Hi

I am in the process of helping design a 'Stainless Steel' Exhaust System for my XJS V12 with the guy who is going to make it, namely 'Mr Mig' the GF's Dad.

So as I was doing some research, I saw that it was possible to eliminate the Center Silencers.

According to what I've been reading, these really choke up a Jag and can hold back the Power. (don't know how much truth there is in that?)

But in the event that I go that route, will I lose the 'Purrrr!' as I don't want to come over all Boy/Girl racer and attract the wrong sort of attention.

Has anybody done this and what did it sound like?

Also would doing something like this 'ie' non standard exhaust system, be regarded as a (UK) MOT Failure?

Worst case scenario, we can replace the whole system as it is in Stainless Steel.

Your Thoughts on this appreciated.

 

I've removed my mid mufflers and all cats and to tell you the truth sound wise you can barely tell the difference, sound came about with the open growler air filter set up and even then it's not annoying at all? I had a drone at highway speeds with the mids removed but had an H pipe put in just aft of the trans and the drone disappeared.

 

OB
I think it depends upon the rear silencers in the tunnels each side of the boot. I have heard a car with the centre boxes removed and it was deafeningly loud, ruining the car. Others say they can be OK. But, as the great Bob Knight, Jaguar's ride refinement genius said: 'You can only impress people with a Jaguar's refinement, not its speed'.

FWIW, I believe that the best value mod for more grunt is the AJ6 enhanced ECU and large throttle bodies. My car has these and it utterly transformed its performance thoughout the rev range, astonishingly so for high speed acceleration. The refinement of the car is unaffected. I also have stainless downpipes as part of my exhaust system, some of the factory downpipes were pretty shoddily welded up internally, so that is also worth checking.

Obviously we are in the realm of personal taste here, for me, but an unrefined XJS loses its "je ne sais quoi" - that undefinable something that makes it so special and addictive.

Greg

 

OB, I had the centre boxes out of my Lister and it sounded really good.
There was no real difference when you were just pootling along but when you nailed it it sounded great (ideal for setting off BMW alarms). It was especially awesome in tunnels!
It was definitely louder than standard but not intrusive.

 

Hi JT

I'm still a bit undecided, as I don't really want to lose that silky smooth purr! at the expense of having a bit more power, so may go for 'Greg's' suggestion of a remapped ECU.

 

Hi Greg

As I don't want to lose that refinement, your idea of having a remapped ECU has much more appeal, though I'm not too sure about bigger throttle openings.

Would that increase the fuel Consumption that much? as I'm only getting 15.9 mpg at the moment.

Same question for the ECU.

The one thing I have noticed about the Standard Pipes is that they seem to have 'flat spots' on the curves, which is one thing that we will be trying to avoid.

So hopefully that will also make a difference?

 

I had this 3" Kiesler system on my car for a few days.....



It was imaging to hear what the V12 actually sounds like when it is not being strangled by mufflers, etc.

I only had it on my car for a few days mainly because I had a lot of ground clearance issues, but also to be honest, after a while the noise got on my nerves a bit.

My "other" British car, which is also V12 powered, has electric bypass valves that open when you step on it, so you get the best of both worlds........ I think I saw a while back a member fitting electric bypass valves to an XJR on the X308 forum......... might be worth a look

 

Hi Steve

I don't want louder, I want faster!

I want the Insane acceleration, that 'Greg' was talking about and while I am very tempted to remove the Centre boxes, I didn't really want to lose the quiet sophistication of the Purrr!

So the remapped ECU may be the best way to go.

Love Your Car and love those Wheels!

But you're Cheating!

They are far too easy to Clean!

 

Hi Sarc

The noise was at the back of my mind, in more ways than one, as noise can be a bit 'Marmite' which you either love or hate.

When I was a lot younger, I did all the 'Big Bore' stuff but its just not for me anymore.

Nowadays, I just like it quiet and very fast!

I can't even hear the Stereo, at anything over 40mph and that's with the 'bog standard system' that I have on at the moment.

Up until a few year ago, I used to have a 'Chimaera' which was a Car I thought I always wanted.

But the noise used to drive me crazy, it was just like having a motorbike in the boot and though it was a 'neck breaker' it really only used to turn heads on those who knew what it was.

I cannot think of any Car that I would rather drive, than the XJS that I have now, although you have probably got 'the bragging rights' with your DB9 but I need all that extra cash for Petrol to run what I've got!

