Please help with diagnosing engine noise
02-11-2010, 12:00 AM
#1
Please help with diagnosing engine noise
I heard this strange intermittent popping noise from the engine (997 GT3). I never noticed that before and is bit worried. Does your engine make this noise too? It doesn't sound like anything I'm familiar like valve, rod, piston, chains, etc. It could be the exhaust also but I couldn't tell. What could be causing this? Is this normal?
It happens at ~25-26 secs in the video. It a low frequency pop which is obvious only when I have desktop speaker/subwoofer hooked up. You won't be able to hear it with speakers on laptops.
It happens at ~25-26 secs in the video. It a low frequency pop which is obvious only when I have desktop speaker/subwoofer hooked up. You won't be able to hear it with speakers on laptops.
02-11-2010, 12:53 AM
#3
Rennlist Member
Played your vid over and over again but can't hear the pop you're talking about--maybe it's my crappy headphones... But generally speaking GT3 engines have a hunting idle and I won't be alarmed if it gives a lift-off-exhaust-pop-like sound every now and then... I've been around four or five 7.1 GT3/RS's and let's just say they all sound a little rough at idle and makes random exhaust pops without throttle activity (mine included). Obviously the pops are going to be even more prominent if you have bypass exhaust installed.
In software engineer speak, it ain't a bug--it's a feature!
In software engineer speak, it ain't a bug--it's a feature!
02-11-2010, 01:40 AM
#4
996flt6, I didn't lift the throttle when that happened. I captured the video when it was idling. When I rev'ed and held the throttle at around 2k rpm, I could hear the intermittent pop.
crex, I noticed that my gt3 has a hunting idle as well. very minor for about 50-100 rpm. it feels like as if the engine is impatient being trapped in a box.
It does sound like a quiet exhaust pop now that both of you mentioned that. I didn't expect to hear exhaust pop at idle though. perhaps this is one of the unique "trait" of the race-derived engine? If there ain't that pop, it ain't a /76
crex, I noticed that my gt3 has a hunting idle as well. very minor for about 50-100 rpm. it feels like as if the engine is impatient being trapped in a box.
It does sound like a quiet exhaust pop now that both of you mentioned that. I didn't expect to hear exhaust pop at idle though. perhaps this is one of the unique "trait" of the race-derived engine? If there ain't that pop, it ain't a /76
02-11-2010, 05:27 AM
#6
Drifting
I think the GT3 does something with the exhaust cycle during warm-up and when it's cold out that makes the exhaust sound like it's popping. If you've had a 993 Turbo before, the emissions system on that car would make the most amazing sounds when you'd fire it up on a cold morning, almost like a drag boat. Maybe the cooler weather is bringing the emissions electronic systems into play?
02-11-2010, 03:03 PM
#7
Rennlist Member
I heard the very low "thump" around 25/26 secs ... was this a cold start idle or warm???
does it do it with the sport button pressed in?
you might also disconnect the sport exhaust flaps (locking them open) and see if it repeats ...
my (totally uninformed and therefore worthless) opinion, if it is a transient and not repeatable then it is probably just some pressure change in the engine due to some transient change in combustion etc ...
and nothing to worry about ...
does it do it with the sport button pressed in?
you might also disconnect the sport exhaust flaps (locking them open) and see if it repeats ...
my (totally uninformed and therefore worthless) opinion, if it is a transient and not repeatable then it is probably just some pressure change in the engine due to some transient change in combustion etc ...
and nothing to worry about ...
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02-12-2010, 12:42 AM
#8
It was a cold idle. I remember hearing the same after a drive but let me try that. The weather may have something to do with that but I won't know because I just got the car.
The sport button is off and I can hear it all the time. How do I disconnect the sport exhaust flaps?
The sport button is off and I can hear it all the time. How do I disconnect the sport exhaust flaps?
02-12-2010, 01:48 AM
#9
Drifting
Whenever I buy a new car, I notice EVERY sound it makes and get worried to the point that my brain can't handle it anymore. When my brain goes into "I give up" mode, the car suddenly becomes a lot quieter.
These are very noisy cars, the suspension makes noise, the engine is somewhat "tappety" and the tires roar so loud that I had forgotten what wind noise is with the windows up.
Drive the car, enjoy it and let the dealer take care of any issues that come up if the noise escalates or gets worse over time. Wait until your struts start to make noise, what a racket!
These are very noisy cars, the suspension makes noise, the engine is somewhat "tappety" and the tires roar so loud that I had forgotten what wind noise is with the windows up.
Drive the car, enjoy it and let the dealer take care of any issues that come up if the noise escalates or gets worse over time. Wait until your struts start to make noise, what a racket!
02-12-2010, 11:08 AM
#11
02-12-2010, 11:29 AM
#13
Race Director
I think the GT3 does something with the exhaust cycle during warm-up and when it's cold out that makes the exhaust sound like it's popping. If you've had a 993 Turbo before, the emissions system on that car would make the most amazing sounds when you'd fire it up on a cold morning, almost like a drag boat. Maybe the cooler weather is bringing the emissions electronic systems into play?
Sincerely,
Macster.
