2011 Atacama Yellow Build

[fmorelli]

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

[ljkiter]

yay
I feel that now that these cars are affordable and still amazing looking.. there'll be alot more enthusiasts out there buying.

[fmorelli]

Like any project in my experience, I needed constraints. This is especially the case with a turbo car where things can get really out of hand. I was not familiar with the N54 platform, which was part of the reason for doing this, and for that matter the E89 chassis. After some research I decided the following:

• retain stock turbos
• retain stock clutch
• no coilovers

The target for the car is street use, so this further makes some choices not so picky. I felt the stock turbo / clutch combo meant a 500whp possible car, which is certainly healthy for a circa 3,300 lb car.

One thing I left open was exhaust, which caused me to vacillate on extent and choices. Ultimately I decided to do a complete exhaust. So with that said, here's a public Google Sheet which we are using to manage what's been done. https://docs.google.com/spreadsheets...it?usp=sharing. I'll not duplicate the spreadsheet information here.

In the next few posts I'll look to talk about different sections—suspension, engine, etc—and discuss specific choices and install experiences. Eventually as the car is on the road I'll have additional observations.

Filippo

[Bob20124]

Great post! Looking forward to hearing more on the issues and solutions, also thoughts when tuned with road time under your belt. E89s can always throw you a "surprise"

[distinctperson]

Thanks for taking the time to write this thread, OP.

I have a few questions, however: What do you suspect is the total cost of all the upgrades ? Parts alone, and installation included ? What is the purpose of undertaking this project to begin with ? Looking to sell for a profit, or just have fun driving it ?

Also, I've noticed that you have added some low-quality tires (Ventus EVO2) for some reason. Any compelling reason why you didn't include higher quality tires such as the PSS ? I've had the Ventus EVO2 on my IS and they are truly unsafe for handling the car at high speeds -- being careful not to exaggerate here.

[35i-Nut]

Thanks for sharing , car looks awesome in that colour !

Eagerly awaiting more photos and updates

[jts1981]

Filippo,

Nice write up! The black f14s look great!!

btw I still think you'll end up with KW's in the future...

Can't wait to see more pics.

[fmorelli]

Okay let me start with jts1981's comment, and talk about suspension changes. I'm concerned - he puts a bunch of smiley faces at the end of his KW comment ... but reality is he has been right many times so I fear he'll be right on this too :-(. But for now, here's where we are on suspension.

I tried to avoid coil-overs. I didn't feel they were necessary for the street, but I felt some work on the suspension should be done to help deal with another couple hundred horsepower. My setup, from the spreadsheet, is ...

H&R Springs
H&R Sway bars
Luxon front strut bar

AKG spherical bearing front tension strut
BMW E9x M3 front lower control arm

Rear spherical rid sway bar end links
BMW E46 M3 trailing arm ball joints
E46 M3 RTABs
RTAB limiters

Forgestar F14 wheels, 19x9 ET35 & 19x10 ET38, bronze burst finish (jts1981 to thank for the specific wheel/tire setup that works on this car)
Hankook Evo v12, 245/35-19 265/30-19

Most of this has been straightforward. I want to share a few observations:

• The rear suspension is E46 based. The upper rear controls are slightly different, though. They are stamped instead of the old cast aluminum. Specifically the rear sway bar link mount is slightly different, which leads us to the next comment.
• The H&R rear sway bar has 3 adjustment positions. We could not get range of adjustment with the factory end link. Furthermore, with the suspension fully unloaded, the bar hit the half shaft. In our book this is bad news. Not that we drive around with the suspension unloaded, but understand in spirited driving it is easy to even over extend the suspension. So this led Barry to source pieces to make rear sway bar end links which now give us adjustability and clearance.
• The dread Rear Trailing Arm Bushing (RTAB). If you decide to buy E46 limiters and stuff them in there. Good luck. The E89 RTABs are ostensibly the same dimension, but the German engineers figured out that deflection could be reduced by extending the rubber 2mm on each side of the bushing (4mm total). So limiters will not fit without removing 2mm on each limiter. That's ok because the E89 RTABs are not the M3 version ... so the simple solution is to push out the E89 RTAB and install the E46 M3 RTAB which is more sturdy, and then the limiters simply fit - two birds killed with one stone.
• There is a heavy, steel damper mounted to the rear trailing arm. I've pulled it ... we'll see if it makes any difference I care about.
• Lower ball joint on the trailing arm is rubber ... E46 M3 slides right in as a ball joint
• The Luxon front strut bar is the only one I've seen for the E89, and thankfully it is fixed (versus adjustable/flexible). It comes from South Korea, oddly ... check out eBay.
• Rather than go to the E92 M3 tension strut arm, I decided to press in the AKG spherical bearing.
• Forgestar did a great job on the wheels - they were a bit tight on the rear hub centers, but a bit of grease and they are good. Reasonably priced for what they are.
• I ended up with Hankook Evo V12 tires - I had tried to get Yokohamas (my preferred tire) but they'd been out of the country for 6 months. The newer V12 had good reviews, though honestly if they turn out to have issues, I'll punt them for a different tire. These came mounted from the wheel provider.

