The M4 GTS belongs on the track

[SYT_Shadow]

Originally Posted by bimmerboyE92

Hell yes to Hawk DTC-70s all around with AP 9668/9449 on Toyo RRs staggered. Love AP calipers but hate the Ferodos they push on everyone. I doubt you’ll need cooling with DTC-70s.

The solution is to switch to a pfc pad. They exist in the front and rear AP fitment

[CanAutM3]

Originally Posted by Gomeler

Attachment 2397332

Thanks to EGbeater for the 997 scoops. I'll repaint the rotors and pads to see if the scoops make a measurable difference. It looks like they'll catch a good bit of the air passing through the auxillary coolers(transmission and intercooler water loops I believe) in the foglight area. Will hopefully also scoop a little air that passes under the front splitter. Otherwise dumping the engine oil and brake fluid tomorrow. AiM Solo 2 DL next week, and then back out to the track.

Looking back a year ago when I bought this car, I thought I'd be daily driving it and maybe take it to the track a few times. COVID-19 means no daily driving, and canyon cruising quickly lost its fun. The car turned 2,000 miles at the track on the 13th..

Just as a tidbit, the passenger side pod radiator is for the lower temp intercooler system while the driver side pod is for the main engine cooling system. Driver side will therefore be hotter.

[Lienrocs]

These cars are an absolute riot on track. Anyone who says otherwise is either lying or hasn't driven one in anger. It's my favorite car I've ever owned hands down. And for the money you can have one and do some mods to it so cars that it's always compared to will only ever see your tail lights.

[fanatic1]

Originally Posted by Lienrocs

These cars are an absolute riot on track. Anyone who says otherwise is either lying or hasn't driven one in anger. It's my favorite car I've ever owned hands down. And for the money you can have one and do some mods to it so cars that it's always compared to will only ever see your tail lights.

Great shot, Thermal?

[Lienrocs]

Originally Posted by fanatic1

Great shot, Thermal?

Yeah. Thermal.

And thank you!

[Gomeler]

Got out to the track on September 18th, but it's taken 2 weeks to go over the data + scrub the video. Same-ish setup, 295 square RRs(started on heat cycle #7 I believe) on 18x11 EC-7, Carbotech pads in AP Racing calipers, stock ride height + recommended track compression/rebound settings.

New for today was 1) efficient throttle setting 2) trying to leverage this supposedly more linear throttle map to put power down sooner. It was an absolute riot to say the least, so many powerslides

First up, wife stomping the brake pedal so I could torque the front spacers for the 18x11s. Kiddo definitely didn't slobber on the wheel.



The consequence of running the car in efficient on the track is an absolutely roasted muffler. Prior to this day, the center section of the exhaust had just a little bit of discoloration. The car sounds like an aggressive vacuum cleaner on track until the baffles open up, you can hear it in the YouTube clip.



I set a personal best(2:01.269 with data) while tooling around playing with this throttle setting. My prior PB on the RRs with Solo2 data was a 2:04.228. I think I'm just now learning their breakaway behavior, and being able to push them to the point of sliding a bit. I repeatedly hovered around 2:01-2:03 with ONE 1:59.xxx predicted before I messed it up and powerslid up turn 7 like a moron(kind of like what I do in the clip).



Here's a clip with my best lap for the day. I wasn't chasing lap times as I had kind of written off the RRs for my skill level. I spent most of the day playing with the new throttle setting and trying to apply 0%-33% throttle much earlier than in the past. You can hear/see this with me poking the throttle in some of the corners, and a kind of sloppy lap with a lot of wheel corrections.

I've kind of been a bit frustrated with this car to be honest. It's heavy as fuck, and you can feel it everywhere. The water injection is a mess. The throttle mappings leave so much to be desired, efficient is close but the baffled exhaust really messes with me. However this morning outing really rekindled my love for this car. I need to see if I can just set the baffles to 100% open for track use to reset that feedback mechanism.

Lastly, water injection is working. The car drank water like a fish. However I think it is still running the CS power map. iDrive never showed above 420hp(I have 2 hours of footage showing that), and my lap times didn't reflect a 50hp change. Going to the dealership next week to work this out with them.

[FormulaMMM]

Bummer on the water system. Maybe this is dense, but... could altitude be playing a role in reduced power output reading??

~3% loss per 1,000 ft. 493 stock at 5,000 ft = 419 bhp.

So you are at stock/street ride height setting and 18s now? Have you run at track ride height yet? If still at street, maybe that is a contributor to the sense of heaviness.

Interesting that the efficient setting parks more heat in the muffler.

To each his own and don't doubt others have gotten the best out of the car in efficient. The sharpness of the sport plus throttle setting is one of the highlights of the car on track imo. Suits the hyper-responsive overall character of it, and pretty much cancels turbo unpredictability.

Corner starting at 1:14 -- isn't that a big wallop of turbo lag on corner exit due to efficient throttle map? Corner at ~0:55 you're on the gas at apex, but it doesn't sound like you're getting a response until almost track out. Corner exit at 1:40 almost sounds like you backed off power because of a delayed power spike.

