getting some exhaustwork done. i was thinking of doing a flowmaster 40 SERIES 2 CHAMBER MUFFLER 2.5" OFFSET INLET/OUTLET Muffler and to have my catalytic converters pulled and replaced with fake ones AllFlow Test Pipe, Stainless Steel - 2.5". so i have to ask will this work out for my 92 v12 xjs. i can get all this done for less then $500

 

The exhaust isn't that demanding. Not much you can do wrong with it... Other than putting more restrictions in it by using smaller pipes.

A decat won't really gain much power, as you still have the lambda metering and that regilates then what is possible...

Where do you intend on putting the flowmasters? Right at the rear will be hard, as those spots are basicaly spot on for the round Jaguar ones. If you want more sound, you'll want to ditch the middle resonators/silencers...

 

DAIM what would be a good exhaus set up that would give a bit of power and good sound ?

 

If you have the funds, the best exhaust specifically made for the XJS v12 from the power point of view is AJ6 Engineering's TT stainless exhaust, with or without straight through silencers under the car, depending upon what you noise level decisions are.
HIGH QUALITY XJS EXHAUST SYSTEMS from AJ6 ENGINEERING / AJ6 Engineering
If your old exhaust is shot, this is not a great deal more than a full replacement, and it does make a substantial difference.

Greg

 

Sound can only be made by making the exhaust reduce the muffling...

Many have already managed to get a better 'purr' by removing the resonators infront of the rear axle and replacing them with pipe (there are stainless steel replacement parts available). It won't drone nastily and you'll have a more Jaguar-like purr rather than scream or rumble.

As Greg said, update to the AJ6 Engineerng exhaust. That seems a good buy!

The biggest restriction in the exhaust setup is the rear overaxle pipe which is diameterwise tiny... Some have removed this by using oval pipes and going under the diff instead. You lose a few cm of axle clearance but that is neglectable.

Real power gains can't be expected, unless you ditch the entire exhaust and go custom headers with sidepipes... Otherwise the power gains start with modding the engine... Larger intake pipes to the airfilter boxes are a good start. Some cold air ducting followed by larger bore throttle bodies (or even the Lister 4 throttle body setup) with matching software...

 

you could try these,
and some places also make them remote controlled

 

On my '88, the exhaust diameter between the cats and the resonators is 2.25" and that decreases sharply between the resonators and silencers to a mere 1.50". If I recall correctly from the exhaust threads on the board that I've tried to keep up with, 2.50" exhaust will have to be routed under the IRS.

I'm planning a 2.25" system next year. I'll find a super turbo style muffler to replace the resonators, and either forego the rear silencers or use Flowmaster HP-2 mufflers. The small profile should fit the tunnels just fine.

You'll have to let us know how the work goes, and more importantly, how the cat sounds!