Exhaust - dreaded centre pipe split

Vintagesixtysix · August 20, 2017

I've been trying to ignore the possibility of this happening, but at 12years old & nearly 100k on the clock it's no real surprise it's caught up with me.

I've read through some of the previous posts and there was a reasonably extensive one that ran around a year ago on the forum, I thought I'd start a fresh one just to see if anyone had come across a fix or recommendations for a S/S replacement & how to keep the sound right as my boy racing days are well behind me! 😇

And I'm not as handy as@IS200Newbie either.... 😢

Any thoughts appreciated guys.

Phil

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Britprius · August 20, 2017

1 hour ago, Vintagesixtysix said:

I've been trying to ignore the possibility of this happening, but at 12years old & nearly 100k on the clock it's no real surprise it's caught up with me.

I've read through some of the previous posts and there was a reasonably extensive one that ran around a year ago on the forum, I thought I'd start a fresh one just to see if anyone had come across a fix or recommendations for a S/S replacement & how to keep the sound right as my boy racing days are well behind me! 😇

And I'm not as handy as@IS200Newbie either.... 😢

Any thoughts appreciated guys.

Phil

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Phil have a word with Mij in Walsall. They were by far the best quote I got for my GS450H rear system. I did actually make up my own exhaust mainly because of a delay in getting a response from them initially due to Email problems at there end. See my post in the GS section "Exhaust problems".

John

is200 Newbie · August 20, 2017

1 hour ago, Vintagesixtysix said:

I've been trying to ignore the possibility of this happening, but at 12years old & nearly 100k on the clock it's no real surprise it's caught up with me.

I've read through some of the previous posts and there was a reasonably extensive one that ran around a year ago on the forum, I thought I'd start a fresh one just to see if anyone had come across a fix or recommendations for a S/S replacement & how to keep the sound right as my boy racing days are well behind me! 😇

And I'm not as handy as@IS200Newbie either.... 😢

Any thoughts appreciated guys.

Phil

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AW come on ... its an easy job...

Seriously tho - this is the exact spot my original one went at - a bit disconcerting when it fully goes as most of the power is lost and it sounds like a tank !

I could suggest a few options:

Repair the hole - I did do a very good job in repairing it myself when it went first and I posted up on the forum the parts I used so you may find it from around 2 years ago (or so) I eventually decided to get a stainless steel one as I did not trust my repair but when the exhaust centre took the centre box of, the repair I done was absolutely solid and would have lasted a very long time. I cant find any pictures I took for the parts sorry.

Weld the hole up - may be a difficult job due to the corrosion on the metal and its position but should be doable but will need a good ramp to do it that way

Stainless steel system - Will cost you around £400 to £600 but be very careful to chose a good manufacturer as these SS exhausts can be noisy in the cabin as I experienced

Lexus fitted one - Will set you back probably around £1700 to £2000 fitted. I am sure they also need to replace the down stream O2 sensors when doing the exhaust.

eBay - these come up frequently on that site and there are two on at the moment - one used at just under £200 and a new one (non oem at just under £400)

Make your own ??!!

If you want to adapt a part to replace this then use the is200 resonator as its a good fit but will need to be cut to fit the one on your car. If you are willing to get your hands dirty there are a few options.

One thing to consider - the two O2 sensors on the centre section run into the cab - I believe they go under the drivers seat and removal of the sensors on the exhaust, so I have been told, needs a special tool (not looked into that to be honest) so its feasible that you will need two new sensors if they are damaged upon removal from your system if replacing the centre section.

If its the centre section you are set on replacing I would ask the exhaust centres such as ATS if they would be willing to accept delivery of a centre section if you bought it from the likes of eBay and ask if they would be willing to fit it. I shouldn't see why not as they do exhausts day in day out.

Linas.P · August 21, 2017

Considering age and value of the car I would really look again into points 1 and 2 from @is200 Newbie post above. That the case unless you planning to keep car for another 10 years.

tim1830 · August 21, 2017

hi Vintage,

we had a quote for our RX400h, £1000 for just the part, luckily the local garage that had it said they thought it was worth trying to weld.

Charged me £70 i think, and that was 3years ago, so def worth a go

Vintagesixtysix · August 21, 2017

Thanks all for thoughts and recommendations.

Technically I've got until mot time in Jan to sort this but as the pipe is comprised from around 3 - 7 o'clock it's going to need to be sorted sooner rather than later.