Not trying to be critical, just looking for the advantages and disadvantages in the footage. Seems like efficient throttle you're inviting turbo spike and losing predictability and control on throttle during corner exit.

For those who have found the setting faster -- is it because you're able to modulate and get on the gas earlier? So you're gaining small bits of speed mid-corner where any throttle application in sport plus setting would have delivered too much power?

Looks like a really fun track and good to see your young mechanic in on the action.

[Gomeler]

Originally Posted by FormulaMMM

Bummer on the water system. Maybe this is dense, but... could altitude be playing a role in reduced power output reading??

~3% loss per 1,000 ft. 493 stock at 5,000 ft = 419 bhp.

I thought it might have been elevation as well, but the monkey wrench is that the car dyno'd identical to a M3Comp, ~440whp altitude corrected, while showing ~420hp on the iDrive. All this year the car has shown 420hp on the iDrive. Unfortunately COVID-19 ruined my plans of going to COTA in August, that would have been an interesting elevation change test.

Originally Posted by FormulaMMM

So you are at stock/street ride height setting and 18s now? Have you run at track ride height yet? If still at street, maybe that is a contributor to the sense of heaviness.

Dropping to track height is my next step. I'd been putting it off because 1) I thought I'd street drive this car 2) I was trying to find the limits of the current alignment/height. COVID-19 broke #1, and I'm getting close to #2 given my skill level.

Originally Posted by FormulaMMM

Interesting that the efficient setting parks more heat in the muffler.

To each his own and don't doubt others have gotten the best out of the car in efficient. The sharpness of the sport plus throttle setting is one of the highlights of the car on track imo. Suits the hyper-responsive overall character of it, and pretty much cancels turbo unpredictability.

I've only driven the car in efficient on the track, and the car sounds real funny. It goes from vrrrrooooom vacuum noises to adorably obnoxious rasp at weird points. I wasn't expecting it to route so much exhaust through the muffler, but basically anytime I was partial throttle you can hear how muffled it is.

I thought sport+ was amazing, until I started trying to put power down as early as possible. I didn't have the harness, so my inputs unintentionally pretty rough. I'm still not 100% sold on efficient vs sport, it's possible I could achieve the same levels of control in sport.

Originally Posted by FormulaMMM

Corner starting at 1:14 -- isn't that a big wallop of turbo lag on corner exit due to efficient throttle map? Corner at ~0:55 you're on the gas at apex, but it doesn't sound like you're getting a response until almost track out. Corner exit at 1:40 almost sounds like you backed off power because of a delayed power spike.

Not trying to be critical, just looking for the advantages and disadvantages in the footage. Seems like efficient throttle you're inviting turbo spike and losing predictability and control on throttle during corner exit.

1:14 is T8, 0:55 is T6. In both cases if you watch the torque meter you can see it goes from ~250ftlbs to ~450ftlbs very quickly, corresponding to a very minor wheel correction in T6, and a full-blown oversteer + correction in T8. It's very important NOT to listen to the exhaust note, T8 for example is nearly full boost/torque while muffled, when the baffles open the rear is already kicking out. This is what fucks with me constantly in this mode, the exhaust note isn't congruent with the power levels.

1:40 is T11 exit, and it's been the rear tire grip fall-off corner test. At the start of the session I can WOT it from a car length after the apex, but as the rear heats up I go from a wheel correction and drive through it, to serious throttle modulation.

Originally Posted by FormulaMMM

For those who have found the setting faster -- is it because you're able to modulate and get on the gas earlier? So you're gaining small bits of speed mid-corner where any throttle application in sport plus setting would have delivered too much power?

Right now I'm not sure if it is placebo, or if it is actually helping. I've got ~6-7 sessions now in efficient, and I've cut some of my fastest and most consistent laps with it. However, in that time I've also gotten much more comfortable with the Toyo RRs so.. . Next time out I'm hoping to remember to test sport and sport+ again.

Originally Posted by FormulaMMM

Looks like a really fun track and good to see your young mechanic in on the action.

Thanks, it's my home track and I love it. I almost never feel unsafe looping the car here, besides other cars there's almost nothing to hit besides the occasional deer. I'm hoping this kid likes karting, because I'm all ready to give him the chance that I didn't have

[h_bakken]

Originally Posted by Gomeler

Lastly, water injection is working. The car drank water like a fish. However I think it is still running the CS power map. iDrive never showed above 420hp(I have 2 hours of footage showing that), and my lap times didn't reflect a 50hp change. Going to the dealership next week to work this out with them.

Thanks for all the GREAT information and video!

Re water injection

I'm very curious to see what you find.

I am having a similar issue with water injection.

I had my valve block replaced and ECU reprogrammed about 2 weeks ago.

I still can't reproducibly hit 490 on the gimmick iDrive power meter, but have seen it hit twice, and it definitely is more than 444 which is the CS ECU map that it defaults to when water injection is not working.

Had car re checked and head BMW tech assured me everything is fine, gave me a print out of the function check.

[chillindrdude]

how much HP increase you guys seeing with the charcoal particulate filter removal?

