gary11

Just a quickie my car 2009 997.2 C4S PDK has A standard exhaust but has a crossover fitted,when the car starts the exhaust is quite loud exactly what I wanted,however from cold after approx 20-30 secs of idle you can clearly hear the note change and become much quieter,there must be a solenoid somewhere that re routes or quietens the note some how,I've studied the GT3-2 PSE unplug solenoid for the sports exhaust but its not the same I cant see any flaps or actuators from below,I definitely do not have PSE any one have any tips?? Thanks.

cwheeler

Cold start sounds different. Once off cold start, the tone will change. Happens with every car.

Cw

93Jaffe

All cars run rich on first start-up. The difference in tone is the air/fuel mixture becoming more lean.

millertimefl

Yup...Like almost every gas engine it has an auto choke like feature to heat the cats up ASAP so they start doing there job.

holgum

Sounds like you need to look into the next step: add the sports exhaust, or maybe Fisters.

wjk_glynn

On cold start, the initial idle is approximately 1,100 rpm.

After 20-30 seconds, your idle drops to approximately 700 rpm.

sandwedge

As others have said, it runs rich on startup and then goes leaner. To really get what it sounds like you want you have to address the side mufflers. On the 997.2, doing the side cans or the x-pipes alone won't do it. Gotta do both and there a lot of options.

gary11

Thanks I take on board the cold start theory but its not that, its much nosier on startup ,its same variance in sound as switching the PSE on my other one on and off or starting with PSE off IE its loud then the PSE closes and its quiet,its not fast idle/enrichment in my opinion,it definitely seems like a flap opening or in this case closing, Ive stood behind it this morning to be sure again.You can hear it even more when blipping the throttle on initial start up cold or not,its not fast idle related, Im going to ask an OPC tech I know.

gary11

I know its not that.

wc11

Do you still have the helmholtz resonator?

swingwing

In the packet of documents PO gave me when I bought his car was a very informative booklet titled "Service Information - 2009 Technik Introduction, All 911 Carrera Models." The part number is PNA 911 021 09. What you're hearing on startup is normal, as the DME is feeding extra fuel to heat the cats faster. On page 34 of the book there's several paragraphs explaining what's going on, but last paragraph gives us the scoop:

"The high exhaust temperature quickly heats the catalytic converters to the temperature for optimal conversion of pollutants. As a result, emissions during the warm-up phase are significantly reduced and the secondary air pumps are no longer required for all engines."

Christian Stark

Oh but it is...

There is no valve flap or solenoid.

TSP

I drive the exact same car. 2009 997.2 C4S with PDK. Mine does exactly the same thing. It takes ten or fifteen seconds for the idle to drop when cold and the exhaust noise is distinctly different between the two states.

93Jaffe

Let us know when the tech confirms what everyone unanimously has said about the cold start.

Christian Stark

We are P-car twin-sies...right down to the Turbo wheels. The difference in my cold start to 30 seconds is huge. When I am pulling out of the parking deck at work, I roll the window down thinking my DIY Gundo is great...30 seconds later I am convinced I need the center muffler delete.