13B Extend Port exhaust question - help needed

RX MIDGET · 11-10-2010, 10:56 PM

Hi,
I hope someone can assist me with an exhaust question I have relating to my 13B Extend Port fitted in an MG Midget.

On purchase it has 2 small "hot dog" size mufflers, (one small on close to headers and a larger one half way along the car).
This leads up to a larger muffler that has both entry and exit from the same end of the can. Never seen this before, I was informed it was required due to fitting placement on the modified car, and was required during the re-Engineering process under our local laws for noise reduction.
Trouble is, it muffles the sweet rotary noise unless giving the car a boot full of throttle. Exhaust diameter is 2". Engine is Non Turbo.

My question:
If I removed / reduced the size of the larger muffler, (obviously the car would be louder than the 88DB @4500rpm) but would there be any issues with:

1. Engine damage through lesser back pressure, or,
2. Performance reduction
As I am newish to rotaries, I do not wish to learn from guessing!

NoDOHC · 11-14-2010, 07:19 PM

Damage due to lack of backpressure???? Are you kidding, rotaries love no backpressure (just ask mine).

Your performance could only go up by removing a muffler. However, your ability to use that performance may go down. The reason I say this is that you will make enough noise to bring cops from every surrounding county to collect revenue from your use of power.

11-10-2010, 10:56 PM	#1
RX MIDGET MG rocket Join Date: Oct 2010 Location: Victoria Australia Posts: 40 Rep Power: 0	13B Extend Port exhaust question - help needed Hi, I hope someone can assist me with an exhaust question I have relating to my 13B Extend Port fitted in an MG Midget. On purchase it has 2 small "hot dog" size mufflers, (one small on close to headers and a larger one half way along the car). This leads up to a larger muffler that has both entry and exit from the same end of the can. Never seen this before, I was informed it was required due to fitting placement on the modified car, and was required during the re-Engineering process under our local laws for noise reduction. Trouble is, it muffles the sweet rotary noise unless giving the car a boot full of throttle. Exhaust diameter is 2". Engine is Non Turbo. My question: If I removed / reduced the size of the larger muffler, (obviously the car would be louder than the 88DB @4500rpm) but would there be any issues with: 1. Engine damage through lesser back pressure, or, 2. Performance reduction As I am newish to rotaries, I do not wish to learn from guessing! Last edited by RX MIDGET; 11-11-2010 at 07:01 PM. Reason: More info provided

11-14-2010, 07:19 PM	#2
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 17	Damage due to lack of backpressure???? Are you kidding, rotaries love no backpressure (just ask mine). Your performance could only go up by removing a muffler. However, your ability to use that performance may go down. The reason I say this is that you will make enough noise to bring cops from every surrounding county to collect revenue from your use of power. __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)