Exhaust Woes...

[Mr OCD]

Right ...

I've managed to somehow destroy my CAT as I've filled up the rear tailbox with bits of burnt honeycomb which was rattling inside the tailbox ... so we removed the rear tailbox and welded a new stainless section from the CAT to the exit (tailpipe) ...

It sounds great and has fixed the rattling issue ... also feels a bit pokier which is always nice.

Now my mate does custom stainless fabrication so sorted the above for me but said he could remove the CAT and install de-CAT for me but I'm concerned with two things:

1. The car running lean due to removal of CAT (so will need modified map?)
2. NOISE!!

First point I can get fixed easily and funnily enough its going on the RR to test this tommorrow...

The noise is a major worry though... I hate noisy exhausts and I do a lot of miles and I'm told on these cars they can get very noisy without CAT...

Can anyone confirm / deny my thoughts?

 

[dav3]

Running a de dact will indeed increase the exhaust note especially under boost, and motorway speed also will make it pop. It may also bring up the EML light as the lamba sensor will be picking up wrong readings. Which can be mapped out but need to go stage2 from what I've been told. My old v6 vectra was running a cat on the exhaust and was way louder than my LCR without the cat.

 

[Mr OCD]

Running a de dact will indeed increase the exhaust note especially under boost, and motorway speed also will make it pop. My old v6 vectra was running a cat on the exhaust and was way louder than my LCR without the cat.

Yeah my 200sx did the same ... it looks like a decat is not a good idea then for me. The drone / noise from my old car drove me mad sometimes...

 

[dav3]

In all honesty mate I'm running a miltek cat back and there's only a slight difference in exhaust note with the cat on as the is with it off. See what it sounds like on the rollers and then decide

 

[ScoobyJawa]

if you do it make sure the cat is easy to put back on come mot time

 

[Mr OCD]

if you do it make sure the cat is easy to put back on come mot time

Aye thats sorted.

I chucked the LC back on the RR this morning after the new rear section was put on expecting to see a little gain... got absolutely nada so the OE rear box isnt restrictive at all

 

[greesha]

So theoretically if i change only downpipe and put a decat on i will see some nice gains even if i will leave oem backbox for now ?

 

[Mr OCD]

So theoretically if i change only downpipe and put a decat on i will see some nice gains even if i will leave oem backbox for now ?

Yep... lol ...

Although worth noting that most aftermarket systems are 3inch... not 2 3/4

 

[greesha]

I know i ask sometimes silly questions. I'm still noob if it goes for car and mechanics. Thanks for help OCD

 

[Mr OCD]

I know i ask sometimes silly questions. I'm still noob if it goes for car and mechanics. Thanks for help OCD

No worries

 

[dav3]

Got question mate how'd you feel about the exhaust note when it was on rollers. I know it sounds lush but is it too loud for you to live with

 

[Mr OCD]

Got question mate how'd you feel about the exhaust note when it was on rollers. I know it sounds lush but is it too loud for you to live with

I've not changed CAT or downpipe so is barely louder than standard ...