Can anyone tell me or have an idea why, i race my 2001 a4 alot, most of the time my car runs 13.2-13.5 but about once a day(race day) it will run a 14.6-14.9 its driving me crazy i m taking it in the shop tomorrow i d like to tell them where to start has this happened to anyone else?

 

pay attention to he circumstances around your slow runs. heat soak can change your numbers.

 

thanks for the reply but sometimes it happens in the morning when the car is cool , 1st run of the day and the car alwys gets 2-3 hrs between runs, i dont think its heat but i m not a mechanic

 

Well the next best thing I can suggest to you is get a tuner or monitor of some kind which can monitor all of your engine's readings from the PCM and record them. The one that I have is Autotap, its not the best but its a pretty good value. They even have a specific package of parameters you can read designed just for LS1 equipped cars. Set it up to record your run and you can play it back and scan through it in detail afterwards. setup sensors for things like timing advance, fuel pressure, intake temperature, MAF readings, coolent temp, oil temp, trans temp, tranny commanded gear ...anything else you can think of which might cause performance issues. Record all of your runs and then study them, review your good runs compared to your poor run and see if you can figure out what's different. You can export that data to excel and you can graph the readings from run to run and see which run has a significant difference.

Another thought, is the engine particularly cold when you get poor performance and warm otherwise? If your engine is not up to operating temperature it will perform poorly. When cold your oil is more viscous than when at proper operating temperature, cold oil robs your engine of power because it resists the motion of the parts. It also is not a good idea to push your car when the engine oil and tranny fluid are not up to proper operating temp. Make sure you're up to temp before your runs.