Abbreviated Test & Tune I had planned a Test & Tune session last Monday 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: [ame=http://www.youtube.com/watch?v=WubrXXMDIJM&feature=player_profilepage]YouTube - Mini Drive By[/ame] I'm planning on trying again in a couple of weeks. 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. We all have to have our hobbies....
A/V Test Video & Pic 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: [ame=http://www.youtube.com/watch?v=fb456QpDH-g&feature=player_profilepage]YouTube - Mini A/V Test[/ame] Pretty cool strobe effect with the wheel rotation... And took a pretty pic while I was moving it today: BTW I have an interesting idea for using an Excel spreadsheet to fine-tune the fuel tables...I'll post it as soon as I have time to write it up...
Update #1: A new tool!! Ok, this may seem a bit odd(!), but here's my logic: I have parts coming next week to modify my exhaust to add a repackable racing muffler, as well as bits to tie the wastegate output (smoothly) into the main exhaust. I'm hoping to do as much of the fabrication myself as I can. But to do that, I need easy access to the bottom of the car. I'm also planning on working on the under-car aerodynamics. And I really need to be able to inspect & service items on the bottom.... In deciding how to work underneath the car, I need a system I feel safe using by myself. So rather than getting four jacks, I decided to go with a slightly more "beefy" solution: It's actually a "portable" two-post lift designed to work within a normal-height garage. A local company came out to install it. They drilled holes in the slab & insert threaded inserts that expand when you tighten down the bolts. You can remove the bolts and move the whole thing out of the way when it's not in use. I picked the spots to mount the bars & I was *very* fortunate to pick exactly the right spot. If it had been just a couple of inches in any direction it wouldn't have fit. But I end up with a good *inch* of room when it's all the way up! I know it looks like a tight fit, but this is actually a good thing. Given the Mini's far-front center of gravity, if it did start to tip forward, it would just hit the ceiling & stop! I must admit I feel spoiled already.... Couple more pics: Coming tomorrow, Update #2: using logging data to adjust tuning data using an Excel spreadsheet:
Yes, it is the MaxJax. Good ol' Jay made a sale on that one! I don't know about how it attracts people yet, but now that you mention it I did notice someone wandering around outside yesterday with a towel and a lug wrench looking very confused.... ut: Now all I have to do is justify the 3d scanner and 3d printer and I'm all set: NextEngine's 3D Scanner - Extras - Jay Leno's Garage Those would be dang useful for the *other* mod I'm working on... Boys & toys...bigger boys, bigger toys...
Another Update: my tuning spreadsheet I mentioned previously I was playing with using external applications to take logged engine & environmental data to adjust the various tuning parameters on the Motec. To play with this idea I made an Excel spreadsheet that combines the logged data with any of the tuning parameters I want and applies a transformation/correction. To begin with I'm testing the idea using the fuel table. The first tab of the spreadsheet is a dump from the logging output of the Motec. The second data tab is the log from the bluetooth weatherstation I'm using to continuously grab environment data during the day: The next tab has the input tuning parameters - in this case the original fuel table used during the run: I then apply a filter to the log data. In this case I'm removing all deceleration data (the lambdas in those areas will skew the analysis): The next tab is a pivot table summarizing the measured lambda values at each RPM and MAP point. Since not all RPM/MAP combinations were measured, there are a number of holes in this table (it fills in at the higher RPMs): The next tab is the correction table. For cells with a measured value, this has the actual correction factor to apply to achieve the desired lambda value. For cells that don't have measured data, the value is interpolated from nearby data. In some cases I override certain cells where I don't think the masurements were accurate, or to help smooth out between the sample points: All of this results in the output tuning table. In this case you can see some interesting additional hills & valleys added to the fuel table: This data is then re-uploaded to the Motec. If necessary this cycle can be repeated multiple times to optimize the solution After the fuel table there's timing, short-term corrections, long-term corrections, etc. etc. With some variation the same approach can be applied to all of them Pretty cool, eh?
do yourself a favor and get the TSW/Way chassis brace. it befits your install moreso than what's currently on your car
I've considered it & probably will get one at some point. Keep in mind that the roll cage helps the stiffness too. But I want to figure out my plan for the under-car aerodynamics before I add any more bits that could interfere...
Yup. Do any of the environmental conditions have a greater influence than the others on the tuning parameters, or are all fairly marginal?
That is way cool! Love seeing all the behind the scenes action and thought process! Keep this bad mofo up
That is some great stuff :yesnod: I love pivot tables, once I learnt of their existence I wondered how I ever did analysis without them! More than 65k thousand rows can't hurt either. Quite an impressive system, especially as you can do it multiple times (invest now to save time later). Planing on doing multiple runs and seeing what kind of variation you get, or is it already a stable result? I haven't done any engine tuning so that might be a stupid question...
Good question. They *should* only affect the global behavior (e.g. shifting the whole chart up or down due to temperature). And by default the temp corrections are just that - a delta to the whole table. But with this process I can see changes at any point in the graph - so I can tell if this is true or not. And the Motec allows you to make corrections as complicated as you want. One of the sensors I'm adding is an accelerometer tied directly into the Motec. This will allow me to measure the relative power output at every point too. (right now my accelerometer is tied to the AIM dash & doesn't play well with the Motec)
I've done one "tuning day" so far & plan on doing more soon. But it is hard to set up the environmental corrections properly with only a single day of testing. Also this lets me check how everything's running on a particular day at the track & make quick incremental adjustments if necessary - without screwing something else up in the process. Someone once said: "There are no stupid questions - only stupid silence." (can't remember who it was) .