Manual Transmission T56 | T5 | MN12 | Clutches | Hydraulics | Shifters
View Poll Results: Do you guys downshift when decelerating?
Yes, all the time.
232
22.92%
Yeah, most of the time
355
35.08%
Nope, once in awhile though
355
35.08%
Never
70
6.92%
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Downshifting

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Old 05-19-2006, 01:41 PM
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a very knowledgeable road racer/race car mechanic once told me "gears go and brakes whoa"



enough said.
Old 05-20-2006, 03:23 AM
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Originally Posted by theantirotor
a very knowledgeable road racer/race car mechanic once told me "gears go and brakes whoa"



enough said.
So your saying he implied not to downshift? Last time I checked downshifting is used almost always in professional racing.

Aside from that, heres something that popped into my mind... A brake booster (in our street cars) relies on vacuum from the engine to operate. When downshifting (and throttle body is closed) the engine is going to create more vacuum, which (in theory) sounds like it would make the brake booster work more efficiently.
Old 05-20-2006, 03:33 AM
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Originally Posted by Charging TA
So your saying he implied not to downshift? Last time I checked downshifting is used almost always in professional racing.

Aside from that, heres something that popped into my mind... A brake booster (in our street cars) relies on vacuum from the engine to operate. When downshifting (and throttle body is closed) the engine is going to create more vacuum, which (in theory) sounds like it would make the brake booster work more efficiently.
Yes. But they don't rely on downshifting to assit in braking.

Racers downshift to keep power to the wheels and turn fast times.

3rg gear at 50mph will accelerate faster then 5th gear at 50mph.
Old 05-20-2006, 12:02 PM
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Originally Posted by Justin00SS
Yes. But they don't rely on downshifting to assit in braking.

Racers downshift to keep power to the wheels and turn fast times.

3rg gear at 50mph will accelerate faster then 5th gear at 50mph.
Of course, but... cant argue that downshifting does not assist braking. I can aleast feel a huge difference between just braking and braking while downshifting.
Old 05-22-2006, 10:45 AM
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Originally Posted by SSCamaro99_3
I never downshift when coming to a stop. That is what the brakes are for.
Same here. Brake pads cost less than a tranny
Old 05-22-2006, 01:04 PM
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Originally Posted by Justin00SS
Yes. But they don't rely on downshifting to assit in braking.

Racers downshift to keep power to the wheels and turn fast times.

3rg gear at 50mph will accelerate faster then 5th gear at 50mph.

exactly!
Old 05-22-2006, 06:47 PM
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My 2 cents isthis: brakes are definitely easier to repair. To turn your rotors costs less than 20 bucks. Another thing that I have found out is this, when braking hard let totally off the brakes for a split second and it will drastically cool down your rotors in order to resist warping, and also keep high speed hard braking to a minimum if possible.
Old 08-13-2006, 11:50 PM
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rev match it and youll be alright!
Old 08-17-2006, 01:31 AM
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This is ridiculous. Watch Formula 1 and Champ Car racing. ESPECIALLY near the end when they push the cars harder for a win. You will notice the revs stay in the same gear as the slow down and the car struggling to stay in control as it BRAKES. Yes, professional racers use the brakes. That is why they are the most highly sophisticated and advanced brakes in the market. I read somewhere in this long thread that coasting and downshifting wastes no gas? Watch the tach as you downshift. The engine is still running at those RPMs.

Coasting wastes no gas? I guess if you turn the car off. As long as you hear it the engine running, it is using gas.

But, in the down-shifting defense. It really doesn't kill you to do it. Although shifting from 6th to 2nd at 80 mph won't be very pretty.

My final point is this: braking is used a hell of a lot in professional racing. Brakes work a lot better than downshifting. There is no arguing that.
Old 08-17-2006, 03:18 PM
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Originally Posted by adillhoff
This is ridiculous. Watch Formula 1 and Champ Car racing. ESPECIALLY near the end when they push the cars harder for a win. You will notice the revs stay in the same gear as the slow down and the car struggling to stay in control as it BRAKES. Yes, professional racers use the brakes. That is why they are the most highly sophisticated and advanced brakes in the market. I read somewhere in this long thread that coasting and downshifting wastes no gas? Watch the tach as you downshift. The engine is still running at those RPMs.

Coasting wastes no gas? I guess if you turn the car off. As long as you hear it the engine running, it is using gas.

But, in the down-shifting defense. It really doesn't kill you to do it. Although shifting from 6th to 2nd at 80 mph won't be very pretty.

My final point is this: braking is used a hell of a lot in professional racing. Brakes work a lot better than downshifting. There is no arguing that.
I think this whole thread has become a misunderstanding... Where I stand is I downshift while braking, you can feel the car slow down ALOT better than if just braking alone.
Old 08-18-2006, 03:37 PM
  #91  
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Gotta chime in here as a clutch manufacturer. Everyone who says matching RPM on the downshift is correct. The wear occurs not only to the transmission, but it is also hard on the clutch center hub. The hub 'floats' on the clutch springs and can only move so far. Most stock clutch hubs are set up with more area for movement on the accel side, and the decel side is closer to the pins or rivets that hold the hub in place. Downshifts without matching can cause the hub to bottom out on the pins and eventually break the center out of the disc. This is one reason we use urethane springs in our center hub, to limit this travel and the eventual 'beating out' of the clutch center.

Mike
Old 08-20-2006, 05:11 AM
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i downshift every singletime
Old 08-21-2006, 02:04 PM
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I will stick to my previous assumption. When coming to a routine stop, there is no case for downshifting through the gears except to put wear and tear on clutch and transmission parts. No thanks.
Old 08-22-2006, 08:10 AM
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I just put it in neutral and coast to a stop.
Old 08-25-2006, 10:48 PM
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Yes, but not at high RPM's, only to conserve on brakes!
Old 08-29-2006, 03:24 PM
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Originally Posted by misfits
i downshift every singletime
amen brother
Old 08-31-2006, 03:35 AM
  #97  
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i downshift ,cuz im sick of buying rotors. stock f body brakes/rotors = junk. who uses the clutch? lol im used to not using the clutch often as i drive a semi for work. and you cant use the clutch on a tractor trailor unless you want to come to a complete stop every time you change gears.
Old 08-31-2006, 02:10 PM
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Originally Posted by Stick only
Gotta chime in here as a clutch manufacturer. Everyone who says matching RPM on the downshift is correct. The wear occurs not only to the transmission, but it is also hard on the clutch center hub. The hub 'floats' on the clutch springs and can only move so far. Most stock clutch hubs are set up with more area for movement on the accel side, and the decel side is closer to the pins or rivets that hold the hub in place. Downshifts without matching can cause the hub to bottom out on the pins and eventually break the center out of the disc. This is one reason we use urethane springs in our center hub, to limit this travel and the eventual 'beating out' of the clutch center.

Mike
Thanks for your input Mike.
Old 09-03-2006, 08:20 PM
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Originally Posted by adillhoff
Watch the tach as you downshift. The engine is still running at those RPMs.
but injecting less fuel...

just thought i'd throw that in there.
Old 09-03-2006, 08:55 PM
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Downshifting to slow down during normal driving wears the synchros in the transmission. They act as brakes to stop the gears while the clutch pedal is down.
Worn brakes are worn brakes. Worn synchro rings are going to cause hard/grinding shifts, etc. Grinding transmissions wear the sliders and gear engagement teeth.


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