Apex

BMW M2 Build - Wheel and Tire Update

I have been asked what my current wheel and tire set up is on the SVMC M2. If you have been following the build you will notice that I started out with a square setup, but then I did go to a staggered setup for a while. While that allowed for a slightly wider tire in the rear I ended up going back to a square setup because I did run into some clearance issues when I went to a 285/305 setup.

I currently run Apex FL-5 ET40 18x10.5 satin black with Nitto NT-01 275x. This setup doesn’t require any fender rolling and it clears the Sparta big brake kit and KW clubsport suspension. Because the wheels are 10.5 yet the tires are 275/35/18 the tires are stretched a bit to give them a slightly larger contact patch. I have found this to be a great all round setup without compromising much of anything. The Nitto NT-01 give me about 20 heat cycles so about 4 full track days. They are my preferred track tires as they are very progressive, very grippy, and handle the heat cycles well. They are not the best for the street as they are loud and they are a bit slick for wet roads but given I am in CA I have no problem using them on the street simply to get to the track.

You got to love the simplicity of a square setup that just works.

BMW M2 Build - Data and Video System

All respectable track cars need a data and video system of some kind to see where you can improve. In my case I need all the coaching I can get. There are plenty of systems out there to choose from. You have the inexpensive iPhone + app setup. The slightly more expensive iPhone + app + GoPro system. The expensive dedicated data and video system that tap into the ECU and receive a multitude of data channels and then overlays that data onto track video. And finally, the pro custom systems that monitor every aspect of the car and streams that data back to the pit crew for real time analysis.

On any given track day the dominant system (by far) is the iPhone + app + GoPro. I started with this system years ago and it is great for the price. You have apps like Harry’s Lap Timer that do a terrific job at capturing some data channels and video and putting it all together for engaging video footage. The only issue is that you can’t do deep analysis on the data or easily compare the data from a reference lap to the rest of your laps. Also you end up with gear all over the windshield (iPhone + GoPro + cables). There is a practical problem with all that gear stuck to your windshield or dash besides visibility……and that is “when” it falls off it may fall into the driver’s footwell and obstruct the pedals. Having something fall by your feet as you are dive bombing into a turn is not a great feeling. The other thing that bothered me with the iPhone setups was the constant management I had to do with the gear. Turn this on, check that, recharge this. All of that time and attention took away from enjoying the day and focusing on driving.

So years ago I switched to an AIM system. My original system was a Solo DL + Smartycam. A system like this is more streamlined, is automated (turns on and records and shuts off all based on you starting and finishing a session), and since it is a dedicated system it is more feature rich. The downside….price. These systems can add up quickly but if you are on the track enough they are worth it. About 1-2 years ago AIM updated their lineup and came out with the Solo 2 DL and Smartycam GP HD 2 which is the system I picked for the SVMC M2. It taps into the ECU, has GPS, draws power from the car, overlays the data onto the video in real time, and has a powerful (albeit cumbersome) computer application to store and analyze all your data. The Solo 2 DL even has wifi connectivity to pass all the data (not video) to your track side laptop.

Keeping with the GTS theme for the M2 I decided to do a custom installation for the AIM system to hide all the wires and make it look like a factory option. So I had a fabricator (TC Design) build a metal housing over the cup holder area of the M2 in the center console and powder coat that glass black so I could mount the Solo 2 DL in a central place that is out of the way but easy to read. It also allowed me to tuck all the wires behind the dash. The enclosure also gives me a place to mount switches in the future. I then mounted the Smartycam GP HD 2 behind the driver in the backseat footwell so I could easily access it but keep it out of the way. I am left with a system that is fully contained, fully automated, pulls data from the car, and makes analysis quick and easy. In short it is fool proof and works every time without having to do anything. The only issue I have with the Solo 2 DL is that the level of ECU support for the F87 chassis is light. BMW is rather strict on what channels they allow to flow through to systems like AIM. This is more of an issue for BMWs as other cars like Porsches are much more open. But the data channels you do get are rather good (some temps, RPM, wheel speed, calculated gear, etc.). A slightly more advanced option would be to run independent sensors and use an AIM system like the MXm. In hindsight I wish I had gone this route.

