Stainless Exhaust Systems - Dizzy {P}
There was a thread in the old forum on stainless steel bolts, with some excellent advice given, especially from FiF who pointed out that there are fundamentally different types of stainless steels and that some (the ferritic type) will in fact corrode. FiF recommended using a magnet to check that the stainless steel is not of the ferritic kind if resistance to corrosion is important.

This magnet test can also be applied to stainless steel exhaust systems. The cheaper ones are ferritic and WILL corrode in time, these usually being in a grade known as Hyform. It will probably be some years before they corrode to a point of failure but they can soon become subject to surface corrosion and this is irritating when it appears on the tailpipe that was so nice and shiny when you bought the system.

The better systems are in austenitic grades of stainless steel such as S309 and especially, but much more expensively, in S321 (I hope my memory is serving me correctly on these grade numbers!). Several exhaust systems on the market have S309 silencers and Hyform pipes which is a reasonable compromise where the main purpose is extending the life of the system to, say, ten years instead of two and surface corrosion is not of concern.

Whatever the grade, it is vital to maintain the exhaust mountings in good order otherwise the system will suffer from stress-related failure.

Hope this helps someone sometime.
Stainless Exhaust Systems - Dave N
Very true about the different types of stainless used on exhausts. On my Land Cruiser stainless exhaust I got from Rimmer Brothers, the pipes have corroded, but the silencers boxes haven't. When I asked Rimmers about this, they said they take a chance on the pipes, despite having a lifetime warranty, that they won't corrode right through during the time you keep the vehicle, but they don't take any chances with the silencer boxes. I also asked them why the flange that bolts to the turbo is mild steel, and they reckoned it had to be a similar material to the turbo, otherwise differing expansion rates would cause problems.

So the conclusion is, if you want an exhaust that won't corrode, buy one made entirely of the better stainless. If you want one that will corode, but will probably take ages to fail, buy a cheaper one.
Stainless Exhaust Systems - Dizzy {P}

I had severe problems with a system obtained from Rimmers for my Triumph 2500. Apart from the attrocious mis-shaping of it, which meant a lot of heating and bending to get it to fit and re-drilling of the downpipe flange, it came with Hyform 409 pipes even though I had ordered the whole system in S309 and had asked for, and received, written confirmation by email beforehand that the system would be only in S309 and not contain any Hyform 409 at all. The pipes on the system that arrived were even printed continuously with the words "Hyform 409" so there was no excuse!

I couldn't wait the six weeks delivery time for a reputable manufacturer (Double-S) to supply a proper system so I accepted some 'free' parts from Rimmers in lieu of a partial refund.

The point of this message is to stress that, if at all possible, see the system and apply the magnet test before buying!

Regarding the mild steel downpipe flange that your system is fitted with, this is quite normal and acceptable. I would not worry unduly even if the whole of the downpipe was in mild steel as this end of the system is very slow to corrode. I do not believe, however, that the reason for the mild steel flange is to avoid differential expansion ; I would say it was only a matter of economics of manufacture, stainless being expensive and relatively difficult to machine.
Stainless Exhaust Systems - Flat in Fifth

Nice to see you back on the forum, albeit with a new moniker, and thank you for the comments you are really too kind.

Your comments are correct in a number of ways, and may I add more points.

Hyform 409 is a ferritic stainless as you say with not much more than enough Chromium in it so that it can be called stainless. It will discolour and corrode even just in exposure to the atmosphere and of course is strongly magnetic.

309 is a much more corrosion resistant alloy, ~23 % Cr 14 % Ni and you can get welding consumables to suit. It is fully austenitic as annealed but becomes very slightly magnetic after any cold work, so the magnet test will show slightly positive near bends, flanges and so on. So that point needs to be born in mind.

Also your comment about mounting is again spot on. The big enemy of stainless systems is vibration and the system moving so that it work hardens and eventually you get a crack.

If I can take a small issue with your comment about stainless being much more difficult to machine, and I am being careful here as I do not want to be accused of abusing the site through advertising. Today one can obtain improved machinability grades of stainless, with corrosion resistance the same as the normal grades. The old free machining grade 303 had very inferior corrosion resistance but product today is excellent.

In the 60s & 70s the machining speed crept up from about 60m/min to just above 100. Today we are machining at >225 m/min and approaching 250! I could provide a link to the website but out of respect I won\'t as its off topic, but if anyone wants more info I\'m happy to provide the detail, the links and the contacts.

