ZX Replacement Rear Box

sooty · Unread post by **sooty** » 18 Nov 2003, 01:36

My ZX 1.9td Elation, exhaust rear box is in need of replacing.
We all know how restrictive the standard rear box is.
Any suggestions of what make/supplier to use with improved flow without being too noisey.
Thanks
Sooty

gjb02 · Unread post by **gjb02** » 18 Nov 2003, 02:06

Try a company called powerflow. They have dealerships all over the country. They'll hand build a stainless system or box to your requirements. Noise / power ratios, type of tailpipe, etc. They are stainless so they aren't cheap! Lifetime warranty though!!

arry_b · Unread post by **arry_b** » 18 Nov 2003, 02:48

Is the standard box restrictive? I'd have thought that a lot of the energy from the exhaust gas would have been recycled into the engine via the turbo. That should leave a low energy gas flow flowing through the tail box. But then again, I may be talking rubbish as it could be low energy/high volume and need a high flow box but not much muffling because the low energy exhaust not making much noise.

gjb02 · Unread post by **gjb02** » 18 Nov 2003, 03:41

?? Yep, I don't think it would make much difference to a TD to have a performance exhaust fitted either, can't see the point.

There is still the same volume (capacity) of exhaust emmissions per revolution in the exhaust, whether it has gone through a turbo or not. And the airflow that exits the turbo may have slightly less energy, but will still be leaving at much the same velocity. But a nice looking stainless steel exhaust may or may not sound better. The frequency of the exhaust gases (4 puffs per cycle) will sound different through different baffles and pipework. And that is determined by each exhaust manufacturer. Too freeflow an exhaust and you loose back pressure, even gases like to have something to push against, slightly less back pressure and the gases can escape more freely, often with an increase in performance and noise. Is there any point to a performance exhaust on a TD? Dunno ask Van Aaken.
No, I haven't got a performance exhaust!![:D

rossnunn · Unread post by **rossnunn** » 18 Nov 2003, 14:31

I've got a Laser back box on mine, 4" jobbie, but you need the volcane type rear bumper to fit it. look quite nice tho
Ross

arry_b · Unread post by **arry_b** » 18 Nov 2003, 16:07

<boggle> 4 inch exhaust on a ZX ?!???! </boggle>

rossnunn · Unread post by **rossnunn** » 19 Nov 2003, 02:21

Yep heres a pic:

Notice the battery in the tail pipe. its a standard AA - to give you some idea of size!!
Ross :[:o)]:

Unread post by **Jon** » 19 Nov 2003, 02:32

And, does it do anything for performance??
It looks bloody good though.
PS on Original rear silencer at 127600 miles.

rossnunn · Unread post by **rossnunn** » 19 Nov 2003, 02:38

lol I Dunno! sound nice tho - kinda burbles but you do have to blat it a bit to get some really sweet notes out of it!!
Ross [:o)]

mg46783 · Unread post by **mg46783** » 19 Nov 2003, 05:21

...The dog in the back looks fed up with the noise of it !!!!!

mike

andyg · Unread post by **andyg** » 19 Nov 2003, 12:48

I have a 93 Volcane TD, the original back box failed (just) after 8 years, cant complain about that. Have replaced that with a Powerflow back box (actually, the complete system has been done now) in stainless steel with a 4" oval tail pipe (more Volcane like but bigger!) and a lifetime guarantee - providing you remain the owner. I wanted a quiet exhaust cos' its a diesel but those sitting in the back of the car reckon it sounds good but from the drivers seat - you cant hear it but they will make any exhaust as quiet or noisy as you like.
Cost? = £120 for the back box. It is not a retro fit but hand made as you wait.

rossnunn · Unread post by **rossnunn** » 20 Nov 2003, 00:27

thats not bad mines a mild steel cost: £75 brand spanking new.
As for the Dog don't be fooled. Churchill is a ninja, gungfoo, dog. one wrong move and he'll Ave ya!

sooty · Unread post by **sooty** » 20 Nov 2003, 01:03

Thanks for your replies, but I'm not looking for a'GO FASTER EXHAUST' with 4in tailpipes etc.
If you have a Turbo driven by exhaust gases, its gases has to escape from the engine as easy/fast as possible, to be efficient, it do'es not need a restrictive silencer full of baffles???
Thats why the proper petrol Turbo's ie Cosworth and others have huge exhaust pipe work, to get rid of the gases as easy and fast as possible to turn the Turbo to ram the gas mixtures into the engine to get their 300bhp.
All I'm looking for is better back box than the standard one fitted without the go faster gizzmo's, as in reality the ZX is never to compete with the likes of its petrol turbo heads.
Sooty

gjb02 · Unread post by **gjb02** » 20 Nov 2003, 03:10

Sorry, typed Baffles because I couldn't think of a better word, or indeed the right words/description. I meant the various silencing materials and inner constructions of silencers, that go to increase or reduce performance / noise. I realise some exhausts silencers have a straight through design, with outer silencing materials (fibre wadding / candyfloss), but there used to be exhausts that used baffles...much like a gun silencer.

AndersDK · Unread post by **AndersDK** » 20 Nov 2003, 05:29

Actually the rear box is more a silencer than a damper - and it's the resonance properties rather than flow restriction properties that silences the blatting.
The center box is needed to accumulate some back pressure - to stabilise the gas flow through the engine - to ensure as smooth run as possible over the speed range. This is not different with a turbo fitted - rather adopted to fit the flow restriction the turbo makes.