THE LARGEST BMW 2-SERIES FORUM ON THE PLANET
2Addicts
2Addicts
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
2Addicts | BMW 2-Series forum Technical Topics Tracking / Autocrossing My track M240i(R?) build

Post Reply
 
Thread Tools Search this Thread
      03-23-2020, 12:23 AM   #1
msendit
Private
msendit's Avatar
74
Rep
86
Posts

Drives: M240i
Join Date: May 2018
Location: San Francisco, CA

iTrader: (0)

My track M240i(R?) build

A little bored cooped up at home, figured I'd start a thread to describe the process I went through with my track car. I don't know of too many B58-based cup car conversions (other than capt_and's), so figured it might be interesting.

I don't want to just put down a parts list, but describe my reasoning at each step, so I'll just post the different "stages" one by one. When I first got the car, I'd never stepped on a track -- it never even crossed my mind that there's an amateur level at motorsports. Having a bit more experience now, I'd definitely do many things differently (and probably not start with the F22 platform). But all in good time.

Anyway, here's what the car looks like now. The chassis and the engine have about 110-120 on-track hours on them. Current goals for it are mostly fun HPDE / occasional time trial. I don't plan to take it wheel-to-wheel racing, mostly because of the pretty high running / repair costs.



Appreciate 7
Maynard1301.00
Dylan861152.00
dradernh585.00
230iZTR62.50
ifobd11.00

      03-24-2020, 10:50 AM   #2
Dylan86
Colonel
Dylan86's Avatar
Canada
1152
Rep
2,099
Posts

Drives: Hard
Join Date: Jan 2016
Location: GTA

iTrader: (0)

More pics of the body panels/fitment if you could! This is a long term goal for me on the bodywork/cage side. Well done, sir

D
__________________
Appreciate 0
      03-24-2020, 12:19 PM   #3
dradernh
Major
585
Rep
1,276
Posts

Drives: 2017 M240i
Join Date: Aug 2013
Location: Ohio

iTrader: (0)

Quote:
Originally Posted by msendit View Post
Anyway, here's what the car looks like now.
The car looks good!

Do you know its on-track weight with you in it; if so, how many gallons of fuel are in the tank at that weight?
__________________
2017 M240i: MT, Moonroof Delete, EB, Black Dakota Leather, Driving Assistance Package, Heated Front Seats
TC Kline Coilover Kit; EDC/eLSD Delete; Wavetrac; Al Subframe Bushings; ARC-8 - 18X9 & 17X9; R888R - 255/35-18 & 255/40-17; Hawk DTC70; Schroth Quick Fit Pro Harnesses
Appreciate 0
      03-24-2020, 02:01 PM   #4
msendit
Private
msendit's Avatar
74
Rep
86
Posts

Drives: M240i
Join Date: May 2018
Location: San Francisco, CA

iTrader: (0)

Quote:
Originally Posted by Dylan86 View Post
More pics of the body panels/fitment if you could!
I'll grab some closeups later. Generally speaking it's OK, some imperfections here and there. I fully expect the panels to get bent / cracked / replaced #becauseracecar, so haven't been obsessing too much with fitment.

Quote:
Originally Posted by dradernh View Post
Do you know its on-track weight with you in it; if so, how many gallons of fuel are in the tank at that weight?
Not on this latest config. I need to get it corner balanced after the next time out, but it's a bit unclear when that will be.

Last weigh in I did was 3715 lbs with me (140) and a full tank (~12 gal). This was before the bodykit -- panels, wider tires, bigger brakes will probably add some, but I also had to remove some pretty heavy bracing to make space, so ... maybe 40-50 lbs more now.
Note I haven't done much in terms of weight reduction (yet?) -- all the interior panels / sound deadening are still there, massive OEM battery, A/C, etc. Oh, and the frigging sunroof!

Last edited by msendit; 03-24-2020 at 02:05 PM.. Reason: sunroof!
Appreciate 2
dradernh585.00
Dylan861152.00

      03-24-2020, 05:32 PM   #5
msendit
Private
msendit's Avatar
74
Rep
86
Posts

Drives: M240i
Join Date: May 2018
Location: San Francisco, CA

iTrader: (0)

Stage 1: stock(-ish)

End track-hours: 15-20
End Laguna Seca time: 1:56-high

End parts/specs:
KW V3 coilovers
Ground control camber plates
Turner thrust arms with monoballs
Apex studs
RBF660 fluid
-2.2 F -2.2 R camber; ?? toe
MPSS/MP4S tires: 225/40/18, 245/35/18
Stock BMW rims: 7.5x18 ET45 F, 8.5x18 ET52
"compulsory" exterior bits: black grilles, black mirror caps, painted front reflectors

