Proboner's Z4 build thread

[proboner]

What a weekend!

Saturday morning I set out to get the calipers put back together. After some frustration I eventually realized that the piston boot on the rear caliper needed to be deformed with a punch and pulled out. With that figured out, they all went together rather easily.






Before getting to work on the car, I wanted to document the before state with regular 35is brakes.






It's all straight forward and something I've done many times on other cars, but despite previous experience, there's always the specific nuance of a new car that builds that frustration. I managed to get the drivers side brakes and suspension finished by the end of Saturday.








Started early today decided to get a few more pictures of the differences between the stock setup and the new parts I was installing.

35is front calipers are much larger than 35i, but a lot the size is superfluous.


The rears look and may in fact be basically the same, except that the caliper brackets are obviously a bit different to accommodate the larger rotors.


And as can be seen the rotors are both a bit larger in diameter, but are also thicker




Also compared the rear springs. ST -> H&R -> Stock


And front springs. ST -> H&R -> Stock


Although the the ST front's are taller than the H&R, the spring perch on the strut is considerably lower.


Although I must say I'm a bit upset that the shock isn't located lower in the strut body. This is usually done on aftermarket lowering springs to keep lowered cars in the shock sweet spot. sigh.


So today I finished up the passenger side install, which went much faster. Unfortunately found that the 513M wheels are now rubbing on the coil seat! Haha, it's never ending. Oh well, now at least I have an excuse to buy the new wheels and tires.






Still need to get the ride height figured out and the brakes bled. I bought speed bleeders to make the bleeding easy, but I've done quick bleeds twice now and still have air in the lines.

Thats all for now.

[Ichiro]

Sweet. well done on the brake and coilover install. How did you get the rear spring in? I struggled with that.

[proboner]

Originally Posted by Ichiro

Sweet. well done on the brake and coilover install. How did you get the rear spring in? I struggled with that.

Got a crowbar into the lower control arm and leveraged it down and had a friend slip the spring in there. It's the one part of the job that really requires 2 people.

[MurphsLaww]

Following.

Picked up a 2011, 3.0, really to use as a Turo car, but I'm in the same boat, without a screen.

If you don't mind, how much did your Hifimaxnavi run you out the door ? Trying to decide if it's worth it. Probably so, if just for the rear camera option.

Beautiful car, BTW. Mine is Titanium, with the M-sport, and the red interior. These cars are really curvy, and I've always loved them. Can't wait.

Thanks,

Shawn

***more I look a pics of your car, the more I'm wishing I had chosen black. Texas summers, though...***

[proboner]

Thanks!

I think I paid like $800 shipped for my screen. You can get them cheaper but can't speak to quality of those units.

[proboner]

Couple little updates...

Washed the lady and couldnt help but take a few pics. Pulling her out of the driveway the sun was making the red of the seats and the calipers pop


Then a bit later in the day grabbed a bit more from a similar angle


And then with this new beautiful picture, I couldn't help but photoshop my desired wheels on the car


I also cut off the mufflers to start on a new exhaust. I realize that a larger exhaust from the downpipes back won't add much in terms of power, but I wanted a little more sound, more aggressive tips, and of course already had the perfect mufflers sitting in my garage waiting for a place to live.


Stock setup that we're all aware of


and test fit muffler




Coolest part is that the tips are a separate piece that can be turned and telescoped in/out, so have a ton of adjustability on where they set and how they're rotated after install.

Plan on taking it to an exhaust shop tomorrow to get them installed. Usually I do this kind of work on my own, but I'm so sick of laying on my back to mock things up and welding in tight spaces. Or even worse, taking the smart route and pulling it all off to finish weld, and having to lug my welder out to the workshop in the back yard. Anyways, will hopefully have updates later this week.

[proboner]

Aaaaand hotter heads have prevailed...
On Cyber Monday, with the Volk photoshop freshly top of mind, I decided that for shits and giggles I'd just SEE if they even had a spec that would fit what I had in my head. After a few minutes of searching found Volk TE73 Ultra M-Spec 19x8.5 +36 and 19x10 +30 in Blast Bronze. Pit two retailers against eachother for best price and ended up with something that didn't make me want to absolutely throw up. And by 5pm that day, had the last setup in that size being shipped my way from Japan. What have I done!?


