MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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ricey
Phil Rice
Chessington Surrey
(14 posts)

Registered:
07/05/2017 02:19AM

Main British Car:
Mgb gt 1975 3.9 rover

Exhaust design
Posted by: ricey
Date: July 15, 2017 02:19AM

Hi all

Following on from the camshaft question (opted for MC1 from V8 developments), I am now looking at exhaust.

Love to move tank and do twin pipes but is it worth it?
Running 3.9 on 500cfm edelbrock with dual plane intake and rv8 style headers. Questions are do twin pipes sound better? Do you need a balancing pipe with twin pipes?

I reckon I can run twin pipes down the same side to save moving the tank and use a twin pipe muffler under the floor which some of you have done but noise wise is it best to have a second silencer?

Or do I make life easy and just do a single pipe and hope I like the sound!!

Thanks in advance


billymgb1000
bill gaulin
harrisville R.I.
(58 posts)

Registered:
11/30/2012 12:31AM

Main British Car:
1974 MGB V8 LS1 5.3

Re: Exhaust design
Posted by: billymgb1000
Date: July 16, 2017 05:48PM

Hello Phil, I always go with twin pipes when ever possible. My set up I have shorty headers and twin pipes with no cross over and I didn't move my tank. I instead came out behind the rear tires one on each side. I had the tech snug each pipe up to the underside of the leaf springs then a little bend downward, then he cut the pipe parallel to the ground. like on the old nova and chevelle.I have pics but I can't put them on this site I don't know how to make them smaller.


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(958 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: Exhaust design
Posted by: ex-tyke
Date: July 17, 2017 07:43AM

Shifting the fuel tank over 3" and running dual exhaust is an aesthetic thing......nothing wrong with having a single side outlet.
Tank relocation is pretty straight forward but then the rear valence needs to be have the two scallop features added.
FWIW, here's my system:

Exhaust1.jpg

Exhaust.png


ricey
Phil Rice
Chessington Surrey
(14 posts)

Registered:
07/05/2017 02:19AM

Main British Car:
Mgb gt 1975 3.9 rover

Re: Exhaust design
Posted by: ricey
Date: July 17, 2017 08:17AM

Hi thanks for that input, Bill I sent you a pm with my email if you get a chance love to see the pics.

Graham that system looks very simple caniask what mufflers you used and if the rear pipes are purely just pipes ? Are you are happy with the sound? Does a single pipe give the sameroarty burble as twin pipes?

Cheers


88v8
Ivor Duarte
Gloucestershire UK
(476 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
TR6 74 2.5 injection six

Re: Exhaust design
Posted by: 88v8
Date: July 17, 2017 09:56AM

Having had twin and single pipes on my car, I think what makes far more difference to the sound is the choice of silencer.

The Hooker Aerochamber will give a lovely boomy burble
[www.jegs.com]

Ivor


ricey
Phil Rice
Chessington Surrey
(14 posts)

Registered:
07/05/2017 02:19AM

Main British Car:
Mgb gt 1975 3.9 rover

Re: Exhaust design
Posted by: ricey
Date: July 17, 2017 11:58AM

Thanks Ivor I'll have a look at jegs now


ricey
Phil Rice
Chessington Surrey
(14 posts)

Registered:
07/05/2017 02:19AM

Main British Car:
Mgb gt 1975 3.9 rover

Re: Exhaust design
Posted by: ricey
Date: July 17, 2017 12:26PM

Ivor I forgot to ask which did you prefer the single system you had or the twin system?



ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(958 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: Exhaust design
Posted by: ex-tyke
Date: July 17, 2017 01:10PM

Quote:
Graham that system looks very simple caniask what mufflers you used and if the rear pipes are purely just pipes ?

Mufflers used on my conversion, are inexpensive universal 2-1/4" mufflers made by Walker (Part # 17614) - Dynamax #17732 is also a good equivalent....lots for sale on ebay. The rest of the system is just 2-1/4" mild steel tubing. Overall, I'm happy with the exhaust note but there is a distinct resonance to the exhaust note >2000rpm.....so highway speeds can add to the overall vehicle noise level.
There's so many variables to an exhaust note: Engine size, displacement, # of cylinders, firing order, pipe diameter, 'X' or 'H' pipe, etc, so finding that perfect note is a bit of a crap shoot. Generally, speaking I don't think I've ever heard any bad MGV8 conversion exhausts.
With your V8, if you decide to keep with a single muffler, there are dual inlet/dual outlet or single inlet dual outlet mufflers available.
Also, as a general note, mufflers mounted at the rear will be quieter than mufflers mounted towards the front, since exhaust gases have more time to cool....and there are some conversions that employ under seat mufflers and add rear resonators to the mix.


ricey
Phil Rice
Chessington Surrey
(14 posts)

Registered:
07/05/2017 02:19AM

Main British Car:
Mgb gt 1975 3.9 rover

Re: Exhaust design
Posted by: ricey
Date: July 17, 2017 01:20PM

Graham great points made especially the position of the muffler , I think I might look to di twin pipes on one side with a crossover and twin through box, like the look of the Jeg ones Ivor mentioned . Bill sent me some pics if his and that looked great without moving tank.

I need to start a build page on this !

Thanks


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