52mm Throttle body found already fitted

[Jonniey]

Whilst renewing the the front brakes, i gave the subframe a good looking over and there is very little surface rust and all looks in good order
also reading through posts i'm learning stuff, but this is what i found while changing the ignition leads
Theres a 52mm throttle body fitted and an aluminium inlet manifold, Now as she looks likes a base model i'm sure this are not standard fittings from the factory, Could someone shread any light on these parts and what performance if any these parts may produce??

[Steve White]

If its a MK1 non-VVC MGF then they won't be standard.
The alloy manifold has larger ports designed to match those found in VVC cylinder heads, but as the Mpi head smaller ports you get a step where the two meet. The resulting disruption to air flow just about cancels out any airflow benefit from the larger manifold ports.
The 52mm will give sharper throttle response but very little or no HP increase unfortunately.
On the plus side the alloy manifolds don't suffer from leaking gaskets any where as much and the plastic ones and look a bit nicer, and as there is no significant power gain from the parts, your insurer shouldn't inflate your premium when you tell them about the modifications

[Jonniey]

If its a MK1 non-VVC MGF then they won't be standard.
The alloy manifold has larger ports designed to match those found in VVC cylinder heads, but as the Mpi head smaller ports you get a step where the two meet. The resulting disruption to air flow just about cancels out any airflow benefit from the larger manifold ports.
The 52mm will give sharper throttle response but very little or no HP increase unfortunately.
On the plus side the alloy manifolds don't suffer from leaking gaskets any where as much and the plastic ones and look a bit nicer, and as there is no significant power gain from the parts, your insurer shouldn't inflate your premium when you tell them about the modifications

Steve, it an X reg year 2000, quite a basic model, 1.8 MPi Non ABS, no air con, just elec windows, elec mirrors, cloth interia 15' 8 spoke wheels
It looks like it's been on there a while, so it was modded a while ago, and i can't find any receipts in the folder i have that came with the car

[Geoff.F]

An X 2000 will be a Mk2 and an Mpi as the VVC came with ABS.
The only way to determine the standard that you have is to remove the manifold and look to see if the head has been modified accordingly.
Geoff F.

[steveinoxford]

Is there an easy way to identify the 52mm throttle body externally?

I have a VVC 2001 F and it has a metal TB, but I suspect that there may have been a move away from the plastic throttle bodies previously fitted, and as mine seems to be a very carefully preserved standard spec car, I may just have a 48mm ali TB!

Be interesting to know though without stripping down or wasting money on buying a duplicate TB.

Steve

[Steve White]

You can tell the difference if you are able to see the numbers etched into the top face of the square flange.
If the part number begins with 'TV5' is a 52mm, if it starts with 'TV1' its 48mm.

[Jonniey]

As i get to know my MGF, as well as the 52mm throttle body it also has a 2 piece cast alloy inlet manifold fitted,
when i talk talk to people at various shows/meets this seems to be sought after upgrade and i lean a bit more about MG and the MGF