Anyways. Also dug a bit more into the exhaust situation this week. Was planning to go to a reputable shop in the area that many community members had suggested. Ended up making an appointment to get the work done, got to the shop only to realize I didn't have the exhaust rubber isolators and apparently he doesn't stock them, and the work ended up not getting done. Honestly I'm pretty happy about this, because from the moment I got there we didn't seem to get along. So as a result, I spend part of yesterday and today doing the install myself, despite swearing I wouldn't.

The passenger side has less room to work with so I decided to start there. I'd purchased 2.5" vbands as I was hoping to make the stock and aftermarket mufflers interchangeable, and figured it would help the transition from the 2.36" stock piping to the 2.67" muffler piping. Once again positioned the muffler in place and got it sitting how I wanted it.


Then slipped the vband between the piping and muffler, and tacked it all together.




The other nice feature of the vband, is that with everything tacked in place, I can now pull the muffler off and weld it outside of the car, and have much easier access to welding the exhaust side as well.




The muffler side was obviously straight forward and took all of a minute, but the exhaust side was a PITA. Space is super limited and getting the right angle, especially on top, was going to be damn near impossible. Until I realized I could just weld from the inside.


Now I would like to apologize for these welds, but lets get real. This was done kneeling in my driveway with the part sitting on the ground with a Eastwood 120v welder.

And by the time I "finished" the passenger side it was pretty dark, but still needed to get a picture.

[proboner]

And I just had to finish her up today. Took a couple hours between work meetings and since I'd already learned the process on the passenger side and the drivers side has much more space, quickly got it done... and this time with better documentation

First lets start off with our results from last night, not looking to shabby.


And what we have to work with...




Wrapped the vband in tape to protect from welding slag, and tacked it to muffler.


Put the muffler/vband combo on the transmission jack and turned her up to the correct height and slide the other end of the vband over the stock exhaust pipe exit


Moved the trans jack forward to the front edge of the muffler and adjusted as necessary to center it in the bumper cutout.


Once all was in place, I got back under and tacked the vband to the stock piping.


Pulled the tape, loosened the vband clamp, and pulled the muffler out for finish welding.


As I rolled out from under the car, I happened upon this beautiful sight, and had to snap a quick pic


Then went back under the car and finish welded the vband on the exhaust side, from the inside.


Put it all back up into position, tightened the vband clamp, and put her back down on the ground to step back and admire.




Looking pretty good, the drivers side sits just slightly higher than the passenger... maybe 1/8". It's all good, I still need to fabricate points on the muffler to connect to each stock mounting point at the bumper, at which time I can try to work out the difference. Of course had to take her for a drive and I must say she sounds quite nice!








As noted previously, these are Varex mufflers with internal valves that you can open and close to make loud or quiet. Still need to run the wiring and mount the switch in the interior.

[spyfish007]

Thanks for sharing your build. I am enjoying following along.

[proboner]

Well the diamond floor covers I ordered 7 weeks ago finally showed up today. Didn't realize it was going to be that long, but for the price I probably should have. My main reason for this purchase is that I hate how difficult it can be to clean carpet. Well I'll admit, they're pretty decent. Fit well and super easy to install, too like 3 minutes per side. We'll see how the cleaning goes, but it seems like a decent purchase already.








Also met up with a buddy of mine for a quick race. He's had his ESS supercharged Z4M for about a year and a half now and is about to sell it, so we decided we should probably line up just so see where the cars stand. The freeway was busier than we'd have liked, so we decided on a 3rd gear roll at 60. He honked it off and honestly I left a bit early, but pulled ~2 cars by the top of 3rd at 100mph. We raced once more after this, with me doing the three-honk and this time I left a bit late, to make up for the first race. He pulled about a fender on me before I reeled him in and put about on before once again letting off at the top of 3rd. I'm not too upset with the showing!

After the race we took a few pics of the cars together, for posterity's sake.




