How do you know if your tune is working?

So you got a tune. Either its the greatest thing since sliced bread (or so you think) or it really doesn't seem much faster than stock ! Not to mention you hear all this talk about tuners removing torque management and wonder if your transmission is ready to explode because they removed all of yours.

This article is about simple ways to check up on your tuner and make sure your tune is all it can be. I am sure most of you will agree its hard to make judgment based on a SOTP readings (seat of the pants). A recent example comes to mind. I received a Vector tune and their new intake. The intake is LOUD and really gives you a sensation of speed. After installation I was immediately convinced that I had a rocket and it pulled hard. So I head for the test strip and make a run. First run was 1/10 slower than stock! So I make two more runs to find the same results. Before you abandon Vector, you can check out their page under the performance results to see what is going on. It's being updated and I have no doubt they will make it right.

To find out if you are moving forward (getting faster), you need to either go to the track or use some type of electronic instrument to measure your times. This device does not have to be extremely accurate, but it does have to be repeatable. For testing I am currently running a G-Tech RR, Hptuners scan/programming software as well as the new DashHawk available at Vector Motorsports.

Our objective here is to a) Log PIDs (information from the vehicle) and b) measure performance. HPtuners does a great job at logging PIDs but cant calculate performance. The G-Tech can measure performance including everything from a 60' time to 1/4 mile time and trap speeds but can't monitor PID's. The DashHawk is the only tool I am aware of that can monitor both.

The DashHawk is a tool that plugs into your OBDII connector under the dash. It needs nothing else. All power is derived from this connection and as soon as you plug it in it's ready to go. It works on CAN bus vehicles like the SS as well as others. The complete list can be seen here.

Performance testing. The DashHawk has two options for testing performance. It will measure and plot both 0-60 times and 1/4 mile results. Each result when replayed shows a speedometer and tachometer while plotting a chart. See below for sample runs from a Trailblazer SS.

Warning - Videos are large and may not play well on dial up connections

In addition the 1/4 mile run shows left and right o2 sensor levels which is handy for those tuning. Click the video links above and see it in action. Note replays are at 25% actual speed.

In all my testing, the DashHawk has been right on when it comes to repeatability which is the most important part. If you are modifying your truck, this is a MUST have. They are $299.99 and money well spent. Order at Vector MotorSports.

Vehicle Monitoring If your truck is not running as well as you want but you are not sure why? Well then monitoring your vehicle PIDs or logging them is the thing to do.

One of the issues I have ran across with a couple tunes is problems with timing where the engine ended up sensing knock. When this happens the ECM initiates knock retard which protects the engine and also drastically reduces your performance. My SS runs runs pretty well with somewhere between 21-23 degrees timing and performance is very good.

In this example, the vehicle had a little too much timing on the bottom which triggered the knock sensors even though I could not hear it. The white line indicates timing and at the small peak is about 23.5 degrees.
In the chart above the vehicle is saying we have serious knock and we need to remove 11.5 degrees of timing. (knock retard is the red line and peak is 11.5 degrees). Even though the knock may have been brief the ECM takes a long time to give the timing back. In this case about 1 degree per second. So if you do the math, you will soon realize that it will take almost the entire 1/4 mile to return all the timing and get back to maximum performance.

It is very easy to monitor about any parameter you wish with the DashHawk. It has multiple screens and each one can be configured with any PID you want. So you can custom configure each one of these screens with the following look

  • 2 Function Digital (Two large font numeric parameters on your screen)
  • 3 Function Digital (Three medium font numeric parameters on your screen)
  • 4 Function Digital (Four medium font numeric parameters on your screen)
  • 2 Function BAR (Two large font numeric parameters with an updating "Bar"
    gauge on your screen)
  • 6 Function Digital (Six small font numeric parameters on your screen)
  • 7 Function Digital (Seven small font numeric parameters in a list)

As an example, I have one screen set up to show timing, knock retard, and torque management retard. Then I have another screen setup to watch short term and long term fuel trims.

2 function digital setting

2 function bar setting

7 function digital setting

Another big topic (and issue) is torque management and sometimes lack of. It is there to protect the drive line and I have no intention of debating how much is required because I don't now. I think that would have to come from serious testing and monitoring failure rates. Something I am not interested in doing ! But most will agree that some level of "TM" needs to be maintained for longevity.

In the chart below the lavender colored line is throttle position (ETC). As you can see I mashed the gas and held it wide open until I let off. The red line is RPM and peaks at 6500. The yellow line is speed and the white line is timing. At max I was pulling almost 23 degrees of timing.

At tip in (throttle) you can see a big dip in timing (10 degrees) right after the rise in throttle position. You can also see a dip just before 2nd gear starts to pull as well as at 3rd gear. Each little dip represents the engines torque management to protect the drive train.

Using DashHawk you can see these timing variations in the logged file as well as watch it live using the torque management retard PID. It clearly shows if your tune has torque management or not.

Beyond all of these things, the DashHawk can read diagnostic trouble codes, reset them, do crank relearns, control electric fans and a multitude of other functions.

When you buy a tune (especially a locked tune) you have no idea what is going on. I can understand the tuners wanting to protect their property so its not pirated. But I also feel consumers should be able to expect a certain amount of comfort in knowing what we purchased is working.

So far my experience with mail order tunes has been less than perfect.

If I had not been monitoring my first tune I would have never known all the torque management had been removed (apparently by mistake).

My second tune (new vendor) did not run any better than stock even though the sound gave me a false sense of improvement. Monitoring it proved otherwise.

So, don't assume anything. Check it for yourself. Even if you had your truck dyno tuned its not the same as monitoring your timing under (asphalt conditions).This page will be continually updated, so check back.