Turbo X startup question - answered!
I got a question via email the other day, and as I know we’ve got a number of Turbo X owners (and Aero V6 owners) here, I thought I’d share it with the wider audience.
The question comes from Dan, who writes:
I purchased a Turbo X back in May, I have noticed that during the first minute or three of a cold start it has superior performance and a deeper exhaust note (perhaps more air intake?, wish it would stay that way). I have consulted many mechanics and received no positive answer. Perhaps, with your expertise you could lend some information on this matter. Thank you. Sincerely, Dan
Seeing as how I don’t actually have a clue about these things (I am a mechanical gimp - but learning), I passed the query on to our friendly GM Master Technician, Tedjs, who provided the following:
He is basically experiencing two things - one is advanced ignition timing that is used during the engine warmup cycle which essentially is used to pre-heat and ignitie the richer air fuel mixture in the cylinder. This will produce some additional mid-range torque and power during warmup.
The other thing is that exhaust cam-phasing is commanded to add some additional valve overlap on engine warm-up to light off the catalytic convertor. Basically what they are doing is in conjunction with the turbo is letting some additional air run through the cylinder to help heat up the exhaust quicker. That is causing the change in the exhaust note in conjunction with timing. I have noticed it on my car as well.
The 2.8L warms up amazingly quick - more so than any car I have ever owned. Even in cold outdoor temps it really gets up to operating temperature in short order to maximize fuel economy. Compared to the lump of cast iron that was in my old car which took a lifetime to warm up - and used a lot of fuel in the process.
So if you’re experiencing the same symptoms as Dan when you start your V6 in the morning, now you know why. Enjoy those first few minutes. If you’ve got a cocky neighbor with an A4 3.2 quattro, perhaps right on startup is the time to show ‘em who’s boss 
My thanks to Tedjs for once again stepping up to the plate.
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TWO SERIOUS (but admittedly anecdotal) drawbacks to this cold start operation are the considerably higher fuel consumption during cold weather (< 30 degrees F) on my 2006 9-3 SC Aero during this warm-up phase AND in my case, the extremely intolerable exhaust smell. It is so bad that I have to make sure I always push the air recirculation button before I start my garage kept 9-3 or the smell (not to mention the possible health implications on the wife and my two young children) is overwhelming inside the vehicle. In the winter, you almost can’t even walk back into the garage unless the door is left open for a considerable amount of time. Warm weather starts are still a bit hard on the nose, but obviously the warm up phase is much shorter. Maybe it is my nose, or maybe it is just “vapor pressure” or something else I forget about from 10th grade chemistry???? Regarding the fuel consumption, using the trip computer, I’ve compared my 37 mile commute to work from a cold start to a 32 mile trip from the gas station after a warm start to work, and the winter cold start always ends up being about 2 MPG lower for the trip. Typically I get 27-28 MPG per tank of mid-grade. In the summers, the same comparison is less than 1 mpg. In 45,000 miles, my trip computer’s MPG has been with 0.2 to 0.4 MPG of the actual MPG calculated by the manual method of gallons to fill the tank/miles traveled, so I have pretty good faith in the trip computer. Honestly the cold start exhaust smell is the ONLY issue I have with my 9-3. Well that, and the fact that my lease is up in Dec.
I have a ‘07 SC Aero, and I am familiar with that smell. It is probably the catalyst getting fired up, wouldn’t want to be in the same room as that.
Thats pretty good milage tank to tank. I had been getting consistent 23.75 mpg tank to tank the first 15,000 miles using Shell 93. However my best milage has always been using HESS mid grade where I get 34 mpg hi-way if I drive at 65 and don’t use the AC. On the highway I find that the car is comfortable, for me, up till about 82 F outdoors without AC.
I may be wrong but I’m guessing the better milage I see using mid grade is engine management lowering boost, and hopefully Trionic is preventing pre-ignition. I console my self saying that if there were significant pre-ignition or extraordinary steps taking place to prevent it the milage would degrade rather than improve.
The only time i noticed a smell from my fathers 07′ convertible was when there was a very small coolent leak.
Swade,
I have another question for other Turbo X owners or your friendly GM Master Technician. I have a manual 6-speed Turbo X and I have noticed when driving with the windows open and either under hard acceleration, down shifting to decelerate, or shifting while climbing a hill, I hear a “clicking” noise when depressing the clutch pedal. Is this noise from the clutch or from the front Haldex transfer unit as it transfers power to the rear wheels? Is it normal to hear this as the power is transferred or does something need to be adjusted? I have owned 4 Saabs with manual transmissions before and have never heard this sound from them.
Hi Ziggy, as another owner of a 6-speed manual Turbo X I hear the same clicking noise when depressing the cluth and (foolishly?) attributed it to the clutch being shorter. Mind you, this is my first manual Saab.
Kroum,
I purchased the car from Herb Chambers in Boston and they will probably sell more Turbo X’s than any other US dealer so I will have them check it out when I go in for my first oil change in late August or early September.
