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Jim_C

Back box delete. How much?!

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Like a number of other owners, the hooligan element within me would like a considerably more vocal sound to the exhaust on my car. But when I asked a week known specialist about the cost for a back box delete on my 545i, he quoted me £450+VAT, which is way more than I was expecting. Now, I don't work in the exhaust business, so I'm not going to tell someone who does that they are wrong, but is there a cheaper way to liberate more V8 aural goodness without compromising MOT or management lights?

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Do you know anyone with a mig welder?

You can buy 2.5" or 3" stainless steel pipe on ebay for less than £30 a metre delivered.

Either unbolt you backbox or box's,  I'm guessing your car is a single box with twin tailpipes?

Removing the backbox & replacing it with a length of straight pipe won't affect the mot or engine check light.

 

Quite a few on the Facebook page are running a 3" straight pipe from the turbos back on the 530/535d's

Along with dpf & cat deletes.

 

Where abouts are you?

Without seeing picture's of your current oe setup , I would say I could do it for you for £150

all in + materials depending if you wanted one single tailpipe or more oe twin?

 

Alternatively find a local Powerflow exhaust place, years ago I had a full system made & fitted

for me because I couldn't do it as cheaply £240 fitted with a bolt in decat pipe but that was back in 2000 but was a full 2.5" custom system from the exhaust manifold back.

 

Edited by dirtydirtydiesel

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most of that is probably labour. I guess his rate must be around £100 an hour. I would assume something like 3-4 hours labour for removal/fitting/fabrication then the rest is materials. 

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Thanks Gents. 

 

I have a setup with two back boxes leading to twin tailpipes. The inboard box is fitted with the vacuum-operated valve, but as far as I can tell it might be stuck open as there seems to be equal gas flow through both tail pipes at idle and no discernible difference in sound when I rev it.

 

I'd like to remove the two rear boxes and just have a length of stainless tubing leading to oem style tips.

 

dj1233 - I think you're most likely right about the labour, but it still seems a lot to me!

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As I said have a Google, I did.

I can see your pipe set up, plenty have done what you wish to do.

Depending on your location you should get it done for under £200 all in,

have a look on eBay there's a few exhaust specialists offering a back box delete service or a sports back box.

 

Having watched a few YouTube videos of 545i & 550i with backbox deletes you had me looking at them

briefly,  but I couldn't cope with 20mpg . Sounds lovely thou B)

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DDD (if I can call you that...), I did look on Google/YouTube - that's what set me out on this quest! And the results are very seductive.

 

We're about to embark on another, totally unrelated, project with the help of a skilled fabricator, so I'm going to ask if he can do this too.

 

We can put up with the mpg, only because we hardly go anywhere not in our work vehicle (a Panda 4x4!), so when we do, it doesn't seem a burden. A long commute or similar would bring a swift end to V8 joy.

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Cool sounds like you've got it covered, a good fabricator should be able to do it in three hours or less

If they have a four poster or a twin lift. So materials £60-80 off ebay + his labour.

Yeah fuel economy  I do approximately 14k a year so need the best I can get, my 530d gives me 34mpg nocking around 

& 45mpg on a run.

I'm happy with that & it's performance, just would love the V8 gurgle.

I've been a petrol head since a young boy watching The Dukes of Hazzard back in the very early 80's plus my old

man had Capri 3.0s & 2.8i's ect when I was growing up.

But that V8 still eludes me, one day hopefully :cool:

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Mine was done for £220. On a 525d, doesn’t sound all that much louder... I can hardly hear a difference.. you will definately hear it on a v8 though.

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I'm not under cover! I'm in Stroud in Gloucestershire. 

It looks as though our fabricator friend has come good; turns out he's done plenty of back box deletes and will happily do mine (using the original tips) for the princely sum of 60 quid! 

I'll reserve judgement until it's done, but right now I'm pretty happy about it...

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That's a very good price :cool:

But he can basically cut out your two oe box's & replace with tube.

Just for the record DDD is fine, infact I'm know by that on a few forums :lol:

& I'm nearly 50 :ph34r: so I wasn't insinuating that you were hiding,

Just I did ask were abouts are you?

 

Edited by dirtydirtydiesel

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There's a vacuum line that opens a butterfly valve in the inboard back box at a certain rev range, allowing gases (and noise, presumably) to pass through it. However, I think mine is stuck open, as I can't detect any difference.

The fabricator is going to cut out the back boxes entirely then weld a length of stainless tube back onto the existing exhaust tips so it will look standard at a glance.

I'm hoping it will sound a fair bit naughtier.

 

 

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Nice - very tempted now!!!

 

I'm sure mine sounds quieter than yours, stock.

 

Torn between the stealthy no one knows whats coming, or something that sounds tasty!!!

 

Be interested to know if you notice any performance differences - read loads of conflicting bs online about closing off that vacuum line causing issues and lack of a back box changing the backpressure and losing torque!!!

Guessing it'd be so minimal you'd never notice on a road car though!!!

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It turned out that the vacuum valve on mine was stuck open anyway, and the other box had blown along a seam. So, yours is very likely quieter than mine in standard form. That being the case, you might want to be a bit wary of going ahead with this mod until you've heard one close up - it is *plenty* loud enough! Some people might find it a bit overly enthusiastic. I knew what I wanted and was ready for the noise - I love it! I also have zero budget for a fancy exhaust, so it was this or stock for me. In fact, if I'd had to replace the blown back box, it would have seriously eaten up my funds!

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Ah, that'll explain it!

 

I won't find it too loud - my other car is a very tuned M20 with a BTB 6 branch and full straight through stainless system and no carpets - you can hear it coming a fair way off and been told it sounds like a V8 with the naughty cam in it!!!

 

Just a novelty, sort of, at the moment, to drive something quiet - but it does feel very boring!

 

I'd keep the original backbox if I did it - not sure how/if it'd affect any resale on this if I move it on in a year or two!

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Sounds like you won't be in the least intimidated by a bit of V8 noise! We had a 4-litre V8 S-Type with a switchable straight pipe that was fairly noticeable, so this is quite civilised for us too. As long as your back boxes are in better nick than ours and you have space, you may as well hang on to them. No idea what effect it'll have on resale though...

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Ha, S-Type sounds interesting - always looked at those cheap V8's and thought about playing with one!

545i Touring is my version of sensible, now I've got a little boy and a pending house extension - pretending to be a grown up!

 

It's going in with my usual guys for an Oil change friday, so I might see what they say about it!

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How did you get on, miniblob? Sounds like you could do with a little more V8 noise!

 

The Jag was OK - it was a 2000 MY and almost everything was worn, shabby and faulty, so exactly as we expected.

We bought it for a specific purpose, which was to fit a straight pipe exhaust, paint fiery flames down the sides and amuse ourselves, whilst generating outrage among the string-back driving glove community.

 

https://youtu.be/HpvgrJKcitI

 

Mission accomplished.

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Ha, sounds good!!!

 

They weren't keen to do it at all - which surprised me given the jobs they've done at my request in the past!!!

General consensus was it'll be a lot of messing around for no real gain, while putting off any future buyers if I sell it on in a year or so!!!

They suggested keeping an eye out for an aftermarket back box, or even a used but complete standard back box to cut up, if I was that keen!

 

Think that made me want it more over the weekend!!!

 

If I see a used back box going cheap enough, (anyone got one lying around???), I might have a play!

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