Volumetric Efficiency Comparo
#17
01-01-2011 | 06:49 PM
Thread Starter
|
Registered User
Joined: Oct 2008
Posts: 2,319
From: Fastlane USA
Rep Power: 245
Well, I tried to upload the spreadsheet but evidently Excel is not a file type that is acceptable for uploading. 
So if you want me to send you the spreadsheet just email me at ttdude997@gmail.com.
All one has to do is to input RPM, MAF, and IAT from your datalog. It does not necessarily have to be from Durametric although the spreadsheet is designed to use metric units which Durametric records. Use the plotting function in Excel to generate your graph. This calculation assumes air density at sea level and 3.6L engine. A little tweaking of the density parameter would be necessary if you're running in the mountains or displacement for stroked engine. Peak VE would correspond to peak torque. This is like a "poor man's" dyno. Have fun.
So if you want me to send you the spreadsheet just email me at ttdude997@gmail.com. All one has to do is to input RPM, MAF, and IAT from your datalog. It does not necessarily have to be from Durametric although the spreadsheet is designed to use metric units which Durametric records. Use the plotting function in Excel to generate your graph. This calculation assumes air density at sea level and 3.6L engine. A little tweaking of the density parameter would be necessary if you're running in the mountains or displacement for stroked engine. Peak VE would correspond to peak torque. This is like a "poor man's" dyno. Have fun.
I set up this gmail account so I can distribute the VE spreadsheet but when I went to log in I get a message that says, unusual account activity, please submit your cell phone number so we can send you a message with a verification number--lol. No way that is happening. Last thing I need is gmail spam on my cell phone. So please send me a PM with your email address and I will distribute that way.
#18
01-01-2011 | 10:31 PM
Thread Starter
|
Registered User
Joined: Oct 2008
Posts: 2,319
From: Fastlane USA
Rep Power: 245
Last edited by TTdude; 11-17-2013 at 12:07 PM.
#19
01-02-2011 | 12:07 PM
Thread Starter
|
Registered User
Joined: Oct 2008
Posts: 2,319
From: Fastlane USA
Rep Power: 245
X50 vs K2420g
X50 data from 996ttalot. The X50 graphs are truncated because of gear changes which otherwise looks like an etch-a-sketch by connecting all the dots. Thanks Ken for sharing!
Last edited by TTdude; 11-17-2013 at 12:08 PM.
#20
01-02-2011 | 06:34 PM
Thanks a lot for posting this. I reduced Bobby's formulas to make it convenient to plot from Durametric data. This uses the data as reported by Durametric (MAF in kg/hr, T in deg C):
VE = 2.63*(MAF)(T+273)/RPM
My results seem to be about 11-12% higher than the reported engine load. I've posted data from my car, which has UMW Stage 2A (K16/997 GT2 zero-clearance)
Jon
VE = 2.63*(MAF)(T+273)/RPM
My results seem to be about 11-12% higher than the reported engine load. I've posted data from my car, which has UMW Stage 2A (K16/997 GT2 zero-clearance)
Jon
#21
01-02-2011 | 07:57 PM
Thread Starter
|
Registered User
Joined: Oct 2008
Posts: 2,319
From: Fastlane USA
Rep Power: 245
Thanks a lot for posting this. I reduced Bobby's formulas to make it convenient to plot from Durametric data. This uses the data as reported by Durametric (MAF in kg/hr, T in deg C):
VE = 2.63*(MAF)(T+273)/RPM
My results seem to be about 11-12% higher than the reported engine load. I've posted data from my car, which has UMW Stage 2A (K16/997 GT2 zero-clearance)
Jon
VE = 2.63*(MAF)(T+273)/RPM
My results seem to be about 11-12% higher than the reported engine load. I've posted data from my car, which has UMW Stage 2A (K16/997 GT2 zero-clearance)
Jon
#22
01-03-2011 | 02:22 PM
Nice job simplifying Jon! Interestingly with my 997t, the calculated VEs range between 0-5% lower than recorded engine load values with higher discrepancy occuring at higher load, i.e. VE=44, load=46; VE=226, load 240. Perhaps the 997.1t DME does a better job of calc engine load? Dave
Edited - okay I know the reason why - it is because the engine load calculated through durametrics will be wrong with the FORD MAF. That explains the difference to VE.
Last edited by 996ttalot; 01-03-2011 at 02:33 PM.
#23
01-03-2011 | 02:25 PM
Okay another question thinking out of the box....if a non turbo car typically is around 100-130 VE, if we were to take say a standard Gallardo, surely this would mean that the figures are distorted? Or would the Gallardo have say 185 VE figure?
#24
01-03-2011 | 03:04 PM
Registered User
Joined: Sep 2009
Posts: 2,666
From: GTA, Ontario, Canada
Rep Power: 235
lol, probably true. But I'm really curious about how well the TPC/Proto 65mm version works. That's probably what I'll end up with. I would've bought them already but Todd seems awfully busy these days...
#26
01-03-2011 | 03:08 PM
Thread Starter
|
Registered User
Joined: Oct 2008
Posts: 2,319
From: Fastlane USA
Rep Power: 245
#27
01-03-2011 | 03:11 PM
Registered User
Joined: Feb 2007
Posts: 485
From: Michigan
Rep Power: 66
Thanks a lot for posting this. I reduced Bobby's formulas to make it convenient to plot from Durametric data. This uses the data as reported by Durametric (MAF in kg/hr, T in deg C):
VE = 2.63*(MAF)(T+273)/RPM
My results seem to be about 11-12% higher than the reported engine load. I've posted data from my car, which has UMW Stage 2A (K16/997 GT2 zero-clearance)
Jon
VE = 2.63*(MAF)(T+273)/RPM
My results seem to be about 11-12% higher than the reported engine load. I've posted data from my car, which has UMW Stage 2A (K16/997 GT2 zero-clearance)
Jon
wa = hp (crank)* AFR * BSFC/60
wa = lb/min of actual air flow
1 lb/min air flow = 27.21 kg/hr (MAF in above equation)
#28
01-03-2011 | 03:15 PM
Thread Starter
|
Registered User
Joined: Oct 2008
Posts: 2,319
From: Fastlane USA
Rep Power: 245
Thanks for posting. What values would you estimate for BSFC for 600-900 bHP P-turbo?
#29
01-03-2011 | 03:19 PM
Thread Starter
|
Registered User
Joined: Oct 2008
Posts: 2,319
From: Fastlane USA
Rep Power: 245
Not quite following you Ken. What are distorted? Is it something more than just total displacement that you're asking?