so i got most everything swapped from the a3 to the z3. here is a photo of what the timing chain side looks like with all the a3 accessories on z3.


i had problems with swapping the thermostat housing, but after some tweaking of the metal tube that runs to it i got it lined up where i felt comfortable with it not leaking.


to put the rear mount from the a3 onto the z3 you have to remove the exhaust manifold from the z3. there is not clearance because of the heat shields. i removed the one on the manifold and the one over the halfshaft. both need to be removed for the manifold to be removed. you also need to install the a3 manifold so the downpipe lines up.



while the manifold was off i wanted to show the differences in the two. there will be a great increase when using a header, the a3 manifold really looks like it is going to choke the z3

z3 on left


also the port sizes on the z3 are quite larger than the a3.

a3


z3


z3


a3


i used the a3 gasket because the bore was big enough for the z3 head without hindering flow and it fit the a3 manifold better.



at this point i moved to the transmission and removed the shift arm mechanisms from both of the transmissions. differences below.

a3






z3





what i did was remove the metal from the a3 housing to make it looked like the z3 housing, tapped the holes, slotted the shift arm shaft. although i goobed it up by cutting the slot in the wrong spot and when engaged let me go to 1st and 2nd and thats all. it will work you just have to do it correctly, i may do it correctly soon, im really scared of hitting reverse on the highway. i know i could just use an a2 mechanism but i just wanted to see if this would work. if you want pictures of this just pm me.




also...
i broke the stupid air assist valve on both of the engines, these things are stupid fragile so be careful. after reading up they really dont do all that much so i just bypassed it. here is how to do that.



the hose runs to the middle of the manifold , i just put a screw into it to seal it, just make sure it is a tight fit.



ok for the idle air control valve, i didnt have the correct hoses so i bypassed the coolant to it. it is still electronically controlled so i wasnt too concerned.

the lines that run to it i ran into each other


and on the throttle body i just did the same thing.


now for installing the shift mechanism from the a3 onto the z3. dont forget about the 8mm hex screw on the side of the transmission directly in front of the mechanism, this has to be removed! but two holes line up, the front two, the back left doesnt at all just fill it with hondabond or rtv. the one on the back right needs to be drilled/tapped there is a spot casted for it. i guess you could just have the two scews but why risk it it is fairly easy to tap threads.


i installed it and forgot to remove the shift cable bracket. the mechanism needs to be off when removing the bracket if you have the lockout solenoid on the a3 mechanism. if that makes any sense...but you need to use the a3 one basically.

i also used the slave cylinder and clutch line from the a3, the z3 clutch line ran a different route and i didnt like it. and i wanted it to bolt up just like i removed it. the slave cylinder inlet port is on the other side for the z3.



ok so that's all for now, some things i did not picture are wiring up the digital speed converter, this is pretty straight forward , if you cant figure that out you should NOT be doing this swap. and installing the throttle body adapter and throttle body, just forgot pictures, will show pictures of it installed tomorrow. also i ran the wiring harness on the z3. also straight forward.

all that is left is to switch shift cable bracket and reinstall into car! woot