V12 primary cat delete opinions

[dg73]

I have a 2017 Rapide S, currently stock. Think it produces about 550bhp as standard.
Car is currently at Bamford Rose for some other work.
Mike has suggested a primary cat delete with high flow secondary cat and ECU remap which I think will take it up to about 600bhp.

Have never felt the car lacks power or sound and not sure how much I'd notice an extra 50bhp on a 2 tonne car but I am open minded to anything that would noticeably enhance the drive.

If any V12 owners out there have had this done I'd be very interested to hear how you percieve it changed the power delivery experience or the sound!

Many thanks

[dg73]

My car is under extended AM warranty which i plan to renew, so think I would be covered against the rare primary cat ingestion risk, so not inclined to remove primaries just for that reason.

My understanding is that secondary cat delete pipes just make the car louder all the time which I don’t really want. More interested in tone rather than volume.

Also my understanding, which could be wrong, is that secondary cat delete adds nothing in the way of extra performance?

[dg73]

For those of you that have had the primary cat delete + high flow secondary cat + ECU remap, would you say the power enhancement is more low range torque or more power mid-high rev range?

I am not so bothered about louder or enhanced sound as think it sounds perfect as stock, and the BR 3 way switch will make aggressive sound available more of the time hopefully!

[dg73]

I dont think I want the car any louder than it already is with the valves open, so would probably rather give the secondary hi-flow cats a miss.
Not sure how much the secondary hi-flow cats add in terms of extra power, get the impression they are mostly for extra sound?

Tempted to go for just primary cat delete and ecu remap if that makes sense - has anyone out there done just these bits without the secondary cats?

[dg73]

AdamV12V said:

In simple terms removing either just the primaries or the secondaries will give you pretty much the same result in terms of noise increase and a mild power increase. Very little to choose in the two paths if you keep the other set of cats as original.

However removing the primaries will cost you 4-5x as much as the secondaries for a cheap chop out and reweld job (as I believe you likely being recommended to have), or 10x as much to do it properly with a new manifold such as the QuickSilver one.

Removing the primaries also removes the very miniscule change of a primary cat ingestion. I would suggest you do a bit more research on the chance of such ingestion happening.

There is a lot of hype on the subject and I concluded it is probably cheaper to self insure in the long run as
a) it almost certainly wont happen anyway
b) if it does the cost of a swap out replacement engine is nowhere near as much as you might expect and
c) removing the secondaries is an OEM supported option, whereas removing the Primaries is not.

Also a third party ECU remap may make your car harder to sell in the future, certainly AM main dealers take a dim view on this. OEM mods do not affect their view on part-ex. Given your car is not that old, you may want to consider this point too.

You pays your money and makes your own choice..

Edited by AdamV12V on Tuesday 6th July 08:35

My understanding is that primary cat delete is obviously invisible externally to anyone but are you saying the ECU remap would be immediately visible to main dealer when plugged into their diagnostics machine? Concerned about this as want to extend my official warranty at end of year and don’t want to be told I’m precluded from doing this with the ECU remap…

[dg73]

Thanks to everyone for their input. Given I’m not bothered about making the car louder and the power increase is only circa 5% I’m not sure it’s worth all the potential hassle with the warranty and the cost of doing this mod for the time being.

Given all the minor but irritating issues I’ve had with the car and resultant heavy usage of the warranty I’m reluctant to jeopardise renewal…