Quote:
Originally Posted by 42pilot
First of all, what make and model is the dyno? Mustang? Dynojet (known to most tuners as dynojunk)? They are very different and most common. And I have to throw this in, make sure it is a 4WD dyno. Make sure you know the correction factor (and why) they will use. You can throw in any correction factor and come up with whatever number you expect. The correction number will take into consideration temperature, humidity, altitude, etc.
You must run a baseline to know stock versus the various chip settings.
Also, make sure they provide plenty of fans pointing at the front of your car for the intercooler and intake. The biggest improvement you can make to an engine's performance for $0 is cool air. If you let the car sit at an idle on the dyno too long (getting ready for the run and between runs), you will get heat-sink in the intercooler and intake which will further lower your numbers.
What gear are you going to use for the run? You need to find out the optimum gear for the F15 for a dyno - just flooring it in an automatic will not provide any useful data.
As for expectations, if you think your car will produce 255 hp on the dyno in the baseline run, you will be very disappointed. I would estimate 15% - 20% loss just in the drivetrain. I wouldn't be surprised if the HP peaks at 200 - 215. Make sure your air conditioner is off too.
I am more interested in torque. HP is simply work over time. Torque is what pushes you back in your seat. Make sure the print-out (graph) you get shows torque and horsepower (X axis) over RPM (Y axis). This way, you know where the power is being applied and how long it lasts. A setting that peaks at 1500 rpm, then drops off from there is not very useful for the street. For example, my 550i peaked at 1800 rpm for torque, then held the peak torque until nearly 5000 rpm. That was a freakin' impressive tune from Dinan. A print-out of your results every 100 or 50 rpm, in a spreadsheet form, is much more detailed and informative if you really like hard data. Check to see if they have the BMW PID's and can tie into the OBD port to check engine parameters during the run. Knowing EGT's, coolant temps, fuel flow, etc for each run would be outstanding data.
Remember, if you trip a check engine light, you will need to clear it manually (scanner) or drive it for 15 minutes. Without clearing the CEL, the ECU will default to OEM settings and you'll waste time/money.
Here is the most important part - call RaceChip US and ask them for settings guidance, and let them know what you are doing and you are going to post the results on this forum. You will find they will be very accommodating and give you great guidance as well as what to expect. They might even tell you which gear to use for the most accurate result. This is a good forum but I can only tell you the setting I like for my style of driving - it might not be the peak setting for hp/torque, and I would hate to see you waste your money chasing peak numbers based on a bunch F15 junkies recommendations. You might want to do the run during working hours in case you need to speak to them during the dyno.
Good luck.
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This will be dynoed on all 4 wheels with a dynapack at my local tuner, Church Automotive Testing. You are correct I need to find the right gear that is closest to a 1:1 ratio(6th gear)
As to what I am expecting from the results, I'm fully aware and not expecting the base line to be anywhere near the stated paper values( I'm guessing after the tune I will end up meeting the values stated lol).
Good point as to calling Racechip and getting them involved in my dyno session. I will definitely do so.
I'm also very curious about the stock A/F ratio and how each step of the tune will effect it. With that data I can hopefully fine tune the fuel pressure and timing better.
Any idea what is the "ideal" A/F ratio for Diesel engines?