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Discussion Starter · #1 · (Edited)
Well I finally got round to decatting the van, after the cat broke onto two - for the second time...

I'm a great advocate of keeping my van as it was intended - an EU2 Umwelt cat diesel 1.9TD (what with all my lobbying on your behalf re the London LEZ,etc). At 220,000 miles, I run it on 5w/40 PD fully synthetic C3 cat diesel oil, suitable for cat diesels and DPF's, and my van runs clean even with the turbo boost and fuel pump timing wound right up (re pp1.9). Even so I was surprised to see so much ash in the cat itself, which was still intact, which must affect it's efficiency.

All that has passed and all these efforts improve air quality have made no difference to pollution levels. Indeed the new generation diesels run hotter, generating more nitrous oxide in the air, which has health implications on a par with lead in petrol.

So, I decided it was time for a decat.

I purchased a mild steel decat pipe off Ebay from GT3 (contact [email protected]), based in the Wirral - total price including postage and VAT was £51.00.

I choose the mild steel version to the stainless one (which they also sell) mainly becuase of the price difference, but also because stailness steel is brittle and can easily fracture, especially when the van is driven hard like mine is. Front pipes and cats are known to fail on T4's. Also the exhaust note is not as tinny, and as the function of the Cat was to turn all those nasty exhaust gases to water, hopefully the rest of the system will last longer as well.

When it arrived I was totally impressed by the quality of there workmanship and the pipe was painted gun metal grey. Sure enough everything lined up so fitting was a doddle.

Removing the old pipe however was not so easy. The three flange bolts had completely corroded away and rounded off as soon as a socket went anywhere near them, and a stub was left in the centre box. However, I have the benefit of a 4 post ramp and an air compressor, so the old unit was off with some choice cuts of a disc cutter.

I can whole heartedly recommend this product, but it didn't come with new flange bolts and nuts, or a gasket, but I was able to use the old one, with new bolts and locking flanged exhaust nuts...

I have also blanked off the EGR valve and installed a second spring on the turbo wastegate, to hold it shut for longer, and I can honestly say that the turbo boost flicks up to 1 bar more readily (great for hills), and the van runs better, smoother and quieter than ever - which means it's more efficient, which means it's saving fuel.
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