Primary cat removal

[crispyj]

I am thinking about removing my primary cats and fitting a couple off 200 cell cats where the secondary’s go. Has anyone removed the ceramic elements from the manifolds and refitted them.
If yes what gains did you see and will it need a remap.

Cheers.

[crispyj]

Forgot to mention it’s a 2005 db9

[Archimedou]

That looks tempting as the cost would be close to zero, in comparison with buying new manifolds.
My understanding is that it would need to do a longitudinal cut in each catalyst, empty them, and then weld it back.

Has anyone done this ?

[dbs2000]

I don't know of any DIY jobs but there are cars running without the primaries, and wonderful it is too.
You will need a remap to keep the emission service light off, or you'll be resetting it every 100 or so miles.

[Archimedou]

Would someone know if Is it needed to put down the engine and the whole transaxle system ?
Or can the exhaust manifolds be dropped directly (maybe by removing the intake manifolds only) ?

[crispyj]

Would you need a remap? If you fit a couple off 200 cell cats where the secondary cats are, then fit the O2 sensors after them they will still read correctly.

The only difficult bit is access to the manifolds, which is tricky. I have looked at the manual and you need to remove the lower suspension arms, steering , starter motor to gain some sort of access.

[JaseB]

I'm sure I had this chat with Mike at BR and he estimated something like 10 hours labour including all the cutting and welding so about a grand, that sounds like a reasonable amount of removals and refittings?

I can't remember if he mentioned a remap either, maybe he can answer if he sees this? Or give him a call?

[anonymous-user]

I had the primary cats removed on my DB9.2 and it is glorious. Bamford Rose did the work and also did the remap, otherwise you will get engine mangement light issues/warnings. Worth speaking to mike at BR because they can also help liberate more power. Mine now is supposedly somewhere around 570-580 from 510, although the better exhaust noise is worth it alone .

I had mine done primarily to avoid the potential ‘cat ingestion’ issue, the extra power and noise were a very much welcomed added bonus.

[Archimedou]

A 10h job to have this done, looks very tempting. Too bad I am in France, otherwise I would have given it to BR directly.
How much HP would that bring out of my DBS engine (with secondary cat removal also) ? 540bhp ?

[Happy2B]

Soofsayer, what was the cost at BR to remove the primary cat and remap? Thanks

[paulrog1]

I'm thinking about getting this done next spring, i did ask Mike from BR earlier in the year and he said £1500 all in.

[steveirl]

I am getting this done to my DBS next month. Mike at BR expects that it will yield about 30bhp, but the main reason I am doing it is to prevent the possibility of cat ingestion. I know someone who suffered this, and a full engine rebuild was needed.

[Archimedou]

I am planning to come all the way from East of France to do it this year with my DBS, but I need to call Mike and arrange it first :-)

Could someone share the expected price ? I have seen many different variations depending on what is done.
My understanding of the different mods are (with secondary cats already removed in my case, and replaced with empty tubes)

- Basic removal of primary cats + remap (530bhp?)
- Basic removal of primary cats + remap + new camshafts (550bhp?) (that would be a shame isn't it...)
- Fitting of new spaghetti exhaust manifold without cats + remap (580bhp?)
- Fitting of new spaghetti exhaust manifold without cats + remap + new camshafts (580-600bhp?)

[8Tech]

Archimedou said:

I am planning to come all the way from East of France to do it this year with my DBS, but I need to call Mike and arrange it first :-)

Could someone share the expected price ? I have seen many different variations depending on what is done.
My understanding of the different mods are (with secondary cats already removed in my case, and replaced with empty tubes)

- Basic removal of primary cats + remap (530bhp?)
- Basic removal of primary cats + remap + new camshafts (550bhp?) (that would be a shame isn't it...)
- Fitting of new spaghetti exhaust manifold without cats + remap (580bhp?)
- Fitting of new spaghetti exhaust manifold without cats + remap + new camshafts (580-600bhp?)

I have the details of a DBS done in 2009 with tubular manifolds, cams, fully ported heads, titanium valve retainers and new valve springs, lightened flywheel, sports cats and air filters and a remap which made 612PS @ 6650rpm and 684Nm @ 5900rpm. Done in Germany, the total cost was a staggering 70852.60 Euros in 2009. Was it worth it? That depends on how much of a dent in your wallet 70,000 Euros makes I suppose.

