Re: update: s/steel exhaust & my Pug 305 (yes I am mad)

It's only been on about 5 months so far! My first warranty check is due first week in november. BravoMan

Man, let me know how it goes. I'll be keeping an eye on mine. I must admit when it looked all new and shiney under there, I was really rather happy. However, I have a feeling that the 'brown' look is kinda natural for the outside after a while. Of course, if it breaks into a hole, you have a serious complaint. Surface rust probably wouldn't be considered a problem though, paradoxical as it may sound.

Chris.

Hang on, if its *stainless steel* then it *can't rust*. If it is rusting you havent got good 402 stainless.

Tim..

Well, it's not grade 402 stainless. Powerflow's website states that they use a combination of 409, 430 and 304 grade stainless steel. A quote from the website: 'The tubing used in most Powerflow systems is 409 grade' (...)

I found this in an article from Atlas Steels Australia, located on

'Its [grade 409 stainless steel] applications are those where appearance is a secondary consideration to mechanical properties and corrosion resistance and where some weldability is required.'

I have been unable to find anything out about a grade 402 stainless steel. Simply because a particular steel is supposed to be 'stainless' doesn't mean it won't rust. Even some of my stainless steel cutlery has started getting small spots of rust since it's been going through a dishwasher regularly. Stainless steel is basically steel that has been combined with another element (such as Chromium) to make it more resistant to corrosion and acids. That doesn't mean it *can't rust*, just that it's much more resistant than plain steel. I think a bit of surface rust on grade 409 stainless steel wouldn't be a problem. Even non-stainless steel can vary massively in terms of corrosion resistance.

Chris.

In article , lord snipped-for-privacy@yahoo.com spouted forth into uk.rec.cars.modifications...

Yeah. Mate had a powerflow exhaust made up. He said that after about 2 years it was positively pitted and flaky like a standard cheap mild steel one.

He asked about getting it wirebrushed down when he was in for the annual inspection. They said best not to, as once it has reached that stage it is protecting the steel beneath it. If you take it off, it will be thinner metal and will just do the same again.

Indeed. I've heard of iron surfaces with similar properties - let the top surface rust and the rest is OK. I must admit, I'm no expert on the subject but as far as I know, rust is an electrolytic process that relies upon water and oxygen in the presence of a metal - so if the surface has oxidised, nothing underneath will. This is a bit of a shame really - I looked at my exhaust just after getting it and it was so incredibly shiney, I rather hoped it would stay like that. It occurs to me that maybe you should wirebrush down a small area of the exhaust pipe every year after the annual inspection. that way, give it a few years and you'll probably get a hole. Time for a new pipe under warranty? ;)

Chris.

I don't see it as an issue though. People buy stainless exhausts, cos they don't need replacing. It doesn't matter one jot whether it goes rusty or not - as long as it doesn't rust-through in the car's lifetime, then it's performing it's duty just fine :)

Yup, I don't see it as a problem - rather more an annoyance as mine's still nice and shiny at the minute. I think I'm starting to get obsessive as I'm thinking of looking for some form of heat-resistant laquer I could paint it with?!! ;)

Chris.

Gah ! Just leave it alone. It's not like you can see it from outside the car anyway !

:)

????????

Which word didn't you understand ?

If you can see a car's exhaust, you're either lying underneath it, or it's

what sort of exhaust is 6 foot off the ground? lorries and such I should imagine.... tbh I thought you were talking about the backbox/tailpipe... why would anyone bother with making the middle n front shiny I dont know.

when I get my stainless Im asking for it to be completely hidden, I dont like exhausts.

The sort of exhausts that are six foot off the ground are the ones that are up on lifts in the garage ;)

And yes, I was looking at it when I was both a) on the floor and b) down a pit and, well, it just looked so shiny! Whooo! Don't worry though, I've calmed down and I haven't gone looking for appropriate heat-resistant paint ;)

Only problem with mine is the tailpiece at the back. I think they're all designed to kinda stick through the back of a bumper, wheresas mine, being an older car, sticks out noticably underneath the bumper and rear valance. Looks a bit out of place.

Chris.

thats good, cus u will have a job to find it.

does it droop towards the floor? getting it taken up may make it look loads better (without thinking of plastic surgery)

Yeah, I have to admit I've never come across heat-resistant laquer before... but then I started thinking, maybe I could get silver paint from somewhere... Anyway, it was a passing thing, I'm feeling much better now ;)

I doesn't exactly droop as such. The problem is that it actually starts out as a smaller pipe, then gets bigger at the point where it's welded to the tailpiece. Seems a bit pointless to have a big exit exhaust if it's welded to a 2" pipe after the silencer. I guess on most cars, it isn't a problem as you can't see the rest of the exhaust, but my car sits kinda high off the ground and since the exhaust has to appear from under the rear valance, from certain angles (yes, angles where you're standing normally!), you can see that the end pipe is welded to a smaller piece and it just looks... a bit stupid! I wouldn't mind so much if it stuck to the same smaller size - maybe if I'd have chosen a different exit pipe things would have looked a bit different. Whatever, I think the only solution might be to raise the pipe up a bit and cut a section out of the valance - but I'm kinda getting used to the weird looking exhaust being where it is now.

Chris.

Exactly !

Nope. But anyhow, you can't even see the backbox on most cars - just the very end of the tailpipe.

Er, that was the exact point of my post :)

But it will be hidden ! Again : "If you can see a car's exhaust, you're either lying underneath it, or it's 6-foot off the ground !" Exhausts are UNDERNEATH the car. How can they NOT be hidden ?

:)

bah! u know what I meant, pedant. :P