Hi Guys

1989 XJS V12

During her recent MOT the Tester remarked that her Exhaust was 'Blowing' a little bit on the join at the Down Pipe, apparently not serious and suggested a bit of Exhaust Pipe Sealant could be all that was needed

But even so, I got 'The Look' if you know what I mean

So I'm thinking of replacing the entire Exhaust from the down pipes and probably also Center Box Delete

Can I buy something off the Shelf that I can fit myself, without getting in to anything very expensive

Also in the UK is it legal to delete the Center Box?

 

OB,

The legality of centre box delete hinges on 2 aspects:

- Does the car still pass the relevant emission standard?
- Does the car pass any noise limit requirement?

For a well-maintained V12 XJ-S, you should be fine on both counts.

There may well be cheaper options in the marketplace, but read through the Simply Performance website content for both info and prices:

Also have a look at the AJ6 engineering website for their systems

Jaguar Performance Exhaust Systems (simplyperformance.com)

XJS Systems – V12 & 6 Cylinder | aj6 engineering

Cheers

Paul

 

Hi Paul (ptjs)

Excellent!

Many Thanks for that

AJ6 Engineering seem to have just what I need

Cheers (OB)

 

Bell Stainless from SNGB are excellent and (for stainless) not catastrophically dear. I have had one since 2001 and still rock solid.
I cousel against the centre box removal, it makes the V12 horribly loud and unpleasant.

 

Hi Greg

I will Check them out but I kind of like the Burble

A lot depends on how much it all comes to

 

Bell Exhaust from SNG Barratt is an excellent choice. SC Parts also have a stainless exhaust, one of which I have, and it might be a Bell. Hard to tell because it is not marked Bell. Both are excellent, but I’ve gone mostly with Bell… probably done five of them.

 

TYPO, I meant to write SINCE 2001 !!

 

I will second that. I have sold my centre delete pipes again after around 15.000 km. They make a drone at around 3000, and that corresponds to continuous noise at motorway speed for me…
Really nice execution and quality of the parts from SP though. I also have their down pipes, very nice and good fit.

 

Third on the centre delete. It's not a nice noise. Hard to describe, but certainly not "V12 growl", more like "mosquito in your ear"

 

From a bit of research, I think the center box delete question is a "it depends situation".

What does it depend on? Catalytic converters, and the number of them. Coupe or Convertible?

I'll take the latter question first, and actually disagree with Roger Bywater's comments on the center box delete. He said something along the lines of 'it might be too loud for a convertible, so straight through mufflers might be a better choice.' I think it is the opposite. If you have a coupe, why on earth would you want it louder or more aggressive or rumbly, etc.? The whole point of the coupe is the embodiment of a stealthy chariot, the ultimate Grand Tourer that is a cocoon from the elements. I imagine it's what Jaguar engineers spent inordinate amounts of time perfecting the correct quiet tuning. Any increase in decibels would be difficult to engineer to not create droning or other unwanted resonance in the cockpit.

However, having only owed the convertibles, and I wouldn't drive the beast if I could help it with the top up, I find myself more and more driving with the audio system off, and just enjoying the sound of the beast when it is well sorted. I wouldn't mind more from the exhaust, so I've contemplated the center box delete.

From reading nearly ever thread here and other forums, the presence and number of catalytic converters seems to be a factor in how much people like the delete. Straight downpipes with no cats, I imagine would create a different tone and db level than a two cat set up, or four cat US spec car. From what I can glean, on the US spec cars, the delete isn't as loud or droning as the no cat cars.

The other piece of the puzzle is the final section the exhaust -- the resonator. Again, I'll bet there was lot of engineering cycles to make that work harmoniously with the rest of the system. So it seems quite a few people have done some tuning by replacing that piece as well, and the resonators chosen appear to be inexpensive enough that one could try a few options.

With all that in mind, I'm going to try the center box delete, and I'll report my impressions. Fortunately, my center boxes are in good shape, and I have to replace my intermediate pipes, so I can reverse course if I don't like the results.

@orangeblossom if you can wait a few weeks, I'll let you know what I think once I've done the delete.

 

Here a video of take off. No cats, probably not original rear silencers. There are other videos on my profile before/after, inside car and so on

BR Leo

 

Hi Jagboi@leo@Greg@Mac

Interesting opposition to 'Center Box Delete'

I thought you might be all in favor of something like that

But even so Jaguar could have made a much better job of designing it than they did

Has anyone tried the X Pipes?

I'm with you Mac, same here with my Convertible and 'No Cats' on my Car in the UK

Leo, I can't get your Video working from your Link and so I will see if I can find it on YouTube

 

There is no need on an V12 ( or straight 6 with dual exhaust) because there are all even fire engines. The exhaust puffs follow one after the other, so there is "space" in the exhaust system for the discharge of each cylinder to follow the one before. A typical V8 is not even fire, they often have 2 cylinders fire on the same bank sequentially, due to crankshaft geometry. Thus there is part of the entire cycle where there is a greater volume of exhaust on one side than the other, and the crossover pipe evens out the pressures. A crossover pipe would do nothing on a V12.

 

Well said! There is a site with headers on a V12 ( Camp Chaos) spending one whole summer doing a beautiful job of fabricating a set of equal length headers properly designed based on camshafts used.
With al that work he gained 4% more power then the stock cast iron manifolds . ( Oh, each manifold weighs only 4 pounds ) I’m sure any set of headers will weigh a lot more.