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5 Tips to get the most out of your Custom Tune

5 Tips to get the most out of your Custom Tune

"If your vehicle has a weakness, the dyno will find it" 

Time and time again customers leave the dyno disappointed. Often time’s people look to the tuners as if the short coming is in the calibration. Well I’m here to tell you that is not case (most of the time). It is up to you, the owner of the vehicle, to take the proper steps ensure that your part is done so the tuner can do his/her job.

In this article we’ll go over some tips on how to ensure you leave the dyno happy. The article will focus on the BMW 335i, but many of the tips are general and will carry over to most any platform.

I would like to begin this article by showing you two datalogs. Both cars are running pump 93 octane (from the same station), have similar cam timing profiles, and are equipped with 6 speed manual transmissions.

The first datalog is from a 2007 bmw 335i. It is a Full Bolt-on (fbo) car, meaning it has Catless Downpipes, upgraded front mount intercooler, and Jb4. In the logs boost peaks at 14psi.

The second Datalog is from a 2008 BMW 335i. This log is of a completely stock car with the addition of a custom flash by us.

Now taking a look at these 2 graphs, we see one really big difference. That difference is the smoothness, or lack thereof, of the ignition timing curve (dark purple line for datalog one, yellow for datalog 2). We can see that the timing curve of the first vehicle reflects that there is a lot knock retard while running less boost with more modifications. So why is this happening??? In the case of this vehicle its maintenance. 

So here is where I'm going to lecture you on how to take care of your car, mod it, and how to think. 

Tip #1 

Go in with a realistic expectation. Many times people expect numbers they see on forums, or don't have a complete enough setup to get where they want to be. Remember, every dyno reads different, and numbers are only that, numbers. Take into account variables such as weather, altitude, and fuel type. 

Tip #2

Do your maintenance. Many times peoples cars have weird issues and the owners feel it will be fixed with a tune. Most times, it won't be, and may make the issue(s) worse or not allow the tuner to complete the tune properly. In the case I showed above, you see an example where a car should run much better than its counterpart, but it doesn't. The car in Datalog 1 has old injectors, old sparkplugs, and has never had the intake valves cleaned. Make sure these types of things are taken care of. 

Tip #3

Talk to your tuner. Your tuner will have recommendations for you to make sure that your experience with them is positive. They might tell you what to upgrade before you come, what your spark plug gap should be, what to expect on their dyno power wise, or anything else they feel should be important to completing your tune. 

Tip #4

Bring your car to get tuned the same way you are going to have it configured when you use it. This one is a big one. If there is a particular gas station you always fill up at, make sure that fuel is in your tank when you get tuned. If you are planning to do another engine related upgrade, wait until after it is done to get a tune. 

Tip #5

Inspect your car before taking to get tuned. Check for fluid leaks, make sure all the hardware is working properly, and inspect the drive line. If your vehicle has a weakness, the dyno will find it. 


Hopefully these simple tips will save you some headaches, time, and money. After all, all we really want to do is enjoy our vehicles the way they were meant to be. 


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