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

[Speedraser]

Mike,

I assume that up-to MY 2010 V8s can't ingest a failed cat since there aren't any in the manifolds, correct?

Is it really true that the early and late 4.7 cars have identical hp and torque figures (and at identical rpm) before and after the changes to the exhaust system? I noticed that the early 4.7s that were tested by magazines seemed to be slightly quicker than later cars. Is this just the normal variation car to car, or might early 4.7s be slightly more potent?

[Wayne95]

BamfordMike said:

Exhaust Gas Recirculating valve is on left of throttle body, the black round component in middle of pic. On a 4.7L EU5 spec car the inlet manifold has the mounting hole cast / blanked off, the car in pic has upgraded exhaust manifolds so has a blank plug fitted in the valve because some performance increase comes from deleting EGR, but normally coming out of the valve is a pipe which links valve to exhaust manifold.

EGR pretty much only helps a engine reduce Nitrous Oxide emissions, it doesn't help with other pollutants. When the 4.7L moved to EU5 spec (cat in manifold) from EU4 (cascade cat downstream), the cat in manifold took care of enough NOx meaning EGR wasn't needed - good job too because EGR makes engines feel lacklustre when accelerating due to a certain % of combustion gas is already 'spent'

So this is what mine looks like. So is it EU4, and is the braided pipe coming out of the valve going to the exhaust manifold?



Shame because I was getting excited about a de-cat.

[66MK]

Wayne95 said:

So this is what mine looks like. So is it EU4, and is the braided pipe coming out of the valve going to the exhaust manifold?



Shame because I was getting excited about a de-cat.

So was I! Looks like 400 to 200 cell for us then!

[Wayne95]

66MK said:

So was I! Looks like 400 to 200 cell for us then!

More from the piggy bank, but at least it comes with extra horses as well as volume.

[justin220]

Nick,

Any update on how you're finding the decats?

I've finally got round to ordering a pair, and being fitted tomorrow hopefully

Genuinely excited to hear the results.

This will sound wrong, but my brother's V8 Mustang sounds much better at normal speeds, and much more volume / burble aswell. I like the Vantage at high revs, but it's a bit quiet when driving sedately.

[Craig]

Does anyone know the part number for the AM secondary cat replacement pipes for a post 2010 V8 Vantage?

I've tried calling a couple of dealers - HWM and Brentwood - but they couldn't find anything listed. I've tried Kyle McLoughlin at AM Bristol as mentioned here but he hasn't got back to me.

I know Quicksilver and Larini produce them but I thought from reading this thread that there may be an AM part so I can preserve my AM warranty

Any help appreciated

Thanks

Craig

[nickv8]

Craig said:

I've tried calling a couple of dealers - HWM and Brentwood - but they couldn't find anything listed. I've tried Kyle McLoughlin at AM Bristol as mentioned here but he hasn't got back to me.

Middle of summer holiday season - he may be away?

Perhaps try Finn at AM Bristol. He kindly phoned me back the other day and is likely to be able to help.

Wouldn’t surprise me if it’s the same part as later models. Sorry - don’t know the number.

[mhurley]

Hi Mike
Am i correct in saying a 4.3 with the cat and exhaust upgrade is more powerful than a 4.7 S?

[Speculatore]

All,

Be aware of the latest government directives to MOT testers issued in June 2018.

Under the Road Traffic Act 1988 (Section 75) it is an offence to alter a vehicle in such a way that the use of the vehicle on a road would be unlawful.

A person altering the vehicle (if they knew or believed that the vehicle would be used on the road) could be found guilty of an offence under the Act. -

Potential penalties are unlimited fines.

Making changes to the engine management, emissions control, exhaust or braking systems carry the highest risk of unintended consequences.

For example, removing a catalytic converter or diesel particulate filter will almost certainly result in a vehicle’s emissions exceeding type approval limits and make the vehicle illegal to drive on the road.

Engine re-mapping may also result in non-compliant emissions.

[divetheworld]

Speculatore said:

All,

Be aware of the latest government directives to MOT testers issued in June 2018.

Under the Road Traffic Act 1988 (Section 75) it is an offence to alter a vehicle in such a way that the use of the vehicle on a road would be unlawful.

A person altering the vehicle (if they knew or believed that the vehicle would be used on the road) could be found guilty of an offence under the Act. -

Potential penalties are unlimited fines.

Making changes to the engine management, emissions control, exhaust or braking systems carry the highest risk of unintended consequences.

