mg metro 4-2-1 downpipe

[alan george]

hi
my downpipe is blowing and I need a replacement hopefully in stainless (hopefully I have attached a photo). Could someone be so kind and point me in the right direction for a replacement or a company that will manufacture a complete stainless system?

ta

alan

[DavidL]

Don't know where you'd get a stainless LCB exhaust (long centre branch, which is what that's normally called), but you can get mild steel versions from places such as Mini Spares.
Buying one from them would get you the Y-piece which joins the two parts to the rest of the exhaust included in the price.

[ACourtney]

Maniflow do a stainless LCB for the Metro. Mini LCBs tend to be a bit longer than the Metro ones so you have to either modify the manifold, or the exhaust. They are also able to take advantage of the Metro (and Midas Gold) having more space behind the engine and give the manifold more generous radii. I am fitting a Maniflow st. steel LCB to a Gold coupe at the moment and apart from needing to trim around 4" off the manifold's tail pipe(where Maniflow were just too generous with the length), it all fits very nicely with the standard Midas stainless steel exhaust system.

Alistair

[DavidL]

Is there not a greater risk of cracking with a stainless steel manifold, or is that an old wives' tale?

[ACourtney]

Is there not a greater risk of cracking with a stainless steel manifold, or is that an old wives' tale?

Yes, but it depends upon the design. Stainless steel is more brittle than mild steel, that means it is more likely to crack if the exhaust bottoms out. However, any exhaust that persistently hits the ground is going to fail eventually, so a manifold and exhaust that fits up snuggly close to the subframe and in the tunnel is better, whatever material is used. The other potential cause of cracking is due to differential expansion. Stainless expands more than cast iron, at around 10m/m°C x 10^-6 in the operating temperature range of an exhaust, the figure for mild steel is around seven, whilst for the cast iron of the block the figure is around six. However, on something like an LCB, where you have two long outer branches the expansion isn't a problem as there is plenty of length of tube to accommodate flexing. If the two outer pipes were short and met the centre one almost level with the ports, which you might do with an exhaust manifold for a turbo engine, then using stainless steel could be a problem.

[alan george]

hi
ta to all. I will have a look for a maniflow exhaust.

alan

[Hans Efde]

I bought this one:
http://twinkam.co.uk/Stainless-Steel-Mi ... t-Manifold
Didn't know it was longer than the Metro one, but got it to fit.

flexjoint welded on:


Looks good and is dead cheap, suppose it's made in China:


But ends up lower, so tricky with speedramps:


Also made a center support for the exhaust since with the flexjoint it sagged, the previous exhaust had a kneejoint, which is more rigid.
Bonus of this LCB is that it has holes for lambda probes. Fantastic for setting up the carburettor.

[fozzza]

How much longer is the Mini LCB, than the Metro one

[Hans Efde]

1 inch

[max midas]

I've got the Specialist Components one as well
http://twinkam.co.uk/epages/191f6b26-60 ... ucts/SC001
No cracking after at least 5 years.