dibbler

New Member
I want to remove the middle silencer on my L reg 3.9 Disco (200). Anyone know if a simple replacement pipe is available & if so where from, I’ve had a look about & totally failed to find such an animal,. This is despite the fact that according to a mate who has the “discovery customisation book” by Haynes it’s supposed to be a “common upgrade” (or is it just another lie, from the book of lies)

I’ve not had the Disco long & the previous owner replaced the whole system just before he sold it, its silent, what’s the point of owning a V8 if it doesn’t burble ><
 
just go steel pipe stockists get a bit cut two slots in each end and rejoin pipe without box.clamp with u bolts and cement to seal.Job done.
 
I know I&#8217;m being picky but the front connection is a flange connection & I don&#8217;t really want to cut the flange off in case I ever want to reverse the upgrade. But I guess I may have to unless there is an off the shelf solution. Or I could make a new flange up & weld it to the new pipe but that&#8217;s a pain.

Also, does anyone know if the new pipe will be straight or if it will need to dogleg slightly? Lying on your back underneath, without it being jacked up, doesn&#8217;t give you the best view to judge the alighnment.
 
you could get a flexi but they so ****e.just wack it on.
OR cut the flange arf th box put it on the straight pipe and replace without box.
as long as it dont leak its legal.id be inclined to get a flange from scrapper and leave box intact as the MRS wont like it and you will have to put the box back on for tesco:D

Boomer done this and his woman at the time was hell up.The reverb at 2500rpm is some rumble but thats the best bit
 
Hi. Mxm 4x4 on the internet, mid box replacement pipe, £40 ish with post+packaging, fits Discovery and RR Classic 3.9.
Fitted myself in about 15 mins. Don't forget the sealing paste. Revs a little more freely, sounds much nicer:)

Cheers, Nick
 
Yes i probably could, but i didn't......... and it was stainless and i can put the stainless silencer back on when it goes for the annual government fund raisi.....mot.
 
Ok, if its going to wind the misses up it may be a step too far,she's driving it more than me at the moment.

Is there an option for a happy medium, if it was as loud as a TVR for example I would be happy, its just silent at the moment.

I may as well have a doosel, I just want a bit of V8 burble.
 
Ok, if its going to wind the misses up it may be a step too far,she's driving it more than me at the moment.

Is there an option for a happy medium, if it was as loud as a TVR for example I would be happy, its just silent at the moment.

I may as well have a doosel, I just want a bit of V8 burble.
just do it 118.com

straight through and be done...:eek:
 
Hi.

When you get to about 35 its just a very pleasant burble, and if you buy the mid box replacement pipe or do a good job on the diy side, if she does not like it then you can change it back.

Simples peeps.
 
mine is twin exit straight thru pipes, the wife can hear me so far away she can get her fella out the bedrom window and get the kettle boiling before i get on the driveway. She would complain if i removed it :D
 
It's O.K. with just centre box replaced but you should try it straight through!! a tad loud but quite entertaining as long as you don't have far to drive.

I've a 2.5 inch system with just a medium sized middle box. sounds nice without being too boomy and loud
 
Ive had a look on some other land rover forums (yes they do exist, really they do :D )

There is talk on them about damage to the valves (I assume in the engine) if you reduce the back pressure in the exhaust by removing the mid section.

Now I know that 2 strokes require back pressure & a specific length to the pipe to give the right frequency to draw gasses out. So mucking about with the pipes can reduce the power in a huge way.

I also know that you may loose some performance on a 4 stroke if you reduce the back pressure too much. Something to do with the way the gasses flow into the cylinders or some such black magic involving complicated equations.

But I&#8217;ve never heard of it doing any physical damage before, can anyone comment on this? It sounds to me like scare mongering. :confused:
 
Yes, I miss the 'propper' V8 noise on my 3.9 Rangies.... but it 'escaped' on the old one as the tail box rotted out!
Always pondered the idea of taking out the mid-box, but [sigh] getting old; remember how 'wearing' the noise is on a straight thru when doing a long run at constant revs.
One thing that DOES interest me; both Rangies, and I presume Disco likewise, the mid-box sits right under the floor in the middle of the rear seat feet area, just behind the cubby....... and it gets a bit warm....... as I discovered when we went on a day trip, and put the lunch box there, as it's the most convenient spot for it...... and had 'toasties' by lunch-time!
Without the mid-box, does the floor still get hot, or SO hot?
 
