FAQ 2.0! <- New Members Read First

Synchros shot? Weird noises while shifting? Not sure what needs to be replaced?
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Postby jomotopia » Thu Feb 07, 2008 12:09 pm

Slushy / Slushie / Slush / Slushbox - An automatic transmission, or a vehicle with an automatic transmission. So called because of the fluid filled torque converter and the "slushy" shift feeling in lower end automatics.
2013 Subaru Impreza WRX in Orange

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Re:

Postby jomotopia » Thu Oct 09, 2008 9:03 am

Winter Driving

Author - Prodigal Son

Prodigal Son wrote:Here's the thing about winter driving: torque is not your friend.

Basically, torque pushes against traction to move the car. Where traction > torque, the car moves and stays under control. Where traction < torque, the wheels spin and the car goes out of control.

In summer, you generally have more traction than torque. It takes some work to break traction and lose control of the car. In winter, you often have very little traction, meaning that it is easy to have torque exceed traction and to lose control of the car. Here are the things that contribute to lack of traction in winter:

* Cold. Cold rubber does not grip cold asphalt the same way warm rubber grips warm asphalt. Even on bare pavement, you have far less grip in cold conditions than you do when it is warm.

* Snow and ice. Duh. Not much grip on snow and ice. But if you spin you tires on snow, you are likely to turn it into ice. And if you spin your tires on ice, you are likely to melt the surface layer, and if ice gives little traction, wet ice gives absolutely none.

Just about every winter driving technique is in some way about reducing torque so that you don't break traction. Luckily for you, the lack of low end torque in your Fit becomes an advantage in Winter driving. Here are the basic winter driving techniques:

* Travel at low speed in high gear. Low gears multiply engine torque, so keeping in as high a gear as possible reduces the amount of torque you are putting down to the road and helps keep you under control.

* Launch in second gear and release the clutch slowly (where it is particularly slippy -- generally not necessary on dry pavement). Again, higher gears have less torque, so using second helps you moderate the torque you put down.

* Accelerate slowly. Again, reduce the torque you are putting down.

* Don't run at hills. Slow and steady in as high a gear as you can will help you minimize torque to just what you need to climb the hill and avoid breaking traction.

* Braking. Brake gently. Again, you want to minimize the braking torque you apply to the wheels so they continue to roll until the vehicle is stopped. A locked wheels generally does not stop as fast under slippery conditions (thought there are exceptions) but the main reason to avoid locking up the brakes it to maintain directional control. With locked wheels, differences in the surface can change your direction and send you sliding all over the place. If you have ABS, though (and I'm pretty sure you must have), let it do its job. If you don't, and you find yourself self sliding uncontrollably towards some object, you have to do the counter-intuitive thing and get off the brakes. This will (hopefully) restore steering control and let you avoid the obstacle. (If it doesn't, well, you were going to hit it at that point no matter what you did.)

* Steering. Wheels only steer if they are rolling. If you break traction while turning, you will stop turning and slide. Always complete your braking in a straight line before entering the corner. Once you enter the corner, keep neutral throttle until you have completed the turn. (Neutral throttle means neither accelerating not decelerating.) Do not stay off the throttle altogether, as this will cause engine braking -- braking torque to the wheels that will limit their ability to turn the car.

* Skid control: Clutch in and steer where you want to go. By clutching in, you remove all torque from the wheels (other than that generated by the momentum of the car) and give the wheels the best chance to grip, roll, and steer.

* Engine braking. There is a persistent myth out there that you should use engine braking to slow down in winter rather than using the main brakes. This is not only untrue, it is dangerous. Engine braking comes on fast (which can help break traction) cannot be easily modulated or canceled, applies only to the drive wheels (which unbalances the car), and cannot be controlled by your ABS (though some cars do have a system to modulate engine braking). Generally speaking, the amount of engine braking you get merely from lifting off the throttle and coasting will not cause a problem, but if it does, throwing in the clutch may allow you to regain control. If you have ABS, throwing in the clutch and hitting the brakes should allow you to slow down and steer without losing control. And, of course, if you have been using the highest gear available while you were running, your engine braking will be proportionally less when you lift, which will help keep things under control.

* Winter tires. Winter tires give you more traction under all winter conditions: cold, snow, ice. The rubber compound is formulated to stay flexible in the cold, the tread is designed to clear snow, and the snipes help you grip on ice. A good set of snow tires are worth more than all the above driving tips put together.

Good luck with your first winter in a manual. A manual is definitely an advantage in winter because it give you lots of ways to limit the torque you are putting down. So remember, torque is not your friend, and you should be fine.
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Re: FAQ 2.0! <- New Members Read First

Postby blauenlanze » Wed Oct 15, 2008 9:02 pm

On the Frequently used terms:
Straight Cut - Many cars have straight cut teeth on reverse gear. This makes it harder to engage and produces a whining sound when traveling in reverse. This is normal. If you have trouble shifting into reverse, try first shifting into a forward gear, and then into reverse.

