[dradernh]

The purpose of this build was to achieve a good balance between street and track. The car is not daily-driven. Track use will be three events per year, and I'll drive ~50 laps per event. Two events will be at Mid-Ohio, a handling track, and one at Watkins Glen, a high-speed track.

This is what was done to the car:

TC Kline Suspension Kit
Spring Rates: 350 F & 600 R
Camber: -2.6° F & -2.2° R (originally posted as -1.9° F & -1.6° R (see post #13 for explanation))
Toe: 1/32" IN F & 1/8" IN R
Corner Weight: 50.1%
Fender Roll (slight): F & R
Ride Height Drop: -1¼" F & -1" R

Turner Motorsport Aluminum Subframe Bushings

Limited Slip Differential: Wavetrac

Tires: Toyo R888R - 255/35-18 R & 255/40-17 F
Wheels: Apex ARC-8 - 18X9½ ET58 R & 17X9 ET42 F
Spacers: 5MM R
Studs: 60MM M14X1.25 Phosphate-Coated
Nuts: 17MM M14X1.5

Brake Pads: Hawk DTC70
Brake Fluid: Castrol SRF
SS Brake Lines

Harnesses: Schroth Quick Fit Pro 4-Point

Cloth Tow Straps: F & R

Coding: EDC & eLSD Delete

Cost:
Parts - $10,140
Labor - $ 3,200
Tax - $ 735
Total - $14,075

Various Notes:

For me, this is a basic build. It's streetable, and it will be safe on the track. That's all I wanted.

The suspension kit is Koni-based and has single-adjustables up front and double-adjustables in the rear. Double-adjustables up front would have made too much noise on the street.

Post-install, there is some additional noise, but it's not enough that it bothers me - the trade-off has been well worth it to me.

If front roll is unacceptable on the track, an H&R front bar will be installed. [Note: it was installed; reason: I wanted to see how much it would help at the track; while it helped slightly at the track, and NVH-wise it didn't detract on the street, if I had it to do over I'd skip it for price/performance reasons]

The alignment is designed to be used on both the street and the track. Expected tire life on the street is 8,000 miles. By blocking annual track days into a short window, a street alignment could be used for 10-11 months of the year.

I won't run this alignment nor these brakes particularly hard on the track. I built it to show novice and intermediate students the way around the track at my 7/10ths.

Coding was performed remotely by BPM Sport (http://www.bpmsport.com/).

The limited slip differential was supplied by DiffsOnline (http://diffsonline.com/).

A square setup was the goal - the resulting wheel and tire combinations were due to what was available, cost, and fitment issues. The 2 Series is not easy when it comes to fitment.

While the car was in the shop, screens were installed inside the openings in the front bumper cover. This was to minimize the chance of debris coming through and damaging the radiator, whether on the street or on the track.

----------------------

Initial Report

I took the car to Mid-Ohio last month, and I was satisfied with how it handled. That's a track I don't yet know well, and I used the laps to get a feel for the nuances of the corners. For a fairly heavy street car, even one with a suspension and moderate alignment specs, I found the car a real pleasure to drive. I ran with DSC OFF.

What's Next

I'm looking forward to running the car at Watkins Glen in a couple of weeks. I've run many hundreds of laps there and will have a pretty good idea of what the build has accomplished after that event. To see how the brakes fare on that heavy-braking track, I'll put brake temp paint on the rotors' edges and caliper temp strips on each of the calipers.

----------------------

Final Report

I've updated the build with the parts listed below. I think the purpose of each is pretty much self-explanatory.

August, 2019

Central Side Jacking Points - $N/C; details here: https://www.2addicts.com/forums/show....php?t=1668225

Brake Scoops - $N/C; details here: https://www.2addicts.com/forums/show....php?t=1670372

October, 2019

H&R Front Sway Bar (Part No. 70878-2) - $839 installed; this is a 28mm bar with two holes of adjustment - it's set on 'soft'

Dinan Elite V2 B58 (Part No. D440-0122) - $1,277 installed

Dinan Cold Air Intake (Part No. D760-0046) - $710 installed


Photos

[Dylan86]

Nice, seems well thought out. Can't wait to see how things pan out for you at the Glen

D

[WolfGTI]

How are the differential bushings? I feel that the rear end moves around under heavy power and I notice it more with the diff. I think differential bushings should feel much more planted, however my car primarily a street car so how is the NVH with the solid bushings?

[dradernh]

Originally Posted by WolfGTI

How are the differential bushings? I feel that the rear end moves around under heavy power and I notice it more with the diff. I think differential bushings should feel much more planted, however my car primarily a street car so how is the NVH with the solid bushings?