Now let’s talk about predictive grip data. One thing that most data systems lack is true predictive grip data which is the level of potential grip your car has at any given moment. The only system I know of that has this capability is APEX. This little device has a series of lights that show you the potential grip at that moment compared to the amount of grip you are using. The APEX device wirelessly connects to your iPhone and does have other data recording capabilities, but for my purposes I only really use the APEX system to record potential grip compared to actual grip. It is a great way to see how effective you are using the grip….AKA how hard and smooth are you driving. If you are not interested in buying an AIM system you can use APEX for an end to end system that is better than most iPhone + app setups.

Once you have all the data and video information handy then you need to know how to read the data. For that get a book or take a class or watch training videos to make sense of all those squiggly lines. Good luck with that.

SVMC M2 video by Apex #2

Another short video by Apex focused on the SVMC M2.  This time we were trackside at Sonoma doing some test and tuning. I currently run their matte black 10.5” wide FL-5 wheels, their stud kit, and spacers in the front.  This gives the SVMC M2 a 275 (stretched) square setup which is about all we can fit without body medications given we are also running a KW clubsport suspension and a BBK. Also featured in this video is Sparta Evolution's M2 racing brake kit.

SVMC M2 video by Apex

Apex, who makes street and racing wheels with specific fitment for various cars, was kind enough to share the video they shot that featured the SVMC M2.  I have run Apex on a few different cars with great success so they were the obvious choice when building out the SVMC M2.  I currently run their matte black 18x9.5 ET28 FL-5 wheels and their stud kit.  If you want to learn more about my wheel and tire setup for the SVMC M2 go here.  Thanks again Apex for featuring the SVMC M2 in your promotional video.  Also featured in this video is Sparta Evolution's M2 big brake kit.

BMW M2 Build - Wheels and Tires

One of the first things I do with any build is get new wheels and tires with the goal of getting more width and thus more grip.  I also want a set of tires that are designed for the track versus the street for better turn-ins and braking.  I once again used Apex wheels as I like that they are designed for BMWs and thus don't need spacers.  They also fit many big brake kits, are lighter than OEM wheels, and are reasonably priced.  They have a BBS sort of look but without the BBS premium price.  Here are some pictures of the before and after, but don't mind the large gap between the tire and fender as we have not dropped the car yet.

I went with 18x9.5 ET28 FL-5 wheels in satin black.  I wanted to go as wide as possible without rolling the fenders or having to buy or fabricate a wide body kit.  The stock wheels have a staggered setup, but after consulting with Edge Motorworks and Apex we decided to go with a square setup.  This will give the front a lot more width while also giving the rear some more width.  This also has the added advantage of allowing some tire swapping to prolong the life of the tires.  I also went with an Apex stud kit to make wheel changes a snap.  While many people prefer the bullet nose style of stud kits (mostly I think because they look good and resemble a professional race car) I always go with the hex head style.  The reason being is that the hex head is far easier to install and maintain proper torque settings.  The exact kit I used was the black 14mm by 75mm hex head which can be found here.  

For tires I went with Nitto NT01 275/35ZR18 95W.  These are DOT compliant competition tires and thus are much more suitable for the track than the various OEM tire options.  The stock tires are 245 in the front and 265 in the rear so with a 275 square setup I am adding considerable width and grip especially to the front where the car needs it the most (in my opinion).  I am not planning on adding any more power to the car outside of what I have already done with a Dinan tune, so I feel the 275 should be fine for the rear.  Ideally I would have 285 in the front and 305 in the rear but we plan on adding a big brake kit by Sparta Evolution and KW Clubsport coilovers and we were not sure if 285/305 would fit properly without rolling the fenders.  Once we have the brakes and suspension done (in April) we can make the necessary measurements to see if 285/305 would fit and if they do we might swap over to that.

I have taken the car out on the track with these wheels and tires and my first impression is positive.  I certainly have better turn-in, braking, and grip overall even with a rather stock alignment.  Once I get the brakes and suspension on I will have a better idea on how the whole package will perform, but so far I am pleased.  Keep in mind you either need to add TPMS sensors to your track wheels and then constantly reset the system when you lower tire pressure or change tires.....or better yet code out TPMS from your car as I mentioned in my "Coding" blog post.

Next up....brakes and suspension come mid-April.