Hey, guys! I've been sharing my progress across various Facebook groups as this car has gone faster and faster on JB4, but thought I'd put together a quick-and-dirty thread to share the progress here.
Quick background: coming from an 2020 Toyota GR Supra as my previous fun daily driver, G80 seemed like the naturally progression after my son was born. So, I ordered my 2023 BMW M3 Competition xDrive to learn the platform, and I immediately fell in love with it for reasons we all understand.
After an 8 month wait, delivery day!
Tucked in with her garage mate...
Ronin loves his cruises with daddy, especially when we're cutting up...
Initially, I planned on immediately unlocking, and proceeding with flash tuning to develop our packages. However, I realized that one question we were getting frequently from our S58 customers had nothing to do with flash tuning... "which is better? JB4 or RaceChip GTS Black?"
So, I got both and started testing. The findings are beside the point of this thread, but after seeing the capabilities of JB4 on various maps and fuels, I was impressed. After speaking with our BMW customers, I learned that 8/10 would prefer a piggyback solution over flash tuning, as long as they could gain 100whp or so. With that information in hand, I decided to invest some time here.
After that point, I spent months learning the platform, and learning JB4. And the further in I got, the more confident I was that 9s on an unflashed ECU with JB4 is 100% feasible! This became my goal for this phase, and I'm happy to say that hypothesis proved out. I'll save the whole zig-zag progression story for a video, but here's where we stand currently. Vehicle details and modifications performed are as follows:
- 2023 M3 Competition xDrive, standard seats, steel brakes
- 3,945lbs with me in it (passenger seats removed, 201lb driver)
- JB4 with my Map 6 settings
- MAD down-pipes with 200-cell catalytic converters
- Front wheels & tires: stock 275/35R19 Michelin PS4
- Rear wheels & tires: Apex VS-5RS 18x10.5 with 305/35R18 Mickey Thompson ET Street S/S
And the result thus far?
9.99s at 138.08mph on the street, on E50...
5.99s 60-130mph on the street, on E50...
10.15s at 135.13mph on the street, on 93 OCTANE!
What's crazy, is that if I cut my normal 1.51s 60ft on that run, it would have been 10.07-10.08s on 93 octane! Absolutely bonkers. Planning to revisit 93 octane and see how fast I can go after the below improvements.
And here are a few shots of the car as it sits with the rear drag pack...
I believe the car is making as much power as it can with the current hardware in place, so from here, it's an exercise of efficiency. Next steps below:
1. Swap out MST Performance intake for Mishimoto closed air box intake. At this point, the benefits of a closed air box and plastic construction may knock a couple hundredths off. Worth it!
2. Install Apex 19x10 +12mm VS-5RS on stock 275/35R19 Michelin Pilot Sport 4S. The reduced rotating mass over stock will have a considerably impact.
3. Test out various ethanol contents at the same boost level, and see if there are any gains to be had. Low confidence in this, but worth a try.
4. Try out a custom xHP transmission tune. Not fully confident it will make a difference, but worth a shot.
5. Install Apex 20x10 +8mm VS-5RS on stock 285/30R20 Michelin Pilot Sport 4S. Same logic as point 2.
6. Dial in custom launch control settings via xHP to try and cut similar 60fts on stock tires. If this proves to be feasible, trap speed should increase considerably without the 76lbs and high rolling resistance of the 305/35R18 Mickey Thompson ET Street S/S out back, which should translate to faster times. Could be challenging with winter temperature right around the corner.
I'll keep everyone posted on progress from here!