In moving to the Vorshlag camber/caster plates, a previous post shows how Barry Battle and I converted the shock towers to E90 strut mount orientation, which is with the leading top strut bolt being oriented forward-most on the tower. As a consequence the previous Luxon bar no longer fit, and its design precluded modification.
It turns out the strut tower spacing on the E90 and E89 is identical. So I purchased an E90 carbon fiber strut tower bar from ECS Tuning, which was a straight bolt-on, or so one might have thought. Turns out the Z4 hood is lower than the E90, so the bar would hit Z4 hood.
I used a borescope to help determine what was going on, thankfully not closing the hood all the way the first time! With some experimentation, taping the bar in different backset locations, I determined setting the bar rearward would both clear the hood and make room to access the oil cap. The E89 motor is set further back from the strut towers than the E90 (E90 guys, this is where you get to be a bit jealous).
To install the bar further rearward, two aluminum shims are needed to mate the bar to the strut bar base. The bar would then mount in line with the leading strut tower top bolt. The bar was currently held to the base with an M8 hex button bolt with lock nut underneath. The new location would bolt straight into the base which would be threaded to accept the M8. So in summary two shims, the base drilled at an angle, and a Heli-Coil installed in the aluminum base to take the M8 button bolt.
We cut the front mount on the strut bar base leaving about a 1/4" shoulder, which the shim could index against.
Needing two shims, we began with a piece of 1/4" 6061 bar stock.
The shims were cut on a table saw at 8 degrees, then sliced to 40mm x 40mm. Finish work with files and PSA adhesive sandpaper on a granite block, all edges chamfered.
The complete assembly was dry fit, then taped in place. A pilot hole was drilled to locate the hole in both the shim and the base. Note when drilling, observe that the strut bar mount hole is drilled at an angle relative to the top of the mount - one wants to drill perpendicular to the bolt shoulder.
One the pilot holes are drilled through the shim and strut mount base, the assembly was taken back apart. The shim was then oversize drilled.
The base was drilled appropriately to be tapped with an M8 Heli-Coil. The initial pilot hole established the angle of drill entry, since the cross bar to the strut bar mount is not a square orientation.
Finally with all the cuts sanded and chamfered, a few coats of VHT (Gloss Black - SP650) epoxy chassis paint covered the bare aluminum. The color was a perfect match to the existing finish.
The installation came out pretty good. The oil cap has clearance (shown here with an E46 cap, not the taller Z4 cap), and the hood clearance is great.
Filippo
It turns out the strut tower spacing on the E90 and E89 is identical. So I purchased an E90 carbon fiber strut tower bar from ECS Tuning, which was a straight bolt-on, or so one might have thought. Turns out the Z4 hood is lower than the E90, so the bar would hit Z4 hood.
I used a borescope to help determine what was going on, thankfully not closing the hood all the way the first time! With some experimentation, taping the bar in different backset locations, I determined setting the bar rearward would both clear the hood and make room to access the oil cap. The E89 motor is set further back from the strut towers than the E90 (E90 guys, this is where you get to be a bit jealous).
To install the bar further rearward, two aluminum shims are needed to mate the bar to the strut bar base. The bar would then mount in line with the leading strut tower top bolt. The bar was currently held to the base with an M8 hex button bolt with lock nut underneath. The new location would bolt straight into the base which would be threaded to accept the M8. So in summary two shims, the base drilled at an angle, and a Heli-Coil installed in the aluminum base to take the M8 button bolt.
We cut the front mount on the strut bar base leaving about a 1/4" shoulder, which the shim could index against.
Needing two shims, we began with a piece of 1/4" 6061 bar stock.
The shims were cut on a table saw at 8 degrees, then sliced to 40mm x 40mm. Finish work with files and PSA adhesive sandpaper on a granite block, all edges chamfered.
The complete assembly was dry fit, then taped in place. A pilot hole was drilled to locate the hole in both the shim and the base. Note when drilling, observe that the strut bar mount hole is drilled at an angle relative to the top of the mount - one wants to drill perpendicular to the bolt shoulder.
One the pilot holes are drilled through the shim and strut mount base, the assembly was taken back apart. The shim was then oversize drilled.
The base was drilled appropriately to be tapped with an M8 Heli-Coil. The initial pilot hole established the angle of drill entry, since the cross bar to the strut bar mount is not a square orientation.
Finally with all the cuts sanded and chamfered, a few coats of VHT (Gloss Black - SP650) epoxy chassis paint covered the bare aluminum. The color was a perfect match to the existing finish.
The installation came out pretty good. The oil cap has clearance (shown here with an E46 cap, not the taller Z4 cap), and the hood clearance is great.
Filippo
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