Sourcing a sports/performance exhaust silencer/centre box for MG Maestro 1600

[John C]

My rally car's back box is rotten (and it turns out to actually be a centre box i.e. 'straight through'!), so I'm considering the following:
a) Using another centre box as a silencer (to minimise back pressure) -but you need a certain amount of back pressure to help the combustion cycle, so not sure if this would be ideal

b) As above but with a big straight through silencer that my mate found in his garage. However, this may prove too noisy for scrutineering -no way to tell until we weld the right pipe onto it and fit it to the car though (although I do have a decibel meter App on my smartphone so at least we can check it before we get to an event).

c) Buying a generic sports/performance silencer for it (preferably one that is repackable for maximum life): http://www.maestro.org.uk/pp_class/s...p?product=2361

d) Using a normal road silencer from a similar power/spec car (we have an old centre box and also a silencer from an Escort XR3i knocking about that we could use). However, it isn't a 'straight-through' silencer so this won't give max power: http://www.ebay.co.uk/itm/Exhaust-Re...item2ec5e6cfcb
N.B. There is no centre box on the car at present (is it worth putting one in?). The engine is an early 80s 1600 8v in a mild state of tune producing between 100-120Bhp estimated.

e) Get a standard MG Maestro 1600 silencer (and also possibly the centre box) for £40 & £51 respectively off ebay -or even the local exhaust fitting depot
http://www.maestro.org.uk/forums/sho...hlight=exhaust
http://www.maestro.org.uk/forums/sho...hlight=exhaust

f) Get a sports/performance exhaust for the MG Maestro 1600 (if you can find any!):http://www.maestro.org.uk/forums/showthread.php?t=9212
http://www.maestro.org.uk/forums/sho...hlight=exhaust
This is for the 2.0 EFi (and is too expensive for me):
http://www.ccw-tools.com/product.asp...488&P_ID=26404
but there are a couple of useful exhaust contacts on this page (search for 'Bell Silencer Services' and also 'Exhausts'):
http://www.mg-cars.org.uk/cambs.mgoc/fwd/faq.html

Any tips on which way to play this one?

[Russ]

I think maniflow still do competition exhaust systems for the maestro.
If your on a budget try and get a used straight through silencer from an exhaust supplier

[John C]

I've just spoken to this firm http://www.moto-build.com/ and they don't have any exhausts for the 1600 R Series any more (although the S-Series will accept a 2.0 MG Maestro exhaust). Darryl didn't know of any other firms doing performance exhausts for the Maestro nowadays.

He said that the standard exhaust system isn't great (both the downpipes and the silencers). For racing they used to use a 2.25" & 2" system with no centre box and a 10" rear silencer (straight through), which worked well, but he thought that a Cherry Bomb would be unbearably loud unless it also had a centre box. He thought that the idea of engines needing a certain amount of back pressure is a myth, and 'the least resistance to gas flow the better'.

Back in the day they tuned R-Series 1600s up to about 130-135bhp.

[John C]

++++++++++++++Centre box for MG Maestro 1600 rally car
++++++++Custom Chrome (Nigel) recommendation
Bullet-shaped silencer with a 3-3.5" external diameter case
Length is TBC by me(whatever you can fit in there
Constructed so that it sleeves over a 2" pipe
Internals: 1 7/8" or 1 3/4" internal diameter perforated tube (to create a slight pinch/constriction inside the pipe).
3" x 16" 3.5" x 16"
mild steel £45 £55
Stainless (gives a bit more resonance noise) = +£10 on the above prices.

[John C]

MG Maestro Exhaust System - 2.0 Efi 1984-1991
http://www.rimmerbros.co.uk/Item--i-GRID010762

Maestro Rear Exhaust - Maestro 1.3/1.6 - Genuine MG Rover (not sure if this will also work MG)
http://www.rimmerbros.co.uk/Item--i-WCG003969EVA


http://www.ashleycompetitionexhausts.com/systems.html
They did exhausts for all variants of MG Maestro (and also MG Montegos). If they can get an order of 10 or more together then they will do a production run (Brian Ashley). They didn't do manifolds.

The following firms don't list doing exhausts for the MG Maestro or Montego (and I have also phoned them to confirm that they can't offer anything):

http://www.piperexhausts.co.uk/piper...x.php?cPath=88

http://www.sportex-exhausts.com/MG/cat/8

http://www.janspeed.com/contact-us

[John C]

http://www.maniflow.co.uk/?view=category&category=139
David. Salisbury in Wilts.
Still has face plates but no patterns for the Maestro (although he still has patterns for the Maxi which has an E-Series engine similar to the R-Series).
A combined inlet manifold would be around £600-700. He still has jigs for the rest of the Maestro system and can do it for £180-200 in mild steel (60% more for stainless). The system will use straight through centre and rear silencers. 1 7/8" diameter for up to 105/110 Bhp and 2" diameter for above this power. Best not to go to 2" unless definitely making the above power or it will mess up the back pressures etc.

http://www.ccw-tools.com/Automotive/...61-1488-26403/

http://www.ccw-tools.com/Stainless-S...88-1488-26404/
Tom will investigate & call back

http://www.eu-linco.co.uk/
Various branches -the Colchester outlet is 01206 796000
manifold: unavailable
front pipe: 40 +VAT
centre box: 35 +VAT
rear section: 28 +VAT
128 inc VAT for a complete system

[John C]

The old exhaust system had no centre box and for its rear box it had a rotted out straight through centre silencer! With this system in place it was very noisy. With the new Cherry Bomb DIVER in place for the Woodbridge Targa Rally (Nov 13) the Noise check showed a very reasonable 83Db. However, the exhaust had been bodged on the day before with an ARC welder (and so it had to come off to be put back on properly (without leaks, knocking on body and pointing straight).