3.9 Y pipe

[Lumbering Jack]

Just been having a go at sorting out the blowing exhaust on the disco, managed to snap every bolt holding the front pipe onto the manifolds so that's one job I wasn't planning on doing, but hey ho.

It seems to have been mainly blowing from the join between the Y pip and maifold on one side but there is a crack a few inches back and also there the pipes are welded onto the flange there seems to have been a bit of blowing.

Now, having a look online a Cat front pipe is horrendous money (approx £300 upwards).  I had a chat with the MOT man and he says that as it's got 7 seat, if it goes through the MOT on LPG the cats don't come into it. 

What I'm wondering is does anyone know if a Y pipe off say a 3.5 non cat D1 or maybe a 3.9/3.5 non cat RRC would bolt straight on?

Also, what would I have to do with the Lambda sensors - just leave them out?

[fezzy192]

i got a y pipe down ere in birmingham off a 3.5efi rangie non cat but a bit to far

[Range Rover Blues]

Depending on year, the exhaust on the 3.5 routes above the gearbox crossmemeber, not below and the bore is smaller.

The catalyst exhaust is different on the RRC, but the headers are the same so you would need the downpipes and Y piece, with fittings for Lambdas sensors or you need to change the TSR on the EFi wiring loom to suite.

[craig_midz]

what i did on mine was fit an early 3.9 disco y piece as its the right size bore as 3.5 y piece is smaller bore an as said above routes differently an then i welded a couple of nuts on the y piece the same thred as lamba sensor an then drilled hole inside the nut to screw lamba sensor in as i needed lamba sensors in for my gas kit an its been fine an gives u a bit more get up an go too

[Range Rover Blues]

Agree with the last comment, I got a couple of extra MPG on mine by fitting a decent exhaust

[Lumbering Jack]

I think I might have found one of the elusive non cat disco 3.9 y pipes at famous four - £55 plus vat - which i didn't thin kwas bad.

Having a bit of trouble with the manifold studs as even whn drilled out an extractor wont budge then so thinking I might have to just drill and re-tap but need some half decent bits too.

Was looking at rimmer brothers site too - they do a set of tubular manifolds with down pipes in stainless for less than a cat y pipe  :-k

Am guessing then that I'll need to keep the Lambda sensors for the gass too as mines a multipoint system with lots of electrickery.