Ive had a look on some other land rover forums (yes they do exist, really they do :D )

There is talk on them about damage to the valves (I assume in the engine) if you reduce the back pressure in the exhaust by removing the mid section.

Now I know that 2 strokes require back pressure & a specific length to the pipe to give the right frequency to draw gasses out. So mucking about with the pipes can reduce the power in a huge way.

I also know that you may loose some performance on a 4 stroke if you reduce the back pressure too much. Something to do with the way the gasses flow into the cylinders or some such black magic involving complicated equations.

But I’ve never heard of it doing any physical damage before, can anyone comment on this? It sounds to me like scare mongering. :confused:

Same sort of reasoning as damage on a two-smoke, where the expansion chamber resonanse 'scavenges' the cylinder of residual exhaust gasses.

On a 4-stroke, removing silencing, and reducing back pressure does a similar thing, but as the gasses are mostly pushed out by the piston, so not as critical as a highly tunes stink-wheel.

On a two stroke, the spannies are designed so that as the leading edge of the exhaust 'pulse' hits the change in section of the pipe, it creates a shock wave that 'echoes' back along the pipe, in order to create a vacuum over the exhaust port to help suck the last bits of gas out, then a pressure pulse to push charge being squashed into the cylinder from the crank case ,back in, and stop it escaping down the exhaust while the exhaust port is open.

On a 4-stroke, musch simpler, valve opens, piston pushes exhaust gas down the pipe; reduce the back-pressure, gasses can get out more easily, and travel faster, sucking more exhaust after them, as the piston gets towardss TDC and isn't pushing so hard.

This means tha the exhaust valves get hotter, as they have more hot gasses passing over them while they are sat in the gas-stream unable to 'dump' that heat into the valve seat.....

Main effect, though, is that extra 'scavenging' taking lingering exhaust fumes out of the cylinder, means that the engine effectively runs 'weak' as the mixture is tuned for a burn that's not as clean...

That means knock, it also means higher running temperatures, and associated maledies..... so usual consequence is the hotter running exhuast valves burn out....

BUT, depends on whether the ignition and carburation have been adjusted to suit.

Old 'problem' on Jap multi-cyl motorbikes was that a 'straight through' 4-1 Motad or whatever would be fitted when the Jap pipe rotted out; power would go up from free'r flowing exhaust, but the carburation & ignition wouldn't get set up, cos of the cost and availability of Mikuni main jets, and needing four of them, and eventually exhaust valves would start burning.......

On cars, same affliction, but not so frequent, old mini's had SU carbs that were a lot easier to 'adjust' to get the mixure right to suit the new pipe, as do old rangies.

And on more modern motors, with EFi, many of them will 'self tune' to compensate......

Can screw the emmissions though for the MOT test, though added noise may be more of an issue depending on tester....... My local freindly chappy applies the 'unduly loud' principle, and to him the sound of a V8 is aural bliss.... others may not be so apreciative though!
 
Same sort of reasoning as damage on a two-smoke, where the expansion chamber resonanse 'scavenges' the cylinder of residual exhaust gasses.

On a 4-stroke, removing silencing, and reducing back pressure does a similar thing, but as the gasses are mostly pushed out by the piston, so not as critical as a highly tunes stink-wheel.

On a two stroke, the spannies are designed so that as the leading edge of the exhaust 'pulse' hits the change in section of the pipe, it creates a shock wave that 'echoes' back along the pipe, in order to create a vacuum over the exhaust port to help suck the last bits of gas out, then a pressure pulse to push charge being squashed into the cylinder from the crank case ,back in, and stop it escaping down the exhaust while the exhaust port is open.

On a 4-stroke, musch simpler, valve opens, piston pushes exhaust gas down the pipe; reduce the back-pressure, gasses can get out more easily, and travel faster, sucking more exhaust after them, as the piston gets towardss TDC and isn't pushing so hard.

This means tha the exhaust valves get hotter, as they have more hot gasses passing over them while they are sat in the gas-stream unable to 'dump' that heat into the valve seat.....

