http://www.z1motorsports.com/product_info.php?cPath=6_7&products_id=1911

 

looks like a good buy

look good but why would increasing the throttle bodies without changing the intake plenum make any difference? I would have thought that would have governed how much air it could take in and be matched to the standard throttle bodies for airflow?

they look pretty cool but how much difference would they make?

you can gain a little more by bigger throttle bodies but not a great deal and only if your already pushing big power, i had some 60mm throttle bodies that i was going to install on my project car, think jaffa has them now ;)

more throttle response because the butterfly is larger so flows air a bit quicker , youre right about a plenum being a bottleneck( thats really incorrect its more to do with the headwork) but with the turbos forcing the induction its less a issue.

Less throttle response, less torque but more bhp with bigger turbos!

surely for the same pedal movement the butterfly opening is larger so it flows more air than the smaller butterfly even part open

There air will be moving at a slower speed, this means the speed of air used to swirl air and fuel in the chamber will be reduced, meaning less torque and less throttle response.