Mini Racecar Test & Tune

I originally wrote this over a year ago, but never got around to posting it. I had planned a Test & Tune session at a nearby drag strip. My plan was to start with a bit of straight-line tuning & then measure a number of characteristics using roll-down tests & other techniques (coefficient of friction, wing & splitter drag, downforce, IC efficiency, etc.).

Unfortunately I didn't realize that the upper bands of tropical storm Hermine were approaching. I ran two brief runs at low boost levels to adjust the fuel table before it started to rain. I got a couple more brief runs in between rain bands, but puddles started forming & I wasn't able to do any WOT runs.

Here are a couple of pictures, as well as a very brief drive-by video:


I'm planning on trying again in the near future. In the mean time, I'm going to go ahead and add some additional sensors:

- Three additional MAP sensors (one in the manifold *before* the turbo (!), one before the Supercharger (at wastegate takeoff), and one after the Supercharger/ before the intercooler).

- Four EGT sensors (one for each cylinder)

- Four linear sensors (one for each wheel)

To achieve this I have to add an expansion box to the ECU (i.e .basically another computer). This will give me a large number of additional inputs, as well as additional outputs. I'm thinking of using one of these outputs to actively control the supercharger bypass, and perhaps another one to drive a fuel injector to provide precise water/meth injection....

One bit of data I did get regarding the IC: the maximum temperature difference between the intake temp & ambient was less than 5 degrees. I wasn't able to compare this to the stock IC (too wet to put it on), but given the fact that I have *two* compressors, I think this is pretty darn good. I am still planning on doing a side-by-side comparison in session #2. And I will have MAP sensors on either side of the intercooler to measure pressure drop at the same time.

FYI I posted up a quick test video I did playing with audio levels & video recording with the camera down near the wheel. I'm trying to get better dynamic sound levels for recording the engine:

Pretty cool strobe effect with the wheel rotation...

And here is what it currently looks like:


Posted on January 31, 2014 .