Farty Exhaust Noises during warm-up

[Tony B2]

I am probably very much behind the curve on this one, but here goes.

Initial cold start followed by fast idle, all seems normal to me.

I always wait fro the revs to drop normal before moving.

Then I drive away (and normally turn off the "stop/start" function, and turn "on" autoblip) and it all still seems OK.

Now the embarrassing bit - at some point in the first mile or so (therefore probably within the first 5 to 7 minutes from switch on, after reversing out and driving off) and generally when on the over-run (almost or fully closed throttle) there is the most embarrassing noise which I can only describe as "badly blowing exhaust".

It can be so loud that pedestrians walking away from me, 50 or 100 yards away, turn to see what awful ropey old banger is approaching.

Once warmed up beyond this early period no problems.

Is it actually normal?

[SV_WDC]

You don't say which version car, but they are designed to operate within a temperature window

[TheOctaneAddict]

My 981 2.7 with the PSE does this. I think its part of the warm up cycle programmed into the ECU. I get to the bottom of the road lift off to coast to the junction and it lets out a huge bang and some crackles, seems to be worse when its single digit temperatures.

[Tony B2]

SV_WDC said:

You don't say which version car, but they are designed to operate within a temperature window

Sorry - was in a hurry and forgot!

718 Spyder

To my mind, the warm-up cycle is well and truly over at this point, as the car has been running for at least 5 minutes.

When I say say "warm-up cycle", I mean the emissions manipulating/cat-heating stuff has surely finished by now, but I do not assume that the engine is warm enough for "beans" until at least another 10 miles have been covered.

And it is definitely VERY loud. Embarrassingly so.

It reminds me of the exhaust brake things that large trucks used to have (not sure they still do).

I would ask the OPC, but do not feel like leaving the car with them overnight, only to be told "they all do that, Sir"

Edited by Tony B2 on Saturday 16th December 15:19

[Haltamer]

Air densities, exhaust temps etc. all have an impact on sound - Even if the engine is warm and running closed cycle / off "choke" I've found you can still get rorty noises for quite a while in any car.

If it's so loud that it is scaring pedestrians and on a standard exhaust though, I'm inclined to say something is broken.

May be worth checking flexi's for damage - Prime culprit for some thermal expansion tomfoolery.

[WG]

I have a 718 Spyder and never experience what you have described. The warm up cycle doesn’t last long, in fact the blue light goes out and the revs drop after about a minute. Mine is PDK, I assume yours is manual as you mention auto blip so it may well be different.

[Tony B2]

WG said:

I have a 718 Spyder and never experience what you have described. The warm up cycle doesn’t last long, in fact the blue light goes out and the revs drop after about a minute. Mine is PDK, I assume yours is manual as you mention auto blip so it may well be different.

Yes, mine is a manual.

The duration of the cat warming is similar to yours, and the revs drop very clearly (i.e. a step change downwards) at the end of it.

[LiamH66]

My Cayman 718 GTS 4.0 can make some pretty weird exhaust/induction sounds at low speed 3-5 minutes into the warm-up period. I'm guessing it's an emissions related thing. Driving away from home is all 20 mph limit, and that where I notice it. Leaving work and straight into 30 limit I'm not sure I notice it at all.

Liam