XJR8 Exhaust options
Discussion
The LH exhaust finisher has broken off with the end of the rear box inside. Also much of the intermediate exhaust looks to have seen better days, The RH rear box is reasonably new.
Has anyone removed the intermediate silencers and had straight through pipes connected from the centre box to the rear. I would like a bit more noise from the V8 and wondered if this could be the way to go?
Has anyone removed the intermediate silencers and had straight through pipes connected from the centre box to the rear. I would like a bit more noise from the V8 and wondered if this could be the way to go?
Whilst it would be possible to make the exhausts louder, I'm not sure it would ever make a particularly nice characteristic V8 burble.
The reason for this being the rather crude manifold design where all 4 cylinders one each bank are emptied out into a single cast iron collector. This mashes the pressure pulses into a right old porridge long before it can give any aural pleasure from the tailpipe. The supercharger is a bit of a blunt instrument for engine tuning. Note Jag also binned the variable cam timing on the s/c engine.
Peter
The reason for this being the rather crude manifold design where all 4 cylinders one each bank are emptied out into a single cast iron collector. This mashes the pressure pulses into a right old porridge long before it can give any aural pleasure from the tailpipe. The supercharger is a bit of a blunt instrument for engine tuning. Note Jag also binned the variable cam timing on the s/c engine.
Peter
Hi,
We have changed many an xj/xjr exhaust and it largely boils down to what you want to achieve long term.
Removing the intermediate silencers under the seats and having straight through sports rear boxes will get you quite a nice sound externally on idle and under acceleration, if you go to open they tend to sound horrid and 'flappy' on accel. IMO.
Removing just the rear boxes gives an equally pleasing sound externally but in our experience leads to a horrid droney boomy cabin noise around 2000rpm.
Both of the above will introduce noise inside the car, it is personal as to what is acceptable vs any external sound improvement.
My personal choice on an xj/xjr is a full system from the cats that retains all five silencers but a tad smaller and straight through in design, this keeps cabin noise to an absolute minimum in fact almost unchanged and gives a subtle increase outside, I feel the xj's do not warrant the same levels of noise an xk/xkr can carry and if to loud soon begin to annoy rather than please. As always though one persons perception of loud and nasty is the next guys perfection, personal choice is the name of the game!
Dan
www.eapj.com
We have changed many an xj/xjr exhaust and it largely boils down to what you want to achieve long term.
Removing the intermediate silencers under the seats and having straight through sports rear boxes will get you quite a nice sound externally on idle and under acceleration, if you go to open they tend to sound horrid and 'flappy' on accel. IMO.
Removing just the rear boxes gives an equally pleasing sound externally but in our experience leads to a horrid droney boomy cabin noise around 2000rpm.
Both of the above will introduce noise inside the car, it is personal as to what is acceptable vs any external sound improvement.
My personal choice on an xj/xjr is a full system from the cats that retains all five silencers but a tad smaller and straight through in design, this keeps cabin noise to an absolute minimum in fact almost unchanged and gives a subtle increase outside, I feel the xj's do not warrant the same levels of noise an xk/xkr can carry and if to loud soon begin to annoy rather than please. As always though one persons perception of loud and nasty is the next guys perfection, personal choice is the name of the game!
Dan
www.eapj.com
I am thinking that maybe a free flowing exhaust system may be the way to go.
Amazing the price differences between the Midlands and the South coast. Most powerflow/longlife centres want £700 down South whereas several proflow and other indys in the Midlands are quoting £350. In Leeds they're down to £266 for a cat back longlife system.
I had a longlife rear section fitted to the Tuscan and am very happy with it. Got to be worth a 3 hour drive to Birmingham to try the proflow system!
Anyone here used them?
Amazing the price differences between the Midlands and the South coast. Most powerflow/longlife centres want £700 down South whereas several proflow and other indys in the Midlands are quoting £350. In Leeds they're down to £266 for a cat back longlife system.
I had a longlife rear section fitted to the Tuscan and am very happy with it. Got to be worth a 3 hour drive to Birmingham to try the proflow system!
Anyone here used them?
This is the full stainless exhaust option. I would be interested in your opinions! It sounds a little squeally on lift off but could be the recording!
http://www.youtube.com/watch?v=h6YGDCnUCW0
http://www.youtube.com/watch?v=h6YGDCnUCW0
6speedmanual said:
Whilst it would be possible to make the exhausts louder, I'm not sure it would ever make a particularly nice characteristic V8 burble.