Best regards,

Email :
Stainless Exhaust Systems - Flat in Fifth

1) All the apostrophes put up the strange text above?

eg I ' m became I’m (the spaces were not in the original)

2) The full message will not show in the preview, it stopped somewhere about 225 m/min.

Is this a demon ruse to make me precis? A cunning plan Baldrick!
Stainless Exhaust Systems - M.M
I'm sure I'm not having trouble with I'm!

You have chanced upon a tiny issue with the preview window though. My explanation is that the facility was intended for average length forum posts, not writing a novel ;-)

I will flag it up on a bug report, thanks.

David W [Moderator]
Stainless Exhaust Systems - Flat in Fifth
I'm not going to harp on about it, because I'm sure you will find I'm also having trouble with other things, won't you?
Panto season - Flat in Fifth
Oh no I'm not!

Maybe it was due to the other issue on preview, sort of knock on effect? teach me to click post instead of preview anyway, sorry.

Stainless Exhaust Systems - Mark (RLBS)
Sorry to butt in.......

FiF, the problem is that those are not apostrophe's that you are using. They are another character which may or may not be interpreted correctly.

Notice how for me its ok ?

Apostrophes - Flat in Fifth

seeing as its boring at the moment on your side of the fence I've come back over here ;-)

I assume you have edited the original long post which gave the trouble.

That was on another PC, so I'm not sure what you mean by those were not apostrophes.

what were they then? I'm sure I used the key to the right of the semi-colon, colon key? I'll check tomorrow.

Apostrophes - Mark (RLBS)

That is a column of three characters which all look like apostrophes on my keyboard, and in word-processing software or e-mail would all come out as apostrophes.

However, if you look closer you can see that they are different, and under some situations, some of them don\'t work. I always assumed that it was because I was typing English on a Portuguese keyboard, but now I wonder if it is the same issue you have.

And what do you mean boring, the speeding thread has started.
Apostrophes - Flat in Fifth
Whats the alt codes for these as I only have the ' key.

are the others accents grave and acute? I'll reboot and look in the keyboard map.

No time to visit the speeding thread, too busy checking HJ's weblinks. At least I found someone who has as many typos as I do.

Apostrophes - M.M

You on some sort of death wish? (I may remove this later!)

David W [Moderator]
Apostrophes - Flat in Fifth
You on some sort of death wish? (I may remove this
David W [Moderator]

Not really DW, just seemed to me you lads have your hands full and I can spend a happy hour following the links (or not) before Teachers comes on.

If the results of my efforts means I get a call from Vlad's Mum and the gang, no problem. If I can sort out our attack rabbit HJ's easy peasy ;-)
This Apostrophe thing!!!! - Flat in Fifth
Answer to this apostrophe thing, not that anybody is interested.

I seem to get a different response with the apostrophe key dependant upon whether the laptop is docked or not. Docked its a normal 102 windows keyboard, and with NT one is not able to edit the map.

The conclusion I come to is that certain characters create some sort of conflict in the code? Plus it is not just me, also see Smart antics thread on t'other side of the fence.


‘ = keystroke ´ (ie the key to the right of : ; key )
` = keystroke ` (ie the key to the left of 1 on the top row)
‘ = ALT+0145 (which should give `)
’ = ALT+0146 (which should give ´)
´ = ALT+0180

' = keystroke ' (ie the key to the right of :; key)
` = keystroke ` (ie the key to the left of 1 on the top row)
then ASCII Codes
‘ = ALT+0145
’ = ALT+0146
´ = ALT+0180

This Apostrophe thing!!!! - Marcus

This was typed direct - not 'cut and pasted'!

This was typed in MS word – and ‘cut and pasted’ into the post!

inserted below was the text above copied an pasted

This was typed direct - not 'cut and pasted'!

This was typed in MS word – and ‘cut and pasted’ into the post!

This Apostrophe thing!!!! - Marcus
My problems are caused my typing in MS word and cut and pasting into this box. Thus

- - 'cut' becomes - - ‘cut’

or does it?
Keyboard errors. - M.M
Oh yes we are interested! Thanks for doing the tests guys. I'll paste in your findings and mail it to Stephen.

David W [Moderator]
Speeding Thread Started - David Lacey
"I couldn't wait the six weeks delivery time for a reputable manufacturer (Double-S) to supply a proper system"

Ah, just down the road from us, in Cullompton!
Back to Stainless Steel Exhausts - Dizzy {P}
David, some 'local' questions to which you may or may not have instant answers ...

Aren't GFL Exhausts, who make the systems for Rimmer Bros (or at least did so 5 years ago) also in Cullompton or thereabouts?
I assume that GFL was formed by a breakaway group from Double-S?
Are GFL still in business and what is their reputation down your way?

