De-cat-ed it

sitrials

sitrials

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well i got a de-cat from ebay arrive today was second hand off a TT only paid pennies for it and wanted to see what difference it would make, so fitted this afternoon and so far i have noticed.
spool up is quicker, pulls right up to the redline as before it would slow down after 5k, its louder and pops like a bugga now!

The strange thing was the decat pipe had space for a lambda sensor but it wasn't there on mine so had to nip down to the local welders and he filled the hole for me which cost me nowt! (billy bonus) i even offered the guy a pint but he said no (the local boozer is only over the road):thumbsup:
pic of new pipe
www.sitrials.co.uk/decat.JPG

and before you say anything about why, what was the point, it didn't cost much, and I'm Happy!:thumbsup:
 
do you think it uses more fuel now?
 
sounds more raspy and more pressure noise
 
was that a question? if so, then yeah not so much raspy though.
I've got the non resonated milltek and its still not over loud! after its a massive box at the back of the S3.
 
Sounds quality Si - does it pop when hitting red line or when backing off? What make de-cat?
 
Looks small? Must be 2.5" though right?

I have a decat too, it does indeed give ace popping and occasionally flames!
 
Looks pretty easy to swap out if needed (MOT). You should do a back to back dyno test some time.

Mine pops every now and again with a cat. Scared the bejeezus out of an old lady the other day................oops, sorry luv.
 
I've never needed to swap mine back for the MOT.

If your engine is older than the car, as long as you prove it (onus is on you) they dont test for emissions.

Telling the tester the engine is a 1992 Audi Quattro engine has worked for past 3 years.
 
Its in the MOT rules, the onus isnt on them to disprove, the onus is on you to provide information.

Thus why would they even bother check?
 
I personally like to be upfront. Just me I suppose.

If you want to go for the "wink, wink, nudge, nudge" approach then thats your decision. I do see your point with the wording of the rules, but if a guy came into the garage I used to work at and said, hey my car has X engine fitted from X year when we knew otherwise, we'd have told him to go away.
 
Dave_Bayern said:
Its in the MOT rules, the onus isnt on them to disprove, the onus is on you to provide information.

Thus why would they even bother check?
Click to expand...

wouldnt that invalidate your MOT, that invalidates your insurance in turn from what i believe?
 
No and no.

The MOT is valid as the car is 'roadworthy' and no MOT does NOT invalidate your insurance.

Go check your insurance documents, theres nothing in them about having a valid MOT.
I also had Brentacre confirm to me that you do not need an MOT for insurance to be valid, otherwise, how would you legally drive your car to the MOT centre for a test if it had run out????
 
Dave_Bayern said:
No and no.

The MOT is valid as the car is 'roadworthy' and no MOT does NOT invalidate your insurance.
Click to expand...

Thats not true, I know someone who crashed there car and failed to get his MOT done, it was 2 mths overdue and his insurance company informed him it was 2 mths overdue and would not pay out because of this.
 
DaveMk & Ash_s3

Again, if you dont have your MOT how do you drive INSURED to the MOT station.

And I mean check your documents, not just heresay or conjecture.

If you do actually do this, you'll find the MOT test itself isnt in the insurance prerequisites. A roadworthy car is, but the MOT is not considered proof of a cars roadworthyness at any time other than the date/time of the actual test.

If the MOT is actually specified in your insurance documents, I'd like to see it, as its never been in my insurance, ever. That said I'd never been with a mainstream insurer, I always go with specialists but even the insurers told me they couldnt ask for MOT as you could then never perform the scenario above.
 
I used to run a de-cat on mine with no mid box and the remux backbox, the responsiveness and pickup was brilliant even on my non turbo, it used to rev all the way into the red and poped alot! But I hated the loud noise and because i couldnt sneak back into my house at early hours without waking everyone up! so unfortunatly i had to revert it all back to stock. (which cost me silly money)
 
Dave_Bayern said:
DaveMk & Ash_s3

Again, if you dont have your MOT how do you drive INSURED to the MOT station.

And I mean check your documents, not just heresay or conjecture.

If you do actually do this, you'll find the MOT test itself isnt in the insurance prerequisites. A roadworthy car is, but the MOT is not considered proof of a cars roadworthyness at any time other than the date/time of the actual test.

If the MOT is actually specified in your insurance documents, I'd like to see it, as its never been in my insurance, ever. That said I'd never been with a mainstream insurer, I always go with specialists but even the insurers told me they couldnt ask for MOT as you could then never perform the scenario above.
Click to expand...

I thought the idea of having a expiry date on your MOT was that you went to the MOT station BEFORE your MOT ran out, the law states you can only drive your car without MOT to an MOT testing station. Your making it sound like you can let your MOT overrun by X amount of time without any worries.
 