For example, removing a catalytic converter or diesel particulate filter will almost certainly result in a vehicle’s emissions exceeding type approval limits and make the vehicle illegal to drive on the road.

Engine re-mapping may also result in non-compliant emissions.

Which is why we v12 users were all chuffed to bits when AML put decat pipes on the Vanq-S.

[bogie]

mhurley said:

Hi Mike
Am i correct in saying a 4.3 with the cat and exhaust upgrade is more powerful than a 4.7 S?

If you do the whole system i.e. manifolds, cats, back box then you will get close to the output of a 4.7 - Im sure there are dyno charts on Bamford Rose website

[bogie]

Speculatore said:

All,

Be aware of the latest government directives to MOT testers issued in June 2018.

Under the Road Traffic Act 1988 (Section 75) it is an offence to alter a vehicle in such a way that the use of the vehicle on a road would be unlawful.

A person altering the vehicle (if they knew or believed that the vehicle would be used on the road) could be found guilty of an offence under the Act. -

Potential penalties are unlimited fines.

Making changes to the engine management, emissions control, exhaust or braking systems carry the highest risk of unintended consequences.

For example, removing a catalytic converter or diesel particulate filter will almost certainly result in a vehicle’s emissions exceeding type approval limits and make the vehicle illegal to drive on the road.

Engine re-mapping may also result in non-compliant emissions.

If you remove the main cats then it will throw a MIL and fail MOT

On a later car with the secondary cats, if you remove them it will go through still un-noticed....well at least my car has the last couple of years

The secondary cat function was explained on another thread by Mike at Bamford Rose

[simon578]

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.

[bogie]

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.

Its still deep, it just ups the volume overall, and a little more popping and crackling on the overrun. So on startup its quite noticeable, when the valves open at 4k very noticeable. Certainly more classic V8 and not higher pitched.

cars ive heard with different "more sporty" back boxes start to sound more Italian and higher pitched. Im not a fan. Im quite happy just with secondary cat pipes on my 4.7, and a remote switch

[LordBretSinclair]

bogie said:

cars ive heard with different "more sporty" back boxes start to sound more Italian and higher pitched. Im not a fan. Im quite happy just with secondary cat pipes on my 4.7, and a remote switch

I know different systems will have different sounds but I have decat pipes and a sports rearbox and the sound (to my ears) is epic and just what I had hoped for.
Deep burble on tickover - immense noise under acceleration and just a nice background growl when cruising and no droning at all.
My system was made (and tuned after a couple of goes) by a local specialist (Phoenix Performance Exhausts) and I couldn't be happier

Never had a problem with emissions and my friendly MOT tester couldn't care less (he is under the impression the straight pipes replaced front silencer boxes!!!!)

Edit - just woke up and noticed I already posted last year !!!!! Senior moment - sorry guys.

[Craig]

nickv8 said:

Middle of summer holiday season - he may be away?

Perhaps try Finn at AM Bristol. He kindly phoned me back the other day and is likely to be able to help.

Wouldn’t surprise me if it’s the same part as later models. Sorry - don’t know the number.

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

[mhurley]

bogie said:

If you do the whole system i.e. manifolds, cats, back box then you will get close to the output of a 4.7 - Im sure there are dyno charts on Bamford Rose website

n400 n400 modified 4.7 4.7s
bhp 400 436 420 430
torque 310 346 347 362


Just looked at the dyno charts, for an N400 with the full upgrade its slightly more HP than the 4.7s and the same amount of torque as the standard 4.7

[bogie]

mhurley said:

bogie said:

If you do the whole system i.e. manifolds, cats, back box then you will get close to the output of a 4.7 - Im sure there are dyno charts on Bamford Rose website

n400 n400 modified 4.7 4.7s
bhp 400 436 420 430
torque 310 346 347 362


Just looked at the dyno charts, for an N400 with the full upgrade its slightly more HP than the 4.7s and the same amount of torque as the standard 4.7

that makes sense as the N400 has the different airbox/filters too which are worth a bit more power

Its a nice upgrade for £6k ish if you have an N400.......depending on how much your car is worth, mileage etc you do have to consider a whole car upgrade with 4.7s in the mid £40's and N420s low '50s

[AstonV]

Velocity AP sell and X pipe. From their website it say.

"The ultimate V8V XPipe Center Section Exhaust system from Velocity Automotive Performance! This new design was introduced in 2015 for those customers who aspire to a smoother, higher pitched, more 'Exotic' sound for their Vantage."

I was wondering if anyone had one installed on their Vantage along with the secondary cat delete?

[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