MalbecG37S

The exhaust systems on the G37 and the G37S are identical - correct? I am speaking specifically about the Sedan.

I swear they sound different. I have a G37S - model year 2012 manufactured in 08/11. It sounds quieter during acceleration - but actually has sexy little pops on the overrev... The 2012 G37 - manufactured in 10/11 - sounds more aggressive during acceleration, but doesn't produce any of the 'pops'.

Any thoughts?

I also assume that the sound deadening is the same on the 2 cars...

Maybe it's just mental....wouldn't be the first time

JSolo

iTrader: (14)

The pops are typically a result of a lean mixture at higher rpms in between shifts. Lean due to air being injected into the exhaust for emission purposes. It is strange for same model year cars to sound differently. Are they similar in mileage?

On my bike with aftermarket exhaust and no cats, I'll get some popping when shifting or closing the throttle at high rpms. This is because the injectors actually stop firing above a certain rpm with a closed throttle.

MalbecG37S

Yes - both are only a couple of months old - mileage is within a couple hundred of each other...

carz

they should be exactly the same....unless they changed manufactures somewhere in between the build process

Tazicon

iTrader: (1)

I can't see there being any differance but I have never driven any G's manufactured after 7-11.

cruzmisl

A service guy at the dealership actually showed me that the g37 coupe exhaust has changed manufacturers at least 3 times so far.

G37Sam

Where'd you get this information from? And how exactly is air injected into the exhaust?

JSolo

iTrader: (14)

^^It's part of the emissions system on most cars. Adding fresh air to the exhaust helps burn off hydrocarbons, reducing emissions. A byproduct of this is the pops you hear with after market mufflers since they don't 'silence' to the same level as OE parts.

I'd have to review the FSM to see exactly how this is implemented in the G.

Older cars had an actual air pump. My bike has something called an AIS valve (air injection system) that pulls fresh air from the airbox into the exhaust ports. After installing an after market exhaust, there was considerable popping anytime the throttle was closed while in gear. Removing this valve eliminated the popping.

JSolo

iTrader: (14)

Update, the only reference I can find is in the Engine Control portion of the fsm, EM-570 (2010 sedan fsm) makes reference to a secondary air system DTC's and secondary air injection system.