Intake & Throttle Body

I decided to try the E12 528i throttle body to cope with the increased air flow. I found on e12 528i throttle body from a guy on ebay who was selling some other e12 stuff. Once setting next to the stock TB I found that the bolt pattern was very close to the stock TB. The 528i TB is 65mm vs. the stock 48mm TB.

Mounting the throttle body required grinding off the external coolant passages (shown below) so it would sit flush on manifold and slotting the mounting holes slightly. This wasn't a problem for me since I was going to use the cooling lines for the turbo anyway. I sealed the throttle shaft with putty and bead blasted the housing to clean things up, then began test fitting on my spare intake manifold. You can see the stock inlet hole vs. the hole marked from the new throttle body.

I bead blasted the intake manifold and cut a larger hole in the plenum for the throttle body. I port matched the intake manifold and gaskets was careful to radius the top of the new throttle body hole as much as possible to promote good air flow. While I had the manifold off I spent a considerable amount to time grinding off all the casting lines and defects, cleaning up the appearance of the plenum by removing a poorly defined set of bars and lettering, and smoothed the surface.

Throttle Cable

Ultimately I had to retrofit a custom throttle cable as the stock cable was too short and I couldn't get wide open throttle. I finally found a decent throttle cable for the E12 throttle body that works perfectly, it only cost $25 at autozone. I had to modify things slightly to get it to fit, but it was an easy install. I also notice a little bit more power at the top end.

Here's a pic of my temporary weld job to get my too short stock cable to hook on to the e12 throttle body. It got the car on the road and drivable but it was preventing me from getting WOT

Here's a comparison of the end fittings for the firewall, I couldn't believe how close they were:

Here's the stock gas pedal hook/lever:

and after grinding a little to fit in the new cable end:

Here's the 2 cables side by side:

And here it is installed, I slipped a piece of rubber hose over the housing to protect my shock tower from abrasion:

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