Stainless exhaust system for 1992 LS400?

[Spottedlaurel]

At some point I need to try and get this old thing back on the road:

It's far from perfect and it never will be, but for the foreseeable future it's the only way I can afford to keep myself in LS ownership.

I'm going to put it in for an MoT soon, I know of a few things it will fail on (or that at least require attention) and the exhaust system isn't exactly healthy. Assuming I can get the other items sorted then that is something I'd like to do properly, maybe after a bit of strategic welding/bodging of joints to get it through the test.

Previously I've used a local Powerflow fabricator for 'challenging' big Japanese cars, is that still likely to be the best way or is there a recommended specialist? The last one I had done was a single pipe system with a couple of silencers and it was £400-odd - with the LS's additional pipework and price rises since then I imagine it'll be rather more nowadays.

I suspect I will have to replace the cats too. When a coil pack failed last year they were glowing cherry red and the joints were getting rather weak. Might be some salvage value in them which can go towards paying for non-OE replacements?

Would be very interested to see/hear what others have done.

I tried doing a search but I couldn't find any recent threads on this subject, sorry if I've missed one.

Thanks.

[Howplum]

This company, MIJ Exhausts,  advertise a stainless cat back system on eBay from £500, although they are a fair way from Norfolk. If you end up replacing the cats then no doubt the nuts securing them to the manifolds will be seized, necessitating some ingenuity in removing them. Non OEM cats are available, but presumably not to the same standard as the originals. If possible all fixings should be stainless as well, for longevity (unlike the originals).

https://www.ebay.co.uk/itm/224557964475?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=8d8kaVw2Say&sssrc=2349624&ssuid=bPQ54hZdSAe&var=&widget_ver=artemis&media=COPY

[rich1068]

As always I'd recommend Tony Banks in Leeds but again, quite a distance.

[Spottedlaurel]

Thanks both! What I'm hoping is toget it roadworthy again, then travelling to get the exhaust fitted would be feasible.

I saw that ad on eBay for MIJ, based on what I paid previously I imagine it would be a fair bit more than £500 - if/when it gets its new MoT I shall have to make enquiries.

I shall also have to see who people in the local East Coast Japanese Car Club use - I suspect they'll be more performance-oriented, but still worth a try.

[Malc1]

from my experience of these cars  ................ and i had J54DAP some while back .  15" wheels too  .  same as yours maybe or has yours 16" ones ?

Anyway, the exhaust system should outlast the car .  it's tank like stainless steel APART from the front box which will rot out, about now, causing the gasses leaks you have ...  OEM not available ( well not for me anyway on my Mk3 ) and when it was it was about £6/700 .  so I got a recommended local Kent exhaust fabricator to make a new one ..........  £300 + vat .  and a good half day job 

The existing very limited cats could be simply re-used and were fine .....  and this was at 235k + miles when it was done earlier this year

The exhaust heat shields fell off some while back but they seemed to be a little superfluous anyway

Good luck

 

Malc

[BigBoomer]

Getting the CATs cherry red will not damage them. Quite the opposite in fact as that is how they clean them for reuse.
The high heat burns off any deposits that have accumulated and are clogging the CAT.
CATs do eventually wear out but it takes over 1/2 a million miles or more for the catalytic metal plating to wear off of the ceramic matrix sufficiently for them to cause an MOT failure.

As for the rest of the exhaust, get her MOTed and see if you can take a look at the underside whilst she is up on the ramp.
Chances are most of yours is fine with just a bit of repair/replacement needed.

[BrettMRC]

I had a custom CAT back system made for mine, was by the simplest and most cost effective solution. 

Be aware that whilst the OEM system is very well made, the CAT flanges do tend to rust quite badly and often need attention. 

[Mikaelse]

Be very carful when deciding what to do with the exhaust. Often mending it locally is smart I think.  Most of it will outlast the car and is of very high quality .

The front Y section though has a not so smart design with a extra layer of thin stainelss steel cover and some insulation in between. 

on my 1998 I found that I had a number of small pinholes in the tubes under those covers.  I bought very thin stainelss steel sheet metal and many stainless steel clamps and wrapped the tubes and sealed the pinholes with that. Supported the tubes also for a foot or so , roughed up the sheets surface and used muffler seal in between.  Been leak free for 5 years now. I do not expect it to last forever but probably many more years.  I also have a 1995 LS400 and that exhaust is flawless and original after 27 years .

   

 

[Spottedlaurel]

Thanks all, useful info there. Good to know that the cats shouldn't have been adversely affected, but I do recall the flanges had to be bodged previously.

Hopefully there's enough left of the cat pipework to weld new flanges on, then get a bespoke stainless part system made up to join onto the existing stainless at the back end.

12 hours ago, Malc1 said:

from my experience of these cars  ................ and i had J54DAP some while back .  15" wheels too  .  same as yours maybe or has yours 16" ones ?

Mine's an early one with 15" wheels, small brakes etc. I know the later 400s are more useable, but there's something appealing about having one in its purest form.

[BrettMRC]

This is the old girl! 

 

 

[BigBoomer]

That sound is excellent ..... apart from the fact that it is totally wrong for an LS. 🤪
I can just see some spotty yoof hearing that, turning to see the super sexy V8 monster,.... and being sooooo let down and deflated by the LS. 🤣
Let's be honest, she ain't no beefcake musclecar. 😁

[BrettMRC]

Can't believe that was 11 years ago!

After I sold that car it went on to do a charity run to the Monaco and back I think... there is a video somewhere of it on a French GP track hammering along the straight! 😄