Gas Flow a 165 Throttle Body

Why gas flow the Throttle Body?

Surely the 165 Intercooler is a larger flow restriction?

This is correct. However as stated above reducing all the restrictions helps to develop more power.

Do you have any measurements?

Below is an illustration of the stock versus the new throttle body. The new gas flowed body's dimensions are in brackets.

Throttle body dimension comparison

Can't I get any old machinist to do this?

In a word no... For a start the butterfly valve is not circular, doh! You are going to need specialist tooling...


What does you Throttle Body look like?

Something like this...

Note the different thickness of the TB walls Side by side comparison
Old TB New TB
Old TB open. Note how far the bolts protrude from the butterfly support bar, this disturbs air flow, and the ridge around the TB before the butterfly valve New TB open. Note the machining undertaken on the butterfly support bar - every little helps! The front edge has now been knife edged to increase flow further


Are there any other options?

Yeah, what about fitting an ST205 TB? This is the largest of all the GT4 TBs and measures ~60mm as standard. Whether or not this will fit either a 165 or 185 manifold remains to be seen!