Dyno questions and associated ramblings

Modshack · 12-16-2009, 08:44 AM

All dyno set-ups I've witnessed here use a single probe. Probe sampling is not perfect and is off a bit from tru A/F ratios. Good numbers (most accurate) can be sampled from ahead of the CAT with a dedicated probe but few cars are set up to sample there. A good operator will understand the differences and compensate when tuning.

There are various "corrective" calculations applied to raw numbers to make them somewhat comparable. Differences in temps and barometric pressures can be calculated and applied to the raw number. "SAE" is a typical corrected algorythm, but may not give as high a reading. You can play games with the numbers all day long. I once had a Vette dyno'd on a Very cold day. Hit 440 RWHP, but only 410 when SAE corrections were applied..

12-16-2009, 08:44 AM	#1 (permalink)
Modshack A True Z Fanatic Join Date: Mar 2009 Location: Greenville NC Posts: 2,883 Drives: 370Z Sport Rep Power: 977	All dyno set-ups I've witnessed here use a single probe. Probe sampling is not perfect and is off a bit from tru A/F ratios. Good numbers (most accurate) can be sampled from ahead of the CAT with a dedicated probe but few cars are set up to sample there. A good operator will understand the differences and compensate when tuning. There are various "corrective" calculations applied to raw numbers to make them somewhat comparable. Differences in temps and barometric pressures can be calculated and applied to the raw number. "SAE" is a typical corrected algorythm, but may not give as high a reading. You can play games with the numbers all day long. I once had a Vette dyno'd on a Very cold day. Hit 440 RWHP, but only 410 when SAE corrections were applied.. __________________ Steal my car! (SOLD)...Now Porsche Cayman S Oil Cooler DIY: Here!

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