Manifold to Cat join conversion to v band?

[Matthew_]

Hoping someone with more knowledge or experience than me can help.

For context I'm currently running a standard 182 manifold and cat as far as I can tell.

It's using the standard mounting & gasket system between them but it's awful, I've replaced all the components but the cat still just sags and makes my exhaust look like a V shape under the car which means Im scraping the cat on speed bumps etc

I wanted to move to a v band system for the join to make it run straight under the car which I've seen threads on here where people have done it however I was hoping to keep the original cat which is where my problem is.

The threads I've seen show a Flexi being added after the v band in the section where the cat would be as by adding the v band join youve removed the flexibility the OEM exhaust gasket gives the exhaust for when the engine moves.

So my question is do I need a Flexi?
Has anyone had any experience or done this exact job of converting to v band and keeping the cat and if so how?

Or any other help, suggestions or advice would be much appreciated

 

[Matt Cup]

I’d just take it over to JP exhausts in Macclesfield and let them sort it out. Surely it just needs a sleeved section adding to the mid section? Which I’m sure was a common mod done on here?

 

[Louis]

Your problem is after the cat, but the prejoint always leaks too.

 

[OssPoop]

Before and after on my old 182.

Oe cat replaced with one that worked and the flexi moved too.

 

[Louis]

Better having the flex on the cat though so it can be dropped to be replaced easily

 

[OssPoop]

Probably. Blame the super dooper exhaust place for fitment though.

 

[Mertin]

Im running a v band on my 182 manifold with a sports cat installed. No flexi. Used for sprints / hills so low miles but plenty abuse and not had any issues. Has been like that for around 7 years now.
Its sleeved after the cat

 

[Matthew_]

I’d just take it over to JP exhausts in Macclesfield and let them sort it out. Surely it just needs a sleeved section adding to the mid section? Which I’m sure was a common mod done on here?

Thanks for the recommendation, I will give them a call and see what they can recommend, I'm pretty sure my OEM cat has had the PMS Cat derestriction kit on it and so my exhaust has got a small join pipe from the cat to the centre section which probably isn't helping the situation either, so I definitely need to get that sorted as well.

Your problem is after the cat, but the prejoint always leaks too.

Yeah after the cat is the lowest point on the car but the cat to manifold join seems to be where the droop is starting. I had the leaking cat to manifold join when I bought the car and have fitted a new gasket so got rid of that issue but an exhaust should definitely not droop like this. This is the current state of the cat to manifold join which is another reason why I want the v band to replace all the rotten bits.

Before and after on my old 182.
View attachment 1802478
View attachment 1802479
Oe cat replaced with one that worked and the flexi moved too.

Amazing thank you I like this idea to fit the flexi then go into the cat. I will go and look at the measurements to see if this will fit with the exhaust components I have but don't see why this shouldn't work. Is that flexi welded to the manifold?

Im running a v band on my 182 manifold with a sports cat installed. No flexi. Used for sprints / hills so low miles but plenty abuse and not had any issues. Has been like that for around 7 years now.
Its sleeved after the cat

Ah right ok thanks really good to know. What engine and gearbox mounts are you using? are they solid?

 

[Mertin]

Yeah Im running vibratechnics mounts and powerflex dogbone. Just away to change them to PMS ones
Also running the BTT motorsport polybushed exhaust mounts to replace the poor standard ones so that helps keep it in place

 

[Matthew_]

Yeah Im running vibratechnics mounts and powerflex dogbone. Just away to change them to PMS ones
Also running the BTT motorsport polybushed exhaust mounts to replace the poor standard ones so that helps keep it in place

Ah right ok thanks, I'm running OEM gearbox mount and then power flex dogbone and engine mounts