[4play]

Originally Posted by chillindrdude

how much HP increase you guys seeing with the charcoal particulate filter removal?

There is no petrol particulate filter on the M4 GTS.

BMW added them on 2018+ cars for EU only.

[Day Laborer]

Originally Posted by 4play

There is no petrol particulate filter on the M4 GTS.

BMW added them on 2018+ cars for EU only.

He's not speaking about particulate filter - the stock airbox has two sets of air filters in them- one charcoal filter and one air filter on each airbox

[Gomeler]

Originally Posted by Day Laborer

He's not speaking about particulate filter - the stock airbox has two sets of air filters in them- one charcoal filter and one air filter on each airbox

Huh, neat. I wasn't planning on touching the air filters until my planned Spring 2021 refurbishment. Guess I'll explore that then. Don't see myself running without whatever BMW stuffed in there though, warranty and all being critical

[Gomeler]

I'm a terrible photographer, but . Been pretty warm for the last few days so I pulled the car off the battery tender and got to rip up and down a canyon with no traffic. That's it, nothing much of interest happening with the car for now.

[YKIGI]

Get lighter wheels and more rubber and it would be even more fun ( for OP )

[Gomeler]

Originally Posted by YKIGI

Get lighter wheels and more rubber and it would be even more fun ( for OP )

I mean, 18x11 squared w/ a 295 Toyo RR is a lot of rubber, and Pirelli slicks planned for 2021. What more do you want from me?

[4play]

Originally Posted by Gomeler

I mean, 18x11 squared w/ a 295 Toyo RR is a lot of rubber, and Pirelli slicks planned for 2021. What more do you want from me?

This is the right setup haha. I'm running 18x11 et44 with Pirelli slicks.

[YKIGI]

Originally Posted by Gomeler

I mean, 18x11 squared w/ a 295 Toyo RR is a lot of rubber, and Pirelli slicks planned for 2021. What more do you want from me?

Duuuuude, huge error on my part. I was lazy and missed the wheel/tire setup. I only saw the stock photo. My apologies 1000%
Have fun man

[Gomeler]

There might not be much happening with the F82, but the E82 is getting some love. Not going to bother posting to the 1er forums, because I won't have this car for much longer. I'm refreshing/upgrading anything that cools the car, adding brake scoops + pads, and then shipping it down to Florida for my father. This was my first BMW, I have some good and bad memories with it, but I'm glad it'll get to finally go on track for a little bit.

Dumped the oil and coolant, pulled the radiator fan + intercooler. Pulling the radiator later tonight once the coolant stops trickling out. Swapping in an all aluminum radiator, possibly upgrading the intercooler after getting a good look at it, and adding a beefy dual oil cooler setup over the dinky factory one. I'll likely install an air/oil separator as well, replace the intake filter, and call it good. It'll go to an independent shop for a valve clean + hvac evaporator replacement(). Won't be adding any power, factory engine mapping will be enough. Maybe in the future it'll get a LSD if my dad really enjoys the car on track.



Original hood struts clearly need replacing. This car is bone stock, ~65k miles. I never let myself mess with it while I constantly exploded Subaru engines.



There was about a pound of gravel sitting in front of the radiator/intercooler.





In related news, it took me ~8 months to build and install the ej257 in my Subaru. I'm guessing it'll take me ~3 months to wrap this car up. That doesn't leave me enough time to acquire a M235i and prep it for the 2021 NASA time trial season. There are several race ready M235iR on racing junk. My wife will likely be displeased with me

[FormulaMMM]

Originally Posted by Gomeler

There are several race ready M235iR on racing junk. My wife will likely be displeased with me

I don't allow myself access to that site. The shit you can find in the road racing category will ruin a marriage.

Nice work on the 1er.

[bioman]

Does anyone know the boost psi you should be hitting with the water injection working?

Thanks!

[Gomeler]

Been a while since I've updated. The GTS is still in storage, I ended up pulling the battery and putting it on a charger in my basement since I kept finding the GFCI circuit tripped where the car is currently stored. I'll pull it out of storage at the end of this month.

I've been working away on the 135i whenever I have a warm day but it's been pretty brutal in Colorado whenever I have a free weekend. Going to have to address this frozen garage slab issue this year.

Anywho, enough bitching about the garage, progress has occurred!


First batch of goodies, coolant and IATs will be nice and stable on track. Grabbed a solid charge pipe to keep the OEM one from cracking on track. Some bimmerworld race studs because I'm not slinging tires onto studless hubs. Lastly some hood supports, the originals were very tired and couldn't support the hood when it was cold.




I was shocked at how small the OEM N54 intercooler is, and how absolutely massive the VRSF intercooler was. I was also surprised that everything had a very OEM-like fit.


The first victim, cracked the hell out of the OEM radiator when I was trying to remove this line. Ended up just ripping this hose off once I cracked the plastic, I wasn't planning on saving any of this.





The install process was pretty straight forward, and it all just fit. Pretty neat.


This shows how the intercooler just fit. Also, check out that oil cooler