Silvia Club of NSW
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how to analyse this dyno sheet?
https://www.silviansw.com/forum/viewtopic.php?f=12&t=27595		 Page 1 of 1
Author:  keioffice [ Tue Jun 26, 2007 12:34 pm ]
Post subject:  how to analyse this dyno sheet?
ok this isn't my car but a good mate of mine's

just wondering how to analyse torque, power band, afr, peak figures etc

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any help would be appreciated as i dont even know how to read dyno sheets properly myself..
Author:  Chanboy [ Tue Jun 26, 2007 1:17 pm ]
Post subject: 
Hmmm can you give some details on the car spec? (I'm guessing stock?)

Polo 1.8 GTI - its a turbo model right? (diesel/petrol?)

Dyno was run in 3rd gear?

Looks like peak power (kw) is around 5000rpm, and then it drops off.

Fuel looks like it goes rich after 5000rpm, which is probably restricting a bit of power, though a stock ECU is tuned on the safe side so I would expect that to be normal.

Stock 1.8 Turbo - 112kw isn't bad, plenty of potential there.
Author:  182Go [ Tue Jun 26, 2007 1:47 pm ]
Post subject: 
It's too rich the whole way through the rev range...
Author:  keioffice [ Tue Jun 26, 2007 2:03 pm ]
Post subject: 
sorry guys.. its a gti, stock but running the APR (tuner) ecu..

is meant to be gettin 140ish at the wheels apparently

thanks, how do u note its too rich thru the whole rev range?
Author:  182Go [ Tue Jun 26, 2007 2:10 pm ]
Post subject: 
Third pic at the very bottom the AFR bearly gets over 12.5:1, it should be at 12-12.5 at WOT (wide Open Throttle) and full load not the whole way leading up to it.

It dips to like 10.5:1 near the end which is probably costing him power through being too rich.
Author:  Chanboy [ Tue Jun 26, 2007 2:14 pm ]
Post subject: 
according to the dyno chart, the max is 112.9kw. If you can tune some of the fuel out of it it might get closer to 140kw. (though hard to imagine with stock exhaust still...)

Since getting the APR ecu, has he noticed worse fuel consumption?
Author:  Phantom Snail [ Wed Jul 04, 2007 8:55 pm ]
Post subject: 
From what i hear, mainline dyno's read lower then dyno dynamics dyno's...
So a figure of 112 on the mainline dyno could read nearly 130 on a dyno dynamics dyno...
This is just for power kw....however with their torque figures, mainline seem to be a little figure happy as opposed to dyno dynamics...something reading 600Nm or so will only read about 400Nm on a dyno dyamics dyno.
Air fuel ratio of 12.5-8 as seen on the graph is lean up to about 5000 where it decides to go really rich to about 10.8....
The norm is 12...anything above 12 is leanish and anything below 12 is richish...

Hope that helps 8)
Author:  182Go [ Thu Jul 05, 2007 11:31 am ]
Post subject: 
Phantom Snail wrote:
The norm is 12...anything above 12 is leanish and anything below 12 is richish...

Hope that helps 8)

In a word...CRAP!
Stoich for petrol is 14.7. 12:1 is rich
Author:  clip [ Thu Jul 05, 2007 11:42 am ]
Post subject: 
sure 14.7:1 is the perfect fuel to air ratio. but there is no way you can run that on a street car.

by experience running anything higher than 12.5ish is going to get you into a danger zone due to the likelihood of detonation.

sure the dude used the wrong words, but the theory is correct. most people tune to run around 12:1 for a safe tune. anything leaner than that on a street car without lots of work done is considered "too lean" and unreliable. anything below 12 is considered "too rich"
Author:  182Go [ Thu Jul 05, 2007 12:40 pm ]
Post subject: 
Yeah maybe I was a bit harsh but statements like "The norm is 12...anything above 12 is leanish" without clarifying that he is refering to WOT will have people thinking that 12:1 is acceptable for idle.

Which anyone who knows anything about tuning a car will tell you, you will be under the bonnet changing fouled plugs every 5 minutes with those settings. I was told by a reputable tuner that you should be no richer than 14:1 at idle.
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