Some perspective regarding the increased NVH...my wife said upon her first extended ride in the car after I had the work done "I can't believe these sounds don't bother you. You are ALWAYS so picky about little noises!" Of course, I'm like "Honey...car guy, you know?" And truthfully, I haven't tried to figure out what goes 'clunk' (a very minor 'clunk', mind you, and one that comes up only when poor pavement is encountered), what occasionally goes 'click-click-click', etc. I just don't care, where someone else might care or would care for sure.

My overall opinion is that the increased NVH is very minor compared to the improvement in the car's handling performance. And I'm 70, not 25, so I'm way past being willing to put up with my cars' having anything that's excessive in nature.

Regarding the bushings, which got installed at the same time as the diff and the rear double-adjustables (which are an item in Koni's motorsports line), all I can say is that the rear-end is certainly hooked-up when I go to gas coming out of a corner. The car is definitely well-planted in those circumstances.

I've had a lot of built diffs, and I know what the diff did for the car. I've had two-way and three-way motorsport shocks, and I feel like I have a handle on what the shocks did for the rear end. That leaves the bushings, which I think tied the whole package together. I mean, they're central to what's going on back there, right, whatever else an owner may or may not have installed. Without the bushings, the car's rear-end would definitely behave differently in the corners.

It's too bad you don't live closer, as you'd be welcome to drive the car to see what you think. As it is, I can't really say exactly how much the bushings changed the rear-end's NVH. My take is that it's not enough for me to notice.

I'd recommend making the change, but it's not trivial labor-wise (yours or a shop's), and if you didn't like the result you might end up choosing to put the originals back again. Sorry I can't be more definitive.

[capt_and]

Originally Posted by dradernh

The purpose of this build was to achieve a good balance between street and track. The car is not daily-driven. Track use will be three events per year, and I'll drive ~50 laps per event. Two events will be at Mid-Ohio, a handling track, and one at Watkins Glen, a high-speed track.

This is what was done to the car:

TC Kline Suspension Kit
Spring Rates: 350 F & 600 R
Camber: -1.9° F & -1.6° R
Toe: 1/32" IN F & 1/8" IN R
Corner Weight: 50.1%
Fender Roll (slight): F & R
Ride Height Drop: -1¼" F & -1" R

Turner Motorsport Aluminum Subframe Bushings

Brake Pads: Hawk DTC70
Brake Fluid: Castrol SRF
SS Brake Lines


If front roll is unacceptable on the track, an H&R front bar will be installed.

The alignment is designed to be used on both the street and the track. Expected tire life on the street is 8,000 miles. By blocking annual track days into a short window, a street alignment could be used for 10-11 months of the year.

I won't run this alignment nor these brakes particularly hard on the track. I built it to show novice and intermediate students the way around the track at my 7/10ths.

To see how the brakes fare on that heavy-braking track, I'll put brake temp paint on the rotors' edges and caliper temp strips on each of the calipers.

Nicely done. Have you considered going toe out? The car drive lighter than it is but it's still a pig. The turn in is considerably better with toe out. The stock brakes handle the casual DE day great. Plenty of stopping power. I only swapped them out for stoptechs because they caught on fire after the seals kept leaking. As you already know, it's way cheaper to have your street pads/wheels/tires and swap them out for the track grear for each event. If you do decide to go that route, Carbotech XP20 F and XP12 rear is perfect.

Originally Posted by WolfGTI

How are the differential bushings? I feel that the rear end moves around under heavy power and I notice it more with the diff. I think differential bushings should feel much more planted, however my car primarily a street car so how is the NVH with the solid bushings?

He swapped out the subframe bushings, not diff bushings. I can't say for sure if you'll hear any noise from the bushings being swapped out but I will say that there is a huge difference in noise. I have my interior stripped out and without the bushings, there is a pronounced gear whine (think race car). If you are planning having the car as a primary street car, I wouldn't touch many things. I can't imagine any circumstance on the street where you'd be able to tell any performance advantage with bushings. But yes, the oem bushings are very soft, you don't need a lot of power to make things shift. Get the car on the lift, take off the rear wheel, and give some things a wiggle. You can get a lot of stuff shifting with just your hands and body weight.

[WolfGTI]

I mis-spoke I meant subframe bushings. I have a fair bit of track /circuit experience with my highly modified Cooper S, so I can tell when I get the 'squirm' or 'squirelly' movment with the subframe bushings under WOT. The car will see a couple track days but it's focus is primarily enthusiastic DD.
Thanks for the input about noise, maybe I need to look at the Delrin subframe bushings as opposed to solid aluminum.

Originally Posted by capt_and

He swapped out the subframe bushings, not diff bushings. I can't say for sure if you'll hear any noise from the bushings being swapped out but I will say that there is a huge difference in noise. I have my interior stripped out and without the bushings, there is a pronounced gear whine (think race car). If you are planning having the car as a primary street car, I wouldn't touch many things. I can't imagine any circumstance on the street where you'd be able to tell any performance advantage with bushings. But yes, the oem bushings are very soft, you don't need a lot of power to make things shift. Get the car on the lift, take off the rear wheel, and give some things a wiggle. You can get a lot of stuff shifting with just your hands and body weight.

Thank you for your input , it is muchly appreciated.

Originally Posted by dradernh

Some perspective regarding the increased NVH...my wife said upon her first extended ride in the car after I had the work done "I can't believe these sounds don't bother you. You are ALWAYS so picky about little noises!" Of course, I'm like "Honey...car guy, you know?" And truthfully, I haven't tried to figure out what goes 'clunk' (a very minor 'clunk', mind you, and one that comes up only when poor pavement is encountered), what occasionally goes 'click-click-click', etc. I just don't care, where someone else might care or would care for sure.

My overall opinion is that the increased NVH is very minor compared to the improvement in the car's handling performance. And I'm 70, not 25, so I'm way past being willing to put up with my cars' having anything that's excessive in nature.

Regarding the bushings, which got installed at the same time as the diff and the rear double-adjustables (which are an item in Koni's motorsports line), all I can say is that the rear-end is certainly hooked-up when I go to gas coming out of a corner. The car is definitely well-planted in those circumstances.

I've had a lot of built diffs, and I know what the diff did for the car. I've had two-way and three-way motorsport shocks, and I feel like I have a handle on what the shocks did for the rear end. That leaves the bushings, which I think tied the whole package together. I mean, they're central to what's going on back there, right, whatever else an owner may or may not have installed. Without the bushings, the car's rear-end would definitely behave differently in the corners.

It's too bad you don't live closer, as you'd be welcome to drive the car to see what you think. As it is, I can't really say exactly how much the bushings changed the rear-end's NVH. My take is that it's not enough for me to notice.

I'd recommend making the change, but it's not trivial labor-wise (yours or a shop's), and if you didn't like the result you might end up choosing to put the originals back again. Sorry I can't be more definitive.

[dradernh]

Originally Posted by capt_and

Have you considered going toe out? The car drive lighter than it is but it's still a pig. The turn in is considerably better with toe out.

If this was a dedicated track car, front toe would definitely be out. But I'm not going that route for three events a year, as it will reduce the life of the street tires even further.

My race car had toe-out in front, and turn-in was indeed quite sharp. I loved it!

I asked the builder why the front toe wasn't 0 instead of being 1/32" in; unfortunately, I don't recall his answer and didn't make a note of it. Off the top of my head, I'm guessing he told me that the static toe-in changes once the car is moving and/or turning, but I'll have to ask him again.

[DaveCN]

Are you driving on Friday at the Glen?

I'll be there instructing that weekend - Black e36 m3 with Kentucky tags, Garage 10(I think?). I'd be interested in riding shotgun with you at some point to see how the car does. My M235i may eventually become the dedicated track car - I'm interested in seeing how the diff and suspension change the car.

[dradernh]

Originally Posted by DaveCN

Are you driving on Friday at the Glen?

I'll be there instructing that weekend - Black e36 m3 with Kentucky tags, Garage 10(I think?). I'd be interested in riding shotgun with you at some point to see how the car does. My M235i may eventually become the dedicated track car - I'm interested in seeing how the diff and suspension change the car.

I'll be there on Fri., the 21st, for the joint GVC - Boston BMW event. I'm in garage bay 23, just a couple of bays away from you on the other side.

You're welcome to come out with me on Friday. I'm not sure about the other days as I won't know what I'll have in the way of students until Thursday or Friday.

[Maynard]

I'll be there for Sat--Sun, will stop by to say hello. Still appreciating that video you sent of a good line, we'll see if I can get anywhere close to it.

[racer_951]

With your front 17x9 255 wheels/tires setup, do they rub? I've tried 17x8.5 D-Force wheels with 255-40-17 Toyo RA1s, They rub the front fender lips a little with my stock M Sport and OEM camber setting. I plan to upgrade to BR Racing coilovers and get about -2 degree negative camber and hope to clear the rubbing with 255's. Otherwise, I will have to switch to 245's.

[dradernh]

Originally Posted by racer_951

With your front 17x9 255 wheels/tires setup, do they rub? I've tried 17x8.5 D-Force wheels with 255-40-17 Toyo RA1s, They rub the front fender lips a little with my stock M Sport and OEM camber setting. I plan to upgrade to BR Racing coilovers and get about -2 degree negative camber and hope to clear the rubbing with 255's. Otherwise, I will have to switch to 245's.

There's no rubbing up front with -1.9° camber and a slight fender roll.

The builder did tell me that I'd tear up the fender liners, but that hasn't happened. Maybe I'm just not leaning on the car hard enough?

[dradernh]

I had my alignment checked on a Hunter HawkEye Elite® Alignment Machine.

The builder told me that he'd set the camber to -1.9° F & -1.6° R, while the HawkEye Elite® showed the car as having camber of -2.6° F & -2.2° R. I wasn't surprised, as the car drives like it has the greater negative camber.

Also, after 9,073 miles I still have 6/32nds left on the original MPSS tires, so I've only used up 3/32nds of tread. I expected the tires to be used up by now, but I guess not.

[dradernh]

I've added a 'Final Report' section to the first post that lists further performance-oriented modifications I made in August and October of 2019.

It's final in the sense that I've aged-out of this hobby, and I won't be going to the track anymore. I've still got four straight days scheduled for the Glen during the first week of June; it was to be a sort of grand finale at what is by far my favorite track (and one that I think is especially well-suited to our cars). In the present situation, however, I won't be going anywhere any time soon.

As far as the car goes, I'm very satisfied with what the mods did in terms of making this heavy, powerful street car reasonably track-worthy. I find it to be a wonderful street car, too; except for the occasional brake pad squeak, nothing I've had done to it detracts from the car's streetability.

When I started taking this car to the track, my frame of reference was a fully-built race car (see photos below). As a result, it took me a while to get comfortable leaning hard on the car. I just wasn't used to a car that was so soft when I was trying to get the most out of it. Gaining confidence took longer than I expected. That was me, however; the car hasn't bitten or surprised me once.

I'm not sure what I'll do with the car now. I originally bought and modified it primarily so I could use it for instructing at the track while still running at 7/10ths on my own. I figured I'd do that for 2-3 years at the most, so I'm right on schedule. Having finished that process, I'll probably just take it out every 4-6 weeks long enough to raise all the fluids to full operating temperatures. Luckily, Southern Ohio is a very nice place to do that.

[K8_M235i]

That was a great read.

Hopefully when all this blows over we will both be able to get some track time.

Would love to run into you (not literally) at the glen.

[dradernh]

Originally Posted by K8_M235i

That was a great read.

Hopefully when all this blows over we will both be able to get some track time.

Would love to run into you (not literally) at the glen.

Thank you!

You know, if I hear that someone I'd like to connect with is going to be at the Glen, I can think of no better excuse to be there. The Glen is not just a world-class track, it's also in a world-class spot in North America.

[K8_M235i]

Originally Posted by dradernh

Thank you!

You know, if I hear that someone I'd like to connect with is going to be at the Glen, I can think of no better excuse to be there. The Glen is not just a world-class track, it's also in a world-class spot in North America.

It is seriously a magical place both at and around the track.

[Maynard]

GVC is still tentatively planning to be at WGI early in June. I'm keeping my fingers crossed.

[dradernh]

Originally Posted by Maynard

GVC is still tentatively planning to be at WGI early in June. I'm keeping my fingers crossed.

I get the newsletter, so I saw that they've still got it on the schedule. The Harbor Hotel never closed, so it may be business more or less as usual in town.

I was going to attend the NEQ Audi HPDE on Mon.-Tue. and the David Murry Track Days open-lapping event on Wed.-Thu. immediately prior to the GVC event. AFAIK, neither has canceled their event.

Update: Audi has cancelled events of all types through Mon., June 1. Presumably that means the NEQ event is cancelled, or maybe they'll just run a one-day event on Tue.

[230iZTR]

What factors went into selecting a Wavetrac over something like a 4-clutch 35/60?

[dradernh]

Originally Posted by 230iZTR

What factors went into selecting a Wavetrac over something like a 4-clutch 35/60?

I emailed Dan at Diffsonline, told him that I'd use the car for a few events each year for 2-3 years, after which it would be a fun car for back roads and road trips, and asked him what he'd recommend. He said the Wavetrac with the stock 3.08 ratio.

I'd bought clutch pack diffs for a track car and a race car from Dan before and was confident he'd suggest something that would work well for my use case. Given how I was planning to use the car, his recommendation was what I expected.

[scott_f22]

Originally Posted by dradernh

I had my alignment checked on a Hunter HawkEye Elite® Alignment Machine.

The builder told me that he'd set the camber to -1.9° F & -1.6° R, while the HawkEye Elite® showed the car as having camber of -2.6° F & -2.2° R. I wasn't surprised, as the car drives like it has the greater negative camber.

Also, after 9,073 miles I still have 6/32nds left on the original MPSS tires, so I've only used up 3/32nds of tread. I expected the tires to be used up by now, but I guess not.

Very nice build! I'm working on a similar spec on my 2015 m235i project. Do your brake calipers come close to rubbing the ID of your front 17x9 ET42 wheels? I'm seeing a very slight rub on my wheels. I wouldn't think the m240i calipers would be smaller than the earlier m235i but I could be mistaken...