I recently upgraded from a 440xi to an M4 Comp.. This past weekend I did an Advanced performance driving day at Eagles Canyon in Decatur Tx. I am not a highly experienced track driver, but have been on track several times already in different cars. So this will be a "no shit" kinda post for more experienced drivers..
Eagles Canyon is a 2.7 mile track with 2200 ft back straight where I was getting top speed of 120s working up to mid 130s before heavy braking into the 90 degree corner turn 11.
Overall I am ecstatic with the upgrade, and there is a universe of difference over the 440 vs M4 Comp. I was really debating putting 20k into the 440 to make it trackable, but it would still lack the basic components of an M car that make it track worthy, so I ultimately decided to start at a much higher baseline, and see where I go.
Car Setup:
2021 M4 Competition RWD with M Drive Professional
1000 Miles, Break in Svc completed
Michelin PS4S Star spec..
(learn about the OE tire here
)
RaceChip GTS black (only ran this in one session, but had my fastest lap with it).
Started with tires at 34 cold and they got to 48 hot, aired down to 26 cold and they stayed at 40 hot thereafter.
Factory Alignment
DSC off, Started with MDM set to 10 and backed down to 5 after first session and then to 4 for last session.
Sport/Sport+ all the things.
Weather - 86 part sun, on session in pouring rain, on in drying track, and 3 dry sessions.
Total time on track was just about 2 hours over 5 sessions with one double session.
Impressions:
Compared to my 440 this car grips a whole lot better. Less roll, more control, and much much snappier braking(no surprises there).
Transmission:
The transmission is super fast shifting, and I drove in full auto all day, letting the car up and downshift which it did well IMO. I was focused on learning the racing line, and gaining confidence in the car, and learning the braking locations. The wet session was really enlightening, as the car still had tons of grip in standing water while pouring.. Throttling out of the corners required some finesse, and stomping on the pedal too early was met with oversteer handily.
MDM - With MDM on 10 there was marked power reduction coming out of all the corners. it persisted for several seconds down the straight, so I turned that shit down to 5 after session 1 and down one more to 4 for last session because i wasnt having oversteer issues, or traction problems and want to work down to it totally off.
Power - The car has a boat load of power, and in the straights I was maintaining gap to GT3's and C7's. I did not feel underpowered when behind those guys.. there were a few worked C6s that were un touchable tho..one of the instructors was in a 10yo GT3 and I was putting up 5 sec lower lap times then him late in the day, he was super impressed by the speed of the car.
Grip - Shit load more grip than the 440. little Body roll, and not much understeer in the dry, however, i wasnt driving near the grip limit because i am still learning the car, but my 440 was plowing in every turn and not able to hold speed in the sweepers at all, vs the M4 was yearning for more speed - like come on puss, I can go faster.
Braking - Sport brake is SUPER GRABBY....I wasnt used to it so I was biting hard in every brake zone...I had to dial Brakes back to comfort to regain control of the brakes (this is operator error, and I just need to learn the pedal feel here). But there was no problems braking, in straights, in the corners, at all..Engaged ABS a bit, but again thats operator learning curve, making sure I am getting on the brakes hard first, then backing down from there...
Race Chip
Ran stock all day but last session, b/c why not.
Even though i was warned waiting at tech end of the day by yourself for the tow truck is a really lousy experience...I turned it to Map 7 ...Yee Haw!
It wasnt like holy shit different car faster, but it was...faster. I have a video of the lap timer dot plot from my fastest stock and tuned laps, and it clearly shows gap opening up on with the tune on...
Fastest untuned lap was 2:16.21 Top Speed 130 mph
Tuned I hit 2:15.45 and Top Speed 135 mph
See here:
Consumables..see pictures.
The tires held up well, wore to the right part of the shoulder after airing down...I will rotate them to even out the wear, but they did really well. After the first session there was a lot of graining, but I think this was them scrubbing in.
Brakes - The pads wore, but not terribly, maybe 1-2mm..
Laptimer - It worked well, has some gaps.
I didnt run in track mode, because that turns the screen off and stops recording video. So I triggered collision detection in heavy braking (windows went up) which also stopped recording..I need to figure out if I can enter track mode then turn on laptimer and get recording up.
I accidentally didnt record audio for all sessions cause theres a mic mute button that must have been pressed..
It does not recognize this tracks start/finish line, so I have to manually edit each session to put it where it belongs...
Whats next?
1. More seat time, and instruction. I am definitely the limiting factor and have a boat load to learn on the car and track, and finding where I am comfortable pushing it.
2. Economical Brake pad replacements. With no aftermarket race pads yet, I will need to get another set of stock pads, and send the old ones out for new race compound. So I plan to learn to do pad swaps.
3. Tires...I think the OE tires are great on track for a street tire, but I am in Texas, and have a truck for bad weather, so I am thinking these are gonna be replaced with something more track suited and not $375 a tire + $45 mounting and balancing at the dealer. Eventually I might spring for a second set of forged wheels and put dedicated track tires on it, but who knows....
I have this awesome dewalt cordless compressor that I highly recommend for all your air needs.
4. Alignment - I may mess with the alignment as time goes on to see how it impacts cornering.
Overall, I think the car will stay as is for the foreseeable future until I start getting my lap times down, and hit a plateau and start looking at where I can shave more time. Its my DD as well, but I dont drive much since WFH.
If interested I have some session videos with some coaching and banter on a youtube channel I am starting for the car. -
https://www.youtube.com/channel/UC4q...EUZ6GauTN02hmg