I am not expecting to buy another stainless system for a few years but have a general interest in what is happening in that market. I know that Double-S had expanded into the USA and I expect they are doing quite well, given their good product and equally good service in my experience.
Back to Stainless Steel Exhausts - David Lacey
Dizzy - there is a company called Guaranteed Exhaust Systems situated at Willand (Which you drive over when driving down the M5 Southbound between J27 & J28) This is less than 2 miles from Cullompton.

I had an exhaust made there 4 yrs ago and was very pleased with the quality etc and the service was good, too. I'm 99% sure they do indeed supply Rimmer Bros. Found this contact info on the web:-

Guaranteed Exhaust Systems Ltd
Unit 4/5 Willand Ind Est
South View
EX15 2QW
Tel: 01884 821237

There's another Stainless Steel Exhaust manufacturer on the Kingsmill Industrial Estate in Cullompton, too. I think they are called Phoenix Exhaust Systems, IIRC.

I couldn't find any contact info. Next time I'm down there I'll check for you.

Quite why there are so many stainless exhaust manufacturers within 3 miles of each other.....any ideas?

(I think I may know the answer, it's been hinted previously, see above!)
MG-Rover Questions? Click on
Back to Stainless Steel Exhausts - dan
Had to re-register to get back. Like the site but the frameless frames flicker constantly.

Anyway TKTopGear of St Albans, London Rd also make custom exhausts, made to your requirements guaranteed for life. (Which sounds impressive until you realise that your car's probably scrap in 10 years anyhow).

Prices comparable to stock non-stainless parts and although one suspects that Max Power readers make up the bulk of their customers, l would recommend them for any car.

Back to Stainless Steel Exhausts - Dizzy {P}
Thanks, David. I now recall that it was "Guaranteed Exhaust Systems", not "GFL". "GES" was on on the label of the system that I bought from Rimmers even though Rimmers had previously told me that "we make our own, so we know what they're made of".

I would personally still use Double-S as they gave me exceptionally good service with two different systems that I bought from them and I know that they made quite a substantial loss on one of them, as related below ...

I met Double-S at their stand at the (1992?) NEC Motor Show and asked them to quote for my 1981 Vauxhall Royale Coupe. They didn't have a price to hand to quote me so they gave me an estimate. I immediately asked to place an order since the estimate was around £250, almost £1000 less than I had been quoted elsewhere for the twin-pipe, multiple-silencer, multiple-bend system! I was then able to overhear the enquiries that they were making and it turned out that they would have to buy a standard system as a pattern and this would cost them more than they had estimated for supply to me of the complete stainless system! However they insisted on keeping to their estimate ("our mistake, not yours") and delivered a superbly made stainless system on the promised day.
Back to Stainless Steel Exhausts - John S

GES made the S/S exhaust for my Minor, supplied via the MM Centre at Bath.

Certainly seems well made, heavy gauge material and a good fit.

I've not had it long enough to comment on longevity.


John S
Back to Stainless Steel Exhausts - smokie
Just enquired of Jetex who say their coding is the "equivalent of T301 which is very high grade" (as they are Swedish they do not use T-coding).

Is this good or bad? Certainly prepared to do me a very reasonable price...
Back to Stainless Steel Exhausts - SjB {P}
From experience, I second Dizzy with respect to Double-S.

Some years ago, I ran an MG Metro, and when the standard exhaust failed, I replaced it with a Double-S item purchased though the MG Owners Club. The price, at the time, was not much more than an original fit replacement

Some time later, the flexible joint just after where the downpipes met, failed.

I contacted Double-S, and it was replaced without question.
I then ran the car for another six years, and when I sold it, the exhaust was almost like new: Wipe it with a cloth, and it came up shiny, even on the centre section when I tried, having been amazed at the health of the tailpipe.

Another three years later (My venerable MG Metro was by then eleven years old), I chanced upon my previous pride and joy in a car park.

The car was a heap.

Rust everywhere.
Kackered wheel rims.
One bald tyre.
Broken aerial.
Broken parcel shelf.
Torn seats.

But the Double-S exhaust?

Like new! :-))

Back to Stainless Steel Exhausts - smokie
Double-S don't do one for my car unfortunately.
Back to Stainless Steel Exhausts - Dizzy {P}

I was surprised at the very limited range of Vauxhall systems shown on the Double-S website but they do say that they can make a system for non-listed cars. Obviously this would mean a bit of a wait; this was '4-6 weeks' when they made my very complicated Royale exhaust some years ago.


Value my car