There shouldn't be any difference in my opinion. Either method is removing the secondary cats and blending both banks together with an x-pipe. Not sure which method is easier ? My thinking was purely that I found a used pair of cat-deletes and I immediately wanted to do the x-pipe.

 

Either works. Soon as I get a car in the shop we'll make an X-Pipe cat delete section to offer as well.

But sometimes people might do our power kit with the headers & secondary cats, and still want an X-Pipe so we will still offer the center section because it could pair with that and an OEM back box and still sound really nice.

 

Totally makesmakes sense.. I just wanted to make sure I wasn't missing out on something You know how tough it is to leave even a single hp on the table. Haha

I like the idea of headers, Xpipe and oem rear box.. I never really noticed a performance increase from (only) changing the muffler, whereas the headers would be a huge difference I'm sure, and not "much" more $$.

 

Headers make a big difference, removing 4 x 600 cell cats and equalizing the primary runner lengths is worth a lot. The muffler section is a weight/sound thing, and it doesn't really make a substantial difference to HP.

 

A picture's worth a thousand words

 

I'm sure this has been covered at length but what happens to emissions with the removal of those cats? Obviously you'd need to use a sport cat at least to do the scrubbing? Or is that still not enough?

 

Earlier Irish mentioned 4 cats that are monitored - those are the ones in the headers.

The cats in the headers are as close to the engine as possible so they heat up to operating temps quickly for cold-start emissions. You can see the o2 sensor ports above and below the cats in the pic I posted above.

Since they're monitored, removing them will trigger an emissions-related fault code and CEL. If you get a tune, it basically programs the computer to ignore the o2 sensor readings so you won't get any fault codes. You'll also get more power from the tune at the same time.

You still have the two down-stream cats cleaning your exhaust gases.

Aston redesigned the headers on all their cars to get cats closer and closer to the engine for better cold-start emissions to keep up with increasingly-stringent regulations.

 

I understand.. I'm referring to installing the Velocity headers without those cats in play now of course.

 

What we do is use a 200 cell motorsport unit in the location of the original secondary cats, along with O2 sensor harness extending plugs to make them reach. The primary cats in the headers are deleted. Keeping a couple of motorsport cats keeps the gas smell down, makes sure it's not too raw of a sound, and keeps a visual 'cat present' for visual inspections.

We also recalibrate the ECU for the new setup both in terms of emissions parameters, and do adjust a variety of response rates for primary O2 sensors as well as changes to the heated circuit cycle for cold starts etc.

On any V12 Aston, with an XPipe in there, should sound similar to this:

 

Wow! That is fantastic Stuart! This is headers, Sport cats and Xpipe center section? Which rear box is being used here? Really brilliant.. Great work and I love the long video without background music etc. Just that lovely 12 cylinder sound track.

 

Headers, Sport Cats, Filters, Tune and XPipe Supersport back box. Standard Center section.

It sure does sound good doesn't it.... I can only assure you it's even better in person.

 

I've yet to hear one in person..is it loud?