For the MT owners: how do you downshift?

[Norm Peterson]

Sorry, I did not quite get this ...

Look at the probably faint yellow trace - that's the acceleration/braking line - and you'll see where it recovers pretty sharply at around 3 seconds and doesn't start going back down again until 4.5 seconds or so. I've added the two vertical lines more or less at the beginning and end of the brief stretch where the speed remained essentially constant at about 90 mph (green trace, red trace is lateral acceleration), which actually starts at about 3.75 seconds. Deceleration starts dropping off a fraction of a second sooner because it's picking up the fact that you can't physically get your foot all the way off the brakes in zero time.

That's a braking & downshifting event from about 125 mph in 4th approaching a 65 mph corner that's best taken in 3rd.

Aim Solo datalogging, and why they insist on breaking 5 second major time steps into only 4 minor steps is a mystery to me.

Norm

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[Horse]

Oh I was gonna say no way you can do that with Mustang because of the pedal height difference.
I had an RX-8 and the pedal setup was perfect. All three pedals same distance, same height.

:cheers:

 

[Horse]

Look at the probably faint yellow trace - that's the acceleration/braking line - and you'll see where it recovers pretty sharply at around 3 seconds and doesn't start going back down again until 4.5 seconds or so. I've added the two vertical lines more or less at the beginning and end of the brief stretch where the speed remained essentially constant at about 90 mph (green trace, red trace is lateral acceleration), which actually starts at about 3.75 seconds. Deceleration starts dropping off a fraction of a second sooner because it's picking up the fact that you can't physically get your foot all the way off the brakes in zero time.

That's a braking & downshifting event from about 125 mph in 4th approaching a 65 mph corner that's best taken in 3rd.

Aim Solo datalogging, and why they insist on breaking 5 second major time steps into only 4 minor steps is a mystery to me.

Norm

Thanks for the explanation. Not claiming to understand it all (never been to the track myself), but I think I could follow what your trying to explain.

 

[StangLuver]

I always rev match

When I down shift the amout of gas I give it when I rev is based on the speed and gear I'm in, for example. If I'm in 4th gear and going about 30 MPH and downshifting into 3rd gear, I will give it a low rev about 500 RPMs. If I'm in 6th gear going about 50 MPH and downshifting into 5th gear I will give it a medium rev about 1000 RPMs. If I'm driving in 3rd gear doing about 20MPH and downshift into second (aggressive driving, passing another car) I will give it about 1500 RPMs. Remember its better to give it just a bit more of gas when downshifting at higher speeds, read the info above, you don't want to loose control when that slow moving engine RPMs hit that high RPM clutch disc. Once you get good you will know how much to rev and just the right amount.

 

[Old 5 Oh]

Yes, I do (or did, with the car I traded in days ago for my mustang) it all the time in traffic. That car (the trade in) had very soft brake pedal (with free play on top, see my post above), so I don't need to slow down very much in order to perform h/t. In fact, I have practiced many times on resting my right foot on the brake ever so slightly and rolling the foot the the right and blip the throttle (and with repeated success).

I have gotten so good (at least I would like to think so) at h/t in street traffic with my old car that I miss it very much now that I can not do the same with mustang.

I have been able to H/T every stick-shift vehicle I have ever driven, including the 71 Ford F100 with off-road 4-speed that I was taught in. That also includes my Fox, SN95 and New Edge Mustangs.

If Ford has screwed up the gas/brake relationship so badly in the S550 that no one can H/T, then I have just lost any minor regrets I might have had about not ordering the MT82. I will enjoy the AT fully. It would P##s me off every single drive if I were unable to pedal the car as I have been able to do for nearly 45 years.

 

[Horse]

I have been able to H/T every stick-shift vehicle I have ever driven, including the 71 Ford F100 with off-road 4-speed that I was taught in. That also includes my Fox, SN95 and New Edge Mustangs.

