that 1gs tend to read higher than 2gs, so you cant readily compare Hz values across generations.

 

[scottr126]

what the hell, now i feel left out, I max out at about 1603Hz all the time pretty much under any boost. is this normal?? I have a big 16g.

 

[KeltonDSMer]

This is completely irrelevant because every mas reads differently. The reason putting a 2G MAS and 550s in a 1G and having it balance out is because the 2G MAS reads about 25% less Karman than the 1G and the 550s are 25% bigger than the 440s.

These air meters create a regular turbulance in the intake that is then measured in frequency, so hacking them screws with the turbulance which means it will read differently. This is why a common fix for fuel cut is to hack the MAS; the turbulance is reduced so the ECU thinks less air is entering the motor. AFC readings and pretty much any fuel controller that is a piggy back totally screw the readings too because they work by altering the airflow value in the first place. Any positive setting is proportionately incresing the value, and vise versa for negative settings.

This also explains why you can't use these air sensors in the IC pipes becuase the predictable "turbulance" would be affected under pressure.

 

[CanadianTSi]

what the hell, now i feel left out, I max out at about 1603Hz all the time pretty much under any boost. is this normal?? I have a big 16g.

Your reading your Hz off your Logger...thats the highest value the logger will show even though your actual value is higher.

Also I see about 1350 on my t-25

 

[DSM_23]

I get about 2250Hz on my car with a 14b at 18psi

 

[gsxtacy]

When my 98' GSX was pretty stock (turbo, exhaust, injectors) but I had a air filter, MBC, UICP, Inlet pipe, LICP,stock smic......@ 16 psi I was seeing 1450 hz on the T25.

When I upgraded to the Big28 I instantly saw over 2000, and my peak HZ I have ever seen was at 19 psi....2235 hz.

I am going to do the Dodgemod to my 1G Bov, and see if it picks up any more "seat of the pants" Hp.

Hopefully the boost that isn't escaping over 17 psi will pick up some more power.

GSXTACY

 

[90AWDTalon]

AFC readings and pretty much any fuel controller that is a piggy back totally screw the readings too because they work by altering the airflow value in the first place. Any positive setting is proportionately incresing the value, and vise versa for negative settings.

I don't know about other tunning devices but with the emanage I can log reading's before correction and after correction. For example when I logged that 2802 reading, the reading after correction was around 1800. Which matches my injector correction value perfectly.

 

[KeltonDSMer]

That makes sense but I'm just trying to say that it really doesn't mean anything if you are reading a value that has been skewed; this basically means that adding bigger injectors and taking away fuel on an AFC or something will make the karman value drop, even though the airflow hasn't.

 

[90AWDTalon]

That makes sense but I'm just trying to say that it really doesn't mean anything if you are reading a value that has been skewed; this basically means that adding bigger injectors and taking away fuel on an AFC or something will make the karman value drop, even though the airflow hasn't.

Exactly, I was just pointing out that with atleast some systems you can get a value before all the skewing takes place.

 

[Kevin Jewer]

Even the AFC shows airflow before it is modified. For those that may not be aware of this.

 

[gsxtacy]

What are you talking about, before it is modified?

I have not read anything on this.

Any clarity here?

GSXTACY

 

[CanadianTSi]

What are you talking about, before it is modified?

I have not read anything on this.

Any clarity here?

GSXTACY

The way the S-AFC works is that it intercepts the airflow signal going to the ECU and changes it...either lower if your leaning it out or higher if your richening it up. That way the car thinks it is seeing more or less air therefore adding fuel accordingly.

 

[Kevin Jewer]

Right. And the number displayed on the AFC will be the unmolested figure straight from the sensor. At the ECU (datalogger) you will see the new adjusted airflow number.

 

[pickens]

yep, I see a much lower figure on my logger in comparison to the AFC. So I always presumed that the AFC displayed the "unmolested" signal.

Also, over the weekend I added a RNR 70mm downpipe. My Karman readings now average 1950-2000Hz.

 

[Darktalon92]

With my 2G MAS and 17psi on my 18g I hit max 1900Hz... +25% airflow from the 2G mas would be about 2350Hz assuming I still had my 1g MAS.

 

[1_bar_goes_far]

I don't know about the 2g cars, but the ecu in the 1g's only has a maf lookup table that goes to 1600hz.

 

[yo2001]

1G ECU can see higher than 1600Hz. Mine sees 2200+Hz

 

[Kevin Jewer]

I don't know about the 2g cars, but the ecu in the 1g's only has a maf lookup table that goes to 1600hz.

If this was true, all the fast 1Gs would have blown motors The ECU doesnt have limits, but it will only output up to 1600 to the dataloggers.

 

[ASZRAEL1266]

I don't know if its just my area but with my 16Ged car at 13.5 psi i am getting about 2020 on my safc and on my other talon that has the stock turbo still at 15 psi i am reading 2040 and hiting fuel cut in the 14b talon .

 

[zhjiln]

sorry to bring this dead thread back ... but

mine is 1930 hz.. s16G 18psi (22psi peak)

 

[knochgoon24]

T-25 trying to push 15psi @6500RPM (only made about 7psi)
90*F intake temps
29.5 inHg Baro
2g MAS

1300Hz + the 6% correction from the SAFC so about 1380Hz.