Best way to gun the car?
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From: Germantown, MD/Rehoboth Beach, DE
2024 GLS450
Again you've changed the story. We were not talking about revving to redline. That was not the point at all. I'll leave it at this since you do always seem to hang on to your opinions regardless of anyones arguments around here. It's a trivial argument anyway, so you can have it 
It's pretty damn brazen to make a statement like "He's wrong about this" when you don't even own the powertrain in question...
You're damn right I hang to my opinions. Why else have them?
Last edited by MDMercedesGuy; Jun 26, 2012 at 11:13 PM.
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From: Delaware
2004 Mazda6, 1993 RX7
I find that unless I am trying to be ridiculous, mine pulls hardest in E if you give it 3/4 throttle or so and let it shift at ~4,400 RPM....
......We're going to have to agree to disagree then. I own one, I drive it every day, and I know how it drives. It doesn't like to have the **** revved out of it, and once you run it out of the peak of the torque curve at 4,300 RPM it falls off rapidly. With 7 ratios to pick and a wide torque curve, it does not need to be revved to redline to put it back in the powerband after a shift.
E keeps it in the fat part of the torque curve longer.
Your 3/4 throttle conditional makes what you say true, but only if you stay at ~3/4 throttle, and even more likely if you are talking about 3/4 pedal travel, which results in less than 3/4 throttle.
But if your looking for max accelleration, you want the engine to be putting out max hp at all times. That means ~stradling the peak hp rpm while shifting, which means flooring it asap in s mode.
Remember by definition:
Hp from engine = (work done) per second, and is a max of 201 at 5500 rpm.
HP delivered by wheels = (the tractive force x unit distance moved) per sec
Torque Peak = The most efficient rpm for HP production, ie: Point of Max Hp per rpm.
If you line up at a strip racing against an identical car, and you shift based on the "fat" torque curve, and the other guy base on HP curve, you will lose.
"We're going to have to agree to disagree then."
If you disagree, you are wrong. Sorry.
BTW, I've owned 3 turbo charged cars with 4 turbos.
.
Last edited by kevink2; Jun 27, 2012 at 02:42 PM.
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From: NYC
2012 C300 4Matic
kevink2,
Thank you for explaining this much better than I have the knowledge or patience to.
Gunning the car means putting the pedal to the floor. Flooring it does not equal revving to redline. Further, the bulk of the time when someone 'guns it' or 'floors it' they don't hold the pedal down all the way to redline. Even so, if you "floor it and hold it to redline" in E you've added a delay as the car has to shift back down to first gear which it would have already been in were you in S. I don't care if your car is powered by a V8 or a turbo charged lawnmower engine, the transmission is still the same one with the same software and the same (or very similar?) gearing. Sorry. I give up!
Thank you for explaining this much better than I have the knowledge or patience to.
Gunning the car means putting the pedal to the floor. Flooring it does not equal revving to redline. Further, the bulk of the time when someone 'guns it' or 'floors it' they don't hold the pedal down all the way to redline. Even so, if you "floor it and hold it to redline" in E you've added a delay as the car has to shift back down to first gear which it would have already been in were you in S. I don't care if your car is powered by a V8 or a turbo charged lawnmower engine, the transmission is still the same one with the same software and the same (or very similar?) gearing. Sorry. I give up!
Last edited by acr2001; Jun 27, 2012 at 04:51 PM.
Member
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2005 CLK500
Again you've changed the story. We were not talking about revving to redline. That was not the point at all. I'll leave it at this since you do always seem to hang on to your opinions regardless of anyones arguments around here. It's a trivial argument anyway, so you can have it
Firstly, when he said that leaving the car in E mode and giving it 3/4 throttle netted some of the hardest pulls, my first thought was "Aha! So it isn't just my imagination." I have experienced this myself and, knowing not only the power band of the C250 but also a decent amount about how turbos work in general, I realized that it probably was due to the fact that the transmission does not downshift as agressively.
From a dead stop, there is no doubt that S mode will get you a quicker getaway. If you are rolling at around 30-40mph, or even cruising at low freeway speeds, E mode will, without a doubt get you a real nice, steady pull--chock full of thick torque and plenty of steady boost. Whether or not it's fast than smashing the pedal in S mode remains to be seen, but I know that there are a few times I merged onto the freeway in E mode with a quick half-throttle stab and by the time I was done riding the wave of boost/torque the hair on the back on my neck was tingling and my pupils were dialated from the adrenaline rush.
It's not something that can be easily understood if you drive a NA car.
Thread Starter
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Joined: Jun 2012
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Mercedes Benz C250 Sport Sedan
I'm pretty sure only the newer cars have it with the "blue efficiency" thing, "E" meaning eco mode which is for conservative driving, to save gas nonetheless and "S" is sport mode which is of course more sportier driving. Its like a mode you can press, mine is right under the D.
Thread Starter
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Mercedes Benz C250 Sport Sedan
So if I'm going to be doing a run from lets say 30, I'll just leave it in E mode and push it to 3/4 throttle and let the car downshift to get max accel? Then at dead stops, S mode will be the way to go because it starts in first gear! 
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Older cars = W-winter, S-summer or sport
Intermediate cars = C-comfort, S-sport
Latest cars = E-economy, S-sport with auto default to E at every start.
Intermediate cars = C-comfort, S-sport
Latest cars = E-economy, S-sport with auto default to E at every start.
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MBWorld Fanatic!
Joined: Sep 2008
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From: Delaware
2004 Mazda6, 1993 RX7
I feel the need to weigh in here as someone who has owned several turbo cars, including my C250 that I drive every day.
Firstly, when he said that leaving the car in E mode and giving it 3/4 throttle netted some of the hardest pulls, my first thought was "Aha! So it isn't just my imagination." I have experienced this myself and, knowing not only the power band of the C250 but also a decent amount about how turbos work in general, I realized that it probably was due to the fact that the transmission does not downshift as agressively.
Firstly, when he said that leaving the car in E mode and giving it 3/4 throttle netted some of the hardest pulls, my first thought was "Aha! So it isn't just my imagination." I have experienced this myself and, knowing not only the power band of the C250 but also a decent amount about how turbos work in general, I realized that it probably was due to the fact that the transmission does not downshift as agressively.
From a dead stop, there is no doubt that S mode will get you a quicker getaway. If you are rolling at around 30-40mph, or even cruising at low freeway speeds, E mode will, without a doubt get you a real nice, steady pull--chock full of thick torque and plenty of steady boost. Whether or not it's fast than smashing the pedal in S mode remains to be seen, but I know that there are a few times I merged onto the freeway in E mode with a quick half-throttle stab and by the time I was done riding the wave of boost/torque the hair on the back on my neck was tingling and my pupils were dialated from the adrenaline rush.
It's not something that can be easily understood if you drive a NA car.
It's not something that can be easily understood if you drive a NA car.
1) Fact: For a specific gear, the car will accelerate the quickest at the engine's rpm for the the highest torque, ie the torque peak. But that is for a single gear, with no downshifts allowed.
2) Modern, well sized turbos will provide a torque curve that has a big hump at the lower half of the torque curve, vs a NA engine.
The combination of these two factors results in the ability tto use low end turbo-torque to merge into traffic in a fun grunt of low end torque. My first turbo was a classic 900T 8V saab. I had a project to persue no lag and max low end torque ... it was very successful but it cost me a transaxle.
"Whether or not it's fast than smashing the pedal in S mode remains to be seen"
Not really, based on post #28
.
Last edited by kevink2; Jun 29, 2012 at 01:58 AM.
