Just dynoed for the first time!
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Joined: Sep 2002
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From: idbracing
Looks pretty good. In a real life situation, the air box off will probably result in a loss of low end but a gain in the topend. If you think about it, your engine bay isn't really that hot when the car is moving.
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From: Columbia
One thing to keep in mind is that Dynos can vary a LOT from one shop to another so a car that may have 205 on one will only show 185 on another! Also, the S is very, very sensitive to air temperature. Dyno on the coldest day of the year for best results.
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Joined: Feb 2001
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From: You wish
Hey Ulrich,
Assuming that you car is an S2K, your dyno operator screwed up. First, the gear ratio is wrong (it should be 5.52 for 4th gear, and 4.61 for 5th gear). 2nd, it peaks at only 7500 rpm? You might want to demand a retest since they didn't set things up correctly.
Also, on the topic of dyno consistency, if the dyno operator sets things up properly, your tires are inflated to the same pressure, etc., dynos are very consistent, even from dyno to dyno (using the same brand of course). But you have to ensure that all the variables are as close to the same as possible, and if you can't control them (weather) that there is a correction factor available. Coolant temp is a big deal on S2K dynos and you must ensure consistency.
UL
Assuming that you car is an S2K, your dyno operator screwed up. First, the gear ratio is wrong (it should be 5.52 for 4th gear, and 4.61 for 5th gear). 2nd, it peaks at only 7500 rpm? You might want to demand a retest since they didn't set things up correctly.
Also, on the topic of dyno consistency, if the dyno operator sets things up properly, your tires are inflated to the same pressure, etc., dynos are very consistent, even from dyno to dyno (using the same brand of course). But you have to ensure that all the variables are as close to the same as possible, and if you can't control them (weather) that there is a correction factor available. Coolant temp is a big deal on S2K dynos and you must ensure consistency.
UL
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Joined: Mar 2002
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From: Houston, TX
Hmm. Interesting, I need to run that by the organizer. It was the first time I went on a dyno, so I really had no clue what to look for. The whole event was rather anti-climactic. 
On this particular dyno they took off the rear tires and hooked the machine up directly to the wheels. Hood was closed, engine was luke-warm, they did set up a fan (though I assumed it was just to get the exhaust fumes out of the garage).
On this particular dyno they took off the rear tires and hooked the machine up directly to the wheels. Hood was closed, engine was luke-warm, they did set up a fan (though I assumed it was just to get the exhaust fumes out of the garage).
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From: You wish
Ulrich,
I own the same type of dyno (dynapack).
The overall hp reading should be accurate (since hp is measured), but the torque reading and rpm range will be off if the dyno operator doesn't enter the correct gear ratio.
Also, you usually want to test cars with the hood up to aid cooling airflow. Even the biggest fan has a hard time simulating actual street airflow and putting the hood down makes it even tougher. The nasty spiky lines indicate to mean either detonation or misfires. The curve should normally be smooth, but when the engine is exceptionally cool or hot the performance degrades.
UL
I own the same type of dyno (dynapack).
The overall hp reading should be accurate (since hp is measured), but the torque reading and rpm range will be off if the dyno operator doesn't enter the correct gear ratio.
Also, you usually want to test cars with the hood up to aid cooling airflow. Even the biggest fan has a hard time simulating actual street airflow and putting the hood down makes it even tougher. The nasty spiky lines indicate to mean either detonation or misfires. The curve should normally be smooth, but when the engine is exceptionally cool or hot the performance degrades.
UL