 

@orangeblossom

I have to tip my hat to ANYONE who can afford to run ANY Jaguar in the UK. I have been around Jags since I was 14, yet it took me until 35 before I finally got one, and that was only because I moved to the US so I could afford the gas/insurance/not worry about it rusting before my eyes/have other cars for when it broke down.

I hear you on the TVRs..... a friend of mine had a Griffith and it was fun for about 5 minutes, but then it continually tried to kill you and it got a bit tiring with the noise.

The DB9 is a beautiful car and I am very lucky to have it, but like you, I have a stronger connection to my XJS and will likely be buried with it.

 

Hi Sarc

You are just bang on with that observation!

The TVR was fun for 5 minutes but after that the novelty wore off and as such will be remembered by me as a very forgettable Car!

Even when I see one now, it just doesn't do it for me, as for one thing the powers that be, just won't let you play anymore!

The XJS is a totally different animal altogether and on the day they first came out, I wanted, No! I lusted after one!

The only problem being that I didn't have 50 grand in my back pocket!

So I saved up for an old 'Pre He' and then gradually worked my way up to the Car I have now, which is just so beautiful, if I could get it in the house then I would sleep with it.

Every time I look at her, I just find myself going, 'Wow and double Wow! and not just for 5 Minutes, I do it every single time I take the cover off.

Taking the 'Diva' out for a drive for me is a really big deal and is the kind of experience that words on their own cannot describe.

As from the moment you turn the key, you are well aware that a wicked 12 cylinder power house, is hiding under that achingly beautiful bonnet (hood)

Some say that you can do 80mph while still in 2nd gear auto before you change up into third, so what I'm saying is 'eh! Hello! is this Car Fast or What!'

Even thinking about her now, She's leading me into temptation, like a Woman who's wearing Chanel, It's that sort of Car.

One minute the epitome of pure sophistication and then the next a wild child who is intent on wrecking the most intense relationship you may have had with any other Car.

But as I may have said before, you need to have a 'few screws loose' and a wallet full of cash to back it up!

Or you won't be going very far, not in a Car that drinks petrol like its going out of Style, which can easily do an eye watering 15 mpg!

Plus as you say, Insurance and all that kind of stuff and though She seems very reliable, when once sorted out (Thanks to 'Greg' for his help) When they go wrong its either Minor or enough to melt a set of Credit Cards!

If She doesn't rust away before your very eyes but as for the cognoscenti in which I include myself, I never want to ever own any other Car.

Except maybe for your Aston!

 

It's too bad you don't like your car, OB.
Just think of all the fun you could have if you ever wanted to actually Drive it anywhere.
ROTFL
(';')

 

OB

You should get about 17 to 18 real world MPG, unless you spend your entire time in traffic and doing short journeys - quite possible in the south of England! That is what I get, but it was definitely improved by changing the main engine driven fan to an electric one and by a new stainless exhaust - your old centre boxes may be a bit coked up. I take it that you have Marelli ignition? If it were Lucas I could suggest things to check.

The AJ6 ECU and throttle bodies have to go together. Their third stage, the tweeked inlet manifolds, are meant to be most desireable too, but were too dear for me and anyway what I have got is exactly right for me and I am never left feeling I need more grunt. It will not noticeably affect your MPG, and may even improve it, as the change down to 2nd is less needed to get the car moving in the vital 50 to 80 range, plus the induction losses are reduced.

Hitting 80 in 2nd is nothing, lad, nothing. Second, selected on the stick, will hold indefinitely. I have hit 125 in mine, three up, no bother. Love it.

 

I well know the feeling. My 2001 XJR1300 was like that(had it for a life time). Until I had to sell because after 29 years of riding(on all sorts of fast bikes) I realised I was tempting fate every day using every one of those horses. (one of those morons you see doing really stupid stuff)
Bought a Bonnieville and a Jag,loving it. But I do miss the redline scream and absolute thrill of just blipping the throttle to do a massive mono or just plain go fast... but as I was getting older I was getting less responsible so gave it away for red wine and grace.
My manager of 12 years is wondering why I suddenly changed to captain slow.
Passing a mobile speed camera car at 176km/h on the back wheel accelerating out of sight(in a 70 zone),then him catching you 14km later at your off-ramp slows you down. That was my dialy trip to work for many,many years.
Suddenly realised I was 44 and not 19.

 

Hi Greg

Is that AJ6 ECU and those Throttle Bodies anywhere near as 'Wallet Busting' as I fear that they are going to be?

