Greetings! I'm going to give updates on my “SuperTurbo†Mini here going forward. But first, some background to get everyone up-to-speed. Over the last few years I've steadily progressed through multiple stages of enhancements/improvements on my Mini. One of the motivations for this has been my steadily increasing interest in DE track events. Fortunately, I had had an *excellent* shop nearby (BHS) to make it all work together efficiently and reliably....that is, until they shut down earlier this year. (note: larger versions of all the pictures are in my gallery) Stage 1 Early-on my car started out as a “normal†heavily modified 2004 Mini. I did the standard bolt-on aftermarket stuff: GRS intercooler, Detroit Tuned brake kit, Leida suspension, better seats, etc. etc. Stage 2 The madness started to increase when I found BHS. They specialized in getting high-end BMWs to insane power levels. We started with simple stuff (Quaife LSD, lightened flywheel, etc.). Along the way we went so far as to replace the internals with lightweight, high-strength, balanced components: Stage 3 Things really started getting crazy when I acquired components of a twin-charge (Supercharger+Turbo) kit. With a good bit of rework, BHS was able to produce a well-integrated system with a very non-turboesque behavior. Here is a picture of the installation at that point, including my crude but effective temporary heat shield: Here is a system diagram I put together showing the interconnections and control of the twin-charge system: I have been pretty consistent with getting a dyno run on the same machine after each modification, so I have a pretty good history of the performance gains at each stage. With the addition of the turbo, it progressed to a *much* higher level: 298whp/234ft-lb tq. The really phenomenal thing about this is the tabletop-flat torque curve through most of the power band, and the consistency from run-to-run. It behaves & sounds much more like a bigger engine than a turbo. I had the chance to try the car out on the track for the first time at aTexas BMWCCA DE event in 2007. The event was held at the MSRC track near Dallas. It's a technical track with medium length straights that favors cornering over power, so I wasn't expecting it to be magically different than before. Net net, the car was *fantastic*. Even though it was the first outing & I wasn't pushing the car to the limit, I improved upon my best lap time for that track by over two seconds. And it really felt like a very different car....which also means that I have to totally relearn how to drive it. There were at least two turns that I used to be on full-throttle at the apex that I couldn't anymore because I was spinning *both* of the front wheels - even with a quaife differential and wide sticky tires! To get a feeling for it yourself, here's a video from the afternoon session. FYI the Miata in the video is a heavily modified with a Turbo...they don't usually take me that long to pass Note: the audio is a bit deceptive. With the waste gate open, the car is *very* loud. So I had to really turn down the Mic input...which means you don't hear much of the normal engine sound until the Turbo is fully spooled up: [ame="http://www.youtube.com/watch?v=uh6DDMsmgPc"]http://www.youtube.com/watch?v=uh6DDMsmgPc[/ame] At that point I had a data logger hooked up to gather standard GPS information as well as RPMS, Oil pressure/temp, boost, A/F Ratio, etc. Just to give you a sample, here is a graph of the boost vs. speed for one lap: I'm also experimenting with a math channel that calculates deviation from "theoretical optimum power delivery". With a perfect car & driver this graph should be zero everywhere. Overlaying this run with one from the previous year, you can see how the peaks are generally sharper indicating faster acceleration/deceleration. But in other areas it's actually worse...mainly because I'm wasting too much time spinning the wheels and/or being less consistent through the turns...more confirmation that the biggest thing needing improvement now is the nut behind the wheel : Stage 4a I ran it this way for about a year before the car developed an electrical fault. At this point I decided to make it into a track-only car & get rid of the stock computer. With BHS's help, we replaced it with a Motec ECU and AIM GPS data logger. The interior was stripped, sunroof filled in, and new seats & rollbar added: I particularly like this picture up through the roof with the sunroof assembly removed: There were a number of challenges in this process. I'd say the first challenge was caused by our decision to try to reuse existing Mini sensors instead of buying new (and expensive) MoteC sensors. It seemed logical (and cheaper) to try to reuse as much as possible...but in the end trying to figure out the behavior and properly calibrate the sensors was not worth the effort. Almost all of the sensors on the car now are MoteC. The second challenge