I need new cats, mine are broken and exhaust blocked one side.

[andyp250f]

To bury a myth. Cats, exhausts etc. are NOT rocket science. I say this not as an uninformed internet nerd who has just read "something" on a site somewhere. I say it as a maker of stainless exhausts, mainly ferrari, but more or less anything. I dont make "Cats", and no-one I know does. We all buy them off the shelf according to spec, and what the application is.
Yes, I admit there is a skill to making exhaust systems work effectively, however, (in my opinion) a lot of what I see is worked out cost wise according to the "badge" on the bonnet, not the some of parts, labour etc.

 

[BJL]

Well said.

A voice of logic and practical knowledge..... breath of fresh air no less.

 

[Mr.Cambio]

Agree Andy. The main secret behind the brand is the specification of an exhaust, not building one. If someone has specific stainless steel thickness, or other specs, then he can build one. But who has this info?

 

[andyp250f]

A fair point. I am not for one minute suggesting its a DIY job, however, I do feel that Certain companies "cash in", on the assumption that people with expensive cars expect to pay a fortune for parts that in reality cost no more to produce than lesser brands. Again, its just my 10 pence worth. Its not the way I work, and even though I supply 458 race exhausts, which have been fitted to winning cars, I dont double my prices off the back of it.

 

[BRR]

Spoke to MIJ today who said they could fit me a pair of 200 cell sports cats for £500, seems good value to me

 

[QP4Me]

Hi,

On a general note, whats the expected, average, lifespan of the cats?

 

[Parisien]

Supposed to be lifetime of car...........but am sure ten years min.

Difficulty is these are ceramic and way too low down....clips anything and everything on the coupes, not sure its an issue on QPs though

P

 

[Mr.Cambio]

Lifetime?? When i had the Saab, they told me the cats are good to be replaced every 120000 kms. Never did it, cause i upgraded it only.

 

[Mr.Cambio]

In general, i think that in every car a cat replacement is an expensive job, no matter if it is for a Toyota, a Hyundai or a Lambo. Cat manufacturers know that a car cannot move without an exhaust, so the cat price statistically is not cheap.

 

[Fossy]

Well, bit of a shock to empty the pipes and have this lot fall out of them.






But it did confirm the problem. Never thought it would happen to me, just read about it happening to others ..?

Well, i've gutted both fronts now and cut off the rears before they go boom, and TIG welded a pair of 200 cell stainless metal core cats in their place, with the rear sensor boss in-situ, and all look good. Spotted them all in place on the car as I went, so have turned out perfect, just got to do last bits and try her out.

Hope I didn't offend anyone with my last post, but I got a rant on after contacting a few exhaust people, inc. the Maserati genuine route, and left me quite boiled. Sorry.

 

[2b1ask1]

Kin ell Fossy.....



That is a shocker!

 

[Parisien]

They look like something from the Pompeii exhibition.....shocking!!!!


P

 

[CatmanV2]

All that platinum!

C

 

[adam01]

Fossy
Can u load pics. of the solution ie SS welded

Txs

 

[Fossy]

Also I found out the main reason the ceramic cats break up (apart from damage and fatigue).

If you use the car for short journeys during winter time, the front ones especially become full of condensation from the short run, then hold the water for ages as they are just porous soft plaster, then -3 degrees comes along and freezes them, and blow apart they do. This is what happened to me as the last time i used it was shops and back round the corner, then we had a -5 overnight, and next time i started it, both front cats were totalled.

Just a heads up really.

 

[adam01]

Also I found out the main reason the ceramic cats break up (apart from damage and fatigue).

If you use the car for short journeys during winter time, the front ones especially become full of condensation from the short run, then hold the water for ages as they are just porous soft plaster, then -3 degrees comes along and freezes them, and blow apart they do. This is what happened to me as the last time i used it was shops and back round the corner, then we had a -5 overnight, and next time i started it, both front cats were totalled.

Just a heads up really.

Great piece of advice Fossy,never occured to me, less of a problem down under but i'm sure usefull in the colder climates

 

[conaero]

Speaking to Mathew at Giallo yesterday about cats. I have a fault in my secondary air system. I must confess I dont know much about this system with the exception of the valves on a GS. I thought it was vacuum driven but I was wrong.



The secondary air system is to cool the cats and only usually cuts in upon start up. Its the hoovering sound you hear. Its not vacuum driven but from a pump on the aux belt system.

This could be why if it fails, your cats break up on short journeys...its a possibility. Just check you get the hoover sound on start up. Common is for pipe 4 to corrode or rub or the hoses to fail or the pump leaking at the rivets that holds it together.

 

[CatmanV2]

Also I found out the main reason the ceramic cats break up (apart from damage and fatigue).

If you use the car for short journeys during winter time, the front ones especially become full of condensation from the short run, then hold the water for ages as they are just porous soft plaster, then -3 degrees comes along and freezes them, and blow apart they do. This is what happened to me as the last time i used it was shops and back round the corner, then we had a -5 overnight, and next time i started it, both front cats were totalled.

Just a heads up really.

Oh dear! Do we know what the definition of short journeys is in this context? I normally do about 8 miles each way in mine. I would have *thought* that would get them hot?

C

 

[CatmanV2]

What sort of hoover, Matt? Ive not heard anything that I can think of that would fit that description.

C

 

[Fossy]

Speaking to Mathew at Giallo yesterday about cats. I have a fault in my secondary air system. I must confess I dont know much about this system with the exception of the valves on a GS. I thought it was vacuum driven but I was wrong.

View attachment 14515

The secondary air system is to cool the cats and only usually cuts in upon start up. Its the hoovering sound you hear. Its not vacuum driven but from a pump on the aux belt system.

This could be why if it fails, your cats break up on short journeys...its a possibility. Just check you get the hoover sound on start up. Common is for pipe 4 to corrode or rub or the hoses to fail or the pump leaking at the rivets that holds it together.

Thank god you told me this. No joke, i've owned my 4200 for ......guessing over 6 months now, and only yesterday since doing the cats did it start making this excact noise. I thought it was the fans kicking in for some reason, and was going to call Mathew tommorow about it (he's looked after mine since i've owned it, and all there are very nice).