Pretty Cat

[robo]

The question of cats keeps popping up with ref to fitting different engines post iva to circumnavigate emmisions. I dont understand why when cats can be fitted anyway. I know they are clumsy looking gadgets but things like this http://www.americanmuscle.com/pypes-...converter.html are available so why do the job twice

Bob

[The V8 Files]

I'm not planning to fit anything different post iva, but the cats that came with the donor I've got on ebay priced up a bit, if they sell then I'm happy, if not then I'l keep them as a backup.

Must admit those in your link look nice tho

[ozzy1]

Stay off that link as it has a trojan on it as my Kaspersky went mental on it.
What about one like this and much cheaper!

http://www.ebay.co.uk/itm/HIGH-FLOW-...50827619065%26

[snapper]

It's not just the fitting of a cat usually you need fuel injection, a programable ECU etc
The cat also saps a fair bit of power, if you can do without at IVA then you have a much easier ride when tuning engines after and still complying with the emmisions required on the V5 for MOT.

[voucht]

Originally Posted by snapper

The cat also saps a fair bit of power

Hi,
I have to disagree with that. I remember in the 90's we use to sell a lot of catalyst converter replacement tubes (called “Tube Afrique” in France, I never really understood why ). They were just empty tubes, and came with a bossing for the lambda sensor when needed. The belief was that a catalyst slows the exhaust gas down, and eats part of the engine's power. Friends of mine have a company (ECU and chips manufacturing) with a dyno bench. In 1999, they put a customer's unmodified Renault Megane 16V on the bench, first with the original cat, and then with the cat replacement tube. Guess what happened ? The car had more torque and power with the original cat than with the replacement tube. Why ? Because this car has been designed from the beginning for running with a cat converter. So replacing the cat on an “old” car (VW Golf 2, Peugeot 205, Renault Clio 1 and 2...) which engines and exhaust pipes were not designed to run with a cat might be a bit efficient (but the gain is never extraordinary), but on an engine which has been designed for complying with the emission regulations, most of the time it will not give you any benefit.
Just my little experience, but no offence of course !
Bye

[robo]

Originally Posted by snapper

It's not just the fitting of a cat usually you need fuel injection, a programable ECU etc
The cat also saps a fair bit of power, if you can do without at IVA then you have a much easier ride when tuning engines after and still complying with the emmisions required on the V5 for MOT.

I was thinking more in terms of the standard installation on a budget. Wasa had started a thread on the st engine using all the standard ecu etc off the donor car http://www.haynes.co.uk/forums/showthread.php?t=8494. That amounts to a big saving let alone the ball ache and time to install carbs etc. I just thought this might compliment a stock system without looking pig ugly while being up to speed on the emissions.

Edit a bit from dave walker on the subject of carbs vs inj http://www.emeraldm3d.com/articles/C...ction_Project/

Bob

[Big Vern]

Originally Posted by voucht

Hi,
I have to disagree with that. I remember in the 90's we use to sell a lot of catalyst converter replacement tubes (called “Tube Afrique” in France, I never really understood why ). They were just empty tubes, and came with a bossing for the lambda sensor when needed. The belief was that a catalyst slows the exhaust gas down, and eats part of the engine's power. Friends of mine have a company (ECU and chips manufacturing) with a dyno bench. In 1999, they put a customer's unmodified Renault Megane 16V on the bench, first with the original cat, and then with the cat replacement tube. Guess what happened ? The car had more torque and power with the original cat than with the replacement tube. Why ? Because this car has been designed from the beginning for running with a cat converter. So replacing the cat on an “old” car (VW Golf 2, Peugeot 205, Renault Clio 1 and 2...) which engines and exhaust pipes were not designed to run with a cat might be a bit efficient (but the gain is never extraordinary), but on an engine which has been designed for complying with the emission regulations, most of the time it will not give you any benefit.
Just my little experience, but no offence of course !
Bye

Totally agree with you - the EBP is always downstream of the catalyst so its the cat back exhaust system that restricts the engine not the Cat.
But if you don't need one for the IVA then don't make life harder than it is.

[flyerncle]

Cats are usually close to the engine and there aint much room under the Roadster bonnet and will look pig ugly stuck out side unless you use an aftermarket expensive bespoke one,interestingly the Teamtrain race car needed one to comply with new regs for cars built last year.

Dont forget the other junk that goes with them O2 sensors etc and rich mixture or leaky injectors wreck them.

[The V8 Files]

Originally Posted by robo

I was thinking more in terms of the standard installation on a budget. Wasa had started a thread on the st engine using all the standard ecu etc off the donor car http://www.haynes.co.uk/forums/showthread.php?t=8494. That amounts to a big saving let alone the ball ache and time to install carbs etc. I just thought this might compliment a stock system without looking pig ugly while being up to speed on the emissions.

Edit a bit from dave walker on the subject of carbs vs inj http://www.emeraldm3d.com/articles/C...ction_Project/

Bob

That's the way I'm looking to progress, I think I've probably got more than enough challenges and expenses along the path to just getting it built, while I've got all the original ecu and associated bits and bobs I should use them at least until its built and then if need be change afterwards, hopefully won't need the cats.

[baz-r]

Originally Posted by voucht

Hi,
I have to disagree with that. I remember in the 90's we use to sell a lot of catalyst converter replacement tubes (called “Tube Afrique” in France, I never really understood why ). They were just empty tubes, and came with a bossing for the lambda sensor when needed. The belief was that a catalyst slows the exhaust gas down, and eats part of the engine's power. Friends of mine have a company (ECU and chips manufacturing) with a dyno bench. In 1999, they put a customer's unmodified Renault Megane 16V on the bench, first with the original cat, and then with the cat replacement tube. Guess what happened ? The car had more torque and power with the original cat than with the replacement tube. Why ? Because this car has been designed from the beginning for running with a cat converter. So replacing the cat on an “old” car (VW Golf 2, Peugeot 205, Renault Clio 1 and 2...) which engines and exhaust pipes were not designed to run with a cat might be a bit efficient (but the gain is never extraordinary), but on an engine which has been designed for complying with the emission regulations, most of the time it will not give you any benefit.
Just my little experience, but no offence of course !
Bye

its a simple case of back pressure and mapping to suit it