Wbx exhaust- how rigid are they?

[slowcoach]

I've a Subaru engine, but I'm in the middle of re jigging my exhaust because of a few cracks over the 8 years having it.

I can't really remember from my old wbx, but how rigid are they to the engine? There are no flexy joints are there. Is there any provision for expansion and flex, or are they bolted down good n solid? Are they just hung from the manifold studs and silencer? Hard to find much info on rear engined exhaust setups in this regard.

Thanks all

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[MarkHughes]

I fitted one of these to mine a few years back.

https://vwspeedshop.com/product.php?pro ... 513&page=1

As you can see, No flexi joints or anything, As long as it doesn't touch the body anywhere and is well supported it can be fixed rigid.

As I thought about it I realised my Skyline also has no flexi joint, The pipe is rigid fixed from the turbo back and it all hangs on a few rubber hangers. Where in that situation you would expect a flexible joint near the front to allow for both movement but mostly NVH isolation.

I am drifting off topic

 

[maxstu]

Early version exhaust did have support bars. But rarely seen nowadays. So weight taken on the cylinder head exhaust manifold studs or bolts. All swings together.

Later version exhaust is isolated by engine bar and carrier rubber engine mounts. Or is it?

Will have to pop out and take a look after rain stops.

[Robsey]

Someone mention the early exhaust with steady bars mounted from the cylinder heads?

Here is my exhaust waiting to be fitted to my DJ.

It will be a 2.1 litre version of the DH / GW early digi-jet.



No flexy's on the WBX engines in my experience.

[Aidan]

I believe only the Syncros early style exhaust was fitted with the support bar because a. 4x4 and b. had cast 90' knuckles (so heavier overall and more leverage) to tuck the exhaust back box up higher relative to engine as engine is 50mm lower

The late style Wbx exhaust headers have a plate clamp mounted to the front of the engine and a a triangulated support mounted to the left side lower engine stud and another clamp on the rear cross pipe which is attached to the engine mount and the whole back box is mounted to the saddles which are fixed to the engine mount, so the whole exhaust is attached in multiple places to the engine and engine mount which itself sit on rubber mounts on the engine support bar

As long as you can attach the back box rigidly to the Subaru engine then you are sorted, that's why Small Car in the states and LMBtechnik in Germany make their Subaru engine mounts to mimic the Wbx engine mount and sit on the Wbx engine bar, the small car headers were designed to utilise the Wbx back box; there is an issue using the RJES engine bar that there is no provision for exhaust mounting and support, and the back of the engine is a plastic cam cover, so you end up needing to hang the exhaust off bespoke bracketry attached to the auxiliary brackets or their securing bolts on top of the engine

flexis can be helpful in allowing expansion and contraction due to temperature especially in systems with tight bends and in stainless systems - VW used good quality mild steel for the Wbx exhaust systems because it is less prone to cracking when it moves repeatedly and added the extra supports to limit movement and vibration in the long runs of pipe. The VW Longlife back boxes were really well made and would usually outlast the rest of the system, unfortunately they are nla and what is available new now is not as good

[slowcoach]

Thanks everyone! Good info all round. Sounds like rigid is the consensus so far. I had two flexis waste away in pretty short time, which I think were under strain and perhaps too close to the manifold (too hot for them?) . They were bad quality stainless too (very magnetic!) Anyway I'm doing away with those and replacing with sleeved rigid joiners. I'll try my best to have everything aligned well and beef up the hangers to take out any wobble.

Hangers as you say Aidan are from the alternator and power steering mounts. Something from underneath to the silencer brackets would really help.

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