Ziggy: Does the noise only occur when the clutch is being disengaged or when it is fully depressed? If it happens with the clutch fully depressed (coasting) throw the gear selector into a neutral position as this essentially disengages the gears from the output shaft of the transaxle which is still somewhat under the influence of wheel torque. If it completely goes away in neutral, it can be isolated to some gear noise in the transaxle which may be normal. If it is still going on, your issue is elsewhere.
Additionally, fourth gear is as close as you get to 1:1 so if the noise is in the transaxle it should be the most subdued due to the fact input and output are close to the same speed. One of the cool things about a manual transaxle is that is can neatly be isolated from the engine when diagnosing noise conditions, and shifted as needed.
If it is happening during clutch apply/shifting/clutch release this may be normal in that if memory serves the 9-3 with six-speed manual uses a dual mass flywheel. Think of the unit as a shock absorber between the engine and transaxle. The primary mass in the dual mass flywheel is mounted on the engine (crankshaft) and the secondary on the transaxle side. They are flexibly linked with a spring assembly that absorbs torsional vibration from the engine. Essentially these vibrations are absorbed with strong springs as torque is reduced (during a shift) and the system momentarily encounters negative torque being applied.
Dual mass flywheels were typically used in diesel applications, but they are now being used in some automotive due to the high torque output of some engines and the need to somewhat smooth out the clutch apply – especially during shifting at higher loads. The 2.8L puts out some rather aggressive torque so that has to be somewhat controlled.
Back in my ‘Chevy dealer’ days we routinely used to see these ‘blow up’ on dump trucks when the driver dumped (no pun intended) the clutch at high loads. Cool if you are not paying the bill.
The XWD system uses an electrically controlled fluid pump so it does not rely on input from the driveline to operate like some more mechanical systems for operation (and lubrication). Under normal operation I would expect the system to be nearly transparent and quiet.
Overall manual transmissions are pretty quiet, but they still tend to make some noise due to the fact your are moving rather strong gears in and out of relationship to each other during shifting.
Tedjs,
Your explanation about the torque is probably correct as the “clicking” is most pronounced during the clutch apply/shift/clutch release cycle and most evident during a 1st to 2nd and 2nd to 3rd gear shift, and not so evident during a 3rd to 4th gear shift. The “clicking” is not loud enough to be annoying and only raised my concern because my other Saabs did not have it but they were all 4 cylinder engines.
I have the manual shift Turbo-X. I’m not sure what you mean by a “cold start” but, in normal conditions the car will have what I would call a “warm-up” cycle for the fist 60 seconds or so where the idle speed and exhaust note are elevated.
I have 5000K miles on my car now and I have never heard any kind of “clicking” from the clutch. If you shift gears well below 3000 RPM you can definitely hear normal gearing noises, but you really shouldn’t be shifting up when that low in RPM. I find about 4000 RPM as the best shift point unless you are accelerating hard. When pushing the car very hard I’ve never induced any funny noises except during braking when you get the normal ABS action.
Never heard any noises when down-shifting at all. In fact I’m amazed at how smooth the down-shifting is.
So our Turbo X just arrived at the dealership. The Australian official fuel consumption sticker read 18.4 l/100km!!!!! I almost passed out when i read it. Surely this must be incorrect?
This figure is the city driving value.
From http://www.saab.com.au:
City / Highway / Combined (l/100km)
SS M6 - 16.2 / 7.8 / 10.9
SS A6 - 18.4 / 7.6 / 11.6
SC M6 - 16.5 / 7.8 / 11.0
SC A6 - 18.8 / 7.9 / 11.9
Not too bad for a 200+ kw XWD 1600kg car …
Mmmm - wonder what the 2.0T XWD consumption will be …
After some shocking numbers durng break-in, like the 18 l./100 km., my SS M6 now averages 12 l./100 km. on mixed city and highway driving. Not too bad for such a powerful car.
Over the first 5K miles I average 21.9 MPG.
kdsaab, an Australian delivery?!! Which city? Keep us posted please!!
18.5 mpg the first 1000 miles (spent a bit too much time doing some spirited driving). The next 600 miles were at 23.5 mpg; that includes some mixed city and highway miles. This car doesn’t lug unless you get below 1000 rpm. Cruising around town in 5th or 6th with the tach at 1500 is quite easy, and easy on the fuel economy.
Also, I absolutely love the sound of the car during warm-up!
Response to Dan , l read the responses to cam overlap , ignition , pre heat , yadda yadda yadda, an exhaust system simply responds to detonation (firing ) pressure ( pulse and flow) heat (expansion ). A cold exhaust system has a particular modulation effect that you can only get when the system is cold, this is the sound that you hear first hear , when the total exhaust system heats up the exhaust systems tuned (external sound ) effect is different due to system heating (expansion) and you hear a different modulation ( exhaust sound )
Turbin , as a note my Turbo X is yet to be delivered ( delays again ) l will be expecting to pick it up in Melbourne on the week of the 17th August , on what l have been told from Saab Australia l was the first official order in OZ. My experience so far is been a passenger at the Lang Lang Turbo X drive day with the SCCA , Swade was there as well, looking forward to my first drive , also intend to head of to Tasmania with it to again enjoy Tassie roads with a few other SCCA members.