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Discussion Starter · #1 ·
Due to having to throw what ever exhaust bits that drop off away I intend to get the full 3inch JT system, but what cat to have SPORT or RACE.

I do intend to tune my car ( especially as a Pug 206 can have 180 bhp! ), but is it really worth the £100 extra for the RACE cat over the SPORT cat?

The car is a keeper (1997 CSE 2.3FTP with 177k)
 

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Discussion Starter · #2 ·
I have found out that the race cat uses a metallic core vs. the ceramic core of the sport cat. Subsequently it is more free flowing than the sport cat. This has the effect of reducing exhaust gas temperatures which is highly beneficial to tuned vehicles in terms of both performance and, more importantly, reliability and longevity of the engine/turbo. I have heard that 280bhp is getting close to the upper limit of what can safely be obtained while using a sport cat.

What do you guys think?
 

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Currently running full system no-cat but need to get myself a cat and was pondering the same myself.
Would be interested in any experiences with the full JT3" that include decat also.
i.e.
Decat vs Race cat vs Sport cat.

I'm currently erring towards race cat as it's going to be hard going back from de-cat
 

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Originally posted by Gazolzwurf:
[qb]What kind of emissions are to be expected from sport/race/NO cat?
One of the reasons I buy Saab is because of the low emissions. [/qb][/b]
When I replaced the original combined downpipe/cat with the JT 3" downpipe+sport cat+system on my 9000 Aero the emissions reduced....


Was intending doing the same on the 9-5 Aero until finding out that T.7 will probably 'adapt' down and reduce the
or even throw a CEL....
 

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I'm facing the same dilemma: race cat or sports cat on the 3" downpipe?

I was hoping (ignorantly) that the difference in performance would not be all that noticeable and that the difference in price would be largely due to the presumably higher appeal of the word "race". My tendency so toward the sports cat has also been influence by my speculation on better chances to stay within the emissions limits the authorities set over here, and by the fact that the sports cat at least resembles the standard item, and for that reason too might not create irritation come inspection time.

But, as always, I would also much appreciate if someone could enlighten me what the real story is.
 

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Does anybody care about the environment on this planet?
What's all this talk of passing tests?
There is a far more important reason for keeping emissions low.
We may or may not bare witness in our life times to the affects CO2 has had on the environment but you can be sure that your children and your childen's children will notice the difference.
Do you think they'll thank you for it because you wanted an extra couple of BHP out of your car?
I think not
All IMO of course.
 

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'The general decline in carbon dioxide emissions is due to increased efficiency in energy use, a switch from coal to natural gas and nuclear in power stations, a move away from coal towards gas and electricity in the domestic sector and the decline in heavy industry. Transport is the only sector that shows an increase in CO2 emissions. This reflects the increase in road traffic, which has outweighed improvements in energy efficiency of vehicles.  [/b]
see here

Mods, feel free to delete my posts if you wish as they are way off topic.
 

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IMHO a nice new Race or Sport cat will be better than an 8 year old 100k miles original one at doing it's job.
If I can get more power and better emmissions then all the better. My car now does better MPG with the new exhaust and I would assume now has lower CO2 output too due to less fuel burnt.
If I actually use all that extra power all the time, then yes, I will generate more CO2 than before but I probably drive 'fast' for a tiny percentage of my driving.
I reckon the car 'power' debate is negligable in overall CO2 emissions of an existing car- better not to have a car or start off with or a car with very low CO2 output in the first place.
 

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I doubt the 9000 aero and the 9-5 Aero are very far apart at all in emmissions. Looking at the figures the long geared manual cars are much better than any of the autos in the CO2. The 3.0V6 auto aint too hot at all, but the 2.3 aero isnt miles off the diesels.
Aero manual : 209ppm
2.3lpt auto : 250ppm
V6 auto : 270ppm
2.2 Tid man : 175ppm


I think we have drifter off topic. Still interested in experiences between the different Cat types in terms of drivability/power etc etc
 

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faero, just re-read and realised that you're currently running NO cat.
OK so you're getting better MPG and undoubtedly reduced fuel usage but how does the lack of a cat affect the amount of CO2 that is pumping out of your exhaust?

