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Old 07-11-07, 05:03 PM   #11
papa_lazaroo
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Join Date: Sep 2007
Location: Erdington, Birmingham
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Well as the designer who Issued the design notes to release them into the system I can tell you they were stainless, However, Many people seem to think of a Stainless exhaust as something that will be still standing after we are all dead and gone, but not so.
The Basic Construction (rover 200,400 spec)was 2 lavers of Galvanised Steel 1.6mm thick with end plates roll crimped on the ends and various dots of weld added for extra strength. (weld then ate the galvanising and began the corrosion process) I Then was recruited to switch to Stainless steel. But the finance department at Rover wouldn't fund 2 layers of Stainless, so we went with 1 layer, and thickened it up to 1.9mm. This meant there was a gap, where previous material thickness had been, so the fitment in the Jigs was nasty.
Any way, the corrosive deposits that sit in your exhaust (exhausts rust because of the acids plus condensation concentrated daily attacking them. If you do 30,000 a year your exhaust will last 3 times longer than if you do 3000) and eat away at the (Now thinner walled Exhausts) sides and so you still get corrosion, but not rust corrosion.
Rover Paid the manufacturer - Unipart Eberspacher, in Coventry, less than £20 for each complete car system, this is why although stainless it is not a thick gauge, and not a high grade. A system from Janspeed or similar will cost 3 times as much to make, but will also be something like 304 grade (harder stainless but easier to polish). Hence aftermarket ones all look shiny.Rover only ever used 304 on tailpipe trims.

Hope this makes sense.

Rob
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