As I mentioned, I didn't get this car with tracking in mind -- I'd actually never been to a track before. I don't need a car for work, so it was mostly something for weekends / roadtrip adventures. The day after I grabbed it from the dealer, I took care of the engine break-in with a 2000-mi trip from San Francisco to Denver and back the scenic route, dealer plates and all (CO police was *not* happy about that!). I'd been reading the forums here, so I swapped the "compulsory" exterior bits literally on the side of the road somewhere in Nevada on the way.



I did a few other longer trips and was pretty happy with how the B58 pulled for overtaking. Plus, the usual other things -- some "spirited" runs on local twisties, some onramp kicks -- none of which were really pushing the car anywhere near its limits, but I was definitely enjoying it. Around that time, a coworker mentioned some "racing school" they've done on a local track, and the gears in my head started turning. I've been watching motorsports pretty much my entire life, but never really connected the dots that you can take a "normal" car on the track between the real races. Having a fast car, it was a no-brainer to try it.

First HPDE with the car (and for me) was pretty typical -- some nerves, big sensory overload, tiptoeing around, learning the line. Honestly I wasn't too impressed until I took a ride with my instructor (in some M4 IIRC) for a couple of hot laps. That was the holy cow moment when things clicked! I realized: (i) why the line was what it was, car just goes there anyway; (ii) how far away I was from any reasonable limit. These two laps were better than any crack that instructor might have given me... Now that I occasionally instruct myself, I always encourage my students to come along for rides.

Anyway, at that point, the car was bone stock. I did a couple more events in the next few weeks, learning to pick up the pace a bit. I destroyed my first set of front tire shoulders between two consecutive days, and put on whatever terrible all-season fronts the local Les Schwab in Yolo county had for the second day. This would pretty much set the tone for the next quite a while -- I'm pretty aware I'm the limiting factor for the car -- so I don't need a perfect setup to learn something new. Bonus points, I'd learn how to adapt to different setup changes.



I was reading the forums for camber solutions and it seemed like the M2 LCA thing was more or less half-assing it, but camber plates didn't work great with the stock suspension. So, decided to focus on the long term and invest in good coilovers and camber plates. I talked to a local performance shop, and they spent a while convincing me that the KW clubsport I had my eyes on didn't work with the new M240, only with the M235. In hindsight, total bollocks, but I ended up with KW V3s, Ground control plates, some camber, a fairly slammed ride height, and better brake fluid. Note to self, a pretty instagram page with shiny cars in front of the shop doesn't guarantee solid track knowledge.

With the KWs the car was leaning less in corners, and the front tires had a higher chance of surviving. Went through some more MP4s tires, stock pads (yay warranty), cracked the front bumper in my first off track excursion (it's still that way despite bondoing it like 5 times), moved to slightly more aggressive alignment settings each time, and put in thrust arms with monoballs mostly on a whim (and really appreciated the improved steering feel).

At this point, I'd learned how to push this setup hard enough that the MP4s were starting to chunk. Plus, I'd corded my tires a couple of times in the middle of nowhere, with very few replacment options. Sounded like the right time to jump to dedicated track wheels / tires. I put on some Apex studs to prepare for that.


Last edited by msendit; 03-29-2020 at 07:34 PM..
Appreciate 3
ifobd11.00
Maynard1301.00

      03-26-2020, 05:11 PM   #6
kthor703
Enlisted Member
12
Rep
49
Posts

Drives: 2015 M235i
Join Date: Nov 2017
Location: Washington, MI

iTrader: (0)

Sub'd for more. Fun read and enjoy seeing what other people are doing. I'm tracking on a mostly "stock +" set up now (GC Camber plates, 8.5" square with 235s, Hawk DTC 60s). Have a downpipe and just recently an intercooler, but run the stock map on the track, as it is plenty of power and keeps the consumables in check.
Appreciate 1
msendit74.00

      03-26-2020, 09:27 PM   #7
K8_M235i
Second Lieutenant
K8_M235i's Avatar
United_States
87
Rep
232
Posts

Drives: 2016 M235i 6MT
Join Date: Jan 2018
Location: Boston, Ma

iTrader: (0)

That's awesome. I went through a similar process as you described, but decided to buy an e36 track car.

This season (if it happens) will be its first as a legal race car.

