There is no need to have 4 cats replace the under floor units with California approved magnaflow items The Official Site of MagnaFlow Exhaust Products - Exhaust Systems For Trucks, Suv's, American Muscle, Diesel, & Sport Compact Vehicles

Remember the cats they make now are newer technology than the ones in the XJ not only that they are new and will flow a hell of a lot better

From what I have read and been told they are only good for 100 000 miles anyway not sure about your car mine has 249,000 k,s on the clock ready for another 249,000 I think its going that good

 

So I can just purchase the rear left/right cats and I should be ok with passing smog?
Checked applications on this page: MagnaFlow Catalytic Converters - 49-STATE & CANADA Catalytic Converters For Trucks, Suv's, American Muscle, Diesel, & Sport Compact Vehicles

 

And then there's these:



And this for those lucky enough to go catalyst free:




http://www.jagweb.com/aj6eng/exhaust3.php

 

Roger doesn't make the manifolds any more not enough demand tried buying them 5 years ago before I got into the headers

I have since spoken to my builder and he has had staff problems so is short handed at the moment I will be going up next week when I get a chance to help him out with them

 

Seems what they advertise might pay to give them a call to make sure

 

Doc,
I have dropped off the radar a bit re- the exhausts.
I have hummed and haa'ed over sticking with the 3.2 vs a V12 vs an XJS vs a later X350 XJR. Clearly I am decisive...

I am going to stick with plan A, the current X300 3.2, and if there is a plan for a batch of your exhausts, I an in.
There was some talk a few months back (?separate thread) of getting a batch made up in mild or stainless steel. Are you in the loop for that, or was it talk that died?

cheers, Al

 

Folks, here is an update on my exhaust manifolds custom-made by Hayward & Scott (H&S) in the UK. After almost two months of planning and back and forth discussions, the pipes have been done and arrived in 3 days (very efficient courier service!).

I shall let the pictures do half the talk.












The plan was for Hayward & Scott in UK to supply me with the 2 x 3 manifolds with the pipes joining the head flange tack (which can be changed if necessary) so I can re-use the flanges on the existing down pipes to connect to the manifolds; weld the 3 pipes together so they are sealed; tack the cone on and supply me with the EGR sensor flanges and 2 x Lamda sensor sockets and leave the rest for my local workshop to check and weld up.

I am totally out of depth about exhaust systems and shall see how my local mechanic and the exhaust workshop fit those piping on. I hope that the engine runs without issue and the car will be able to pass the aircare inspection. I may have to tackle the catalytic converters and mufflers later on.

 

No problems Al although if you can get your hands on a 4.2 X350 you will be blown away I am in love with mine

As for the headers when I designed them 3 years ago I had plenty of time on my hands and no one was interested fast forward 3 years and I am so busy I cant scratch myself not to mention writing of my work van a month ago
Just getting my replacement van up to scratch

I will head of to the builders next week as he had also been having staff problems and was on his own

 

They look really nice
I Don't think you will have any problems with air /smog testing Haven't had mine tested but I also had my ECU remapped by XJR Engineer as they run rich to cool the valves and with such a free flowing exhaust don't think the richness is necessary

 

Those are really nice, and a great alternative to the cracking OEM manifolds.

Too bad we don't have someone making them in the USA for a reasonable cost.

.

 

I too have ordered a remapped ECU from XJRengineer, but my local workshop has not yet installed it. The original ECU is still on board and I'll see how the two would behave differently. Other pioneers' experience is that the ECU is a must-tackle item upon gearbox conversion. This is a very complicated project. The valve cover, coil, and exhaust manifolds, there maybe more as I proceed. Wish me luck!

 

I'd be interested if these were to become available in the US for a reasonable price.

 

Folks, here is an update. After refitting the manifolds, downpipes, etc. in stainless steel, car went for emission test and failed. I don't have the readings but it was said C02 was too rich. My mechanic is finding what caused this. From a similar threadhttps://www.jaguarforums.com/forum/x...n-fail-118831/ I heard it could be the EGR, 02 sensors, coolant temperature sensor, air filter, etc. But could it be the catalytic converters? I heard that factory originals tend to clog become toasted after a while. From this site some folks suggested simply replace the floor cats with for more updated after-market cat like Magna Flow, but can someone tell me which one to use - I mean round or oval shape, length and inlet-outlet pipe size, or better still the exact Parts Number? I did a search and found several parts interchangeable. I can't DIY, am a tech-idiot and my mechanic is not a jaguar specialist (there is only one or the dealer in town) so I hope to find some answers here.

 

have you made it a dedicated twin system or gone into a single pipe then into a twin system
I used small bullet type 200 cell metal substrate cats on both my cars the XJ8 started throwing dash codes but on the XJR6 id did not
we don't have emission testing over here yearly
I also did my 02 sensors at the time on both cars

Get the remapped ECU installed the XJR6 cars run fairly rich from factory and Andy's tune does lean them out to a more ideal air fuel mixture which should help in rich reading

 

It is a twin pipe as per original layout, retaining the EGR and 02 sensors connections. At the same time I have replaced the valve cover, coil packs, etc. So it could be the usual suspects that make mixture rich. But certainly I have asked my mechanic to try Andy's remapped ECU on to see if it improves, but I need to get hold of the O2 reading first to see far off it is from the approved levels.

 

Is there anyone building headers for a 4.0 in the US?

 

Hear hear

.

 

Please someone make these and I will do my best to buy a pair.

 

I've thought about offering fabricated exhaust manifolds on many occasions. However, the reality is that I could never get them made for less than the cost of the std cast parts from a Jaguar dealer. Whilst many of us have learnt that the cast parts won't last the life of the car, I doubt that there are enough owners willing to pay a heavy premium over the cast pipes to have something that might last longer, given the current age of these cars already. However, I would love to be proved wrong.

 

I started this thread some eight months ago hoping that I would be able to gather sufficient interest in fabricated exhaust manifolds in stainless steel so some group action will create sufficient demand and business interest to build the first lot of stainless steel exhaust manifolds. Andy's idea WAS very clear from the start. No way anyone would expect to get stainless steel exhaust manifolds at factory stock price. But how much more? It depends on volume to justify a lower price. I have mine custom-made at Hayward & Scott, a professional racing exhaust workshop in the UK, at GPB800 (a set of 2x3 larger-than-stock headers plus certain length of downpipes). Andy and Doc custom-made theirs at even higher costs as theirs are head-to-tail performance solution.

The gist of this forum discussion on the exhaust manifolds is
(a) the factory exhaust manifolds are prune to crack sometime down the road;
(b) stock exhaust manifolds are expensive (about GPB550) and may not be available, and WILL crack - H&S observed that the factory design (ultra short and turning angle) would subject the cast iron exhaust manifold to undue pressure and hence liable to crack
(c) welding and/or buying used ones is false economy - moreover, used good ones are getting hard to find
(d) there are different versions of the factory originals (with and without EGR valve, with or without air injection).

So an after-market solution would be difficult to fit all, unless there is a well thought-out universal version.

Doc has tried to develop a mild-steel version with a professional workshop and work out a price. There hasn't been more news. Andy has the same thought but doubt people are really keen to buy them, if made. I believe that X300 ownership has become steady and the will to keep is getting strong at least among several enthusiast - if you are willing to tackle the notorious ignition coils, I wonder why folks would hesitate to go stainless steel.

If going it simple, what would folks say would be a reasonable price for a set of stock replacement in stainless steel, and assuming that the first lot is limited to five sets?