Business In The Front, Party In The Back: The Rear Mount Turbo

My first experiment was to see how the engine would handle boost with the stock ecu, a practice that many have tried and ended up with blown motors. I toyed with it anyway and managed to make it work with out destroying anything. With some simple modifications the setup functioned reliably. The rear mount turbo setup works just like any other turbo setup but the turbo is not in the engine compartment but rather in place of one of the mufflers. Here are some pictures of the old setup:











The car still fit on a standard lift with the turbo setup underneath:

At one point I had a comprehensive write-up on how to do everything in this setup but the site it was hosted on (cardomain.com) was unreliable and it was lost. I may go back and revise this with all those details but for now a general overview and results are the only things we need.

The engine handled the boost rather well, the only things that had to be done were to adjust the fuel injector pulse widths with an Apexi AFC Select (AFC stands for air flow converter and is just a coincidence it is the engine code).



The crank case ventilation had to be re-routed to an oil catch can with a check valve to prevent the boost from blowing the valve cover seals out. The engine was fitted with an adjustable 4.0 BAR fuel pressure regulator. The oil feed line was run from the oil pressure sending unit (the sensor that lights up the oil light on your dash when the oil pressure goes down):


The upper oil pan was drilled for an oil return fitting:

The back side of the fitting secured with a nut and red thread locker:


A Tilton oil return pump was also used because the turbo sat low enough that the oil would not gravity feed back to the pan.

Here is a quick video of the car instruments with the rear mount turbo, not very exciting but worth noting:


Once it was all said and done I made 225hp and 215lbft torque on 93 octane with 10lbs of boost. Not bad but the motor was pushed to its limits and was always on the verge of pre-ignition because of the high compression ratio of 10:1. The motor held up well overall, the transmission however started to slip and burn the clutch packs from the power. It also became clear that the Bosch ECU would never be an option if the car was to make significantly more power. It had to go.