[edit] Be this CO2 issue off topic or not, people should be forced to take responsibility for the part they play.
 

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Could anyone provide any insight as to how much power can be achieve from the different types of Cat?
How much more Volumetric efficiency does it yield?
 

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Originally posted by Gazolzwurf:
[qb][edit] Be this CO2 issue off topic or not,  people should be forced to take responsibility for the part they play. [/qb][/b]
If different types of catalytic converter all keep emissions within permissable levels then I struggle to see the point being made

Perhaps we can keep this topic on the topic of catalytic converters, please

If you wish to discuss the morals of CO2 emissions then you are welcome to start a new topic rather than take over this one. Perhaps you could widen the scope of your new topic to include diesel particulate emissions and also the impact of electric or hydrogen powered engines (the difference here being the displacement of where the pollution is being produced!)

Thanks
 

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I have run a sports cat on my 9000 (280-290bhp) for 18 months and had no emmission problems with the MOT. In fact, the tester said emmissions on a petrol vehicle didn't really get any lower. I imagine the significant cost difference is an incentive for most (apart from those Stage 6'ers!) to go for the sports one.

Best be off, got to get on my environmentally friendly mountain bike for a trip to the pub!
 

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Although I don't believe everything said on government websites, I am convinced that there's probably a good reason why the use of catalytic converters was mandated in the first place.

This being the Performance forum, I would be primarily interested in the restrictions in terms of performance that a sports cat might or might not have as compared with a race cat.

In this, I presume that even a race cat functions as a catalytic converter to some extent, thereby being "cleaner" as no cat at all (which wouldn't be an option for me, regulations or not). So of secondary interest to me would be to learn a bit more about the difference a race or sport cat can make in reducing emissions (and helping to save the planet )
 

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OK, I did a bit of surfing and dug up the following facts on cat operation...

A catalytic converter helps control harmful emissions from engine sources by converting the hydrocarbons (HC), nitrogen oxides and carbon monoxide (CO) in the engine’s exhaust into carbon dioxide (CO2), nitrogen (N2) and water (H2O) vapour.

So, in actual fact, using a cat increases the amount of CO2 produced!

Normal Construction:
A ceramic honeycomb structure (typically cordierite) made up of mostly square channels, to which the exhaust gas can flow through and over the precious metal catalyst. Platinum or Palladium accelerate the oxidation of hydrocarbons and carbon monoxide, while
Rhodium reduces the oxides of nitrogen.

The channels provide a large surface area for the application of wash-coat and precious-metal catalyst to convert the engine exhaust gasses to less harmful components.

A stainless steel honeycomb can also be used.

From the above you can see that a cat is inherently restrictive. The higher performance versions try to reduce that restriction, I would guess by using a thinner walled substrate, thus increasing the open area of the cat without reducing the active geometric surface area. However, thinner wall substrates are also much more fragile so there is in increased risk of damage during manufacture and operation. Thus higher spec cats are more expensive to make...
 

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The reason they use ceramic is the same reason newer cars have what's called "warm up catalyst".

Catalysts have an operating temperature that they work best at, and they do not work much below that temperature. The only part of the catalyst that needs to be at that temp is the surface of the precious metals where they come into contact with the exhaust gasses.

By using a ceramic substrate the surface of the catalyst where the precious metals lie heats up very quickly as the ceramic conducts little of the exhaust heat away from the surface.

The metal catalysts will take much longer to warm up, and won't be as efficient even when warm, because much of the heat is conducted through the metal substrate and away from the surface where the catalyst reaction is taking place.

Another option is two parralel catalysts. Some high output turbo cars have used them. Also a catalyst which is wider and shorter will work reasonably well. Most of the catalytic reaction takes place in the first 6 inches.

Remember though, catalyst warmup is important. Cars produce more pollution in the first 5 minutes with a cold catalyst than they do in the next 30 minutes of driving.

Dubbya~
 
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