Posted originally on 09-09-2016:
We've been working on building this car up since late Spring, and are starting to get to the end of the project. I am thankful for the feedback many have given here, especially in private. I hope to throw some posts on this thread with the intent of helping others. This first post is simply an introduction and overview of items I hope to cover in this thread.
IMHO modifying the Z4 has been an utter pain in the butt. I can't count how many BMW's I've had, or the extent of how many cars I've modified or built over the years. Part of the issue is the low production. Yet while the Z4 is in the E30 M3 availability level in the USA, unlike the E30 M3 which was 90% owned by enthusiasts, 10% of the Z4's are owned by enthusiasts. So information is hardly lush. Many of the issues I've dealt with fall in three categories:
Supposed cross-compatibility with other BMW platforms. This is a big gotcha. Both with the N54 ... same motor but all the peripherals and packaging has subtle variation. With the E46 rear suspension, E9x front suspension and front brakes.
Poor quality & lack of product engineering. Simply there is not enough demand to make the product development worth it.
Subtle mid-year changes (especially circa 2011). These are not well documented or well known by what I've seen, that includes vendors being stumped.
In writing this up, I will not name products specific to issues - in part because the issues seem common. I also want to say that I don't see this as a vendor problem ... it's capitalism ... simply there is not enough market and price willingness to solve these problems for such a low production platform. So if you have an E89 Z4 this is owner territory. Many have had issues - the vendors have been almost universally helpful. Three of them have given me partial money-back refunds on their products, without any complaints or request on my behalf. Some items, as of this post, are still not successfully installed. Several have required modification. One vendor has overnighted items 4 times to us. This is the nature of being on the periphery - again, I don't see this as a vendor problem. We bought Z4's - a low production car - this is what one should expect.
Next thing. I actually started by outsourcing this work. I have 2 teenage boys at home and in the last 3 years we have completely restored an E46 for one, a 318ti M-technic for another, and I refurbished my E39 sport package car. Simply time with my boys was more important than this car project. In that regard, I engaged Barry Battle to do the work. Barry co-founded Bimmerworld, and founded Road Race Technologies (RRT) - he's an industrial engineer, suspensions being his speciality along with racecar fabrication, but 20 years around BMW's and in the shop, is a very knowledgeable guy on general work around BMW's. Furthermore, and thankfully, Barry has access to a full and modern machine shop, so lots of stuff has gotten modified or made. As of late, given all the issues, I've saddled up with Barry working alongside him. My observations on this thread will, in part, reflect Barry's opinions as well - we are old school BMW guys and of similar minds. Both of us have extensive race car fabrication experience, racing experience, etc. I only say that so you can take some of the commentary on this thread in context of who the author is ... we might be a bit more picky about some things than others might, so please take my comments in context.
Anyway as I have time to write and post photos on this thread, I hope it helps others on this journey. This would have been 10x harder if it were not for the help those before me provided. In my next post, I will set the context and constraints of the project. In the meantime, a photo or two ...
The car stock, a 2011 35i 6MT with 23k miles, condition was almost virginally new, shipped out of Texas:
Apart and in-flight:
Filippo