It has made me think about how long I'm going to hang onto it but I do love chugging around in the old beast.

It's also got very very slow DMF (manual box) wear creep which is another £1000 to sort when it finally if ever goes.

Ive recently thrown a load of dollar at new discs pads all round and she does still runs sweet as a nut.

I'm going to get it up on the ramps again and have a look at repair but also as I'm in the West Midlands .... automotive heartland I'm going call pop into a few fabrication places and just see if anyone's up for a bespoke fix.

In relation to above has anyone got a drawing of the exhaust system so I can go forearmed with info.

Can I also just confirm if I find a way of getting some kind of metal/welding repairs done to that localised area.... I shouldn't have to worry about the sensors up stream?

Cheers

Phil

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johnatg · August 21, 2017

Here's an exploded pic of the whole exhaust system, connections and fittings:

http://tinyurl.com/yag975wx

Vintagesixtysix · August 21, 2017

Thanks John, hope your well.

Phil

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Vintagesixtysix · August 21, 2017

Thanks Tim that's encouraging,

I'm defo going to tout it around a bit and see.

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Vintagesixtysix · August 21, 2017

Thanks John@britprius I've read your thread over on GS section also .... hats off to you &@IS200Newbie for your resourcefulness on respective vehicles.

All I've got is a junior hacksaw and a black & decker workmate so probably not quite in the same league 😜.

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Britprius · August 21, 2017

10 minutes ago, Vintagesixtysix said:

Thanks John@britprius I've read your thread over on GS section also .... hats off to you &@IS200Newbie for your resourcefulness on respective vehicles.

All I've got is a junior hacksaw and a black & decker workmate so probably not quite in the same league 😜.

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Your one up on me I haven't got a Black and Decker workmate. I'm jealous.

John.

Vintagesixtysix · August 21, 2017

Not an answer to my post issue ...

Found this as replacement back box, just for reference.

https://www.onlineautomotive.co.uk/Products.aspx?ID=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&gclid=EAIaIQobChMIlL-_k6fh1QIVorftCh2RDAR0EAQYAiABEgJUufD_BwE

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johnatg · August 21, 2017

And this - the whole 'centre pipe' ('front exhaust assembly') for £350!

http://tinyurl.com/ycbh8sr8

Can't imagine it's anything like Lexus oem quality, but it's a hell of a saving!

Vintagesixtysix · August 21, 2017

So looking at the drawing...

Discounting the manifolds, the system is in three pieces?

Please check my thinking.

Manifold to cats... centre piece to after middle box ( where mines cracked) ...... finally to back boxes and tips?

If I was going to get just the middle section made up S/S mild or whatever would that suffice or would there be issues?

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johnatg · August 21, 2017

No four basic pieces. One piece from each manifold (left and right) - (just plain pipes attached to the manifolds, ending in flanges to which the rather complex 'front exhaust assembly' (refer to the workshop manual drawing I referenced earlier) attaches), the 'front assembly' and the 'rear exhaust assembly'. The cats and the resonator are included in the 'front exhaust assembly'

Vintagesixtysix · August 21, 2017

Got it... thanks John & also for link.

I dismissed it.... even though it was staring me in the face...thought it was just cats.

Interesting option & may do if not keeping for anther several years.

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is200 Newbie · August 21, 2017

25 minutes ago, Vintagesixtysix said:

So looking at the drawing...

Discounting the manifolds, the system is in three pieces?

Please check my thinking.

Manifold to cats... centre piece to after middle box ( where mines cracked) ...... finally to back boxes and tips?

If I was going to get just the middle section made up S/S mild or whatever would that suffice or would there be issues?

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When I was looking originally I could not find anyone to do a centre section - the company I went with would not touch it due to the cats - like John said above its a complex setup.

Also you need to be careful in having a centre section manufactured, non oem, as you would need to carefully match the cats to retain the back presuures etc in and out of the engine as I believe its a balanced system. You may have issues with the running of the car also due to possible conflicts between the sensors both pre and post o2 ones.before and after the cats?

