V8 Vantage (4.7) High Flow Catalyst Upgrade

[PeteB62]

I’ve been contemplating an upgrade on my V8 Vantage (4.7) to the high flow 200 cell cats. I’m sure I’ve read a thread on here in the past about the AM option to use the high flow cats from the AMR car, but can’t find that. I would be happy if anyone as details of this and/or if anyone as used AM for this option, opinion on results and estimated cost.
Thanks in advance.

[NickXX]

What year is your 4.7? The earlier ones had 1 set of cars, later ones had 2 sets (with one pair built into the manifolds).

For the later cars with 2 pairs of cats, you can replace the 2nd pair with straight through pipes (£500ish). Later cars you’ll have to buy 200cell cats.

[V8V Pete]

PeteB62 said:

I’m sure I’ve read a thread on here in the past about the AM option to use the high flow cats from the AMR car, but can’t find that. I would be happy if anyone as details of this and/or if anyone as used AM for this option, opinion on results and estimated cost.

The AMR V8V was exactly what we were promised the AMR wouldn't be when the "range" was launched - a paint and stickers job that is mechanically identical to the model it is based upon. So what I'm saying is that AML have never done "high flow 200 cell cats" on any model AFAIK. As above, they do offer de-cat pipes to remove the secondary cats on models that have 2 cats per bank.

If you want 200 cell cats then go aftermarket. However, If you really want to get a proper power uplift then you're going to have to get equal length tubular manifolds as well as 200 cell cats. Highly recommended but not cheap.

[NickXX]

Just noticed that you have a 2017 v8v - this means that you have the 2 pairs of cats.

It depends what you want to achieve. If it’s just more noise and a little bit of performance, you can replace your secondary cats with straight pipes- I know that AM Works can do this if you wanted to stay in the dealer network.

On my 4.3, I had 200 cell cats fitted, with a remap and airbox mods last year. I also had the manifolds and lightweight flywheel/twin plate clutch fitted last year. Now a very different car.

I had the work done at Bamford Rose which now has pricing for the various levels of upgrades on their website.

[Moonpie]

What year did the 4.7 move from single to double cats per side and what was the reason?

Thanks in advance.

[NickXX]

I believe it was 2010, and it was for emissions purposes - cats in the manifold are closer to the engine, so heat up quicker. They did also retain the cats in the mid section too though.

[AstonV]

Save your money go for secondary cat deletes to wake things up!

[BigMig]

Moonpie said:

What year did the 4.7 move from single to double cats per side and what was the reason?

Thanks in advance.

Yes it was 2010. A quick way to tell if you have a 4.7 of this vintage it to look to see if there is an EGR valve on the front left of the engine. Mine is 2009 and has the EGR, though this has now been deleted as part of a 200 cell cat install at BR.

[BiggaJ]

Like Nickxx, I had the same work done in twin plate clutch, lightened flywheel, 200 cell cats, GT4 air filters with the original air box delete, EGR delete but didn't yet get the headers done. Then it's remapped... Wakes the 4.3 engines up and removes the dead feeling first inch of throttle pedal. Mine wasn't with BR but with AHM who write their own remap files from their own rolling road. I guess the same as what BR do.

I wouldn't just get the 200 cell cats done on their own, I think you really need to have the clitch/flywheel, cats, air filter and remap, to feel the difference all together it adds around 60 hp and with headers done will add more, torque is up and is felt in the mid range.

You can sell the old cats and airboxes on ebay as I did, got £700 for the cats and could have probably got more if I had pushed the buyers.
Airboxes still available but no rush.

[PeteB62]

Thanks for the feedback, must have been dreaming about the AMR car or mixed up with something else. I've also watched the videos on the BR upgrades which look good, unfortunately being in Scotland this would have to be a road trip in better times. Just out of interest with the BR options for those who have used the service, I assume the majority would be unbaffled?

[V8V Pete]

PeteB62 said:

Just out of interest with the BR options for those who have used the service, I assume the majority would be unbaffled?

That will depend on which backbox you have and personal taste. The V8S backbox is significantly louder than the non-S one and with manifolds, 200 cell cats and S backbox I needed the baffles behind the cats to keep the volume manageable. With the baffles it is loud but not full-on shouty. With a standard backbox I'm not sure.

For reference, with valves open, mine clocked 102dB at noise testing at Cadwell Park. The limit was 105dB that day so that was just about perfect

[V8V Pete]

BTW it is my car on the BR video. Not quiet

https://www.youtube.com/watch?v=5JshVlIBdII

[NickXX]

PeteB62 said:

Thanks for the feedback, must have been dreaming about the AMR car or mixed up with something else. I've also watched the videos on the BR upgrades which look good, unfortunately being in Scotland this would have to be a road trip in better times. Just out of interest with the BR options for those who have used the service, I assume the majority would be unbaffled?

I have had both! I suspect that the majority of the recent ones will be baffled. Generally those who had just the cats done would have gone with non-baffled, with the manifolds (which make things even louder) they get non-baffled!

I loved the sound of the non-baffled cats, they have a really aggressive snarl at the top end which you lose with the baffles.

[AstonV]

V8V Pete said:

BTW it is my car on the BR video. Not quiet

https://www.youtube.com/watch?v=5JshVlIBdII

He says all aftermarket back boxes are bad. I installed a brand new Larini valved back box last summer. First it’s very nice looking, mirror polished stainless steel, double skinned, it’s very solid and well built, beautiful welds, but still half the weight or less of the S box. To my ears it’s sounds much better than the factory box. Has a nice deep subtle burble when you let off the gas, deep and quiet at idle. Never heard any buzzing or strange noises he mentions in the video. And sounds wonderful when you push it. The factory box always sounded a little constrained to my ears. My opinion only.

[BiggaJ]

AstonV said:

He says all aftermarket back boxes are bad. I installed a brand new Larini valved back box last summer. First it’s very nice looking, mirror polished stainless steel, double skinned, it’s very solid and well built, beautiful welds, but still half the weight or less of the S box. To my ears it’s sounds much better than the factory box. Has a nice deep subtle burble when you let off the gas, deep and quiet at idle. Never heard any buzzing or strange noises he mentions in the video. And sounds wonderful when you push it. The factory box always sounded a little constrained to my ears. My opinion only.

There is a used Larini back box for sale on Piston heads classifieds. Only light use the seller claims.... Would this be a good buy in your opinion?

[AstonV]

BiggaJ said:

There is a used Larini back box for sale on Piston heads classifieds. Only light use the seller claims.... Would this be a good buy in your opinion?

I have no idea. You could probably email Larini with serial number and they could help you. It looks like an older design. Doesn't look like the current ones.

[bogie]

If the goal is a bit more noise and 10-15bhp then replacing the secondary cats on a 4.7 is simplest and most cost effective option. About 5 years ago i did mine with a pair of Quicksilver pipes for £550 and 90 mins labour at local garage. Sounds great with exhaust valve closed and open. Since that time the upgrade became an "official" AMR option and you can have it done at a dealer.