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nordberg

How Much Difference Does The Cat Make?

13 posts in this topic

Hi all,

My car is being collected tomorrow and taken to unit 4 to let Gav work his magic. Its not been started for some time so I just wanted to hand it over to somebody that knew what he was doing.

 

I have recently bought a cat from eBay as it was substantially cheaper than what I thought I would have to pay for one.

lotuscat_zps405e1841.jpg

Although I bought the cat with the intention of just leaving it fitted so I don't have to go through the hassle of changing it annually for its mot, I was just wondering how noticeable having it fitted is going to make the driving experience? When I bought my car back in 2005 it had the standard cat on, but the insides had been removed sleep.png and i was quick to change this for a de-cat pipe so i guess you could say I have only ever really driven the car without one fitted and every time its been moted its either been taken to a garage that turned a blind eye, or its been swapped, moted and swapped back by the garage. The reason I am asking is if the general consensus is that its going to make a noticeable difference i can ask Gav to swap it back after he has moted it, but if not I will just leave it fitted.

 

As always, thanks in advance for any feedback smile.png

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It makes very little (often none unless ecu tuned for it) performance gain having it removed, but it normally makes quite a change to the exhaust note and volume.

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On a back to back test, I found with a de-CAT fitted, the engine seemed to rev freer and the obvious noise increase. With a CAT fitted it felt like I had more torque, putting you back in your seat.

 

Might be psychological because of the noise difference, so my advise would be try both options and stick with what you prefer.

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I found that a 5" silenced decat is the best option on track; it may free the engine a bit and more importantly, it gets who well within track dB limits (usually 98)

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My 340r was mapped with and without CAT at Emerald.

 

Without CAT - 198hp

With CAT (200 cell tubular job) - 194hp

 

Done at different times but basically no difference.

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If you'd asked before buying the new cat, I'd have mentioned that Gav has a spare cat for S1 MoTs...

 

Too late now though :-)

 

When we had the standard S1, it was definitely quicker with the decat, and sounded better as well. Can't remember if yours is the 111S. If so, I believe that a decat actually reduced power due to strange back-pressure wave effects.

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^^^ I agree. A very tiny bit more power and more responsive without I would have thought having run a NA S2 Exige with and with out.

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If you'd asked before buying the new cat, I'd have mentioned that Gav has a spare cat for S1 MoTs...

 

Too late now though :-)

Dobbo,

Gav did say that he had a cat i could use to get it through the MOT, but I thought for the price (£62) it was worth me getting one myself just in case i decide to keep it fitted. Cheers anyhow wink.png

 

Just popped over to Gav's to drop the window screen wiper water bottle over as he is going to be MOTing it tomorrow. Whoopee wink.png . Thought I would take a cheeky snap of my car while I was there smile.png

 

20140403_101411_zpshkby53nl.jpg

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Bloody hell, had gav sold his bathtub buggy for a Bentley????

think its a rolls...

 

 

its all that work we are putting his way.

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