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decat exhaust

Black_JPN

Black_JPN

New member
I have a procured a decat pipe for my 944 via a kind member on here and ProMax for posting it out. [:)]

2 questions:

1) I know it's legal on my car to have a decat pipe but what happens come MOT time, is it likely to fail the emissions test?

2) How easy is installation having never fitted an exhaust? I'm assuming its undo bolts and clamps, then re-attach with some exhaust assembly putty?

Thanks
 
I got decat, haven't had a MOT since it was fitted (that'll be October) they don't test the cats for cars before I think it was September/August 1992.
 
Yes, I have the Janspeed de cat system on mine. MOT was no problem...S2 91. Good power gains too........
 
As above, I also have the Promax/Janspeed decat, coupled with a Dansk stainless steel exhaust. Not had it MOTd since fitting, but I believe it should be ok on pre '93 cars. Noticeable gains, especially in low down torque. IIRC, fitting involved cutting the cat off the downpipe & sleeving the decat on. At the exhaust end, the triangular flange should mate straight up to the exhaust.

Cheers,
Robbo
 
Likewise. Mine sailed through MOT but the tester asked (as it was on the changeover date area) if a cat was fitted; I told him there was not. If the tester believes a cat is fitted he may fail it as the emissions will be higher than he is expecting.
 
At the first Mot after deatting my car the emissions actually improved, although this improvement had more to do with getting the turbo off the car and serviced at Turbo Technics - Engine oil usage is virtually nil now.
 
Cats were not legally required after 1993 either, but the emissions requirements from 1993 were tightened to the point it's virtually impossible to pass without one. I believe cats are still not legally required as the emissions test is the key, not the presence of the cat.

A pre 1993 car will have no problem passing emissions without a cat unless there is something else wrong with it but you are supposed to make an ECU change if you remove the cat to tell the car it shouldn't use its lamda sensor any more - it's just bridging two pins and there is a jumper available for the purpose, but I don't know the part number nor the pins involved.
 
Fen, thanks excellent info and something I didn't really consider. Anybody else know what pins need to be bridged?

Interesting comment about the reduced use of oil, mine does seem to go through it...

Actually, thinking about it, I have it in with GT One on the 26th for a small service so I was going to ask them to fit the decat then, maybe I'll get them to sort the ECU pins as well.

Thanks
 
I got my de-cat pipe from Pro-max (Janspeed) last year. Prior to ordering I asked about the MOT situation (my car was registered on 1 August 92) as the rules seem a little open to interpretation - Pro-max say cars registered post 1 January '93, the MOT testing decision tree has 1st August '92 (or the most recent version I could find) - for a 'CAT' test to be carried out - but remember the test is of the emissions not the presence of a CAT so, as Fen says, you can still pass the test without the CAT. Anyway, I had the car MOT'd this year and there was no problem.

I also asked about the Lambda and was advised by Pro-max (via a technical explanation that I can no longer find) that it didn't need to be adjusted. I had the pipe fitted by my Indie without the Lambda adjustment and have had no problems (queue a barrage of posts telling me I should have had it done!).

Finally, if you have the Pro-max pipe it should be sleeved at the front end and comes with a U bracket to secure to the down pipe (after the CAT has been sawn off - make sure they measure twice!), the back end has a flange which fits directly to the existing back box pipe.
 
Iain, love your car in that colour! Peter (PSJ) has an S2 that looks similarly fab, that is full of lots of nice new shiny suspension bits....[:D]
 
Thanks Nick. Most of my money has gone on oily bits so far - three and a half years in and still working through my 'to do' list! I need some body work fettling next - that way it should look as good in the 'flesh' as it does in the photo. Then I'll start to think about other 'shiny bits'.
 
Maritime, fantastic!

I'm looking at the decats too, and then I see the pictures of Big Dave's S2 with the twin pipe Promax (Janspeed) exhaust too - this forum has a real habit of making my bank manager angry!!
 
ORIGINAL: iainfuller

I also asked about the Lambda and was advised by Pro-max (via a technical explanation that I can no longer find) that it didn't need to be adjusted.
Click to expand...

My information came from a dealer trained technician. I'll leave the statement there...
 
ORIGINAL: Wigeon Incognito

Maritime, fantastic!

I'm looking at the decats too, and then I see the pictures of Big Dave's S2 with the twin pipe Promax (Janspeed) exhaust too - this forum has a real habit of making my bank manager angry!!
Click to expand...

Oh yes...:ROFLMAO:
 
I have been running with the lambda on my car after removing the cat, I did try without but it didn't seem to make much difference so I went back. There is a link in the plug (where the sensor plugs into the loom at rear of cylinder head) on factory non cat cars cant remembere if it requires any other changes to delete.
Tony
 
ORIGINAL: Wigeon Incognito

Maritime, fantastic!

I'm looking at the decats too, and then I see the pictures of Big Dave's S2 with the twin pipe Promax (Janspeed) exhaust too - this forum has a real habit of making my bank manager angry!!
Click to expand...

Dont just look at my car. It NEEDS a new home.....
Decat,s. Yes ,,, definately. It made my car rev a lot free-er...after fitting...
http://www.pistonheads.com/sales/640643.htm
 
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