was our decision to try to keep the electric throttle controls rather than switching to a mechanical throttle. The MoteC has an electric throttle control package, but it is very poorly documented. It took a few tries to get the wiring and software working correctly. But having the electric control enables a whole bunch of valuable ECU capabilities (traction control, idle control, etc.) The third challenge was in getting the cam sync sensor working properly. We first tried using the stock HAL effect sensor, but couldn't get it to work. We switched to a MoteC magnetic sensor, but it was difficult to adjust & got out-of-sync frequently due to noise. Finally we got the stock HAL sensor working properly. The timing sync is rock-solid now. One of the last things we added was a front-mount intercooler from GRS. I purchased a top-mount GRS intercooler early-on and have had excellent success with it. But having both the turbo+supercharger was a bit much for it. The front-mount version is a piece of art: Stage 4b Unfortunately BHS closed down early this year, so I had to complete the wiring & various mechanical/interior/finish details myself. To further enhance the ability to capture & edit the settings, I mounted an additional embedded Windows XP computer in the car permanently connected to the ECU and GPS logger. This also enables the use of low-cost USB-based cameras for video recording. And by attaching a USB WIFI dongle, I can now tune the car wirelessly from a laptop (as well as watching the video wirelessly in real time ): Finally, last weekend I finished cutting & installing the aluminum floor plates. Even though I made a cardboard template, I had a few issues with fitment...but I think it turned out good enough: I've already gotten a lot of positive feedback on the floor & interior in general. It feels minimal, but very functional. Tuning Although BHS started doing the tuning in the shop, I ended up having to pretty much start from scratch & learn how to do it myself. FYI here are three great books I've found: How to Tune and Modify Engine Management Systems by Jeff Hartman, Motorbooks Workshop. Dyno Testing and Tuning by Harold Bettes, SA Design Engine Management Advanced Tuning by Greg Banish, SA Design One of my key goals is to avoid some of the issues that have hit other highly customized Minis. In my opinion, a big challenge with tuning these engines comes from the inherent difficulty in tuning a small forced air engine for all the extreme environmental variations (summer/winter hot/cold dry/humid, altitude variations, etc.) - especially if you're trying to do it all in a single tuning session. What complicates this even more are the small but significant differences between running the car on a dyno vs. on the road/track. So my approach has been twofold: 1) capture as much real-time, real-world information as possible (including weather conditions) , and 2) develop techniques for using this data to quickly and precisely adjust the tuning maps to match the real-world conditions. To achieve this the engine has a large number of sensors installed. Three of the most important are the wideband Lambda, EGT, and knock sensor. The Lambda is the most important way to check the fuel maps. And the EGT and knock sensors are critical for adjusting the timing, as well as providing key indicators for other potential issues. Getting the Lambda & EGT working was easy with off-the-shelf parts, but no such luck with the knock sensor. It requires a bandpass amplifier tuned to match the specific engine configuration. I'm working on designing my own DAC-based circuit for this, but in the mean time I found an aftermarket box that seems to be working well. It appears as the small circuit board at the bottom of the wires below (fyi the wiring in this picture looks worse than it does in real life...and I'm working on simplifying it) Here is an example of the kind of log data I get out of a run: Since the main tuning map is a function of RPM and MAP, I created two graphs corresponding to the instantaneous values of these sensors at each RPM/MAP point. The value at each point is represented by a color-coded dot. The color coding is structured to make problem areas visibly stand out. These graphs are automatically generated from the logged sensor data. So after each run I can immediately see where the maps need to be adjusted. The following picture shows Lambda as a function of RPM/Boost, and EGT as a function of RPM/Boost. RPM is the X axis & boost is the Y axis: Over the last couple of months I've taken the car to a couple of one-day track sessions to do additional tuning & adjustments, as well as making sure everything is running reliably before I take it to a multi-day event. One of the features the MoteC supports is boost control using a solenoid connected to the pressure line going to the wastegate. The wiring for the solenoid was not quite right, but I finally fixed it. So the