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3 cats why ???

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Old 29 August 2002, 07:28 PM
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Type_RA
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My classic shape RA went for an MOT and I got the emissions report. The highlights are as follows fast idle CO its 0.06 and natural idle its 0.05 the limits are 0.3 and 0.5 respectively. The lambda showed 1.00 and was smack in the middle of the higher and lower limit, the HC reading was 0. The car just has a DP cat and ie not centre cat.

Why does the new car need 3 cats when one seems adequate or are the limits tighter for newer cars ?

Cheers
Old 29 August 2002, 07:53 PM
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BugEyed
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Errr, not sure of the logic, but it is the new European / North American regs. The extra front cat is for warm-up use, the rear for extra cleaning on the urban setting.

My attitude? More than 50% of the total pollutionants from a car are in its' manufacture, not its emission. So, I run cars without cats beyond their normal life (and balance this with my MY01 ) all without cats. Interestingly they all pass the MOT emissions test (though the pre-war ones don't need a test) without the cats.

Duncan
Old 29 August 2002, 07:53 PM
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john banks
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It is not the MOT limits, it is the new car Euro 3/4 regulations I gather. Cat before the turbo to reduce the light up time - higher EGTs gives a quicker warm up to operating temp for the cat from a cold start when you drive short distances.
Old 29 August 2002, 07:56 PM
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john banks
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OMG Duncan and I agree
Old 29 August 2002, 10:23 PM
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KenG
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Which of the UK Scoobs has 3 cats? The UK STI only has 2.

Ken
Old 30 August 2002, 08:52 AM
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john banks
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01/02 WRX has three cats.
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