Someday my m235 will be a race car as well, but I want to get some more time out of it on the street.
__________________
2016 M235i
6MT, LSD, Apex EC-7, Dinan Res Delete, XPEL, M-Perf Shifter, Carbon Mirrors, Black Kidneys, No moon roof, nav, or backup cam.
Appreciate 1
msendit74.00

      03-26-2020, 09:46 PM   #8
msendit
Private
msendit's Avatar
74
Rep
86
Posts

Drives: M240i
Join Date: May 2018
Location: San Francisco, CA

iTrader: (0)

Quote:
Originally Posted by K8_M235i View Post
That's awesome. I went through a similar process as you described, but decided to buy an e36 track car.

This season (if it happens) will be its first as a legal race car.

Someday my m235 will be a race car as well, but I want to get some more time out of it on the street.
Awesome. Yeah, that's the reason I'm keeping this one just for time trials / HPDE. It chews through consumables like candy and the dings you get in a real race won't be fun to pay either.

My "real racecar" is a '92 MR2. Sitting without an engine at the moment, but should be good to go once things come back to normal.
Appreciate 0
      03-26-2020, 09:51 PM   #9
K8_M235i
Second Lieutenant
K8_M235i's Avatar
United_States
87
Rep
232
Posts

Drives: 2016 M235i 6MT
Join Date: Jan 2018
Location: Boston, Ma

iTrader: (0)

Quote:
Originally Posted by msendit View Post
Quote:
Originally Posted by K8_M235i View Post
That's awesome. I went through a similar process as you described, but decided to buy an e36 track car.

This season (if it happens) will be its first as a legal race car.

Someday my m235 will be a race car as well, but I want to get some more time out of it on the street.
Awesome. Yeah, that's the reason I'm keeping this one just for time trials / HPDE. It chews through consumables like candy and the dings you get in a real race won't be fun to pay either.

My "real racecar" is a '92 MR2. Sitting without an engine at the moment, but should be good to go once things come back to normal.
My e36 is the same way right now. I'm currently re wiring the whole car and adding all necessary safety items like a battery cut off and fire suppression.

After this, I'll pull the drivetrain for a refresh.

At least we have time to work on them now!
__________________
2016 M235i
6MT, LSD, Apex EC-7, Dinan Res Delete, XPEL, M-Perf Shifter, Carbon Mirrors, Black Kidneys, No moon roof, nav, or backup cam.
Appreciate 0
      03-29-2020, 07:33 PM   #10
msendit
Private
msendit's Avatar
74
Rep
86
Posts

Drives: M240i
Join Date: May 2018
Location: San Francisco, CA

iTrader: (0)

Stage 2: spin city

End track-hours: 30-something
End Laguna Seca time: 1:50

End parts/specs:
Pagid RS29 brake pads
-2.2 F camber, -2.2 R camber
RE71-r tires: 235/40/18 F, 265/35/18 R
Forgestar F14 rims: 8.5x18 ET40, 9x18 ET40-high
Eventuri intake
lots of front rebound dampening

So, into the summer of 2018, I was pushing the MP4s tires a bit too much and it was time for a dedicated track set. I was still going to the shop that did the KW suspension, and they recommended Bridgestone RE-71r, which have been kind to me since(*). As people here know very well, our cars need deep-offset wheels and finding these isn't particularly easy. After some searching around, I found Forgestar, who make flow-formed wheels with custom offsets at a pretty reasonable price. 265 tires at the back seemed to be the max people here had done, so eventually settled on 235/40 and 265/35. The distributor I talked to convinced me to do 9" at the back instead of 9.5" and that "the experts at Forgestar will take care of the offsets". Fine.

(*) I've gone through many (20?) sets of RE-71rs on this car. Pretty much everything about them has been said already, but let me recap in short: awesome levels of dry grip; gets maximum grip very fast (2-3 corners); gets greasy / overheated fast too (2-3 laps); max grip on our cars seems to be ~34-35 psi hot; when new, tolerable in the wet. Also, stay away from the 285/30/18 size on our hefty cars (see "stage kaboom" later)!

Sticky tires without better brakes didn't sound fun, so I also grabbed myself a set of Pagid RS29 pads. They seemed to be the default track pad for our cars (and the F8X). In hindsight, after going through a few sets, pretty happy with them overall. The fronts tended to last about 6-7 track days, as long as you don't overheat them too much. The release characteristics are the best I've seen in a pad, great for trailbraking. They didn't handle overheating well though -- the edges tended to crumble a lot and the pad could crack through the middle. Oh, and as any track pad, they sound as subtle as a freight train when cold.



