with the settings below, im getting:

745.64 CMf (kg/hr) [207.12(g/s)]

which is definately too high. should the volumetric efficiency be lowered? pressure drops raised? (stock engine/stock ic/stock airbox)

this is what i have the sheet set to currently:


Bore (mm) 81
Stroke (mm) 86.4
# of cylinders 4
70 Temp (F)
29.5 Barometric pressure (inHg)
14.5 Boost (PSI)
0 Vacuum (in Hg)
1 Pressure Drop (PSI)
0.75 Inlet Pressure Drop (PSI)
7000 RPM
90 VE (%)
108.68 Displacement (ci)

it into your head with my nonstop posting, but i'm only getting 13psi and 140g/s

your numbers are nuts!

They would be lucky to even get close to 175 g/s. The GIAC 2000 J31 K04 chip does hit 210 g/s, but it has to run 28psi to just do that.

I think the Formulas assume a decent compressor efficiency, which the K03 does not have.

I never tried it for a K03, mainly because it's so far out of the efficiency range.

Try to adjust the temps up, and I'm also assuming because the K03 is so small, that it could hurt VE on the top end.

14.5 is way out of efficiency range on the K03, so temp goes up, VE overall goes down, and I think the intercooler sees a couple psi pressure drop. I think its around 3-4psi. I could be wrong though.

I'll try to dig through the k03 map to get some realistic numbers. i know i've boosted 1bar before so that is correct. the g/s is still high i think.


70 Temp (F)
29.5 Barometric pressure (inHg)
14.7 Boost (PSI)
0 Vacuum (in Hg)
4 Pressure Drop (PSI)
0.75 Inlet Pressure Drop (PSI)
7000 RPM
75 VE (%)
108.6757142 Displacement (ci)
8.61104E-05 Di (lb/in^3)
24.56504321 Mf (lb/min)
668.5517651 Mf (kg/hr)
22.98868285 CMf (lb/min)
625.6502124 CMf (kg/hr)
2.290509579 Pressure Ratio

i can't even figure out why i can't get more than 13 hahah

I know for sure that it peaks early and drops down as rpms go up....which makes sense from a "keeping engine safe" viewpoint....hence peak at 3500rpms...

I look at VE as being the mass of air that is actually coming in versus the amount of air that theoretically could come in.

With no boost, you have 1 bar of pressure.

With 1 bar of boost, you have 2 bar of pressure, or twice the air mass.

Just because it flows twice the air, doesn't mean it's 200% VE, since the max amount of air it can flow is doubled as well.

<ul><li><a href="http://www.installuniversity.com/install_university/installu_articles/volumetric_efficiency/ve_computation_9.012000.htm">http://www.installuniversity.com/install_university/installu_articles/volumetric_efficiency/ve_computation_9.012

With those formulas, a car at higher altitudes will have a lower VE then a car at sea-level.

in density?

Assuming:
5500 RPM
72F outside temp
14.7psi of boost
170g/s
=&gt; 87% VE

6500 RPM
72F outside temp
12psi of boost
170 g/s
=&gt; 81% VE

He just happens to apply them to the Actual Air Flow.

Use:
TMAF =&gt; 0.0747 x 600 = 44.82 lb/min
AMAF =&gt; 34.32 lb/min

VE = 34.32/44.82 =&gt; 76.6%

Using a known quantity a t-57 cold side certain trim, the only way I could show my 2.2l Turbo getting 500hp/500lbft was in using a much higher than 100. I also thought it was done the way you are thinking but nothing else allowed the figures I got, and almost all race cars, even N/A run over 100% VE at peak.
Rod

so it now has an entry for Post-IC temps. Before I was using the intake temps as the post-IC temps.

I also added a g/s row.

The numbers should be a lot closer now.<ul><li><a href="http://johnbaas.dyndns.org/audi/massflow.xls">http://johnbaas.dyndns.org/audi/massflow.xls</a></li></ul>

and created a VE spreadsheet that compensates for pressure.

Like the guy in the link said, the MAF numbers from the ECU have to be correct.<ul><li><a href="http://johnbaas.dyndns.org/audi/VE.xls">http://johnbaas.dyndns.org/audi/VE.xls</a></li></ul>

nice spreadsheet, but PR should include intake drop deduction in denominator ... small effect but there.

but wasn't sure if I should include it in just the denominator, or the numerator too. Then I read somewhere that Garret compressor maps assume a 0.75 inlet loss, so I just decided to leave it out.

per this link, PR should be true PR ... compressor outlet over compr inlet absolute pressure, which would include intake pressure drop. The corrected mass flow is only for variation of ambient conditions, and should not include intake pressure drop.

note turbine efficiency around 60% ...<ul><li><a href="http://www.limitengineering.com/catalog.pdf">http://www.limitengineering.com/catalog.pdf</a</li></ul>

I'm really starting to like the looks of that GT32 compressor map....