Believe it or not, I used to be a 'Slow Driver' like the kind that you might find on the end of a Caravan.

The only problem being that driving this Car is a drug! to which I confess I am hopelessly addicted, even more now than 8 years ago when I put her back into the garage for what was to be the last time.

But now I can appreciate her even more than ever, for the Iconic Masterpiece that I think she is and would never have got her back on the road, were it not for your expertise, encouragement and ongoing help.

You would have to have a 'screw loose' to buy one of these, so at least that is one box that I know I am able to tick! as at the time in the UK Petrol if I remember was around £4 per gallon and not over £6 like now.

The problem being these days lots of people either go for diesel, or drive around in these micro type cars that seem to run on fresh air!

So owners of Classics always seem to get hammered, or rather decide to give up the 'Booze' and let the Car do the drinking.

Now really go and upset me and tell me how much a gallon of gas is in France as well as those miles of deserted roads where you can give her the gun or else Swan around in the Sunshine of the French Riviera.

I don't know about you Greg, but I feel a 'Pimms' coming on!

 

OB,

"Speed" is an interesting concept. It's as much to do with aural and physical sensations as it is to do with actual velocity. My first car at 17, a £50 1963 Vauxhall Victor with a rotten exhaust that bellowed and then backfired on the overrun made me feel that I was travelling at warp speeds rather than the pedestrian progress I was really making!

The removal of teh centre boxes will make the car a bit quicker but, even with standard rear boxes, will increase the noise to some degree. A well set-up car will still get through the UK MoT emissions without the centre boxes.

Apart from revised intake systems, one very cheap thing that you can do to increase your driving pleasure is to buy an adjustable vacuum modulator for the gearbox. You can probably get one for £20. That will enable you to have much sharper gearbox changes at higher revs. A simple change that could be the best £20 that you spend!

Good luck with all your decisions

Paul

 

Stock GM modulators on the Jaguar T/H400 are adjustable, never a need to buy the aftermarket one.

 

I cannot remember ever seeing a 'Black' XJ6 before!

Nix looks just amazing, so no wonder She won that award!

But as for me, its been a perfect day, as after continuous showers of rain and one or two gale force winds, the Sun came out from wherever it was hiding and as such I reluctantly had to put the Top Down and go for a Drive

This time out in the Country, calling in for a Pub Lunch on the way, which was later followed by an evening Meal at the Marina, which is one of our favorite destinations.

Its a rotten job but someone has to do it!

 

Now I know why 'Shopping Trolleys' hold no fear for you! 176km/h! that's just 'stark raving bonkers!'

But I've got Cousins who are Speedway Riders and they never stop talking about that adrenaline rush!

Captain Slow you are certainly not and I could not be even more impressed!

And I think that it goes without saying, that those Bikes of yours are Awesome!

 

Hi Paul

This is 'Spooky!' As I also learned to drive on a Vauxhall but this was a Vauxhall 101 Estate, which as I remember was about the size of a London Bus!

Absolutely massive it was and not exactly an ideal Car to learn on, especially as the instructor was my Dad!

Who was as far removed from PC as you could possibly get! and had some unusual methods of drivers instruction!

He sat in the drivers seat, controlling the pedals and speed and all I had to do was steer the Car.

But while I was sitting on the Passenger Side!

Just in case you were maybe thinking that this sounds dangerous, let me put your mind at rest and say that you are wrong, as it wasn't half as dangerous as it seems.

Instead I feel I need to say that this was as close to Insanity as it could possibly get!

For although he started off quite slow, before I knew what was happening we were doing 50 mph

The theory being Steering was the most important thing and if I didn't do it right, then we would both be killed and the worst thing was I really didn't know if he was joking!

Having lived to tell that tale, 'The Mars Bar Challenge' was next, which involved me driving the Car from the Drivers side for a Change!

Where I had to drive along at 70 mph.

During which time, I had to unwrap a 'Mars Bar' and then eat it, while we were going along at break neck speed!

Just imagine what would happen if they ever caught you doing something like that to-day, they would simply throw the book at you!

So while all of this lunacy, stood me in good stead for 'Real World' driving, he gave me so many bad habits, that I not only failed the Test but actually failed it 5 Times!

Those were the heady carefree days that we don't seem to have any more!

My Dad may have been 'Bonkers' but I only wish he were alive to-day!

As of now I'll get genned up on the Modulator, as it sounds that it could be a useful piece of kit!