XJ6 & XJ12 Series I, II & III 1968-1992

Eliminating the Secondary Throttle Housing

Old 08-04-2014, 10:09 AM
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Default Eliminating the Secondary Throttle Housing

I am on a quest that many Jaguar owners go on: Decluttering the engine compartment. Currently, I am working my way through removing the A/C as the compressor is junk and I like to suffer in the 100+ heat that is Idaho summers. Anyway, I have been wanting to remove the secondary throttle housing and mount the carbs to the intake manifold like the non-emission S1s. My housing is leaking through the seals on the ends and as I understand, there is no real gain by having it, and deleting it, or at least the butterflies inside can make the car slightly more responsive with ZS carbs. My issue is the water line coming from the pump (green arrow #1 in the pic). Can this be removed? I've noticed in Clarke's pictures that it is simply plugged, so I think this is the option I'd prefer. otherwise, I'd bypass the Secondary throttle housing and run it into the intake manifold where it ultimately goes. My plan, would be plug that hole on the water pump, plug the hole on the intake manifold (where green arrow #3 goes) and remove the secondary housing (red arrow #4). Is there anything else I should be mindful of? I know the Gulp Valve is on that housing, but honestly, I see no difference with that removed (no backfiring or anything). Thoughts?

The picture: Green arrows are the water line I want to remove, numbers are for explanation purposes only. Red arrow is the secondary throttle housing.
Attached Thumbnails Eliminating the Secondary Throttle Housing-cam01191.jpg  
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