TD5 Exhaust

[Landrovernuts]

Hi All

Just thought I would share this with you as I believe it to be a unresounding success!

Like a number of other TD5 owners (discovery and defender), I would get a harshness between 2000 rpm and 2500 rpm which has taken me ages to get to the bottom of. I have read all sorts on the tinterweb and forums but started looking into this abit more with my vehicle (2002 110 TD5 double cab). The exhaust is a genuine parts exhaust but the down pipe was a Britpart only because I needed the vehicle on the road and the flexy self destructed one day.

I was convinced it was the exhaust that was the culprit and have in the past replaced the flywheel, engine mounts etc. I have even heard that is is a TD% design feature and all sorts of other tosh and was sure it was somthing simple. I even tried running it with only the downpipe in place which was deafening but revealed absolutely no harshness in my 2000 rpm to 2500 rpm window - this confirmed I was going in the right direction. A few weeks ago I replaced all the exhaust hanger rubbers which altered the harshness bit didnt get rid of it. I had the day off yesterday and thought I would have a play in my new workshop (warm and dry!!). I took the Britpart down pipe off and while laying on the ground next to the original down pipe it became very obvious that the flexy was too small for the pipe and the pipe had been tapered to weld the flexy to. Checking the old pipe revealed that the internal diameter of the Britpart exhaust was 30% smaller than the original (original pipe ID 2551.8mm2 verses the Britpart 1809.5mm2)!!

I purchased 2 stainless clamp on flexys on ebay (standard length) and started to chop the original downpipe around (I was going to use the Britpart one until I saw the dimension issues). I did make a mistake and bought 63mm flexy sections but you 60mm ID if you are going to do this. So I fitted one new flexy to the normal position and also one to the back section near the silencer flange. I did it here as there is a suitable straight section but also because there is a mounting rubber in the middle which would stop any excess pipe movement. I went for a drive this morning in the floods and hey presto the harshness has gone completely and what is also very noticeable is that there is much less turbo lag - it is pulling much sooner which probably is excess back pressure on the turbo from the Britpart flexy. My flexy's at least maintain the internal diameter of the exhaust which obviously makes a big differance on a TD5. I wont take the centre silencer out for even less back pressure as I like the relative silence on the motorway (1.22 TB also helps here!).

Ignore the fact the flexy slips are leaking slightly (I will sort later this weekend) but you can see where the new flexy is and how small the Britpart flexy is in the pictures. Whether it is just better flexy's or the fact I have two fitted now is open to debate but I am rather chuffered with my simple and cheap fix. Just out of interest the two new stainless flexys are stiffer than the Britpart one.  Third photo is both my toys in their new dry surroundings.