52mm Throttle bodies and vvc plenum

[daved]

Looking for some technical info

Do 52mm tb come in alloy only? I have found some tb with plenums online but nothing to say if is alloy.

Do all vvc cars have a 52mm tb?

My tb is sticky so I thought I may as well make the change and go the full way.

Any info much apprdciated

Dave

[Rich H]

VVC plenum on a standard K series is generally not a good idea it'll give you more power at max revs but reduce torque everywhere else.
dunno about throttles.
Rich

[robin]

All 52mm tb are alloy so far as I know, but Rover made a bunch of different engines, so maybe there is a plastic 52mm tb out there.

There are plenty of 48mm alloy tbs and these will work just fine.

Increasing the volume/diameter of the intake generally makes the engine worse at the bottom end in exchange for a tiny gain all the way at the top end.

If you're currently running the plastic plenum I strongly suggest you keep it - you'll be disappointed if you fit the alloy plenum to the standard head, because the ports don't match which causes turbulence and generally worse performance except at full throttle, very high RPM.

How sure are you that the TB is sticking (Vs, say, problem with the pedal, poor adjustment of the cable, overtightened jubilee clip on the intake)?

Cheers
Robin