[Green9]

Been following this thread with interest as I’m thinking of a primary cat removal on my 06 DB9. My local AM independent is quoting a crazy amount for the job as he hasn’t done one before so I’d probably go to B Rose to get it done. However, does anyone have any feeling for what the % chance of failure is? Will all the primary cats fail at some stage or is it pure luck? There are some very high mileage DB9s out there and I’m fairly sure they’ve never had this job done. On so many enthusiasts’ forums an issue like this gets magnified due to owners’ fears of high costs and often it’s a case of “forget about it an enjoy your car” in reality. I’m not downplaying the threat, merely keen to know some actual failure data in order to weigh-up the required expense. Thoughts welcome!

[paulrog1]

Green9 said:

Been following this thread with interest as I’m thinking of a primary cat removal on my 06 DB9. My local AM independent is quoting a crazy amount for the job as he hasn’t done one before so I’d probably go to B Rose to get it done. However, does anyone have any feeling for what the % chance of failure is? Will all the primary cats fail at some stage or is it pure luck? There are some very high mileage DB9s out there and I’m fairly sure they’ve never had this job done. On so many enthusiasts’ forums an issue like this gets magnified due to owners’ fears of high costs and often it’s a case of “forget about it an enjoy your car” in reality. I’m not downplaying the threat, merely keen to know some actual failure data in order to weigh-up the required expense. Thoughts welcome!

Interesting point, trouble is i think it's quite difficult to find some exact numbers.

Owners who have unfortunately experienced this would goto all sorts of garages and as the cars were sold globally it's very difficult to gain numbers.

I would like to know how many replacement engines AM have sold in total for the DB9/DBS as that would tell you how many engines have been replaced, but not the ones rebuilt, some of those engines would of failed through oil starvation.

Its a pity the primary cats were placed in that position in the first place and made of ceramic, im definitely going to BR in the spring to get these removed.

Edited by paulrog1 on Tuesday 1st September 21:17

[Jon39]

Green9 said:

However, does anyone have any feeling for what the % chance of failure is? Will all the primary cats fail at some stage or is it pure luck?

My understanding is that the initial fault is not primary cat failure. Should an engine misfire occur, and if that happens during a motorway trip it might not even be felt, unburnt fuel can then enter the primary cat. Being very hot the fuel ignites and begins to damage the cat. The dreadful sequence of events has begun.

Edited by Jon39 on Tuesday 1st September 23:00

[anonymous-user]

Archimedou said:

I am planning to come all the way from East of France to do it this year with my DBS, but I need to call Mike and arrange it first :-)

Could someone share the expected price ? I have seen many different variations depending on what is done.
My understanding of the different mods are (with secondary cats already removed in my case, and replaced with empty tubes)

- Basic removal of primary cats + remap (530bhp?)
- Basic removal of primary cats + remap + new camshafts (550bhp?) (that would be a shame isn't it...)
- Fitting of new spaghetti exhaust manifold without cats + remap (580bhp?)
- Fitting of new spaghetti exhaust manifold without cats + remap + new camshafts (580-600bhp?)

Maybe the regs are different in France, but in the UK (AIUI) you need either the primary or the secondary cats installed to pass an MOT.

Bamford Rose will do a primary decat, new bespoke manifolds, an ECU remap and high flow secondary cats. That’s reputed to add about 60 hp.

Easiest thing is to email Mike at Bamford Rose and talk through what you’re after and what he can do.

[cornershop]

Archimedou said:

I am planning to come all the way from East of France to do it this year with my DBS, but I need to call Mike and arrange it first :-)

Could someone share the expected price ? I have seen many different variations depending on what is done.
My understanding of the different mods are (with secondary cats already removed in my case, and replaced with empty tubes)

- Basic removal of primary cats + remap (530bhp?)
- Basic removal of primary cats + remap + new camshafts (550bhp?) (that would be a shame isn't it...)
- Fitting of new spaghetti exhaust manifold without cats + remap (580bhp?)
- Fitting of new spaghetti exhaust manifold without cats + remap + new camshafts (580-600bhp?)

Details in the BR thread, but this is what I got back from Mike re my V12V:

“ The first step for V12Vantage is a copy of OEM GT12 - straight through secondary cat delete pipe @ £500 inc vat and shipping.

However, and as a second stage mod. It’s far better to remove the primary cats and fit the 200 cell secondary cats at supplied / fitted / inc vat £2750. There will be a circa 30bhp power gain, a slight / nice noise increase

Or the third stage / the Bamford Rose headline modification of high-lift inlet cams, bespoke made exhaust manifolds, 200 cell cats which is circa +80 BHP @ £8000* inc vat and fitting.”

(Or, £6500 fitted inc vat without cams (manifolds, 200 cpi secondaries, ECU tweak)

[Archimedou]

Thank you very much!!
I need to contact Mike and present my case in details.