If you have one manufactured then I would expect it to be more expensive or around the same price as the one being advertised currently on eBay - when you consider the OEM Lexus one is around £1700 then the one on eBay at just under £400 is good value especially for an oem one.....

johnatg · August 21, 2017

I think I'd be inclined to go for it (the Online Automotive one). I suspect the crack you've got (others too) is basically a fatigue crack due to slight flex stresses on that bit of pipe as it emerges from the resonator, due to there not being any separate supports for the front exhaust pipe assembly. It might be worth getting a support strut welded on from the bottom of the resonator to the flange (if there's room and as long as it doesn't disrupt the smooth fitting of the flange to the rear section). (That would make a very stiff triangulated set up - I've had it done before when getting stainless steel silencers made - the pipes at either end are inclined to crack as described but the actual silencer boxes will last forever)

The front section of exhaust pipes tend not to corrode too much because they run really hot. It's the rear sections and silencers which rot as they run much cooler. Quite a lot of exhaust failures are due to fatigue cracking caused by flexing rather than actual corrosion, especially these days when exhausts seem to be made of better stuff on the whole than in previous times.

The £400 eBay one seems to have been removed from sale.

WetMyBeak · February 7, 2018

On 21/08/2017 at 6:11 PM, is200 Newbie said:

When I was looking originally I could not find anyone to do a centre section - the company I went with would not touch it due to the cats - like John said above its a complex setup.

Also you need to be careful in having a centre section manufactured, non oem, as you would need to carefully match the cats to retain the back presuures etc in and out of the engine as I believe its a balanced system. You may have issues with the running of the car also due to possible conflicts between the sensors both pre and post o2 ones.before and after the cats?

If you have one manufactured then I would expect it to be more expensive or around the same price as the one being advertised currently on ebay - when you consider the OEM Lexus one is around £1700 then the one on ebay at just under £400 is good value especially for an oem one.....

Newbie, I have a horrible feeling my centre section has gone in the same fashion as yours and the original posters. How did you get around not having the cats messed with? I was planning to go to JP exhausts as Johnatg suggested and was hoping it would be straight forward. Any info appreciated

johnatg · February 7, 2018

It might be worth trying to get the crack welded up - should last for quite a while.

Otherwise, I think JP would be able to cut the pipe just in front of the resonator, either before or after the Y section, makeup a new resonator and reassemble. It could be made in stainless and sleeved onto the remaining front pipe. As I mentioned above it would be worth getting a brace fitted between the bottom of the resonator at the back end to the front of the flange - that would provide triangulated reinforcement to the pipe where it emerges from the resonator.

That shouldn't cost a fortune, especially if there's room to cut the pipe behind the Y section so that they just have straight inlet and outlets to the resonator to deal with, and would be a good long term solution.

johnatg · February 7, 2018

Looking at the drawings of the pipes again it occurs to me that the things in the front exhaust assembly which look like cats can't actually be cats - the cats are incorporated into the exhaust manifold assemblies - see here:

You'll see that the air fuel ratio sensors are in front of the cats and the heated oxygen sensors (which check on cat performance) are in the front exhaust pipe assembly but in front of the bulges which people posting above (including me) have assumed are cats.

So if the 'bulges' aren't cats, what are they? Just expansion chambers?

WetMyBeak · February 7, 2018

John, thanks for all your help. I took my car to my local mechanic and turns out the drivers side back box was loose. Anyway, he said I’d be fine to leave it until Friday morning and with a bit of grinding and welding it would be a easy repair. Two miles down the road the box dropped down and dragged on the road. Thankfully I was driving slow at the time and I managed to fashion a harness out of one of the material handles off the cubby holes in the trunk. Anyway it’s in the garage now so hopefully will be sorted later this afternoon. I’ll say it again, - many, many thanks to you and all the other brilliant posters on this forum. It’s such a useful resource and all the members are so pleasant which can be quite rare on an Internet forum/messageboard. I’ll get you a pint at the 2018 LOC meet up!

KenMavor · February 7, 2018

5 hours ago, johnatg said:

Looking at the drawings of the pipes again it occurs to me that the things in the front exhaust assembly which look like cats can't actually be cats - the cats are incorporated into the exhaust manifold assemblies - see here:

You'll see that the air fuel ratio sensors are in front of the cats and the heated oxygen sensors (which check on cat performance) are in the front exhaust pipe assembly but in front of the bulges which people posting above (including me) have assumed are cats.

So if the 'bulges' aren't cats, what are they? Just expansion chambers?

The bulges are cats I'm afraid. There are 4 in total. I got a stainless steel cat back done. Leaving the sensors and the two cats in place but everything else is replaced.