If Ford has screwed up the gas/brake relationship so badly in the S550 that no one can H/T, then I have just lost any minor regrets I might have had about not ordering the MT82. I will enjoy the AT fully. It would P##s me off every single drive if I were unable to pedal the car as I have been able to do for nearly 45 years.

I need to mention tat this is my very first mustang, and I don't track my cars. But one thing I am sure of is that, in street driving, it is harder to H/T on this mustang than my previous cars (due to sensitivity of the brake pedal and the configuration of pedals).

A valid argument might be that (6 gen) mustangs will be better suited for track use when the brake pedal is pushed hard(er) than street. (Maybe someone can chime in and confirm this?)

I am still trying to adjust myself to my mustang. If it does not work out (say after 2 months), I will consider modifying the pedals.

 

[StangLuver]

I don't do this double clutch business. All I do is hit the clutch, tap the gas a hair until I see the RPMs roughly around where I think they ought to be for the downshift in question (it's just some quick math in my head) and let the clutch out.

Got an example of a "quick math" calculation you're doing here?

 

[StangLuver]

I love this one :

Because heel & toe and because Ayrton.

And because penny loafers/slippers.

 

[StangLuver]

I was taught to double-clutch when I was well under 16. Still do it all the time, out of habit. Maybe it's harder on the clutch. I don't really care. It's fun, it sounds cool, it makes the downshifts smooth and I don't really know how to do it any other way.

How does it make downshifts smooth? It seems that since it takes longer to do that the RPMs will have fallen further and thus be more out of sync with the new gear being chosen?

 

[Horse]

b/c you blip the throttle between the clutches (i.e., between the two clutch operations), which brings all the rotating part up to right speed.

 

[StangLuver]

b/c you blip the throttle between the clutches (i.e., between the two clutch operations), which brings all the rotating part up to right speed.

Got it - so it's rev matching also. Most info I'm seeing says double clutching isn't useful/necessary on trannies with synchros. Is there still value for using it?

 

[Horse]

Got it - so it's rev matching also. Most info I'm seeing says double clutching isn't useful/necessary on trannies with synchros. Is there still value for using it?

During normal rev-match (not double clutch), the blip only brings the engine rpm to the right speed (but not the lay/intermediate shaft, gears, etc.). Then the synchro must work in order the bring the lay/intermediate shaft, gears, etc., up to speed. Yes, the synchro is design for this task and modern synchros can usually outlast the transmissions. So many people don't bother to do/learn double clutch.

Personally, I always double clutch when downshifting. For one, it is fun, as it makes a unique sound for example. For two, it feels good knowing that the sychro does not need to work (as hard) because I am bringing all the parts to the right/matching speed.

Some may say that double clutch wears down the clutch assembly (b/c you step on it twice). Sure. But I am willing to take that.

 

[Norm Peterson]

Got it - so it's rev matching also. Most info I'm seeing says double clutching isn't useful/necessary on trannies with synchros. Is there still value for using it?

Let's just say that synchromesh mechanisms eliminate the guaranteed absolute necessity that you MUST double clutch/rev match both downshifts and upshifts. At least they do until they've worn too far or been beat up on too much (think "grinding the gears" here).


Norm

 

[StangLuver]

Seems a lot of this will become a moot point once the Mustangs get a rev-matching tranny (both auto and manual) like the Camaro, Vette, Porsche, 370Z have.

 

[Horse]

Seems a lot of this will become a moot point once the Mustangs get a rev-matching tranny (both auto and manual) like the Camaro, Vette, Porsche, 370Z have.

Although I don't exactly know how the (auto) rev-matching works on manual cars, I doubt it will match the speed of the lay/counter/intermediate shaft (which can be accomplished via double clutch). My guess is that it (rev-match by car computer) only match the engine speed to the speed of the output shaft. So we (the double clutchers) will still have a reason to keep double clutching and feel good about it.

It is all for fun.

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