De-cats for the V8V ... AKA the epiphany!

[bignoise]

Craig said:

Thanks Nick - I managed to get hold of Kyle and he has come up trumps! After confirming I had no lambda sensors in the cats he located the correct AM part and the car is booked in next Monday - can't wait!

Craig

Hi Craig

What were the part numbers and rough cost as I am looking to do this to mine

Thanks in advance

Tim

[Bobajobbob]

The more info the better as im also looking to do this. I’d love a before and after video too if anyone can be bothered. With and without Fuse 22/15

[Craig]

bignoise said:

Hi Craig

What were the part numbers and rough cost as I am looking to do this to mine

Thanks in advance

Tim

Hi Tim

Sorry I don't know the part number but should be able to find out next week - seems it depends on model year and whether there are lamda sensors or not in secondary cats. Cost was £740 fitted (I know an exhaust fabricator could do them cheaper but I wanted to use pipes with an AM part number)

[nickv8]

Craig said:

Thanks Nick - I managed to get hold of Kyle and he has come up trumps! After confirming I had no lambda sensors in the cats he located the correct AM part and the car is booked in next Monday - can't wait!

Craig

Good man!

[nickv8]

simon578 said:

Can someone with a de-catted V8V 4.7 (MY12.25+ if possible) let me know what the 'soundtrack' is like? Is it a deep burble at idle and just louder (but same pitch) when pushing on at over 4000 rpm?

I know that what something sounds like is in the ear?! of the beholder, but what I don't want to attain from a de-cat is a higher pitched noise, as per italian cars...I just want a nice deep burbly/bassy sound that's 'classic V8' in nature. Will a de-cat achieve this, and does anyone have an opinion on straight through pipes vs. X-Pipe configuration?

I've watched a few videos on Youtube to get a feel for what an aftermarket exhaust / de-cat / GT4 exhaust / X-Pipe sounds like but of course the sound you hear on a video could be totally different to what it's like in the flesh.

It's an interesting topic that'll come up again and again. I really should have got around to sound recording the previous non-S 4.7 V8V before and after the de-cat. Beforehand it was too "refined" (ie. very little exhaust note in the cabin). After, it had the most glorious and rich American V8 style low-down burble. Pulling at low revs filled you with pride. Hitting the pace with revs above 5k was spine-tingling.

Never high-pitched, it was one of the best exhaust notes I experienced. And you could easily live with it in every situation. It wasn't "boy racer" or too over. The Spot button (ie. opening the exhaust value earlier in the rev range) made very little difference for me personally. It would open up a little bit more, but not a startling difference.

But when de-cat'ing the V8VS... now that appears to be another world.

Just completed a good journey yesterday. About 60% motorway, 30% A/B roads, 10% single track country lanes over 250+ miles. I'm still getting used to this car having collected it two weeks ago (and a week holiday getting in the way between).

I never realised the difference the standard S model's sports exhaust would make. It's MUCH louder. the Sport button really makes an effect. Trailing throttle results in a new noise. The very occasional pop on changing.

I have the Sport button set by default. But now I do consider turning it off when trying to drive in a civilised way through villages, past dogs and horses, etc. (Children definitely require the Sport button ). Is it too boy-racer? Maybe. More Marmite in some ways. But there was a point in the drive yesterday when the noise was soooooo glourious, it literally made me laugh out loud.

However, it remains deep-chested and never becomes Italian / high-pitched in style. It's simply louder.

I wonder how much more the GT8 was. I recall in the reviews (Henry Catchpole in Evo?) that it could even be too much.

Addition: to clarify, even with the de-cats, cruising on a motorway is actually very civilised! As the revs are still just under 3,000rpm and there's relatively little throttle travel, you can't really hear the exhaust. Put your foot down to overtake a lumbering caravan and there's no need to warn others of your presence

Edited by nickv8 on Thursday 16th August 08:00

[Bobajobbob]

I don’t suppose you ever heard a 4.3 with a Fuse 22 switch did you? If so is it similar?

[bogie]

Bobajobbob said:

I don’t suppose you ever heard a 4.3 with a Fuse 22 switch did you? If so is it similar?

I had a 4.3 for 10 years with a fuse 22 switch, it was great

When I changed to a 2012 4.7 the only disappointment was the sound. Even when I fit the remote control to the switch, it really wasnt that noticeable.

Replacing the secondary cats did the trick and gave it back its voice, its probably a few dB louder overall all the time compared with a 4.3 with fuse out. With open valves and roof down it really is plenty loud enough with a nice deep V8 growl.

[SXIV]

Can anyone who has changed these themselves comment on how difficult it was?

Is there enough space to get the cats out / decats in without having to undo all the brackets for the back half of the exhaust?

[bogie]

SXIV said:

Can anyone who has changed these themselves comment on how difficult it was?

Is there enough space to get the cats out / decats in without having to undo all the brackets for the back half of the exhaust?

Yes plenty of room, I didnt do it myself but watched the local tyre/exhaust garage do mine in under an hour. Very straightforward when you have the car up on a ramp.

[Jibberingloon]

2007 4.3 ltr

Equal Length Manifolds
200Cell RS Fab Cats
X-Pipe
With switchable Standard Exhaust

FOOKING AMAZING X-Pipe really makes a great noise more exotic rasp!

Down in Oxford if you want to hear it


PS have another set of New RS Fab 200 Cell Cats if anyone wants Got them in a deal with a load of Aston parts...........

[kippax]

Jibberingloon said:

2007 4.3 ltr

Equal Length Manifolds
200Cell RS Fab Cats
X-Pipe
With switchable Standard Exhaust

FOOKING AMAZING X-Pipe really makes a great noise more exotic rasp!

Down in Oxford if you want to hear it


PS have another set of New RS Fab 200 Cell Cats if anyone wants Got them in a deal with a load of Aston parts...........

Could you please give me more info on this?
Cost who did it etc.
And I’m definitely interested in the 200 cell cats

[Jibberingloon]

Sent you a PM

David Appleby Engineering did the install

Excellent bunch and highly recommended.


"Edited"

2 sets on PH For Sales

Used and New

https://www.pistonheads.com/classifieds/parts-and-...

https://www.pistonheads.com/classifieds/parts-and-...

Edited by Jibberingloon on Friday 24th August 06:38

[telum01]

Here's a couple videos I've made....

600-cell OEM cats compared to 200-cell VelocityAP cats. Factory headers and muffler. Jump to 18:00 for the back-to-back comparison.

https://www.youtube.com/watch?v=rKwkKTOhYMI&t=...

And this one is VelocityAP equal-length headers, 200-cell cats, and sport muffler.

https://www.youtube.com/watch?v=UMfgtcmE9Yo

[Bobajobbob]

Thanks a lot for vids. I'm now booked in to replace mine with the GT8 steel downpipes. It seems reasonable value at 500 quid or so. I balked at the AMR titanium equivalent at 1,500.

[Bobajobbob]

I had the secondary cats removed on my 2013 Roadster and boy what a difference it makes. Throaty lower in the rev range and then at about 4500 it sounds very very angry. I also finally figured out why I couldn't get Fuse 22 or 15 to work as it transpires the previous owner had blocked the valves in the open position which shows how much quieter the 4.7 set up is by default.

Having released the valves and reinstalled the Fuse 15 switch I now I have the best of both worlds. In normal mode you can cruise around without waking the neighbours and in loud mode you can wake the dead.