Have to disagree with that, since the XJR8 engine is basically the same as an XKR and we have managed many, many times to produce a good V8 noise, and you can play with it with various boxes to control the sound. Sure the manifold is a crappy design but it was an easy/cheap cop out to make everything fit, I would love an equal length manifold 4-2-1, one side would be easy, but getting around the steering coloumn would be a nightmare. As I am more of an XK guy than an XJ I am sure you could simply replace the rear box with a straight through pipe, just be aware they are a resonator box at the back and you will get a certain amount of drone.
And yes the You Tube vidoe is just a bad recording but you get the jist and it sounds pretty good.
I have to agree with XKRacer
Although not perfect, as they say 1/2 a loaf is better than none
There is so much wrong with getting the perfect 'Free Flow Bunch' to fit
No room as XKR said there is the steering box, then the inner wing, also the engine mounts
Even then it would not be perfect as the firing order is all over the place you would need crossovers as the GT40's
But as stated before you can still get a good 'Burble'
Although not perfect, as they say 1/2 a loaf is better than none
There is so much wrong with getting the perfect 'Free Flow Bunch' to fit
No room as XKR said there is the steering box, then the inner wing, also the engine mounts
Even then it would not be perfect as the firing order is all over the place you would need crossovers as the GT40's
But as stated before you can still get a good 'Burble'
I had a Longlife ss cat back exhaust fitted just a couple of months ago by Topgear/Longlife in Bridport. The same number as stock silencers were fitted, but they were made quite a bit smaller.
It has made a real difference to the car (I was thinking of changing it but now I am not). Nice deep burble on start-up and under acceleration but no extra noise in the cabin when cruising at 60+mph. There is a bit of a boomy drone in the cabin at about 2000rpm when under light acceleration, but not annoying at all. The sound when under hard acceleration on changing up gears is very addictive! It is definitely a fair bit quieter than my TVR, but much better than the stock set-up. Quite a few people have mentioned how nice it sounds.
It took 2 people all day to make (they didn't finish until gone 6pm) and it cost me £699 inc VAT. I cannot fault the quality of their work from what I have seen - and they were very keen to keep it right for the car.
Definitely recommend them.
Chris
It has made a real difference to the car (I was thinking of changing it but now I am not). Nice deep burble on start-up and under acceleration but no extra noise in the cabin when cruising at 60+mph. There is a bit of a boomy drone in the cabin at about 2000rpm when under light acceleration, but not annoying at all. The sound when under hard acceleration on changing up gears is very addictive! It is definitely a fair bit quieter than my TVR, but much better than the stock set-up. Quite a few people have mentioned how nice it sounds.
It took 2 people all day to make (they didn't finish until gone 6pm) and it cost me £699 inc VAT. I cannot fault the quality of their work from what I have seen - and they were very keen to keep it right for the car.
Definitely recommend them.
Chris
Right I have booked the car into an exhaust centre in the Midlands, the guys that did the exhaust on the youtube link posted above.
On the youtube XJR the system has two large silencers, and straight pipes with a 2" bore size. They tell me that they have found this to keep the drone down and let the smooth V8 purr be heard.
They are offering that If I require more silencers this isnt a problem, what they can do is take the old system off, start her up and place different silencers in position to get an idea of the sound I require.
Sounds like a plan, although I won't know how it will sound under load until I have chosen an option...decisions, decisions!
On the youtube XJR the system has two large silencers, and straight pipes with a 2" bore size. They tell me that they have found this to keep the drone down and let the smooth V8 purr be heard.
They are offering that If I require more silencers this isnt a problem, what they can do is take the old system off, start her up and place different silencers in position to get an idea of the sound I require.
Sounds like a plan, although I won't know how it will sound under load until I have chosen an option...decisions, decisions!
Got the paramount performance system icnluding sport cats on the XJR. Cost pver a grand, At first was slightly dissapointed, but give it a good few thousand miles and now it sounds fantastic. Pops if you hold it in gear, and rumbles on idle. The upgraded supercharger pulley whines alot after 3k which drowns the exhaust out if your inside. Cars only done 30000 miles, so I'd imagine this system well used would sound brilliant
A bit of feedback. I had a stainless exhaust fitted a few weeks back by a company in Birmingham who advertise on ebay. When I got there, a 3 hour drive, they tried the; that price is for a centre back not cat back system. On realizing that it was their mistake in their listing they agreed to make a cat back system including flexi section for £399.
