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The mkiv Supra Owners Club

Emissions


Fulcrum2000

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Hi All

 

So my BPU decatted Supra (93 TT Auto) has just failed it's MOT on emissions for the first time ever.  It's been BPU 3 years but I guess I got a real stickler this time.  It has a 3 inch exhaust system with straight downpipes.  Is there any 3 inch race cats that run BPU but pass emissions that anyone on here use and if so what sort?  Any help you can give would be MUCH appreciated as I am off the road now by law!

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He says they're probably TT cats, other than that contact him. New MOT rules stipulate, if it had 2 cats at manufacture then it has to have two cats at MOT, not having 2 at MOT is technically a fail regardless of emissions. 

This inspection only applies to vehicles requiring a full catalyst emissions test (disregarding the Basic Emissions Test) and is restricted to components that are readily visible and identifiable, such as catalytic converters, oxygen sensors, exhaust gas recirculation valves etc.

 

It goes on to state: ‘(a) Emission control equipment fitted by the manufacturer: missing, obviously modified or obviously defective’ is a major defect and therefore a fail. 

 

It therefore appears missing or modified original emissions control equipment is in itself a major defect. There seems to be no allowance for partial removal even if an emission test is passed unless it is buried somewhere else in the document.

 

On the face of it. the new test looks like bad news for modified cars. From your avatar, you have a mk3 and therefore requiring a full catalyst emissions test. I’d put the ‘upgrade’ on the back burner if I were you. I think there are going to be some ‘interesting’ MOT discussions after May.

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1 hour ago, Swampy442 said:

Id suggest you have another issue if it passed previously, dirty air filter, O2 sensor, ECU temp sensor, leaky exhaust gasket. The emissions limit for an import are very generous so its worth doing a bit of invest before throwing money at it

As it can be compared to the UK spec supra, I'm not sure that applies. Afaik its the na supra import that doesn't have a comparison, hence doesn't get the full emissions test? 

To the OP did they mention it had not cats and that's why it failed? 

Edited by Annabella (see edit history)
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Thanks for all the input guys!  To clarify it is a 93 MKIV TT Auto and the fail (amongst a couple of other niggles to fix) does state there is a cat missing and also emissions level fail, I believe on fast idle but I don't have it in front of me but it definitely stated missing cat and emissions high.  

With this said and many thanks to Annabella for the tip off allowing me to buy a second cat last night .This should be here tomorrow and I already have the first cat from my original car so I am going to have these bolted back on and it should then pass both stipulations.  My only question is do I need any kind of adaptor to bolt it back on to the rear section?  Obviously the two cats will fit to the manifold and each other but how do you connect a 3 inch rear section to the end of the second cat?  What type of adaptor is required or does it just fit?  

 

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23 minutes ago, Fulcrum2000 said:

They're just the standard 3 inch decats from WhifBitz.  I don't know why I just assumed the standard exhaust was 2.5 inch where it joined the back box?

Doesn't matter about the decat pipe diameter, the flanges will match up.

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I’d hazard a real good guess that unless they want to really really look they will see a second cat run the emissions test and pass it. 

I know the 2jz gte engine is in the handbook does it also list number of cats? 
 

The last time I took my na converted to a different mot center they put it though as a mk3 and failed it for no cats. Simple check in vin at another garage and it passed a non cat test. 

 

Edited by The Raven (see edit history)
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On 2/10/2022 at 7:07 PM, Noz said:

Cats and bypass valves are the future.

You have to think that the additional emissions from modified cars pales in comparison to the genuinely knackered bangers spewing vast clouds of black smoke out? As ever, just focusing on the easy targets rather than the real problems. 

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