Dumb Question
 

I'm new and have a weird question. It sounded stupid to the dealer, and it might sound stupid here, but here goes; when I first picked up my Boxster, the engine was VERY quiet. Even with the top down, it was pretty subdued. During the test drive, I kept saying "I don't hear the engine at all." I believe it sat on the dealer's lot for over 2 months, with only the occasional test drive. Then I took it home and started driving it, in a fairly "sporty" way. And the engine started to get louder. And louder. Now it's pretty loud at start up, and it seems to idle a little rough. Not missing or back firing, just the revs don't sound 100% consistent. Louder when running as well.

It has 24,000 miles on it, and it has the PDK (which is awesome, BTW) which has "adapted" to my driving style and revs higher (4,000 to 6,000 rpm) before shifting than it originally did (2,000 to 4,000 rpm).

Would that explain why it's idling rougher? And the whole engine is louder. Dealer thinks I'm nuts.

boxster tends to have pretty quiet exhaust, and the engine compartment is well insulated (close to the driver in a mid-engined car, so noise and heat would be an issue without insulation).

most of the sound you typically hear from the car is the intake, which right behind the driver's left ear. as the engine rpms increase the car tries to draw more air though that intake and get gets louder. it's especially obvious as the cams 'roll over' that is, at around 4000 rpm the cams change profile (vario-cam, or vario-cam+ depending on the year of your car) and some flappers open on the intake tubes in an effort to flow as much air as possible.

so, if you are spending more time at 4000 rpm than 2000 rpm, and if you have the top down more, than the car will sound louder.

not sure if that is your issue, however, if it sounds louder at idle and idle is rougher. the first step i would take is to determine what the 'loudness' is - is it intake, exhaust, or just things rattling and clacking together. that will help determine where to look further.

Reading forums tends to make you more"in-tune" with the engine & listen to it more. You should change the oil anyway & this may quiet the engine some.

Porsche-chick.. it would seem that the answer is this..


your foot is getting heavier.


i'd have to meet you to make an assumption on that.

Porsche's variable valve timing technology provides greater power at 4K rpms and above. Also, the exhaust sound is specifically tuned to provide a very nice "howl" at 4K rpms and above. Combine those two facts with a new driver who has learned to drive the car as it was intended to be driven (hard!) and the result (as expected) is a seemingly louder exhaust as compared to when the car was first driven.

The dealer is right and you're not nuts. Win-win.

PC, you are very lucky! Lots of Porsche owners spend BIG bucks for this.

You may have developed an exhaust leak. This would account for the sound and if it's a significant leak on one side could also cause the rough idle.

Driving up to 4K rpm doesn't acct for the rough idle. PC, do you have any warranty left? Sounds like you've taken it to the dealer and they didn't give you any answers. Is there another dealer around? They should check for any codes it may have thrown. Or you could take it to an Autozone or O'Reilly's and they could check for codes. You shouldn't have a rough idle.

Sounds like IMS failure....j/k
These cars don't like to sit. MAF or TB might be a little dirty...it does not take much. Getting them cleaned in quick, easy and low $$$.

So I gave it a good listen this weekend, and it is a rough idle. Upon start up, around 800 rpm, it's loud. I reverse it out, still loud, put it in drive (remember PDK), it's loud. Then foot on accelerator, it quiets down. The rest of the ride is louder than when I got it, but I think that's just my driving style.

It's the idle that is bothering me.

husker: I did ask the dealer to look at it, plenty of warranty, (which is why I want to figure it out now, before it's on my dime) but no codes came up.

paintboy; don't even joke about the IMS! This is why I picked 2009, to avoid that. Watched DH pour $$$ into 911's for years, trying to avoid that. What is an MAF or TB?

thstone; yes, I think the variable timing is coming into play on the rest of the ride.

BruceWayne; my foot was pretty heavy on the test drive, lol.

savinor; how would I recognize an exhaust leak?

Flavor; this is what my hubby says. He also likes to point out it's still not as loud as his Carrera.

BYprodriver; actually, this noise is the reason I started on the forum.

radiumking; very informative, I knew Porsches are "designed" to sound louder at 4000 rpm, I never knew the mechanics of it, thank you! How do I check the intake? Could dust be an issue? I live in a dusty area.

Yes, check the air filter.

A rough idle could come from a lot of sources from spark plugs or a coil pack to a dirty mass airflow sensor (MAF) or throttle body to a vacuum leak.

Dealer should be able to detect the rough idle and find the source. They shouldn't need a specific code.

Could just be me, but I love the sound of my exhaust when I first start my 2007 from cold. After it has warmed up though start ups are quieter...at least it seems that way.

Take a video of it with some good sound. It's not exactly clear to me what this 'rough' sound or running at low rpm is.

Wait, Porsche Chick, I did not realize you had a 2009. Do you possibly have PSE (Porsche Sport Exhaust)? I have it, and also have a very nice cold start sound and even a little gurgle when I blip the throttle, especially on cold start-up. But, my idle is like budda. Just a thought.

Would there be some kind of button somewhere for that? :confused:

thstone; I am going to write these things down and have the dealer check all this next time I'm in there.

It was soooo quiet when purchased (I wasn't sure it was a Porsche!) and then a month later, it's loud. Still loud.

It might look something like this:

http://986forum.com/forums/uploads01/pse1358398059.jpg

I have done some more careful observation and I have narrowed it down;

I start car with foot on brake.

I turn key.

Car revs to about 1200 rpm. Keeps revving, with or without my foot on the accelerator.

I reverse, back out, it dips to about 1000 rpm.

Put it in drive, it drops to 800 rpm.

Maybe this is just normal and I am being too picky? It didn't do this during the first month of ownership, though.

Is it just a PDK thing? Issue is high revs at start up.

And sadly, no PSE. :(

The higher idle might just be from cooler ambient temperatures. How cold is it where you're at?

Started in September, when temps were in the '90's, still weird now, with temps in the '70's.

sounds like you're concerned about the noisyness or sound of the engine while its idling and not actually in gear.

what kind of oil are you using?