10/13/2025
We're wrapping up our latest individual throttle body installation for an East Coast customer on his beautiful '89 911. When the car got here, the engine was one sick puppy (compromised prior build), so it was rebuilt by Rothsport to 11:1 compression 3.45-Litre specifications, running a 76.4mm GT3 crank and 98mm Mahle pistons and cylinders. We fitted a set of six 48mm Rasant ITBs and topped it off with a pair of our custom 996 GT3 intake plenums and integrated crossover valve / resonance flap.
The engine made a very healthy 322 horsepower on the Rothsport engine dyno soon after initial rebuild (but before complete break-in.) After complete break-in, the car lays down a respectable 300 at the wheels on a local chassis dyno. Electronic fuel injection and coil-on-plug ignition spark are all controlled via an EMtron stand-alone engine management system (our go-to) and one of our inhouse fabricated custom engine harnesses.
We're running a full SSi exhaust system - headers to tips (with 41mm primaries.) The instant throttle response of the ITBs is unbelievable and torque low-down is SO nice! Then around 4,000 RPM the power really starts to build and it revs out clean to 8,000rpm! Driving this car around in that 3-7K sweet spot is so much fun, but the car is also perfectly happy lugging around town in higher gears between 1,500 and 3,000 rpm. The induction sounds are also something to behold!
