Dyno test
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Dyno test
Hi, will dyno my GT tomorrow for the first time,
any specfifc things that I should think of when doing this?
To get A/F readings do you need a wide band lambda installed?
/Peter
any specfifc things that I should think of when doing this?
To get A/F readings do you need a wide band lambda installed?
/Peter
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Hi Peter,
I think it's:
- strap the car down well but no too tight, you want to avoid loss between the wheels and the dyno (feel how warm the tires get, warm = lots of friction = loss of HP)
- do the test in third gear
- no need for a wide band lambda. They'll hook up a pipe to the exhaust to carry off the exhaust gases, there's a A/F sensor in there
- do a run with the hood closed and one with the hood open, to get a feeling for the difference in HP when all the hot air inside the engine bay is released
- bring a video camera and have fun!
I think it's:
- strap the car down well but no too tight, you want to avoid loss between the wheels and the dyno (feel how warm the tires get, warm = lots of friction = loss of HP)
- do the test in third gear
- no need for a wide band lambda. They'll hook up a pipe to the exhaust to carry off the exhaust gases, there's a A/F sensor in there
- do a run with the hood closed and one with the hood open, to get a feeling for the difference in HP when all the hot air inside the engine bay is released
- bring a video camera and have fun!
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Hi Aryan,
mine is a 5 speed manual and I though it would be better to do the pull in 4:th gear?
I also heard that since my car has catalysators the measurement for A/F at the end of the exhaust would give false readings?
/Peter
mine is a 5 speed manual and I though it would be better to do the pull in 4:th gear?
I also heard that since my car has catalysators the measurement for A/F at the end of the exhaust would give false readings?
/Peter
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Ah yes sorry - 4th gear. About the cats: I guess you could put a wide band lambda in your x-pipe, but then you need one and you should be able to relate that data to the dyno data. I don't know how much the cats (100 cpi?) influence the A/F.
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Dan
'91 928GT S/C
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4th is probably correct. The goal is to get as close to a 1:1 ratio as possible.
Makes sure your rear tires are set to max pressure (do you guys use PSI or KPA in Sweden?). Low tire pressure will mean more parasitic drag to overcome on the dyno.
Have fun!
Makes sure your rear tires are set to max pressure (do you guys use PSI or KPA in Sweden?). Low tire pressure will mean more parasitic drag to overcome on the dyno.
Have fun!
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I recently dynoed my car and have just now installed a wideband O2 sensor. I have an X-pipe and metal cats and can tell you that in my case the cats significantly changed the tail-pipe A/F reading. I was freaking out because the dyno WB said I was running way too lean at higher RPM. Now that I have a WB in the car, it's reading way too rich at low end and just right at high RPM. And I don't even have the air pump connected anymore. The dyno WB was on average two whole points too lean with my cats in the way.
Dan
'91 928GT S/C 475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ft
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From: Sweden, Stockholm
First dyno done
Ok, the first dyno session completed,
had a grip problem so we ended up lowering the tire pressure and maybe lost a few ponys there?(we went down to 28 PSI in the end)
Also read out a hall sensor intermittent fault with my spanner after the runs so this needs to be looked at over winter.....
Highest power was 241.4kW and torque 428Nm, slightly down in the last pull which is the only print out I have including torque curve.
U-tube videos
http://www.youtube.com/watch?v=vEDv8ZUZcHg
http://www.youtube.com/watch?v=zGsTSGNqjRo
/Peter
had a grip problem so we ended up lowering the tire pressure and maybe lost a few ponys there?(we went down to 28 PSI in the end)
Also read out a hall sensor intermittent fault with my spanner after the runs so this needs to be looked at over winter.....
Highest power was 241.4kW and torque 428Nm, slightly down in the last pull which is the only print out I have including torque curve.
U-tube videos
http://www.youtube.com/watch?v=vEDv8ZUZcHg
http://www.youtube.com/watch?v=zGsTSGNqjRo
/Peter
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Hi Ken,
Yes correction for temp and pressure and it was corrected numbers based on DIN 70020, rera wheel number was 201.5kW and I would expect a higher number than that actually.
Alsp the P-loss curve looks a bit funny above 5500rpm and it looks to also affect the power and torque curve.(or if it is the other way around)
Not sure if this is due to tire slip or hall sensor retarded timing or something funny with the test rig?
/Peter
Yes correction for temp and pressure and it was corrected numbers based on DIN 70020, rera wheel number was 201.5kW and I would expect a higher number than that actually.
Alsp the P-loss curve looks a bit funny above 5500rpm and it looks to also affect the power and torque curve.(or if it is the other way around)
Not sure if this is due to tire slip or hall sensor retarded timing or something funny with the test rig?
/Peter