We then went to look at his newly purchased 2011 135i. A clean example for sure, but he took me for a ride and now I'm pissed! It came with Solo Werks coilovers and these things ride SO MUCH NICER than my ST's! Just an absolute dream! WTF!

[Ichiro]

New floor mats look very good. What material are they made out of?

[proboner]

Faux leather

[proboner]

And more updates. The new wheels should finally be showing up next week, so I've been doing tons of research and asking around to figure out what I'm going to do. There are two key issues to contend with; ride quality and traction.

Seeing as I'm not a huge fan of the ride quality with the current 18's, moving up to a 19" wheel is a bit of a challenging proposition. The RE71Rs on the current 513Ms are already ~0.6" taller than stock. Due to wanting traction, I'll likely be looking at tires at least as aggressive as the RE71Rs, which will of course be even stiffer when I start losing sidewall, so I plan to increase tire height as well.

This also brings up another area that I'm unhappy with and can change as well... suspension. The stock suspension felt too much like a boat. When I installed H&R springs, the stock shocks weren't enough to keep up and the ride became too bouncy. My new ST XA coilovers have a lot of issues just in basic design, which I would be fine to look past if they didn't ride so harsh. So while doing research on other coilover spring rates, I ended up finding a coilover setup on ebay with a setup that was just so amazingly cheap I almost couldnt say no. And then when I actually found someone running them that could vouch for the quality, I had to pull the trigger.

Hence, CX Racing coilovers have come into my life at $330 shipped. Now let's compare to the ST XA. Looking at the front struts/springs side by side there are a couple things to note.


Overall height- While CX Racing coilovers look much shorter, they actually just mount lower on the strut body (blue line). When installed, the strut body is very similar to the ST's, although the stock shock mount does add quite a bit of height as well.

Stock shock mount- speaking of the stock shock mount, this requires the use of a spring that has a much larger diameter at the top than the bottom. On the stock setup, the spring seat sits above the tire, so it can be a large diameter with no issue. On coilover setup with an adjustable spring perch, the perch is almost always below the height of the tire, meaning that is needs to be smaller in diameter so as not to actually hit the tire. This became an issue when I originally installed the ST's, as I run a 9" wide tire in front which when the suspension was compressed, would rub against those larger coils toward the stop of the strut. I actually had to run 5mm spacers and raise the height a bit to prevent this from being the issue. Notice that since the CX Racing coilovers come with a 2.5" ID strut mount, it can keep that small 2.5" diameter spring and prevent this issue all together. This also allows you to easily swap in different springs to try out different rates.

Adjustable strut body- One of the things that bothers me the most about the ST's, is the method of adjusting ride height. Since only the spring perch is adjustable, you actually have to change the preload of the spring to change the height. Say goodbye to the soft end of your progressive spring rate. As well, this has the hilarious side effect of actually making the spring effectively softer as you drop the ride height, and stiffer as you raise the car. The is the opposite of what you actually want. The CX Racing coilovers have an adjustable spring perch AND an adjustable strut body. This way you just put the correct preload on the spring and adjust the body of the strut to achieve the ride height you want. But a much bigger benefit comes next.

Riding in the sweet spot- Because the ST's require the spring height be adjusted to change the ride height, this can cause the shock to operate outside of it's optimal range. With the CX Racing coilovers, you simply use the spring perch to align the spring with the very middle of the shock ROM, and adjust the strut body to achieve your ride height. This allows you to actually pick where the spring rides on the shock.

Rear springs- This is another area where KW/ST have had a problem. Thankfully I don't get the dreaded clunking sound generated by the rear coils binding, but I do still have the effect. What's the point in having so many dead coils? By comparison, the CX Racing coils are much shorter and are only made up of 4 coils instead of the 6 that ST uses. I haven't checked for coil bind with the car on the ground, but GUARANTEED it's reduced. And the rear suspension can go at least an inch lower in the rear with the CX Racing setup.


Adjustable rear shocks- CX Racing even took this idea of riding in the sweet spot to the rear suspension, and provided adjustable shock bodies to allow you to shorten/lengthen the overall shock height as needed.


