alansrt4
Parking Attendant
Posts: 10
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posted August 15, 2006 09:05 AM
? about dyno tuning and ram air
I was wondering how much does the ram air lean out the bike up top when actually driving it as opposed to just sitting on a dyno. It dawned on me that while on the dyno it might be good a/f but when you get the extra air going into it while riding its gonna lean out. Does anyone have an A/F guage on there bike that has seen the differnce?
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to much greed to be slow
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garth285

Expert Class
200+mph 2011 ZX10r
Posts: 300
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posted August 15, 2006 09:53 AM
I work at a show in South florida and we have tuned bikes on the dyno and on the street using datyaloggers with heated 02 sensors and such and at higher rpms wide open throttle there is a difference of .05 lambda difference.
I tuned my zx10 to .90 lambda and on the street it will read .90 but on the dyno it will read out .85 so in air fuel #'s thats:
.90 is 13.23:1 afr
.85 is 12.50:1 afr
A good dyno tuner will always richen up the top end of the bike to compensate for ram air.
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tslewisz

Expert Class
Posts: 328
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posted August 15, 2006 12:46 PM
A lightly modded 14 does seem to require more fuel than a dyno would indicate. This is good reading that touches on the subject: http://www.dragbike.com/dbnews/anmviewer.asp?a=2196&z=3
Here's a relevant excerpt:
"The chart above shows that the map which allowed the bike to go faster at the track is actually too rich to make optimum power on the dyno. Too rich? I thought it was BOILING HOT with stagnant air in Memphis?! Every tuner knows you would need to lean down the Air Fuel mixture in conditions such as these. Generally, this is true, but we made a change RELEVANT to the bike's educated guess on how much fuel is needed. Apparently the 14's ECU was not supplying enough fuel to allow the engine to accelerate it's hardest on the track. We added more fuel, and the bike went faster. FYI: some models overcorrect naturally, so they want less fuel. Generally, we notice that this trend is typically consistent between models of the same year."
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