VVC plenum

[jimbo]

Another stupid question perhaps, but what's the difference between the VVC plenum and the standard air box on non VVC motors? They are in the same place, roughly the same size, and both appear to bolt straight onto the manifold, so what do they do?
Cheers

[tut]

VVC is an aluminium casting, looks better, but the plenum for the standard S1 is plastic, was designed for that engine, and probably does the job better than anything else.

Many have changed over but if I remember correctly there were no gains measured on the RR, though there were lots of claims made.

tut

[robin]

The VVC inlet manifold, if correctly port matched to the head, will win you some power at the very top end; mated to a non-VVC engine it will cost you some power lower down the rev range.

The standard plenum can be made better by removing any plastic flashing from the inside of the moulding. It is also good for at least 150BHP (plenty of tuned heads on standard plenum/throttle body making that figure). So for a non-tuned or mildly tuned engine there is little doubt that you should just keep the plastic (possibly tidied up) inlet manifold.

BTW, in either case, the air box is the thing in front of the throttle - usually a big black plastic box, like a cornflake packet in dimension, with a tube to the outside world and a tube to the throttle body. The air chamber after the throttle body is called the plenum (whether it's made of plastic or alloy). The tubes that lead from that to the inlet ports are often called runners. The plenum+runners is called the inlet manifold.

So you're comparing inlet manifolds, not air boxes ... hope that makes sense

Cheers,
Robin

[tut]

A cheap upgrade if it has not already been done, is to fit a K&N flat panel filter.

It breaths better so could possibly give a small increase in power, but does not need changing at a service, just cleaning.

tut

[jimbo]

Ok so is the VVC inlet manifold interchangable with the carbon ones I've seen on various S1 Exiges then? I've always been a sucker for some carbon and I think they look pretty sweet

[woody]

Ok so is the VVC inlet manifold interchangable with the carbon ones I've seen on various S1 Exiges then? I've always been a sucker for some carbon and I think they look pretty sweet

No.

The carbon ones are not a manifold for a single butterfly throttle like a standard K. They're an airbox to feed the 4 individual throttle butterflies (1 for each cylinder).

You can convert to this set-up, but it's expensive and works best with further mods.

[Shug]

As Woody says, the carbon you're seeing is an Airbox and not a plenum. Unless you plan on spending 4 figures on engine upgrades, stick with the plastic plenum, deflashed if you want it as good as it can be.

[robin]

Also if you want some carbon-tat ITG (used to?) sell an air box that works with the normal throttle body, but obviously it won't look as hard core as the exige air box.

Cheers,
Robin

[jimbo]

Yeah I've seen the ITG and intend getting one at some point (I love a bit or carbon!) but as you say the Exige airbox looks superb!

[campbell]

I am guessing your 160 Sport already has the VVC style metal plenum? Those certainly shipped on 135 Sports as well as the 111S VVC models.

In which case it's an interesting debate as to whether you'd want to switch back ("downgrade", allegedly) to a plastic one from the boggo std models...

Proceed with caution

[jimbo]

Mine's a VVC so good point, but think I'll stick as is rather than risk it. Now where to get the ITG cheaper...