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[Jeepthang]

I6 4.0 XJ

Something that i've been wondering for a while. Apart from being a convienient place to put your mug of tea and /or your tools on when working on the engine, does the second airbox that sits on top of the engine (and is fed from the air filter box) actually fulfill a purpose.

I've noticed that the I6 engines in XJ's featured on US forums don't have this box whilst the UK vehicles do.

Any reason for this  :?:

[dxmedia]

My ZG doesn't have one, but are you talking about the plenum chamber?

[dxmedia]

heh, yeah it's there for a reason if your talking about the plenum.

If the air in went to a pipe which then fed 1 2 3 4 5 6 cylinders in that order, cylinder 1 would have the highest air pressure, decreasing down to 6. A plenum chamber is designed so that there is equal air pressure across all outlets.

Well at least that's my understanding.

[donk498]

The second box on top of the throttle body is there to cut down on intake noise. It a resonance (spelling?) chamber. You can remove it and fit the hose off a mk1 xj without causing a problem.

Dave.

[Bubba]

it is deffo to put ya mug of tea coffee on

[JamesH]

As Donk said, it's to reduce noise. I removed mine and fitted the earlier model intake tube.

[Jeepthang]

Thanks James and Donk for letting me know what it is. I knew it wasn't the plenum.

So what's the benefit of removing it? I wouldn't have though an increase in intake noise was a benefit and it is handy for your mug of tea!!  

[JamesH]

I needed the extra space when fitting my lpg conversion.

[Jeepthang]

Excellent, I was hoping that extra space was the prime reason for removal.

Mine's coming out!