Main effect, though, is that extra 'scavenging' taking lingering exhaust fumes out of the cylinder, means that the engine effectively runs 'weak' as the mixture is tuned for a burn that's not as clean...

That means knock, it also means higher running temperatures, and associated maledies..... so usual consequence is the hotter running exhuast valves burn out....

BUT, depends on whether the ignition and carburation have been adjusted to suit.

Old 'problem' on Jap multi-cyl motorbikes was that a 'straight through' 4-1 Motad or whatever would be fitted when the Jap pipe rotted out; power would go up from free'r flowing exhaust, but the carburation & ignition wouldn't get set up, cos of the cost and availability of Mikuni main jets, and needing four of them, and eventually exhaust valves would start burning.......

On cars, same affliction, but not so frequent, old mini's had SU carbs that were a lot easier to 'adjust' to get the mixure right to suit the new pipe, as do old rangies.

And on more modern motors, with EFi, many of them will 'self tune' to compensate......

Can screw the emmissions though for the MOT test, though added noise may be more of an issue depending on tester....... My local freindly chappy applies the 'unduly loud' principle, and to him the sound of a V8 is aural bliss.... others may not be so apreciative though!

So in your humble opinion (I'm not going to take you to court lol)

will a 3.9 efi disco 200 be ok, or would you have worries about doing it (IE if it was your pride & joy, would you do it)
 
So in your humble opinion (I'm not going to take you to court lol) will a 3.9 efi disco 200 be ok, or would you have worries about doing it (IE if it was your pride & joy, would you do it)
I'd have no 'worries' about removing the mid-box on my Rangie, not sure about adjusting the mixture on the EFi, as neither of mine are catalysers with Lambda sensors, if your Disco has cats, it'll have a Lambda, so probably even less to 'worry' about..... probably richen the LPG up a little though, but my newer (actually about 8-months older, but newer to me!) one, has Lambda driven closed loop LPG so it would adjust itself.
Might retard the ignition a notch though.
Main reason for doing it IF I did it though would be that 'hot-foot' issue with the centre box heating the floor under the passenger seats and melting my jelly-babys!
However, given £40 JUST for that section...... I'd not bother.... IF I did it, I'd save up the added and get myself a nice shiny stainless 'sports' system and tubular manifolds to get that deep throaty roar out of it, and a bit more grunt form the engine..... again, induction & ignitiuon would have to be 'tuned' to suit..... but if I was chucking money at it, I'd probably turn the motor in the SORN Rangie into a 'Built' motor with a Mega-Squirt kit on it and gas injection......
Which is rather a LONG way from ditching the centre box!
Might be tempted if I could just chuck in a bit of standard pipe for under a tenner..... other wise...... I'm content to avoid unnecessary hassles....
I'tll sort itself out and the roar will escape when the LPG condensation manages to put a hole in the U-bend over the axle!
 
I'd have no 'worries' about removing the mid-box on my Rangie, not sure about adjusting the mixture on the EFi, as neither of mine are catalysers with Lambda sensors, if your Disco has cats, it'll have a Lambda, so probably even less to 'worry' about..... probably richen the LPG up a little though, but my newer (actually about 8-months older, but newer to me!) one, has Lambda driven closed loop LPG so it would adjust itself.
Might retard the ignition a notch though.
Main reason for doing it IF I did it though would be that 'hot-foot' issue with the centre box heating the floor under the passenger seats and melting my jelly-babys!
However, given £40 JUST for that section...... I'd not bother.... IF I did it, I'd save up the added and get myself a nice shiny stainless 'sports' system and tubular manifolds to get that deep throaty roar out of it, and a bit more grunt form the engine..... again, induction & ignitiuon would have to be 'tuned' to suit..... but if I was chucking money at it, I'd probably turn the motor in the SORN Rangie into a 'Built' motor with a Mega-Squirt kit on it and gas injection......
Which is rather a LONG way from ditching the centre box!
Might be tempted if I could just chuck in a bit of standard pipe for under a tenner..... other wise...... I'm content to avoid unnecessary hassles....
I'tll sort itself out and the roar will escape when the LPG condensation manages to put a hole in the U-bend over the axle!

cool thanks mate, I've just found out how overdrawn I am at the bank so I cant see me doing anything any time soon now. but soon I hope :D
 

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