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Discussion Starter #1
Simple question! if I were to de-cat my 9-5 would I gain anymore bhp or just get a faster spool up?
Thanks
 

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Every 9-5 is T7 equipped. The only way to get more power from a T7 Trionic is an upgraded ECU (which you already have )

An exhaust without cat is less restrictive, so spoolup will be slightly quicker. The ECU will aim for a preset amount of torque. It will adjust boost and throttle position to achieve that. Max power or torque will probably not improve, but you'll get it at lower revs.

All of this is theory, though. I haven't got any real life experience with T7 Saabs. Can't afford one .
 

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Originally posted by Maarten:
[qb]Since it's illegal to de-cat your 9-5, I don't recommend this 'upgrade'                . [/qb][/b]
I'll say this again
...the cat is there to reduce emissions to comply with local legislation. Removal of the catalytic converter is not illegal provided that the emissions remain within the prescribed legislation.

Manufacturers fit catalytic converters since it is an easy and quick way to restrict exhaust emissions.
 

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I stand corrected. /john is completely right about this.

The issue is wether a car will be able to pass emission tests, not the fact that a cat is actualy fitted to the car.
 

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I don't know about here, but in most US states, the cat is required equipment to have. When they do an emmisions test, they inspect the car for proper equipment and can fail it if certqin emmisions equipment is not present. And the failure will still stick even if the car passes the sniff test.
 

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My understanding is that while the Cat may have been a compulsory element of manufacture in the UK since 1992, it's not necessarily part of the annual MoT test provided, as /john points out, you still meet the emissions requirements.

But regardless of the legal grey areas, it might mess with your OBDII - see these two threads for more:
De-cat-ing a 9-5?

Sport Cat

Cheers

James
 

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No OBDII to worry about..
the legalities of it are reasonablyclear, the CAT itself is not required to be present for the MOT, assuming it can pass emissions without it.. but not tested a 9-5 sans cat, so wouldn't like to say

However for those running on LPG, removing the cat is fully legal as LPG cars do not have to meet the same emissions targets

But I'm with maarten, no in theroy judging on the basics of how T7 operates, you will not get a BHP increase from removing the CAT alone...
 

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While we're on the subject, how easy is it to remove and reinstall the downpipe on a 9-5, were one to decide to have the second cat removed?

James
 

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Originally posted by Maarten:
[qb]I stand corrected. /john is completely right about this.

The issue is wether a car will be able to pass emission tests, not the fact that a cat is actualy fitted to the car. [/qb][/b]
Maarten Taking my course to become "APK-keurmeester" It states in the rules of Rdw that the "cat" must be undamaged. It must be there.

The best thing to do is to Go to a scrappy find yourself a "cat" from another car. Beat a stick or metal pipe trough it. Till it's completely empty then take a Pipe big enough to make a tight fit through the complete cat. Also check the diameters. And weld it tight at the end of the cat. From the outside you can see no difference or damage. And it is good for The APK.
I'm not sure how it will affect emmisions tough.

If I understand correctly APK should be the same As your MOT.

Succes with building all your Cat replacements.
 

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Originally posted by Injectie:
[qb]If I understand correctly APK should be the same As your MOT.
[/qb][/b]
Similar in the way its an annual inspection to the cars roadworthyness to a minimum standard!

I'd imagine a huge amount of details are different, for example there is no requirement in the UK MOT for the car to actually have a cat fitted, only reequiremnt is to pass emissions limits judged on the year of the car!
 

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As Eric van S pointed out to me, in some markets (i.e. Holland) during late 80s, early 90s there was a tax advantage to purchasing a car with a cat.

If you remove a cat on these cars, not only do you have problems with the vehicle inspectorate (i.e. they won't issue an APK (MOT)) and therefore you can't actually drive the car legally - but also that the tax authorities would want a refund of the new car tax that was not originally paid + plus a fine!!!

So, what Maarten says IS technically correct for the market he's used to (Holland).
 

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Mark and all others from Holland. Cause this concerns only you.

Qoute taken out of "APK regeling permanente eisen Artikel 2.3.9" Personenauto's met een verbrandingsmotor en een elektrische onsteking, die in gebruik zijn genomen na 31 december 1995 , moeten zijn vorrzien van een goed werkend emmissiebestrijdingssysteem dat bestaat uit een katalysator en een lambdasonde.

Pesonenauto's die in gebruike zijn genomen na 31 december 1992 en voor 31 december 1995, moeten zijn voorzien van een goed werkend emmissiebestrijdingssyteem indien deze van fabriekswege is gemonteerd. te zien aan de toevoegin u9 of u2 op het kentekenbewijs. Unqoute

This means In Holland If your car is been licensed after 31-12-1992 and before 31-12-1995 and the manufacterer supplied it with an o2 sensor and a catalic converter. it must be there.
After 31-12-1995 it must always be there.
 

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I believe it is illegal to remove the cat on any car marked with U9 in the vehicle identification papers - I think the aforementioned means, though, that you can de-cat a car built before 31-12-'92 if you have it re-inspected at a state vehicle inspection centre (RDW) and pay back any tax breaks given to first purchaser of the catalyst equipped car.
 

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Of course the "sneaky" way around this would be to find a really low mileage pre 1992 engine, bolt that in, get the receipt confirming it's age and then you don't need a cat at all
 

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Sorry, no go - the registration is for the car, not the engine and thus date of first registry for the chassis # determines whether you need a cat, no matter how old the engine you drop in there... With 'assembled' cars the age of the engine can make a difference though, for instance if the body/chassis is made up from two donor cars, and one of them corresponds with the engine and/or gearbox. So for instance if one half of the car is a 1985, the engine is from the same car, and th other half dates from 1992, the car will be registered as a 1985 (after a strict technical scrutiny, of course!).
 

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Would you (as a tester) consider yourself obliged to check the engine number, Leon, or would you take someone's word for it?
 
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