So that's the bits on suspension for now.

Filippo

[35i-Nut]

which hole are you running on the H&R sway ? , Ive been playing between middle and stiffest hole and settled on the middle as found the stiffest hole made the car a bit twitchy

I had no issue with getting adjustment , however I'm interested in what torque your rear sway bar bolts have been set too ?

The OEM end links are pushed onto the end of the rear OEM sway bar and in theory can rotate around the end but reality they are a pain to twist off

As you know the rear H&R sway are nut and bolted to the end links , Ive tightened mine up until the end link rubbers start to distort , Ive no idea if this is correct struggled to find info, interested in what you have done

Also , I'm on the verge of buying KW3's , Eibachs and H&R sways are a big improvement over stock with EDC but I'm still rolling around in my seat

Front end feels flat and tight , the rear end does not

Cant quite decide if its due to the SE seats being unsupportive or its the car rolling around at the rear!

[fmorelli]

Originally Posted by 35i-Nut

I had no issue with getting adjustment , however I'm interested in what torque your rear sway bar bolts have been set too ?

Not on the road yet, so sorry I can't contribute here.

Originally Posted by 35i-Nut

Ive no idea if this is correct struggled to find info, interested and what you have done

I'll post photos on Monday, when back in the shop.

Originally Posted by 35i-Nut

Also , I'm on the verge of buying KW3's , Eibachs and H&R sways are a big improvement over stock with EDC but I'm still rolling around in my seat

Front end feels flat and tight , the rear end does not

Cant quite decide if its due to the SE seats being unsupportive or its the car rolling around at the rear!

Yeah ... I'm hoping not to have to go back and do KW3's. What else did you do to your Z4 rear? I've put in the E46 M3 RTABs with limiters, lower outer M3 ball joints as well, and an LSD. I'm very curious to see how this plays out.

Filippo

[35i-Nut]

At the moment I haven't done anything else with the rear end , looking at your spec you have some additional suspension components which I'm off to do some research on to see if I get these too

Ive also just purchased some Super pro bushes for the rear end links

http://superpro.suspension.parts/spf2419k

[fmorelli]

I took a variety of photos today, working with Barry. I'll post some of them now, and others later when I hit subjects. It was a long day, not to mention I seem to have come down with some kind of cold, which took the juice out of my system. We are shooting for the car going to the exhaust fabricator this Wednesday, so getting key things buttoned up was critical, such as being able to get the heat shields back on.

We've been fighting the UUC shifter installation. With all the right pieces in hand were able to get it installed, though we had to trim the 6 screws that hold the cup together, as they hit the shifter ball, when installed. No biggie. Another issue we had is the rear bushing that holds the shift platform to the chassis kept popping out when we installed the shifter knob. Between Barry and I we've probably done this on 50-100 cars, neither having ever had that problem. Had nothing to do with UUC's shifter mind you. Pulled the shields again and tweeked the hold-down. Here's what the shifter assembly should look like (the cup to the right is the original one which did not work on my 2011 Z4)



I previously mentioned the RTABs being different. Here's a photo of the Z4 (wider) RTAB versus E46 M3 RTAB which can be used with limiters.



Here's the H&R sway bar with stock BMW linkage. In the middle setting you can see that the bar almost kisses the half shaft. We'll solve that with our own rod end setup soon; we're just waiting on Barry to machine two spacers.



While I was down there, just a quick snap of the MFactory Helical LSD installed.



Finally on suspension, here are the E92 M3 front arms, and the AKG spherical tension strut bearing which we installed in the Z4 tension strut. Note the E92 M3 passenger arm needs the Z4 leveling connector attached to it. This has been covered elsewhere on the forum so I won't discuss it here.

[fmorelli]

We installed MMP silicone inlets and outlets. They are a tight but reasonable fit. I am certainly pleased with them. That said we were not fans of the zip tie them to whatever approach. I'll eventually take some better pictures, but we're working on a few mounts to help hold things in place. The brackets at the alternator will eventually be made in the machine shop, but we had to model up some stuff with 1/8" aluminum to figure it out. Also note the 2 1/2" 45 degree aluminum tubing used to mount the Burger filters. Again I will post some specific photos on the MMP installation when I get the chance.

