Steve Nagata

I have a choice between the Cargrphic 72mm taper bore TB or the Power Haus 75mm TB.

I'm getting my TPC supercharger stage 4 ported, port matched to the intkae and outlet plenum and rebuilt with ceramic bearings.

I was told I should upgrade the 68mm stock TB on my 993.

I know Cargraphic is a good company but I havent' heard much of Power Haus.

Powerhaus also has a 72mm.

toughts?

thanks in advance!

NineMeister

Velocity through the throttle body is a lot more important on a n/a engine in comparison to your supercharged engine especially when running the stock plastic resonance tube manifold. That said it is good practice to constantly accelerate the flow towards the supercharger intake by using a gradually reducing area through the intake tract, so my suggestion would be to calculate the area of your air flow meter exit point and the area of the supercharger intake manifold entry diameter (which will hopefully be less) then estimate the ideal area of the throttle based on the measured taper.

However a "wet finger in the air" suggests that 72mm would be fine, but obviously there is no point in feeding this through a 70mm rubber pipe, ok?

Steve Nagata

Hi Coilin!

Thanks so much for your reply.

I ordered the PowerHaus 75mm throttle body before your post =(. I will be sending my TPC Eaton M90 superchager to get a stage IV port and sending the throttle body, inlet and outlet plenum to get port matched. The charger is also getting fitted with full ceramic bearings and viton seals.

hopefully everything will work out.