Looking at fitting a 160vvc exhaust manifold to my 143vvc libra is surposed to give a few BHP anyone done it, I know the mounting flange is different and there is no lamdba sensor boss.

If you going to the effort of changing it, you really want an exhaust with long primaries. The problem here though is it means that two pipes run under the sump where the rod gear change runs - so if you had a rod change it means then converting to cable shift.

Example image of what I mean;


It is my humble opinion that if you're going to go to the bother of doing something like this (which no doubt will be a pain in the proverbial as exhausts always seem to be especially when hidden against the bulkhead in the Libra) then it's worth going the extra mile so it's 'sorted'. However, a swap to a second hand manifold would be somewhat cheaper than sourcing a full system and then having the headache of fixing it to the Libra exhaust!

http://www.flickr.com/photos/dl-b/5531741272

Rod change would not be a problem as I am running mgf cable change.
what exhaust is it that is fitted to the car in the photo.Was hoping the 6 stud manifold secondhand at around £20 would fit to my exsisting pipe with a different mating flange.

In the photo it's the Janspeed manifold as fitted as standard to the VHPD but also available as aftermarket.

When I was writing the reply earlier I has a thought you may be looking for a cheap few HP rather than investing in a more complicated solution.

I just think the 160 manifold will give you a barley noticeable (if any?) improvement, but the change to a more engineered (or expensive!) item is more likely to give you something meaninful. Also the advantage of a Janspeed type is exhaust is then you're ready to go down the route of a ported head, throttle bodies etc....

That manifold is over £400.

I wouldn't bother with the 160 manifold as the work involved would far outway the rather doubtfull increase in power. The 2 GTM down pipes aren't interchangeable.

I would keep an eye out for a 4 branch manifold on ebay then build a new exhaust to match. The standard is 1.75" (designed for a 1.4 engine to suit the Metro cat) and far too restrictive. I took advice from a Lotus exhaust designer and increased mine to 2.25" along with a piper manifold.