Project Evo Tuning (EvoIXMR versus EvoIXRS)
The Battle is ON. Head to Head, my MR against Rich's RS.
Both cars are Stock, Factory Tuned, and strangely the RS out performs any and all other Stock Evo's I know. It out ran Doug's IX MR and Henry's GSR. Is it just a well built EVO, or are the cars different from the factory? Let's dissect it.
The Meeting
The sky was raining, dark, and abnormally warm (50~60F). I heard a rumbling exhaust approaching from the distance; Rich arrived.
The Goal
We wanted to do enough pulls until we are completely satisfied that we have everything needed to find out the real differences between the MR and the RS. Since I've read that on the IX, the MR 6-speed advantage doesn't kick in until 4th gear, we had limited the agenda to 2nd and 3rd gear pulls from 2500rpm until redline. (We did do a 4th gear pull which I have eliminated from discussion)
The Prediction
I've been told that the IX RS and the MR should have no ECU or mechanical difference. I have not confirmed it, but I will in my next blog. Regardless, here's my original prediction cut and pasted:
Stock to stock comparison, I'm going to expect the RS's timing to be a little more aggressive, the AirFlow value to hike at a sooner RPM and to hold steadily higher AirFlow value all the way to redline.
The Test (2nd Gear Pull)
Initially as 100% throttle is applied, you can see the timing dips really low (MR to 3 and RS to 2) and climbs steadily upward until they both end up at 17 degrees. It is clear that after 5500 rpm, the RS starts to close in on the timing advance numbers but nevertheless reaches 17 deg later than the MR.
I was totally wrong about the Timing Advance Prediction! As you can tell, the MR wins most of the race, and with its more aggressive timing, it should be giving the engine a little more advantage.
Note: The MR showed knock count of 1 between 2700-2900rpm while the RS showed knock from 3000-4500rpm (between 1 and 2 counts). Bad gas? More Aggressive tune? I don't know.
The Airflow comparison is where the RS shined and walked away from the MR. From the very beginning, the RS has a slight advantage on the Airflow and around 3700-4250rpm, it really puts the beating on the MR. Strangely, at around 4300rpm both cars showed a decline of Airflow value! Air restriction, back pressure, resonance frequency, AFR, and critical speed of motor may all have something to do with it.
There after the RS wins the race entirely until the end the MR makes an attempt to catch up (never does).
In this case I was totally right about the prediction of Airflow values. Because the RS steadily flows more air through the intake, with a good tune, it would undoubtedly product more horsepower than the MR.
The Test (3rd Gear Pull)
More of the same, but this time in 3rd gear pull fashion. Ignoring the first portion where the timing advance dips very low, the MR out advances the RS by far (largest gap of 4 degrees at 4400rpm) and continues to hold a steady lead until redline; MR finishing at 17 deg while the RS finishes 1 deg lower at 16.
How much advantage does this help the MR in producing more horsepower than the RS? Since the MR didn't register any knock in its pull while the RS had between 1 and 2 degrees of knock between 4200-4800rpm, the MR presumably has more potential in timing advance tuning than the RS.
Airflow comparison: Again, the RS out performs the MR by light years. Regardless of its knock count and the less aggressive timing advance characteristics, after the turbo spooled completely, the RS pulled an instant 50 Hz advantage, grew the gap significantly between 4600-5700 rpm, and held on for a steady win.
Having a better airflow flow characteristics in both 2nd and 3rd gear pull, I'm not surprised to see Rich's RS pull away from cars like mine. With a lighter car and more horsepower potential due to higher volume intake of air at all rpms, I'm expecting his car to respond to mods better than mine. Who knows?
My Comments
The RS had consistent knock present right at the meat of the power band (3000-5000rpm) even though it has a lower overall timing advance values which is a terrible situation because if further timing needs to be pulled from the map in order to reduce knock, the RS may suffer more horsepower loss. Tuning the timing advance may be where the MR can gain some ground back.
As far as the airflow characteristics goes, did anyone notice that on both 2nd and 3rd gear pulls, the MR has a little bit of a jump right before 3300rpm? It seems like the MR had better response to throttle? Perhaps there's not enough data to make any solid statement or claim here.
Next Steps
- ECU: To bust the myth about RS vs MR, I'm going to break into the ROM and compare chart to chart the differences between the AFR, Boost, and MIVEC maps. I'm not going to be surprised if I find them all to be the same, but at least I have satisfied the itch.
- Boost Leak Test: To cover any mechanical difference the cars may have, I'm going to conduct a boost leak test on both cars to make sure the car is boosting healthily.