We also pulled the DME wiring and did some rerouting in the box, so we could run the second (smaller) transmission loom on a different path, clearing more room for the intake. As well we tied the A/C line to the firewall brace to help establish more intake space. While the vacuum brake booster line is not in the way, it bugs me to have that line just hanging out up there. We've talked about replumbing that ... but for now, I'm not worrying about it too much.



We currently don't have the MMP outlet tube installed, since the exhaust fab guys need access the the VRSF downpipes. We decided to have them modify the Bank 2 downpipe as clearance was not adequate to our liking. It's a tight fit where the pipes go through the subframe / engine mount area. We expect a more gradual turndown of Bank 2's pipe will give more clearance. As well we are discussing with the exhaust fab guys the possibility of cutting off the constriction flange and going full width to the rest of the exhaust, attached with V-band clamps. We'll see what they say, in-person, on Wednesday.

Filippo

[35i-Nut]

interesting to know I'm not alone with the H&R being very tight fit

Also looks Like I have my H&R sway bar bolt tighter than yours as the hex head appears to have dug in the rubber more

I'm awaiting delivery on some superpro bushes , was going to fit a washer to the hex head to stop this digging in.

Its bothering me a bit how tight this bolt should be ?

What were you planning to do to improve the fit of the H&R?

[fmorelli]

Barry's not a polyurethane guy for suspensions. I'm sure you can Google religion around that :-). I'll post some photos but Barry sourced (probably Mccaster Carr) the parts to assemble a rod end based end link, that lets him size the end link and dial in some more clearance. For some reason, I didn't take any photos of that yesterday ...

I'm suspect you are fine with the polyurethane on the sway bar.

Filippo

[fmorelli]

Ok the car was dropped this morning with the exhaust fabricator. They are going to heat and slightly rebend the Bank 2 VRSF downpipe to get more subframe clearance. They plan to run 2 1/2" ceramic high flow cats in the mid-pipes, routing the post-cat downpipe O2 sensors there (so we should not need a delete). X pipe if room, H pipe if not, then back to the mufflers. They recommended Magnaflow over Borla ... their experience was it is a better longevity muffler.

Most of the tubing will be mandrel bent so it should be a clean design. We'll look for pictures next week.

For our cars, with a limited exhaust selection, I believe this solution will be a healthy alternative. Cost is well less than an Eisenmann or Remus system behind the dowpipes, while still supporting cats and post-cat 02 sensors.

Filippo

[fmorelli]

Alright Z4 gets loaded up in the trailer and returns from exhaust shop today. Hopefully we'll have some photos here soon. I understand they ran high flow ceramic cats right after the catless down pipes, then an H pipe, then out the back with quad exhaust through Magnaflow mufflers. They are pleased with the work so I can't wait to see it. I am hoping this gives us both flow and full ODB-II 02 sensors (post-cat mounting behind the new high flow cats).

We've pulled together a punch list as the mechanical work comes to close. I'm out of town until Friday, but hope to be over on Saturday to either help wrap up and maybe pickup the car.

From there it goes to Blue Ridge Wheel so they can do an alignment. Then ... FINALLY ... to BQ Tuning so he can "fix" it :-).

Filippo

[fmorelli]

Car just being picked up at the exhaust fabricator. A few quick snaps for you all. We'll get some photos of the whole system when it is up in the air.

While I've not seen the rest of the exhaust, I've seen plenty of under-car work from them and assume the rest looks as good as these photos. Getting all the placement stuff right as seen here requires skill, attention, and experience. They told Barry they were very pleased with how it came out. A good sign!

Filippo

[jts1981]

Looks fantastic Filippo!!!

Please post some videos as well. The usual inside/ outside and drive by would be awesome!!

[ljkiter]

+1 on the vids!

[35i-Nut]

looking very good !

[fmorelli]

Will post vids. I've got a high quality Zoom x-y mic that can hook up to the Canon, so we'll get a good recording of how it sounds, in and out, once it is back and tuned. Sorry guys ... going to take a bit of time ... I know ... I'm trying to be patient too!

I'll post info on the exhaust, pricing, who did it, once I have a chance to assess. Mostly because options are scant in this area for the Z4. I'd love it, if it turns out we have an alternative that provides cats, 02 sensors, and performance all in a package less than buying Remus or Eissenmann exhaust ... but jury is still out on this!

Filippo