From a practical design standpoint, it's just a much better setup.


In terms of ride, my goal is mainly around comfort, and with adjustments set to full soft all around, the CX Racing coilovers definitely ride softer than the ST's. Truth be told, after a long drive down a shitty road yesterday, it could still be a bit softer for my needs. I've decided I'm going to try one last setup before I make a final decision, and that will be to go back on stock struts and run Eibach springs. My understanding is they basically stock rate but just sit lower. I think with the even taller tires all around, it'll probably reduce wheel gap to pretty much exactly where I want it. If I end up liking the ride quality here I'll then likely have to go with at least a rear swaybar to help with the handling a bit.

I also made a small change after washing the car today, and removed the rear z4 emblem. People already can't figure out what she is, even with the emblem there, so now they're sure to be questioning what just absolutely blew their doors off!




I've got another surprise coming to the door tomorrow, so I'll update when it does. Oh, and I added wheel studs all around. Ugh, they're so much better than stock bolts. EVERYONE should be moving to studs.

[proboner]

And the surprise came yesterday...


MFactory LSD with 3.46 final drive. Bought it off a member who bought if off a member who purchased it new and had it assembled by MFactory. Apparently he totaled his car after putting 500 miles on it, and for the price I knew I couldn't say no. The ratio is significantly shorter than the stock 35i manual 3.07, but given that the tires I'll be running on the rear will be about 1.3" taller than stock, the net effect isnt far off from factory in each gear. Will still cruise around 3k at 80mph. Now to find details of install and decide if I'm going to be replacing anything else while I'm in there. Exhaust comes to mind, but quite decided on that yet.

[proboner]

Took the cover off today to confirm that the diff actually is what it is... was not disappointed

[buiyaa]

Great build thread! Very helpful write ups, amazing pics, thx for sharing frustrations and work arounds. Makes me want to powder coat brake calipers now!

[spyfish007]

Originally Posted by buiyaa

Great build thread! Very helpful write ups, amazing pics, thx for sharing frustrations and work arounds. Makes me want to powder coat brake calipers now!

Doesn't it??!! They turned out really nice.

[proboner]

Thanks guys. Would highly recommend the powder coating. Rebuilding the calipers, after figuring out the rear caliper seal issue, was much easier than I'd anticipated.

Had an incident this week. Had to run an errand about 30 minutes away, parked her for 5 hours, came back out at 8pm to find all her coolant puddled on the ground. Drove to a nearby gas station to see if she'd hold any water, which she wouldnt, so got her towed home. Finally had time to get under her this weekend and take a look and it ended up that a hose popped off from under the expansion tank. PO had the expansion tank relocated and there's a number of non-stock adapters/connections involved. Thankfully it was a super easy fix, but I wouldn't be against finding a more elegant solution to the hoses running there.

Then gave her a wash and completed the debadge by removing the side sdrive 35i emblems.

[kaizzer]

Car looks SICK on those wheels! The exhaust is also a very nice touch. Sound clips asap!

[proboner]

Originally Posted by kaizzer

Car looks SICK on those wheels! The exhaust is also a very nice touch. Sound clips asap!

Yes I need to do this! I'll take some videos this weekend.

[snowild]

Just curious if you ever considered ohlins coilovers? I know a guy at my local track who really likes them

[proboner]

Originally Posted by snowild

Just curious if you ever considered ohlins coilovers? I know a guy at my local track who really likes them

Seems like a huge risk to spend $2500 and potentially not like them, which was the exact situation with the STs. Thought they were the safe bet and everyone LOVES KWs, but I cannot stand them.

If I do decide to pay serious $$ on suspension I plan to buy H&R coilovers and get Fat Cat Motorsports to revalve them for me. This is something I just discovered a couple weeks ago, but they're pretty prohibitively expensive. They are basically exactly what I've been looking for, and the ride quality is supposed to be incredible... however they tack a $2400 charge on top of the $1300 H&Rs! I'm goin to try Eibachs on stock shocks next and then weigh my options.

In better news, I finally took a video of the now old exhaust!