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Nick Burns, the Comp Guy
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Discussion Starter · #1 ·
I understand the concept, but how does it work.

I often hear "match the revs to the gear".. what does that mean? So if I'm downshifting from two to four, what do I match?

I know the idea of heel-and-toeing so that's no biggie, just don't understand how to match revs.

Also, another Q.. My dad has a Nissan Sentra (the only manual in the house :cry: ), and when I downshift on a turn, I'll simply ease the clutch off while applying throttle (like getting out of first) and I get a perfect turn with no hiccup in the car. Is this as good as heel-and-toeing?

Why, or why not? Explain in as much detail as you can :)

Thanks guys!
 

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fahrer
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1,387 Posts
Downshifting from two to four?

At any rate, it sounds as if what you're doing in the turn is
rev-matching.

If you understand heel-toe'ing, it's essentially that, but without
the complication of the brake.

Imagine coming to a long stop, like a freeway exit.
Without touching the brakes, you lift (let off the throttle), and
let engine braking slow the car down. Once the rev.s drop to
a certain point, you downshift to the next lower gear.

Here's the rev-matching part:
Rather than bang out the clutch or ease it out, (thereby spinning
up the engine) - you blip the throttle while letting out the clutch.

The idea is to use the throttle to match the engine speed with
the drivetrain speed. This prevents the engine from momentarily
locking the rear wheels and upsetting the chassis. In order for
the wheels to be turning at a certain speed, the engine must
be turning at a given RPM for the gear you're in.
 

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Meat Puppet
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211 Posts
When heel and toe, if you blip the throttle right, you'd end up with the driveshaft and the engine at the same speed. Matching revs to the gears.....

So you could basically drop the clutch at that moment and nothing would happen, no lurch forward or backwards.

What you're doing with the clutch out and add gas is similar, but not the same thing. Your solution takes longer to activate, and probabably has more clutch wear.

A perfect heel and toe has zero clutch wear as the engine and transmission are moving at the same speed.

http://www.howstuffworks.com/clutch.htm

and

http://www.turnfast.com/tech_driving/driving_heeltoe.lasso

Have more detail on clutches and heel and toe technique. (It's not easy to master.)
 

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Nick Burns, the Comp Guy
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7,645 Posts
Discussion Starter · #5 ·
So how high should the revs go up when I'm downshifting?

That's pretty much my question... when I 'blip' the throttle, what should I put the RPMs at? Or just blip them up at a reasonable level (3-4k) and then let loose?

Lemme know. I have the idea down otherwise.
 

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Registered
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670 Posts
Hercules said:
So how high should the revs go up when I'm downshifting?

That's pretty much my question... when I 'blip' the throttle, what should I put the RPMs at? Or just blip them up at a reasonable level (3-4k) and then let loose?

Lemme know. I have the idea down otherwise.
It's really a question of how disparate the engine and the vehicle speeds are - the greater the difference, the more you'll need to rev-up.

As a general rule of thumb, an increase of 500 to 1000 rpms will give you a seamless double-clutch downshift.
 

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Registered
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404 Posts
Hercules said:
So how high should the revs go up when I'm downshifting?
In theory: *exactly* to the rpm that the next lower gear will be at when you shift into it at that particular speed, in order to avoid any transmission jerkiness (which is the whole reason for doing this).

In practice: 500-1000rpm's higher than when in the previous (higher) gear at that particular speed.

Edit: C-Bear, looks like you beat me to it! :p
 
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