I've never heard so much s'#t in my life !! if you haven't got a legal MOT then i doubt your insurance company would be very happy about that... or the policefor that matter, and in the event of an accident or claim, then your insurance company wouldn't pay out... that being said... if they knew !! If you haven't got an MOT then your car is believed to be off the road in which you have to inform DVLA i believe. Your covered if your've bin pulled over and you can prove that your on the way to the MOT testing station and your car is booked in !!
 
If you get caught out on the road without an MOT and can't produce it within 7 days then you will be prosecuted for driving without insurance.

We are getting a bit off topic here, but you can see how things can go if you choose to run without a CAT.

Yes you can be clever with what you say and to whom, but I just can't be bothered with all that, so guess what, I choose to loose a little BHP and run a CAT for peice of mind.

I also declare everything on my insurance.
 
DaveMK^ said:
Thats not true, I know someone who crashed there car and failed to get his MOT done, it was 2 mths overdue and his insurance company informed him it was 2 mths overdue and would not pay out because of this.
Click to expand...

my dads mate is currently going through this with his insurance company as his car was 2 day out of its MOT.
 
I believe somebody is fighting a losing battle...lol
 
Not at all, unless someone wants to copy the section of their insurance where it states you must have a valid MOT????

I KNOW it wasnt the case for me, as I got stopped without an MOT or Tax, and they tried to prosecute me for driving without insurance, it failed as my insurance WAS valid regardless of MOT.

I got 3 points and a fine for no tax. Nothing else.

The thing thats annoying is you people are believeing something without even actually knowing, or bothering to consult the legal documents YOU signed!!!!
 
It's only if you have no tax which invalidates your insurance. If you have no MOT your insurance will still be valid. People always forget about MOT's but for tax you are sent a reminder in the post.
 
Also, in my case, my insurance was still valid regardless of the road tax issue. That may have been as its a civil offence and not a criminal one though....
 
I change my mind Dave. Just spoke to the guy I know who got done for no insurance.

He had no tax as well as no MOT........lol............um ****! Was a long time ago.

Anyways, I'm still not buging on the CAT thing..........too honest? you decide.
 
I know what you mean about the honesty thing, better safe thabn sorry.

However, this is the interesting thing, mine PASSED emissions without the Cat!!!!!!
 
oh dear whats happened here then! calm down, calm down!
well i just did a vag com log and i'm only seeing 284Nm at the wheels at the rolling road day i saw 222ftlbs at the wheels something is deffo wrong.
when i got the car last march it was logging 299-305Nm.
I'm going to contact superchips as i did last year and i asked about decat pipe and front mount intercooler they said they could remap to suit them for £100 as i was already running superchips and it was their old R&D car.

dave mine won't spit flames thanks to my overly large milltek back box surely!
 
Right, well the extra bore size is giving you less backpressure, so you WILL get less torque.

You do ideally need to have it remapped to account for this.

Are you sure you are only seeing 222ft.lbs, max?

My K03s turboed car is currently doing 288ft.lbs.......... (Prawns is doing 290!!!)

EDIT - Mine had a 3" downpipe, 3" to 2.5" Decat, milltek centre section AND milltek rear box and it still spits flames!!!
 
yeah I've been over this with nick mine is very low on torque.
i have emailed superchips and hopefully i can get the car remapped again for a fraction of the cost!
i have no fault codes at all.
i just seems a little strange! to only get 222.98ftlbs at the wheels! could my haldex upgrade have anything to do with this??
 
I was under the impression that a too large exhaust was detrimental only for normally aspirated. Being beacuse its harder to form the vacuum behind the various cylinder pulses needed for good scavenging of the cylinders.

My understanding is a free flowing exhaust aids torque for turbocharged engines due to less restriction of the turbine allowing it to spin more freely and thus more boost.
 
HTC said:
I was under the impression that a too large exhaust was detrimental only for normally aspirated. Being beacuse its harder to form the vacuum behind the various cylinder pulses needed for good scavenging of the cylinders.

My understanding is a free flowing exhaust aids torque for turbocharged engines due to less restriction of the turbine allowing it to spin more freely and thus more boost.
Click to expand...

thats what i thought
 
Just to add, the turbine is working to a pressure ratio. You want the highest speed possible into the turbine (thus the relatively small manifold and turbine inlet size) to get the highest pressure out across the blades. This effect is increasingly better the more you allow the exit gasses to flow out.
 
That is the case ^ as above, but it also effects the turbocharged engines, the setup is optimised for the current amount of backpressure, changing from the stock 1.5" downpipe to the 3" downpipe for me without remapping to account for it was like losing half the torque...
 
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