The day after I got the wheels and pads, I tried them out at Thunderhill. Stayed with this setup through the summer for another 8-9 days (~15 hours).
To state the obvious, there was lots more grip and times were getting down. But It was a little... sketchy... Quite a few times losing the rear, a few spins, some tank slappers, the whole nine yards. The scariest one was probably losing it going thourgh Riverside at Buttonwillow (in reverse) at 90+ mph. Fun times. Good thing I was only going to tracks with ample runoff at that point, where you have to really try hard to hit a solid object. The worst of it was caking the interior with dust and collecting sand / small stones in various nooks of the undertray or the suspension. And soiled pants, allegedly.

My track friends were of course, giving me a hard time, talking about fidget spinners and things. The consensus was my issues were because of tracking a car with an open diff and soft bushings. The usual: all power to one wheel, plus bushing deflection makes things rather unpredictable. There was probably some of that, but honestly, I just wasn't that good at catching the rear and anticipating slides. It probably didn't help that these were my first few times with sticky tires -- which generally give you way less warning than street tires, and lose grip more suddenly.

There was another thing too. I hadn't had adjustable coilovers for too long and I was still experimenting with the various dampening options. Which mostly meant setting the front rebound higher and higher, because (i) it's the easiest to feel and (ii) hadrer's more racecar, amirite?! I actually wouldn't figure out that I'd set the rear up too loose and snappy until way later -- once I'd forgotten to restore the softer shock settings from a wet day, and the car felt way easier to slide around on the dry too.

Anyway, it would take me a while to figure that out (and a lot more time in iRacing to get better at catching slides), so I went with the most obvious thing and started thinking about a limited-slip diff and solid bushings.



Oh, also around the end of that period, I put on an Eventuri intake. Because you can't go wrong with carbon fiber! This was a bit against my philosophy to keep the engine completely stock[*]. But I'd just spent a few weeks on a death march at work, nights and weekends at the office, so I wanted something nice and blingy dammit! Reason be damned...
[*] It's pretty clear the car isn't exactly lacking power from the factory, and I'd much rather have reliability and lots of track time to improve the nut behind the wheel. This B58 so far has made it to ~120 hours on track with only consumable changes, which still continues to baffle me. Some (very small) problems are just starting to show, so maybe time to refresh it soon...

Last edited by msendit; Yesterday at 01:35 AM..
Appreciate 1
Maynard1301.00

      Yesterday, 07:17 AM   #11
dradernh
Major
585
Rep
1,276
Posts

Drives: 2017 M240i
Join Date: Aug 2013
Location: Ohio

iTrader: (0)

Quote:
Originally Posted by msendit View Post
RE-71rs...let me recap in short: awesome levels of dry grip; gets maximum grip very fast (2-3 corners); gets greasy / overheated fast too (2-3 laps)
Autocross tires behave this way. I've heard reports on the RE-71R like yours before and understand this is why the tire is so popular with autocrossers. I suppose it's possible they don't overheat as quickly when run on lighter, less powerful cars.

I ran A7s and R-1 S' in time trials on a 318 RWHP 2,708# E36 M3, and they could get greasy pretty quickly in temps >80 F. They're also softer than the RE-71R. Due to the TT clubs' formats, I never ran them for more than four laps at a time.
__________________
2017 M240i: MT, Moonroof Delete, EB, Black Dakota Leather, Driving Assistance Package, Heated Front Seats
TC Kline Coilover Kit; EDC/eLSD Delete; Wavetrac; Al Subframe Bushings; ARC-8 - 18X9 & 17X9; R888R - 255/35-18 & 255/40-17; Hawk DTC70; Schroth Quick Fit Pro Harnesses

Last edited by dradernh; Yesterday at 01:31 PM..
Appreciate 0
      Yesterday, 11:10 AM   #12
msendit
Private
msendit's Avatar
74
Rep
86
Posts

Drives: M240i
Join Date: May 2018
Location: San Francisco, CA

iTrader: (0)

Quote:
Originally Posted by dradernh View Post
RE71-r: I suppose it's possible they don't overheat as quickly when run on lighter, less powerful cars.
Yes, I know a few folks that run them on miatas and S2000s. Their impressions are quite different. For one, they usually complain about heatcycling them away, and not wearing the thread at all. Which is pretty much the exact opposite of our cars.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 08:09 PM.




2addicts
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST