Last year we purchased a base model 2014 BMW 228i with a goal to learn as much as we can about this new entry level BMW and explore he possibilities of its potential to serve as a true enthusiast BMW. We’ve been working on development for the last several months so this post will serve as a bit of a catch up and a place document further development on the car.
As I said we wanted to learn along the way so we’ve intentionally taken incremental steps exploring different options rather than tearing the car down and building it straight up as a race car. The end goal is to ultimately build the car up for the Pirelli World Challenge TCA class, which is somewhat restrictive as far as class rules so some things we will explore we may have to end up reversing to meet the rules. Specifically we expect that we may be forced to limit boost or add back some weight to meet the Balance of Performance requirements to compete with some of the other cars in the class such as the Scion FR-S, Honda Civic Si and the Kia Forte Koup.
First, thanks again to Jon Shafer at Santa Barbara for tracking down a base model, low optioned, manual transmission 228i which proved to be much harder than you would think.
When we got her back to the shop we did what every self-respecting man would do, put her on a scale. 3091 lbs with about 1/2 tank of fuel is not too bad for production cars these days and front to rear, like most BMWs is pretty good with a ratio – front 51.6% and rear 48.4%
Next was getting some safety equipment in the car so we can get her out on the track safely. We developed the GSR Technik bolt-in roll bar to meet most sanctioning body requirements which, primarily focus on tubing size as a ratio to the weight of the car. We have selected 1.75/.095 DOM mild steel for our V1 (Mod 0) product. All attachment points use existing bolt locations so no drilling is required.
The rear seat components must be removed to install roll bar. Lower rear seat section pulls out easily as it is just clipped in. The rear seat backs come out with just a few bolts. Rear seat backs and main lower seat section can be reinstalled – only the small bolsters on the left and right must remain out.
Design allows for the stock seat belts to be attached in the original locations with no modification required.
Finally a set of Racetech RT4009 seats and Racetech 6-points harnesses to finish things off.
Next was getting to the all so critical suspension setup. KW Suspension developed the dampers in partnership with BMW Motorosport for the BMW M235i Racing Edition which gave us a jump on damper development for our own BMW 228 Racing . KW developed a custom 2-way motorsport damper that meets the majority of sanctioning body requirements where we plan to run the car including Pirelli World Challenge Series – most do not allow 3-way.
Front dampers come with integrated camber plates.
Inverted rear damper design allows for more wheel clearance in the rear.
For those of you looking for a little more camber without going with a complete coilover setup there is an option to swap out the lower control arms from the M3/M4 cars. Check out the discussion thread here:
http://www.2addicts.com/forums/showt...&highlight=gsr
Next on our list was tackling the drivetrain, specifically the clutch, flywheel and differential.
The 228i, like many production cars, uses a fairly heavy dual mass flywheel to smooth the clutch engagement – nice for driving in LA traffic but torque zapping when you are trying to get the motor to spin up.
Ever wonder how a dual mass flywheel works, here’s a cool animation of how one is put together and functions:
And the weight of the stock clutch kit and dual mass flywheel…
44 lbs!
With the thought 44 lbs hanging on our minds we went to two of our trusted partners to help us out with a solution. First, Clutchmasters developed a clutch kit that increased clamping pressure by 60% and and a clutch disc that incorporates a spring center to help provide some damping since we will be moving to a single mass flywheel. They also provided a bit more aggressive disc material to better handle heat and lock up.
With the stock flywheel in hand Aasco went to town on their CNC equipment and developed a much lighter all aluminum single mass flywheel. All in all the entire assembly saves about 15 lbs. That’s 15 less pounds the engine has to spin up as RPMs increase.
Next step was to address the rear stock differential. We selected the Wavetrac gear type limited slip differential for the BMW 228 Racing.
Selecting a gear type differential was a must to meet the Pirelli World Challenge rules for the TCA class but there is one big difference between the patented Wavetrac design and other torque biased gear type diffs. To state it as simply as possible.
