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TCMdocs944's Avatar
 
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Drivers...Educate me!

Ok, so what is the deal with downshifting..

I have been downshifting all my life why slowing down...

ie reduce speed....shift to next lower gear....let out clutch..

reduce speed....shift lower......clutch......redu..........


Is that ok or should I just clutch, use brakes only?
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Old 02-19-2004, 01:58 PM
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Brake pads are cheap, drivetrain is not. If you're not pretty good at RPM matching or double clutching, I would say use the brakes.
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Old 02-19-2004, 02:01 PM
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Thats what I wonder about....

Been doing that on my Isuzu Rodeo for 10 years and no clutch problems at all.

I want to drive this car right though.
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Old 02-19-2004, 02:07 PM
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Here in Spain (and almost all europe) 98% of cars are manual,and i always heared it´s better to downshift due to the engine brake,everybody says that here.

If you are not good matching rpm,syncros are there to do that.
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Old 02-19-2004, 02:23 PM
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You should NOT use downshifting to slow the car down!

Why put unnecessary wear and tear on your drivetrain when your brakes are perfectly suited for the task?

You may have heard of the 'heel and toe' shifting technique used by most track drivers. The purpose of that is to shift to a lower gear while braking, and not changing the balance of the car while shifting!

If you do a search on rennlist (944 forums) you'll see this topic was covered AD nauseum recently.

-Z-man.
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Old 02-19-2004, 02:37 PM
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I meant downshift while braking of course...
And I meant in real life,not track...eveyday driving

I don´t think entire Europe is wrong....
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Old 02-19-2004, 03:06 PM
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Hey Z-man......What would I be doing over on Rennlist


I DO syn well on deceleration, but I also use the engine as a brake in my daily driver.

I have no problem switching to different driving methods from vehical to vehical...

.Kinda wonder though, if it is so bad why does my clutch have 140k on it in my daily driver and only a slight syncro problem?


Not trying to argue just wanting to get the most from the 44
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Old 02-19-2004, 03:22 PM
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The cars brakes are designed to stop the car with the clutch in at top speed! As Z mentioned never us the brakes as a way to stop the car or to slow the speed. This is one way timing belts break, by over reving the engine by downshifting without matching the RPM's with the gas. Engines are not meant to stop cars! Brakes are! Sreet or track-brakes on, clutch in, downshift to lower gear blip throttle release clutch repeat for a second downshift. This method is not as easy on the street as your RPM's on the street don't get high enough, track is much easier.

So from here on out....brakes only! No gear scrubbing the speed. Ever notice how many of you have timing belts go and bad clutches! BE KIND TO YOUR DRIVE TRAIN! Sman
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Old 02-19-2004, 03:33 PM
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So....heres the scenario

I am going 60 in traffic (i'm not the speeder, its everyone else in this city)


4th Gear

I need to slow....

I clutch

Now Brake

Slow to 30 and need to re engage clutch in 2nd gear


Question - I need to go front 4th to 3rd (without engaging) then move to second and engage?

Still needs to be in sequence correct?
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Old 02-19-2004, 04:35 PM
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I've even seen car manuals suggest that when stopping to put the car in neutral and let the clutch out while braking to reduce wear on the splines.

I am a down shifter. I'm not sure I could break that habit. I don't compression break, but I do select the gears on my way down. All the way to first gear. In a performance situation I will compression break. It is the quickest way to "get back on her" after a corner. A nice deceleration then she's right where you want her when you pick back up.
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Last edited by Sabyre; 02-19-2004 at 04:53 PM..
Old 02-19-2004, 04:45 PM
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Using engine braking was useful on old, drum-braked cars that would overheat easily. Modern disc brakes are far more heat resistant. 944 brakes are up to track standards. No need to worry on the street.

No engine braking!
Old 02-19-2004, 04:46 PM
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I was taught growing up to downshift...... Reason was to save the brakes.

In my wisdom that I acquired over the years, I came to the conclusion that brake pads were cheaper than clutches. Therefore, saving a set of $20 pads to make them last longer, was meaningless when you were adding unnecessary wear to a $200+ clutch disc.

I always just use the engine decelleration down to around 30mph, then I disengage the tranny(clutchless), and finish my stop with the brakes. On rare occasions, such as ice, I might actually downshift so that the rear of the car slows me.
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Old 02-19-2004, 05:12 PM
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Quote:
Originally posted by Z-man
You may have heard of the 'heel and toe' shifting technique used by most track drivers. The purpose of that is to shift to a lower gear while braking, and not changing the balance of the car while shifting!
or to put it more bluntly, to have RsPM match roadspeed when the clutch is released
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Old 02-19-2004, 05:27 PM
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Here is how I do it, did it, downshift to get at a rpm that is in the peak rev band so you can accelerate out of a turn quickly, without "dogging" the engine. Always rev match before downshifting, never just throw it into gear. Your brakes will slow you down a lot quicker than the engine will. Engine braking is for semis and things with a ton of momentum.
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Old 02-19-2004, 05:35 PM
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I always try to rpm match in the Porsche and occasionally engine brake slightly.

Guess its no more engine braking for me unless it has to do with performance.


I am likely not the only one that learned this way as my "teacher" learned to drive in the 60's. Passing on his "good" knowledge to me.

Now what do we do when the new cars are running on polarity reversing electric motors at all four wheels? ;-)
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Old 02-19-2004, 05:45 PM
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TCMdocs944, do you always cruise 60mph in 4th? seems like a bucketload of rpms when you could just go to 5th at 2200 or so...
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Old 02-19-2004, 05:56 PM
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vott does ziss do?
 
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Quote:
Originally posted by TCMdocs944
So....heres the scenario

I am going 60 in traffic (i'm not the speeder, its everyone else in this city)


4th Gear

I need to slow....

I clutch

Now Brake

Slow to 30 and need to re engage clutch in 2nd gear


Question - I need to go front 4th to 3rd (without engaging) then move to second and engage?

Still needs to be in sequence correct?
no, you don't need to make the "layover" in third if your desired end result is to be in second, as long as you make sure that the RsPM match the roadspeed that you will be travelling when you let out the clutch and begin to accelerate again. you should choose the gear and its corresponding roadspeed so that the RsPM (using the throttle to match) will be at the beginning of the powerband when you let out the clutch

what I usually do is to brake - disengage clutch and hold RPM at desired level. brake to desired speed - match RsPM (to roadspeed) and enter appropriate gear, and engage clutch. what this should do is leave the engine RsPM at a point that if the clutch is engaged, the RsPM and tach needle will not move (without a change in throttle) leaving you with the ability to accelerate immediately. remember, for this to be effective, the RsPM an clutch engagement should be at the beginning of the powerband

I hope this makes sense (it is much easier demonstrated than explained)
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Old 02-19-2004, 06:02 PM
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vott does ziss do?
 
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oh yeah. and no, I don't engine-brake
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Old 02-19-2004, 06:03 PM
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I've also heard it's bad to hold the clutch in for long periods of time such as someone suggested following the gears down: 4th to 3rd to 2nd to 1st but with the clutch in the whole time. It makes sense that it'd (1) save the drivetrain by not engine braking, and (2) have you "positioned" in terms of gear selection to make a rapid re-acceleration if necessary by selecting the gear appropriate for the speed you're going through as you slow. I was always told that if you hold the clutch in for more than 5 seconds at a time, you're doing something wrong, though.
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Old 02-19-2004, 06:18 PM
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rub along the curb.....it slows you down too
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Old 02-19-2004, 06:29 PM
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