20i Exhaust Tone

[tomkinson36]

Might be a stupid question but just had my car fixed after some dodgy spark plugs and i can now drive it properly.
I'm noticing a significant change in exhaust tone after about 30mins of driving.
I'm assuming this is supposed to happen just not sure why it takes half an hour? I would've thought the tone would come when the car is warmed up after about 10 minutes?
Much prefer the tone after as when the car is cold I cant hear much at all from the rear, is there anyway to make this occur sooner?
Any advice is greatly apricated, thank you.

 

[Matt.rowley.1990]

Exhaust note shouldn’t be impacted by spark plugs unless you had a misfire or other running issues. They won’t have any impact on the volume or tone of the exhaust.

The tone of the exhaust when cold will be due to a number of factors, with the biggest being:

• Acoustic performance of the metal components under temperature change.
• Cold start and catalyst warm up - the fuel mixtures and timing are adjusted at cold start to speed up the catalyst warming. The exhaust is often louder and deeper during this period, combined with increased RPMs.
• Exhaust valving - if a N20 or N54 equipped car, the exhaust valve will be open and closed under varying conditions. This will impact sound output and tone.

 

[tomkinson36]

Exhaust note shouldn’t be impacted by spark plugs unless you had a misfire or other running issues. They won’t have any impact on the volume or tone of the exhaust.

The tone of the exhaust when cold will be due to a number of factors, with the biggest being:

• Acoustic performance of the metal components under temperature change.
• Cold start and catalyst warm up - the fuel mixtures and timing are adjusted at cold start to speed up the catalyst warming. The exhaust is often louder and deeper during this period, combined with increased RPMs.
• Exhaust valving - if a N20 or N54 equipped car, the exhaust valve will be open and closed under varying conditions. This will impact sound output and tone.

Hi Matt, thank you for the reply. I had a nightmare with a garage after a full service with bad plugs which were causing a misfire, first time I've been able to drive it properly

 

[Pondy]

On the N20 there is a valve in the right (IIRC) exhaust tip. It's a flap, basically, and is controlled by vacuum pressure so can open and close when the pressure dictates.
There is something called a "golf tee mod" that many have done to keep the flap open all the time. It involves removing the vacuum tube to the valve and shoving a golf tee (or similar) into the hose.