Project Evo Tuning (WOT Comparison - '03 Evo8 GSR)
Before I dive into playing around with the ECU, I wanted to do some comparisons of my stock MR against other stock Evo's out there. Out of the list of people I know, I've called up Jeff (Evo8 GSR - Stock with Muffler Delete) and Richard (Evo9RS - Stock) for the following reasons.
Why Evo8?
I really wanted to know how much of a difference does the MIVEC and the larger turbo make on the Evo9 versus the Evo8. Sure you've heard that Evo9's are supposedly more responsive to mods, right?
Why Evo9RS?
That's because they are monsters! Stock to Stock comparison, I know Rich's car pulls away from any MR, any day. It is because of its light weight? Is it because it has a more aggressive ECU tune?
My Appointment with Jeff
Lucky for me, over the weekend I had a chance to meet up with Jeff, who drives a 2003 Evo8 GSR . The only mod that is installed is the Buschur muffler delete (which I thought would not skew the comparison by too much).
Having sat in and drove Jeff's car many times (including autocrosses), I've always thought his car felt about the same as mine power-wise. I didn't think MIVEC added any distinct adventages, nor can I really feel it more.
3rd Gear Pull Result - trouble
In Jeff's car, the Mitsulogger initialized successfully and created a new file to begin logging. Everything seemed just fine. I asked Jeff to put the car in third gear, and start a pull from 2500rpm. He hits the gas and mashed the pedal to the metal...we waited, and waited, and where's the boost? Looking down at the datalogging software, RPM reads 0, Knock Count reads 243, and AirFlow reads 0! Something is going on here.
There were two issues we were combating here. First, Jeff's car wasn't accelerating like it is suppose to, and the weird thing is neither of us could hear the turbo boosting. Could it be boost leak, stuck BOV, or the car being stuck in limp mode? Second, the datalogger wasn't recording the values correctly. Amongst multiple mis-readings, I noticed the following repeating errors:
- RPM values goes to 0 as it goes beyond 4000 rpm
- AirFlow values goes to 0 as it goes beyond 793 Hz
- AirTemp is stuck on 360F (it's FREEZING out)
Because we didn't have RPM's beyond 4000rpm, I couldn't accurately compare my data to Jeff's. In the end I salvaged what was available and rendered the following graphs. Keep in mind I used Log Unit instead of RPM to complete the x-axis of the graph.
Timing Advance Vs Knock Sum Vs Narrow Band O2 (1)
<2700rpm-redline in 3rd gear>
The first thing I wanted to know is, how does the muffler delete affect the Air Fuel (A/F) mixture? Because the modification reduces exhaust back pressure, the end result is air can enter the intake easier. Since Jeff's ECU has not been reflashed, under open loop conditions (WOT), the Narrow Band O2 sensor should read "leaner." In my opinion, it certainly does read a bit leaner, as you can see that it oscillates between 0.940V and 0.920V several times before settling on 0.940V.
Something else to note is, 2 counts of KnockSum value was immediately present occurring as soon as Jeff slammed on the gas at 2700rpm and dropped to 0 at 4000rpm.
Timing Advance on the Evo8 was very impressive indeed. If you compare his values to my MR, you will find that at redline the Evo8 held 25 while the MR only had 16 degrees. I suspect this has something to do with the MIVEC.
Timing Advance Vs Knock Sum Vs Narrow Band O2 (2)
<2700rpm-redline in 3rd gear>
At the point when we logged this 3rd gear pull, Jeff's car was already showing signs of sluggishness. You can see that there was something really weird about the Narrow Band O2 value at the beginning of the pull, dipping dangerously into 0.080V for a while before skipping to 0.760V and climbing to 0.940V at redline. You can also see that his Timing Advance value experienced a dip at approximately 5000-6000rpm range to 13 before climbing up to 23 at redline. KnockSum was recorded at 1 count at redline.Summary
The whole experience was a tuner's nightmare. I wasn't able to read majority of the data and the car couldn't product repeatable results. Next step? I'm going to research on the aktivematrix forum to figure out why the dataloging program is mulfunctioning, and at the same time help Jeff troubleshoot the Evo8. Ultimately I want to be able to:
- Compare AirFlow values to see which car pulls higher Hz across the rpm range;
- Compare Load value to construct correlation amongst Load, Torque, and Boost;
