Manual Shifting and Transmission Mode Behaviors

[dtrayers]

Forgive me if this was clearly answered but I couldn't find it.

I'm considering replacing my 2012 Acura Tl SH-AWD with a Stinger GT2 AWD later this year. My TL has their 6-sp sequential shift auto, and I use the paddle shifters almost exclusively. It has to be in Sport mode, but I like that it will hold whatever gear I select. It will only upshift if it hits the redline, and it will only downshift when coming to a stop or slow enough that the RPMs drop below 1000. So at stoplights I can be a bit lazy and let the car go back into 1st by itself, then I'll control the up and downshifting.

It's especially nice in the winter when I can keep it in 4th or 5th on snowy highways and use engine braking to slow down, or preparing to accelerate for an on-ramp or merging.

The other thing I like about my TL is the torque converter will lock at fairly low speeds and in 2nd gear on up. So I don't get this "rubber band" effect when accelerating that comes from having to first reach the stall speed on the TC. It feels much like a conventional clutch.

So, my question is if the Stinger works similarly? I've read reviews that it shifts on it's own, and others that it only shifts at redline, and still others that it will hold a gear for a short while, but after steady state will revert back to auto. But I haven't seen an in-depth discussion of the various modes and manual shifting.

Would anyone care to provide a more in-depth discussion of the transmission and its various operating modes? Or point me to the correct thread?

 

[Steve O]

Thanks for the nice description of what you have with the Acura [MENTION=448]dtrayers[/MENTION]. I'll share everything I know here. Unfortunately the Stinger is quite a different setup. I have not found the procedure that has the tranny stay in manual no matter what. However, I have had it hit redline without upshifting. One thing is for sure. You can't select manual mode and keep it there. It switches back to shifting when it wants to. That seems to be 'whenever'. I'm going to be waiting for a chip that adds both HP and a full manual mode before doing anything to the ECU. I have noticed that leaving it in full auto in sport mode, the tranny does a great job of staying in the torque sweet spot... A really great job. Now just because I don't have to shift doesn't mean I don't want to. I like to keep it in gear just to hear the exhaust make its music. (BTW, the exhaust sounds P-E-R-F-E-C-T!!) Also for the reasons you mention. Also for down hills, also for FUN! I did notice you can start off in 2nd or 1st and if you select your gear at the stoplight it's in manual mode until it decides it's not. Read the manual and come away confused like me. If you don't manually shift a gear within a certain time it reverts to auto. But the time seems to vary from 10 seconds to 2 minutes. Am I making sense? HELL NO! But so far it is what it is.

 

[MurlinatoR]

[MENTION=148]Steve O[/MENTION], will you do me a favor please? Next time you drive the Stinger, try pulling the shifter to D TWICE before you drive off.

I don't have a GT2 in stock to test on but the manual mentions shifting to D two times. In the GT1 and lower (units without the drive by wire tranny), the vehicle has a "manual mode" that you can shift into to the left of D that HOLDS the tranny in the gear you've put it in until a shift is performed. I believe that there has to be a way to make this happen on the by wire system.

Let me know how she reacts. Thanks!

 

[Kazz]

I'm hoping to know a lot more about this with a temporary thaw around here. I know that the mode setting has a lot to do with it. Comfort, for instance, will get out of your manually-selected gear while Sport doesn't seem to. Also, even in Sport, the mode will revert to "D" when you come to a stop. Sorry this is vague, I just haven't been able to drive the thing other than on snow/ice so far.

 

[TurboTx]

Sorry but I think the TL wins this round. I have played with the modes, tried every technique, it still won't remain in manual after you come to a stop and has the rubber band effect when accelerating. Maybe I'm missing something or there's a secret to it, if so, I haven't found it.

 

[Kazz]

Sorry but I think the TL wins this round. I have played with the modes, tried every technique, it still won't remain in manual after you come to a stop and has the rubber band effect when accelerating. Maybe I'm missing something or there's a secret to it, if so, I haven't found it.

What do you mean by "rubber band effect"? Thanks.

 

[TurboTx]

What do you mean by "rubber band effect"? Thanks.

I'm too foggy-brained from lack of sleep to give a good description..lol. I always hear that term applied to cars with CVT and, to me, that's what the Stinger feels like when you're accelerating around town in manual mode. To me, it feels really unnatural, like the engine RPMs are too high for the car's speed (just like a CVT).

 

[Steve O]

It's the torque converter which is not a mechanical connection to the engine. When the car is idling at 900 rpm, the wheels aren't moving but you're in gear. That's the hydraulic 'slip' doing it's job. At higher rpm the slip reduces eventually becoming practically zero at redline. So between idle and redline there is a momentary slip between the time the gear engages and the engine fully engages through the torque converter. I don't feel anything unnatural in my tranny. It shifts quickly and up and down at the times required to keep the engine above 2000 rpm. REGARDING A SLINGSHOT OR RUBBER BAND EFFECT, the Stinger definitely has a turbo WOOSH that happens in the midrange. It feels like you take your foot off the throttle and the car still accelerates for a second. As a Saab driver for the last 16 years, that's latent turbo boost.

 

[Steve O]

Lemme see on my way home tonight [MENTION=291]MurlinatoR[/MENTION].

 

[mldavis2]

I don't know where one can find the details of the turbocharger system outside of a Stinger Service Manual, but most modern turbocharges have a relief valve or "blow off" valve that relieves inline boost pressure when the throttle is suddenly dropped. This is not the same as the waste gate that controls boost pressure going into the intake runners. There should be a valve on both ends controlling boost at the compressor impeller and at the intake end bleeding off excess boost not needed on a throttle drop.

 

[Kazz]

I don't know where one can find the details of the turbocharger system outside of a Stinger Service Manual, but most modern turbocharges have a relief valve or "blow off" valve that relieves inline boost pressure when the throttle is suddenly dropped. This is not the same as the waste gate that controls boost pressure going into the intake runners. There should be a valve on both ends controlling boost at the compressor impeller and at the intake end bleeding off excess boost not needed on a throttle drop.

In this vehicle, I believe it's a diverter valve (vents into the intake side of the turbo) and not a blow-off valve (vents into the atmosphere). Whenever there's enough boost built up and the driver lifts off the throttle, the valve will activate and relieve the pressure on the turbo side of the intake.

 

[mldavis2]

In this vehicle, I believe it's a diverter valve (vents into the intake side of the turbo) and not a blow-off valve (vents into the atmosphere). Whenever there's enough boost built up and the driver lifts off the throttle, the valve will activate and relieve the pressure on the turbo side of the intake.

Thanks, [MENTION=328]Kazz[/MENTION]. My technical knowledge is not up to date on terminology. It has been a long time since I worked around turbos. Right answer, wrong terminology.

 

[Kazz]

Oh yes! You had the concept right. The air is being metered shortly after the intake so the computer knows how much air is coming in. If there's an unknown quantity of air blown off into the atmosphere, the computer can't account for it. So it's dumped into the intake these days, after the MAF (Mass Airflow Sensor) and before the turbo itself.