I took the dog for a long walk and came back 3 hours later.
On initially driving the car I recall thinking, oh no, what have I done as it was considerably louder and boomy at 2k revs. After an uncertain drive home and a few weeks of using the car I think it was the best £399 I could have spent. It drones a little at 2k revs but not annoyingly so, it just took a little getting used to after the silence of the original system. Under load above 2k revs it has the lovely V8 rumble. At idle it sounds throaty and just the right volume.
It has stopped me driving the car like I am driving Miss Daisy and encouraged me to enjoy the 370 bhp with the aural pleasure that comes with it.
MPG has increased by approx 3 around town and as much as 7/8 on a good motorway run.
All in all I am very pleased with it. The system is straight through with just rear silencers and also looks good from behind.
I took the dog for a long walk and came back 3 hours later.
On initially driving the car I recall thinking, oh no, what have I done as it was considerably louder and boomy at 2k revs. After an uncertain drive home and a few weeks of using the car I think it was the best £399 I could have spent. It drones a little at 2k revs but not annoyingly so, it just took a little getting used to after the silence of the original system. Under load above 2k revs it has the lovely V8 rumble. At idle it sounds throaty and just the right volume.
It has stopped me driving the car like I am driving Miss Daisy and encouraged me to enjoy the 370 bhp with the aural pleasure that comes with it.
MPG has increased by approx 3 around town and as much as 7/8 on a good motorway run.
All in all I am very pleased with it. The system is straight through with just rear silencers and also looks good from behind.
6speedmanual said:
Whilst it would be possible to make the exhausts louder, I'm not sure it would ever make a particularly nice characteristic V8 burble.
The reason for this being the rather crude manifold design where all 4 cylinders one each bank are emptied out into a single cast iron collector. This mashes the pressure pulses into a right old porridge long before it can give any aural pleasure from the tailpipe. The supercharger is a bit of a blunt instrument for engine tuning. Note Jag also binned the variable cam timing on the s/c engine.
Peter
The cast iron log manifolds don't mash the pressure pulses into "porridge" at all. Exhuast noise is subdued due to regulations (74 Db drive by in Europe). This is demonstrated non sense as evidenced by thousands of American Muscle cars from the 1960s and 70s. If you want a V8 burble- the 4th order and half order side bands must be amplified (3 and a half and 4 and a half) and a bit of 8th order would also help. The exhaust silencers should be sized and designed to accomodate this. On the X150 strong 4th order was targeted WITHOUT too much half order.The reason for this being the rather crude manifold design where all 4 cylinders one each bank are emptied out into a single cast iron collector. This mashes the pressure pulses into a right old porridge long before it can give any aural pleasure from the tailpipe. The supercharger is a bit of a blunt instrument for engine tuning. Note Jag also binned the variable cam timing on the s/c engine.
Peter
On the intake side the Supercharger WILL tend to dominate induction noise- so it's perhaps best to use the exhuast to tune for aural delights
richardxjr said:
This is what I had built for my XJR6. Fully custom made by Zero in Ashford Kent. Ditched the centre cats only - still fine on emissions for the MoT. Just enough more noise on full chat.
Well done, now you've destroyed the tuned pulses of the original twin pipe system of the straight six. This will muller your low speed torque. This is why 6 cylinder cars try to keep the exhaust banks seperated as far as possible (BMWs for instance) with the exception of a H pipe communication.
Marquis Rex said:
The cast iron log manifolds don't mash the pressure pulses into "porridge" at all. Exhuast noise is subdued due to regulations (74 Db drive by in Europe). This is demonstrated non sense as evidenced by thousands of American Muscle cars from the 1960s and 70s. If you want a V8 burble- the 4th order and half order side bands must be amplified (3 and a half and 4 and a half) and a bit of 8th order would also help. The exhaust silencers should be sized and designed to accomodate this. On the X150 strong 4th order was targeted WITHOUT too much half order.
On the intake side the Supercharger WILL tend to dominate induction noise- so it's perhaps best to use the exhuast to tune for aural delights
How the hell are you Rup.On the intake side the Supercharger WILL tend to dominate induction noise- so it's perhaps best to use the exhuast to tune for aural delights
Christ, you know your stuff!
Regards,
James
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