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V8 Exhaust system


V8SMYMATE
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Hi to all i have V8 3.9 disco.I want to remove the center section does anyone know if you can buy a replacement straight through section as you can for the diesel as i want a better noise/performance. any advice welcomed

Duncan ;)

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The exhaust pipe on a V8 is part of the tuned induction/exhaust system and mucking about with the exhaust pipe on it's own will be detrimental to the performance.

For a bit more noise and an increase in performance do what I did and fit a Janspeed Cat back system it was a perfect fit, it's tuned for the engine and therefore it works with the engine being much more responsive.

Sound, well louder than the original LR system so people do turn and look if u are travling slowly down a quiet street but it's not as loud like a TVR, also it's still as quiet as the orignal on the inside the disco thanks to the thickness of the metal, just right for me. :P

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The exhaust pipe on a V8 is part of the tuned induction/exhaust system and mucking about with the exhaust pipe on it's own will be detrimental to the performance.

For a bit more noise and an increase in performance do what I did and fit a Janspeed Cat back system it was a perfect fit, it's tuned for the engine and therefore it works with the engine being much more responsive.

Sound, well louder than the original LR system so people do turn and look if u are travling slowly down a quiet street but it's not as loud like a TVR, also it's still as quiet as the orignal on the inside the disco thanks to the thickness of the metal, just right for me. :P

Thanks for that what sort of money did you have to spend? and were did you get yours

duncan

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I payed £291.00 in March 2007 including delivery from europerformance.co.uk that was £20 cheaper than Janspeed themselves, although the system came direct from Janspeed.

Do a search for Janspeed agents and their prices, but not all list LR systems.

The system part no. is J-SS729 cat back system single 76mm pipe, thats 3 inches to me.

I looked at other SS manufactures at LR shows but Janspeed use flanges to join the parts together (back box & pipe to mid box, mid box to existing 'Y' pipe) much better than sliding one pipe into another method and the welding is very neat.

U will need two SS M8 x 50mm nuts & bolts to join the flange that will be over the axel. That cost me 98p from a nut & bolt wholesaler

The exhaust hangers unbolt on the disco (or they do on mine) which is very handy for removing and refitting the rubbers and then fitting the system. :D

That's all I think, so go for-it, fit and forget and a good selling point too.

Let us know what happens ok.

Regards

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I payed £291.00 in March 2007 including delivery from europerformance.co.uk that was £20 cheaper than Janspeed themselves, although the system came direct from Janspeed.

Do a search for Janspeed agents and their prices, but not all list LR systems.

The system part no. is J-SS729 cat back system single 76mm pipe, thats 3 inches to me.

I looked at other SS manufactures at LR shows but Janspeed use flanges to join the parts together (back box & pipe to mid box, mid box to existing 'Y' pipe) much better than sliding one pipe into another method and the welding is very neat.

U will need two SS M8 x 50mm nuts & bolts to join the flange that will be over the axel. That cost me 98p from a nut & bolt wholesaler

The exhaust hangers unbolt on the disco (or they do on mine) which is very handy for removing and refitting the rubbers and then fitting the system. :D

That's all I think, so go for-it, fit and forget and a good selling point too.

Let us know what happens ok.

Regards

Thanks for the info i did try a search for janspeed but as you said some dealers wont do but now i have a part number i will try again thanks again for your help

Duncan

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Or Duncan,

What I have done is put on the janspeed manifolds (which aren't really required for this sound too much) but I have just an original centre box (although stainless) and then the side exit is also stainless, but this setup makes about the right amount of noise as it is not too loud to deafen the driver, but loud enough to catch other peoples eyes, and ears :P

So if you are working to a budget, I would recommend removing the rear box, as this gives a respectable rasp and that all important rover v8 burble :)

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Or Duncan,

What I have done is put on the janspeed manifolds (which aren't really required for this sound too much) but I have just an original centre box (although stainless) and then the side exit is also stainless, but this setup makes about the right amount of noise as it is not too loud to deafen the driver, but loud enough to catch other peoples eyes, and ears :P

So if you are working to a budget, I would recommend removing the rear box, as this gives a respectable rasp and that all important rover v8 burble :)

Thanks for that Rhys did you have any problem with lamba sensors? and was the centre box a janspeed one. As my rear box has fallen off due to rot (hence having to replace) but the sound coming out without the rear box is carp. do you think your stainless mid box makes enough diffrence?

thanks

Duncan

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No problem with the sensors for me as I have a 3.5efi

I think the centre box is a direct stainless replacement from double s. It may change the sound a little, but it still has the same route to go through.

In terms of how different it is, well all I can say atm is that it is much more responsive and freer revving. It will happily rev upto 5000rpm with no noises or struggling.

I don't understand why your one does not sound very good, as mine does sound really very good without being rough or too loud

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  • 13 years later...

Good afternoon 

 

I have just fitted a new straight through ss centre replacement aftermarket one to my disco2 4L V8 and since I have fitted it it’s really low on power and when in neutral will only rev to 4000 can anyone help please ?

 

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Hard to see why an exhaust would limit revs, that sounds like something else and either the installation of the pipe is a coincidence or disturbed something and while being fitted. 

The back pressure that's often quoted as being essential for proper running has been proven to be a myth (though cylinder scavenging is a real thing and can be effected by manifold lengths and various other things) so I don't think this is the source of your issue.

Best thing to do would be to refit the original exhaust and test the running, if it runs better then you know the replacement is at fault. Otherwise, it's back to basics with the old air/fuel/spark. When were the filters and plugs last changed?

I just can't see how it would limit revs; you say specifically in neutral, what's it doing in-gear?

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22 hours ago, Terry whit said:

I have just fitted a new straight through ss centre replacement aftermarket one to my disco2 4L V8 and since I have fitted it it’s really low on power and when in neutral will only rev to 4000 can anyone help please ?

As ThreePointFive says an exhaust alone would not cause that, I'd wager you've knocked a wire or connector or possibly damaged the Lambda sensor(s), they don't like being knocked and can crack internally.

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Lambda sensors also dont really like being disturbed at all once they have been in use for a while. Doing so usually means that you will have to change it/them shortly after

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  • 2 weeks later...

The first time I started my V8s engine after fitting the Janspeed system the idle speed went at 2000rpm for around two minutes the dropped down to the usual around 750rpm thanks to the ECM doing the adjustment.

The system is still fitted and is definitely fit & forget.

 

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