This is technically not correct, straight-cut gears can have synchronizers and if they do they are not any harder to shift into than normal gears. Reverse gears usually do not have synchronizers, which makes them difficult to shift into.

In the downshifting FAQ:
4.clutch out *****
5.blip throttle
6.clutch in *****

Was the ***** intentional or did the swear filter somehow make it that way?
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Re:

Postby InlinePaul » Thu Mar 07, 2013 1:21 pm

jomotopia wrote:Slushy / Slushie / Slush / Slushbox - An automatic transmission, or a vehicle with an automatic transmission. So called because of the fluid filled torque converter and the "slushy" shift feeling in lower end automatics.

Also have heard the term "Juice box."

Short Shifting - Shifting at low rpms to save fuel, as opposed to shifting at high rpms to maximize acceleration and power.

Add that this shifting method is conducive to engine lugging--very, very bad.
I recommend never follow the recommended shift points. I always like to keep my 2.3L Ranger around 2000-2500 rpm for instant quick acceleration.

I have a habit of (if not actively downshifting into a stop) of sliding the shifter into neutral without using the clutch. It will slide right out when the road speed matches the engine speed. This could be considered lazy, but also is one less wear event on the clutch disengagement mechanism.
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theholycow wrote:Why in the world would you even want to be as smooth as an automatic? Might as well just drive an automatic...

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Re: Re:

Postby Squint » Thu Mar 07, 2013 2:15 pm

InlinePaul wrote:
Short Shifting - Shifting at low rpms to save fuel, as opposed to shifting at high rpms to maximize acceleration and power.

Add that this shifting method is conducive to engine lugging--very, very bad.
I recommend never follow the recommended shift points. I always like to keep my 2.3L Ranger around 2000-2500 rpm for instant quick acceleration.

I have a habit of (if not actively downshifting into a stop) of sliding the shifter into neutral without using the clutch. It will slide right out when the road speed matches the engine speed. This could be considered lazy, but also is one less wear event on the clutch disengagement mechanism.

Short shifting is not conducive to the engine having problems. All short shifting means is that you shift before the power band. The power band on my Fiesta is probably 2500-4000 or so, for most gears. However, since I shift usually at 1800-2200, I'm short shifting, getting slightly better fuel economy.

Regardless of the definition of lugging, shifting before the power band does not hurt the engine. Now, if you never exercise your RPM at all, it can hurt it if you suddenly decide to one day. But that's the same as never exercising then pulling a muscle when you try to sprint a mile.
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Re: Re:

Postby tankinbeans » Thu Mar 07, 2013 2:19 pm

Squint wrote:
InlinePaul wrote:
Short Shifting - Shifting at low rpms to save fuel, as opposed to shifting at high rpms to maximize acceleration and power.

Add that this shifting method is conducive to engine lugging--very, very bad.
I recommend never follow the recommended shift points. I always like to keep my 2.3L Ranger around 2000-2500 rpm for instant quick acceleration.

I have a habit of (if not actively downshifting into a stop) of sliding the shifter into neutral without using the clutch. It will slide right out when the road speed matches the engine speed. This could be considered lazy, but also is one less wear event on the clutch disengagement mechanism.

Short shifting is not conducive to the engine having problems. All short shifting means is that you shift before the power band. The power band on my Fiesta is probably 2500-4000 or so, for most gears. However, since I shift usually at 1800-2200, I'm short shifting, getting slightly better fuel economy.

Regardless of the definition of lugging, shifting before the power band does not hurt the engine. Now, if you never exercise your RPM at all, it can hurt it if you suddenly decide to one day. But that's the same as never exercising then pulling a muscle when you try to sprint a mile.

I used to shortshit for mileage purposes, but now I've stopped and change right at or around 3500. Midway through the winter and 30mpg, and plenty of suburban driving - not as bad as city, but not as good as straight highway, I'm happy. Direct injection FTW.
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InlinePaul wrote:The driving force of new fangled features to sell more cars [is to] cater to the masses' abject laziness!

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Re: FAQ 2.0! <- New Members Read First

Postby RITmusic2k » Fri Mar 08, 2013 1:45 pm

Regarding the danger of short-shifting and engine lugging; it depends as much on engine load as it does on engine speed. I can upshift at 1,500rpms without a hassle or hiccup, because I'm cruising along at very low throttle and low engine load. We're talking like, thrumming along in top gear on a 45mph surface street when I've gently gotten up to speed.

If I then floor the accelerator without downshifting, there's some engine strain until she gets up into the power band. But that's why I never do it ;)


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