This is the thread to reveal, once and for all, that the Z4 E85 engine mounting arms are a perfect fit for the N52 into E30 swap. hubcapboy and I were initially confused about this because earlier information on those arms had mentioned cutting them and repositioning 1", and then re-welding. That's why we measured for our own arms and designed them to work with the hydraulic mounts, to boot. The idea was that we wanted guaranteed clearance for the full N52 DISA intake.
I found several issues with those arms. It placed the motor closer to the radiator than it needed to be and the fat hydraulic mounts were too close to the Power Steering rack fittings to be able to unscrew them.
So, last month, I finally tried a set of stock Z4 E85 mounts. They moved the engine back 1/2" for me and up maybe 8mm creating a perfect fit with off-the-shelf AKG DOHC swap mounts. They still provide clearance between the rack and the pan and allow for clearance to the heater core hoses and room for the full intake. The shifter is maybe slightly aft of center. The DOHC mounts have a built-in 5 degree correction and correct bolt offset, but all of the old "usual" DOHC mounts should work, too. E28 M5, etc...
That said, there is room for the motor to go further back, probably another 1", but I wouldn't do it without re-working the shift carrier, probably going rear sump for lack of space in the front and sticking with the N54 intake.
As far as the transmission mounts, it depends on which transmission you get. E90's came with two different manual transmissions. The GS6-17 in the 328 or the GS6-37 in the 330. The GS6-17 (the one I have) is a few inches shorter, 10lbs lighter and is rated for a bit less torque. The good news is that the GS6-17 uses the exact same mounting as the G260. Yep, I didn't need to change a thing. The GS6-37 has a different and more robust mounting style, but needs an adapter. It's the same one that the S54 swaps use, so Kassel, Bayside, etc all have that available.
Bottom line, stock subframe, stock Z4 arms and DOHC mounts.
I found several issues with those arms. It placed the motor closer to the radiator than it needed to be and the fat hydraulic mounts were too close to the Power Steering rack fittings to be able to unscrew them.
So, last month, I finally tried a set of stock Z4 E85 mounts. They moved the engine back 1/2" for me and up maybe 8mm creating a perfect fit with off-the-shelf AKG DOHC swap mounts. They still provide clearance between the rack and the pan and allow for clearance to the heater core hoses and room for the full intake. The shifter is maybe slightly aft of center. The DOHC mounts have a built-in 5 degree correction and correct bolt offset, but all of the old "usual" DOHC mounts should work, too. E28 M5, etc...
That said, there is room for the motor to go further back, probably another 1", but I wouldn't do it without re-working the shift carrier, probably going rear sump for lack of space in the front and sticking with the N54 intake.
As far as the transmission mounts, it depends on which transmission you get. E90's came with two different manual transmissions. The GS6-17 in the 328 or the GS6-37 in the 330. The GS6-17 (the one I have) is a few inches shorter, 10lbs lighter and is rated for a bit less torque. The good news is that the GS6-17 uses the exact same mounting as the G260. Yep, I didn't need to change a thing. The GS6-37 has a different and more robust mounting style, but needs an adapter. It's the same one that the S54 swaps use, so Kassel, Bayside, etc all have that available.
Bottom line, stock subframe, stock Z4 arms and DOHC mounts.
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