1. If you lift a wheel, all gear diffs except Wavetrac®, will NOT power the other wheel.
2. During the transition from accel to decel, all gear diffs except Wavetrac®, do nothing.
This is a big help when we are driving sections like the exit of the Bus Stop at Buttonwillow Racepark where we have a delicate braking zone and then bounce the car off the curbing. For more info on how the Wavetrac unit works check out their website – they have some cool animations showing you the inner workings of the diff.
All in and ready to go. The Wavetrac diff will basically perform a lifetime of service without maintenance or rebuild and has a transferrable limited lifetime warranty.
Finally we mount up some Apex ARC-8 18 x 8.5 wheels with Yokohama 235/40/18 AD08R tires for first few test days at Buttonwillow, the Streets of Willow and Big Track as Willow Springs.
The first shakedown day was at Buttonwillow Racepark.
Our main focus was on the damper setup. We are running KW Suspension Motorsport dampers designed specifically for the car - they were truly phenomenal. We tested our softest spring setup approximately 500lbs front and 600 lbs rear with stock swaybars required by World Challenge.
The body roll was a bit more than we would like but totally manageable. Once the car took a set there was a surprisingly large amount of grip on the Yokohama AD08R tires (180 treadwear).
The amazing thing about the test is how well the car did with the curbing. We were really nailing the curbs especially coming out of the Bus Stop and the car never really got unsettled. The Apex Wheels took the abuse as well. We'll be testing progressively stiffer springs setups as we continue our test program with the car.
The Wavetrac LSD worked flawlessly as well - would definitely recommend for street applications on your 228 or M235 or F30 3-Series. Another surprise was that even though it was 106 degrees out there we didn't have any major overheating issues. The only issue we had on the last session was a momentary loss in power which didn't generate any sort of error or put the car into limp mode - something that we are going to need to look into.
The next two days were spent at the Streets of Willow and the Big Track at Willow Springs.
Turn in on the smaller more technical track was great – actually much better than our E36 M3. The compact inline 4 tucked back into the engine bay makes the car feel much more nimble especially how the car transitions from brake to turn in. The balance of the was absolutely phenomenal. We had five different people drive the car over the weekend and the most common feedback was “this car is the most balanced car I have ever driven.” We hadn’t tested on a high speed track like Big Willow so we weren’t sure what to expect. The big test was the 110 mph+ bumpy Turn 8 running 180 treadwear street tires. The car was rock solid! We were able to run a 1:35.9 which is pretty damn good for street tires with 4 days of hard wear on them and a car that is still over 3,000 pounds.
UPDATE >>> 4/25/2015
Our next goal was to get a bit more tire under the car to see how the chassis would react and how the stock brakes would handle all the extra grip. We went to our buddies over at Apex Wheels and figured out we could get 9.5 inch wheels on all four corners.
Front: EC-7 18x9.5 with 35 offset and 5mm spacer
Rear: EC-7 18x9.5 with 58 offset and 5mm spacer
This allowed us to run a 275 square tire setup… our tire selection for the next set of test days was the Toyo RR (40 tread wear).
With the new grip levels we upped the spring rates by about 100 lbs all the way around and stiffened up the KW Motorsport dampers, both compression and rebound. This better controlled the weight transfer of the car but once the car loaded up there was still a bit more body roll than we would like.
Our next test session was a two day test out at Chuckwalla Valley Raceway. Temperatures were again north of 100 degrees. We just can’t escape the heat – every test day so far with the 228 has been 100+ degrees.
The heat really zapped the power and grip so we really only had a couple good sessions each morning to really push the car hard. Operating intake temps were about 116 degrees in the morning, once they got about 130 degrees you could really feel the horsepower drop.
We collected data all weekend and saw some very impressive sustained g loads considering the state of development of the car – sustained g loads approach 1.5g and that’s at multiple points on the track, not just in the banked bowl.
Porterfield R4 brake pads continue to hold up well with the stock brakes. No real brake issues although Chuckwalla is a pretty flowing track so it’s not that hard on brakes.
We did see the dreaded “Drivetrain failure” message and again; although it displays in the dash there are no error codes. The temporary fix is to fully cycle the ECU and it goes away. We see this on the M4 as well and word on the street is they are having the same issue on the fleet M3/M4 cars at the BMW Performance Center. We are logging temps and displaying data real time – when the warning popped up the temps were not way out of line so it’s got to me some other variables that the ECU is seeing and then cutting power.
We’ve not gutted the car yet so weight is still up there – about 3100 lbs without driver. Here’s a video of our little beast chasing down a GMG 997 Porsche Turbo WC. Our best time of the weekend was 2:01.3.
Our next test day was with our buddies at Targa Trophy for their Super Track Series at Willow Springs.
We wanted to run the car in the TT2 class so we had to go back to a street tire – we selected the Achilles 123S 265/35/18 (200 treadwear) tires. We found the tires to have a large slip angle which took some getting used to but over grip for a street tire was very good. Again the balance of the car was absolutely perfect. The car could easily be throttle steered through Turn 2 and the car was perfectly stable through the bumps in Turn 8 – we were able to hit over 125 mph through Turn 8. The only issue we had was braking stability into Turn 9 which isn’t surprising given the speed. We didn’t have time to diagnose.
The end result was 1st place in TT2 with a 1:33.2 against cars with almost twice the horsepower.
Just to give you an idea of how quick the #BMW228Racing is around Willow Springs here’s a screenshot of the top 20 times from fastestlaps.com
Here’s a video of one of the 1:33 laps – as you can see very little drama – such a fun car to drive.
UPDATE >>> 5/21/2015
Thanks to our friends from 3M Auto Graphic Films our 228i got a full wrap of Matte Orange (we like to think of it as GSR Orange) - on track shooting a review with Michael Harley, Editor-in-Chief of Autoweb.com.
We have developed an axle back straight pipe (muffler delete) exhaust mainly to reduce some weight - this saves almost 20 lbs over the stock muffler. For the track we didn't focus much about the exhaust tip aesthetic as you can see - what type of exhaust tip options would you all like to see?
Here's a little sound clip for ya'll.
We're heading out to the Bimmerfest/Speed Ventures track event this Saturday at Auto Club Speedway with our little track beast. We've been working on a new adaptive ECU flash tune from our new GSR Technik Tuning division - formerly Jailbreak Tuning. Heading to the dyno tomorrow to test tune on 91 and then 109 Leaded to see how the tune adapts. Will report results ASAP.
UPDATE >>> 5/31/2015
European Car Magazine Tuner GP Challenge
A few months back we competed in the European Car Tuner GP Challenge that should be coming out in the July issue of European Car magazine. We decided to bring the BMW 228i #BMW228Racing to see how it would match up. Our only regret was not having any aero for the car given the lower grip tires we were required to run. The Pirelli World Challenge TCA rules don’t allow any aero so it has not been a focus for us on the 228i.
The first day of the competition was dyno day.
Our little N20 four banger was able to put out 335 whp running our GSR Technik Stage 2 tune on 100 octane – about 100 whp over stock. This put us near the bottom of the horsepower pecking order.
Next was the track day at the Streets of Willow running clockwise. All cars were required to run the Continental ExtremeContact DW with a 340 treadwear rating. Based on tire availability we had to run a little smaller 265s compared to the 275s we normally run on the car. This gave us a lot less grip than we were use to running which is where aero would have been extremely helpful. We set the car up soft, similar to a rain setup to try and generate as much mechanical grip as possible. The only challenge was driving around the more dramatic weight transfer with the softer setup.
We faired pretty well in the track day competition, only being beat by one non-aero car, that being the European Auto Source M4 which only beat us by 16 hundredths of a second with 546 whp compared to our 335 whp. We were also able to beat the HG Motorsport Mercedes CLA45 AMG by more than a second which was probably the most comparable car in the field to the 228i which dyno’d just above our 228 at 347 whp but was also running aero and should have been able to create some good exit grip with all wheel drive. The car of the day was Amir’s E36 M3 – light and well sorted out aero proved to be very effective with the lower grip levels.
Check out the European Car Tuner GP video on the Motor Trend Channel.
More upgrades and more testing continue – more to come soon!!!
All parts and installation services are available at our shop in Anaheim, CA - come by, check things out and say "hey".