next step was to set up the parameters for the control algorithm. The first step in that process is to find the "target" duty cycle. This is done by setting a fixed duty cycle. I didn't want to accidentally make the boost too high, so I set a 35% duty cycle to begin with. This increased the maximum boost by about 5psi. to about 20psi. (see plots below). I then had to make some adjustments to the timing & fuel tables at those boost levels. Old Plot: New Plot: Because I just used a fixed duty cycle, the graph is shifted to the right. Once I set up the PID controller properly, I should be able to get it to boost at least along the blue line drawn into the graph below. This graph shows the new data overlayed on the old data (in black): I did have an issue on the second run session where the engine cut out briefly. I traced it to some water that was shorting out the sync signal. When I cleaned the contact & reassembled it, the problem didn't occur again. Also, this is also the first run I've had a chance to log GPS data from the AIM data logger. This software is very different from the analysis software I've used before, so I'm still getting used to it. Just for fun I tried out the engine performance analysis view. By entering the vehicle weight (including driver), frontal area & drag coefficient, it calculates HP & TQ to the ground. In theory this says I'm making 315 HP & 277 ft/lb of torque to the ground...BUT I'm very doubtful of those numbers at this stage. I'm planning on taking the car to the dyno in the near future; that'll give me something to compare this to. --- So that's where we're at. It's running well, but I've still got lots of things I want/need to do to it. I'll keep you posted as I progress....
Wow, amazing! You get my vote for most complete, drawn out, fascinating, over the top, look-at-me-and-the-past-several-years-of-life 1st post EVER Cheers, Ryan
Wow, heck of a project. I'm sure it was a lot of headache to go with all the high points but challenge makes a hobby fun, right? There aren't a lot of us here who've considered going that far and I love to see this kind of detail available and another member with this kind of experience on the site. Welcome to M/A!
Clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap clap Damn... nice setup. So when is one of the ALMS teams going to pick you up to develop their engines?
Another video FYI, Here is a video from the session last weekend: [ame="http://www.youtube.com/watch?v=zzdcLKfNNuE"]http://www.youtube.com/watch?v=zzdcLKfNNuE[/ame] I'm taking it pretty easy, but it gives you a bit better idea of what it sounds like. And yes, that's a TRUCK I pass...but trust me he was no ordinary little truck (or driver). Everyone was commenting on how fast he was....he even had a duel with a full-fledged racecar that was there practicing...
Wow, you drank a LOOOOOOOOOT of the mod cool-aid! You're so far up the learning curve we can't see you. Cool, classy project!
There is a lot of dedication and forethought in this build, from what I can see. I think the thing that impresses me the most is the installation of the Windows computer for data logging and a tuning interface. That's going the extra little bit to capture everything you might possibly need for analysis, and just make your life easier. I've always been a fan of gathering too much data. If you capture it, and don't need it, you're better of than not capturing it at all. You may not have the MOST HP or Tq pulled out of a MINI, but it sure seems like you have one very complete all around package. Well done!
If I ever can afford a separate daily driver I would love to go a similar route with my own mini, especially the weight savings and interior gutting. Very good write up and the interior is very attractive for such an elaborate build. Usually people tend to forget aesthetics altogether with such projects, but you've got a very impressive balance of very functional form. I would love to see it in person. Did I miss it or did you state how much the car weighs at this point? I know it's undoubtedly in that data logging somewhere, but the images are too small to sort through.. at least on my tiny monitor.
Thank you all for your kind words. It has been an interesting path. The funny thing is that before the Mini I had never modified any of my cars (although I had worked on them...usually out of necessity). Next up: Aerodynamics!
I have not had a chance yet to get it weighed. I'm aiming for 2300lb, but I'm probably still a bit over that. I'm planning on replacing most of the windows with plexiglass & going with a CF hood & trunk.
Great write up and a great sounding car!!! It's awesome that more and more MINI's are getting into the Time Attack/Redline racing... Looking for some good numbers in 2010 Cheers!!! Mike
Are those Sparco Pro 2000's? I want a pair of those. Also, were those intercooler horn adapters for the front mount from GRS as well? You have an awesome MINI.