Catalytic Converter Query

[rapidtornado]

Not a whiz on all things exhaust so thought it best to ask the experts....

Taken my exhaust off the donor this weekend, the cat conv looks a bit bulky and I was wondering if I could use a cat from a different vehicle on the roadster instead of the donor cat?

I'm just wondering if the cermaic honeycomb is specific to the car or is it age related i.e. I could take the cat off say a rover 416 and use with my twinky engine

Any advice would be appreciated as always

Cheers
rapid

[Tatey]

Have you considered using a motorcycle exhaust silencer with an inbuilt cat? As it means that you wont need to have a separate cat hidden somewhere else on the car.

However depending on the exhaust length this may affect the designed cat light off temp so it not be enough to keep emissions down when the engine/exhaust is cold. I'm unsure as to how stringent the emissions tests are for cars so you may be able to get away with it.

[Bonzo]

If your engine was manufactured before September 1995 you do not need to use a catalytic converter. ( Even if one was fitted to the donor car ) ;)

That is my understanding of the rules ( Unless they have changed recently )

I guess if you really wanted too, you could fit a cat from another car but would probably need one from an engine of similar engine size.

[rapidtornado]

Didn't know that Bonzo, the car is a 1993 so if your statement is true... happy days!

Can anyone confirm this one? If not then the bike exhaust is a good shout, didn't think of that cheers ;)

[Tatey]

You wont need a cat rapid :D

[twinturbo]

So long as you have your donor v5 with the correct engine number.

TT

[Bonzo]

So long as you have your donor v5 with the correct engine number.

TT

I keep reading stories about VOSA & DVLA tightening up on the proof of engine age .... I believe that some centrers are now insisting on documetary evidence from the engines manufacturer !!?? :confused: :confused:

Guess the problem with a V5, the engine may have been changed for a later unit ( Not absolute proof of the engines date of manufacture )

Must stress though, it is ony information taken from the net & as such, I do not know for a fact ;) :)

[twinturbo]

If it's a ford, then the engine number is part of the VIN. so you can prove the original engine is used.

TT

[mark]

If it's a ford, then the engine number is part of the VIN. so you can prove the original engine is used.

TT

This is how i proved age at iva with no probs, but as always no two test centres are the same so i wouldnt bank on it :rolleyes:

[Big Vern]

V5 doc alone will no longer normally be accepted as proof of engine age. This is because of the large number of people during the SVA years who tried to get round emissions test by registering the donor with a different engine then building their kit.
With SVA, emissions was based on age of donor vehicle and assumed the engine was the original type for that vehicle. Too many people got caught building kits where it was blatantly not the original type of engine from the donor.
As TT says, where you can prove the donor engine is the original from the donor car then V5 doc may be accepted.
It should not, however, be a problem to get written conformation from the manufacturer of the engine as to it's age and this will be accepted as proof.

[snapper]

The engine age for Fords is easy to prove, I used the engine age page from the Burton catalogue, copied the page for the document folder and took a full catalogue with me, the VOSA inspectors have seen this many times before and are both aware of the age chart as printed and accept it.

[baz-r]

if any one is having to use a cat things to take into account are not all cats are of the same constrution and size. some cars have them fitted right at the manifold and some ferther down streem (cats need to be hot to work but not to hot to burn up)
also bikes are not cat tested in the uk so not sure if thay would be a test pass

i would try to take into account engine size/bhp, distence from cyl head for a start.