Now that I've got my process down for back-to-back road-testing my tuning changes, it's giving me something to do with the little bit of spare time I have in my days...LOL.
I had already made some *small* changes to the exhaust cam timing from stock prior to these tests, with the changed timing being used in all my "non-stock tune" runs prior to today.
For reference, here's the stock "Cam Timing - Exhaust Low Det" map:
...and here's my first modified exhaust cam map (using an ECUTEK RaceROM custom map to replace the exhaust cam angle channel output):
Note that because of the custom map dimensions, I had to flip the X and Y axes and extend the information out on both axes as well...
For today's test, I didn't bother making a fully stock run, since I already know there were improvements with my first modified map. So, I did one run with the map above enabled, and another with my new map for comparison.
My aim was mostly to try and pick up a bit more torque from 3000-4800 rpm, and have it pull a bit smoother into the big bump I got from the BPB's above 5200 rpm or so (where it had kind of been feeling like it was lagging a bit heading into 5200 rpm before pulling HARD from there to 6000 rpm). I figured I'd also try and see if anything could be gained above 6000 rpm.
I increased the exhaust retard across the board from 3600 rpm to 4600 rpm to match the value at my stock torque peak @ 3200 rpm, then tapered it down towards 5200 rpm, staying flat from there to redline. Values are increased across the board from 3600 rpm - 7000 rpm by varying amounts.
Here's the new map:
Results:
- 3000-3600 rpm = 3.0% faster on new map
- 3600-4200 rpm = no change
- 4200-4800 rpm = 2.0% faster
- 4800-5400 rpm = 1% slower
- 5400-6000 rpm = 1% faster
- 6000-6600 rpm = 1% slower
I'll basically ignore anything in the +/-1% range, so it objectively looks like there are *small* gains from 3000-3600 rpm and also from 4200-4800 rpm.
The differing *feel* of the pulls would tend to agree - the car seems to pull more evenly from 3000 rpm on up, and it also just sounds a bit smoother / happier pulling through the revs, where it used to be a bit coarse.
The smoother pull is a bit deceptive because it doesn't necessarily feel faster (even though it is), maybe because by filling in the dip a bit, it doesn't have that sharp ramp up out of the dip that the stock map does? Not sure. I'll just go with the numbers telling me there's improvement.
I'm going to try a bit more intake cam advance from 3200-4600 rpm next to see if I can pick up a bit more torque there, and then switch my focus to improving the power and "rev-ability" (for lack of a better word) in the 6000-7200 rpm range with cam timing if possible.
Once that's done, I'm going to turn my attention to ignition timing, and once I'm pretty happy with it, I might get it put on a dyno for a run.
