Heel Toe and Rev Matching

General discussion about our beloved Tercel 4WD cars
Devin
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Heel Toe and Rev Matching

Post by Devin »

Lately I have been trying to save my synchros by matching the engine speed to the speed of the upcoming gear. This makes driving so much fun. Especially like going up a hill in fourth and letting the rpms fall to like 2500, keeping your foot on the gas, shifting into neutral, reving the engine slightly to match your new 3rd gear speed of, say, 3100 and just easing it in. So sick.
Then I finally realized the benefit of heel toe driving. Before when I would be coasting in neutral and a sharp turn would come up, I would just force it into 2nd to anticipate my post corner speed even though the engine is just at idle but the car speed is over 30 mph. With heel toe, you can be braking for the corner while reving the engine speed to match 2nd gear. Pretty cool. Hard to do smoothly though.
How many of you all do this sort of technique?
tercel4wdrules
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Re: Heel Toe and Rev Matching

Post by tercel4wdrules »

When you rev match perfectly you would be able to shift without the clutch (not recommended) and it's very smooth. I taught myself how to do double clutch rev-matching because the syncros were worn on my '84. I've been doing it ever since then and driving became a lot smoother that some people don't realize I'm driving a manual transmission until they look at the shift lever with my other car (less conspicuous shifter than the tercel).
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dlb
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Re: Heel Toe and Rev Matching

Post by dlb »

i rev match on downshifts for the same reason as you devin, but have never needed to heel-toe. i just slow down to a reasonable speed, tap the throttle, and then downshift.
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Re: Heel Toe and Rev Matching

Post by john »

Hey Devin, I do that with my automatic tranny... just joking!
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Re: Heel Toe and Rev Matching

Post by drege »

I do not recomend this, from what I have seen of how this gearset is designed there is just too much damage to be accrued from a slim margin for error, Like when I locked my original; transmission in 5th (pulling it out of reverse without fully depressing the clutch) same as the other gears, I noticved when I tried to power shift more often than not there was drive gear slamming - if you do not perfectly match speed/RPM the drive gear teeth catch on the input shaft and they slam together very hard, the brass syncros are designed to be used in conjunction with the clutch, even if badly worn they will ease the gear in.

I would just double clutch the problematic gears as needed, mine, the transmission that I got from godolovem and put in to replace my original has slight grinding of 2nd gear synchro when the gearbox is cold, so I double clutch and go real slow shifting into or outta 2nd, once the drive train warms up this toothy sound doesn't happen anymore and I don't double clutch anymore.

Every stick shift I have ever driven was fine to power shift, not this one! it makes horrible sounds when you force it out of gear clutchless, 6/10 times you'll hear and feel a solid metal on metal slam reverberate through the whole car, if you get locked in a gear you will be sorry - you'll have to take the transmission down and open it up and take the gear spindle out of alignment by hand, as it will launch in the opposite direction of the gear you were in, lodging it in the opposing gear without taking the fork with it!

For example if your in 4th gear at 3850RPM and you missmatch speed~RPM by 6%, 4th gear teeth edge will launch the 3rd/4th shaft cluster back, passing neutral, 3rd will catch, if you were aiming for 5th when this shaft rams forward, your selector shafts will become misaligned and you will find yourself in 3rd and it will not come out, no matter what you do, your shifter will flop freely in the middle selection area, hitting 1st/2nd, R/5th will produce grindings and conflicting drivetrain movements.
You'll be totaly fucked.

Someone correct me if I'm wrong, but moral of the story is I thought I'd be a smrt and do that with my original tranny with trashed 3rd/4th syncros and it completely disabled my car until I pulled the tranny down.
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Petros
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Re: Heel Toe and Rev Matching

Post by Petros »

double clutching if done smoothly will put less strain on all the transmission parts. It will become automatic the more you practie it, and you will also get better the more you do it. I use it regularly, particularly when it is below freezing just strarting out, the gear oil in the trans is so thick and heavy shifting can be a major chore.

When I was 16 years old and newly licensed I read about about "performance driving" that described the process in detail, I practiced it over and over until it was easy to do. All of my also newly licensed friends did not have a clue what I was doing, it was kind of satisfyingly to have mastered a "performance" driving technique that my guy buddies were clueless about (you know, that guy thing again). but it has come in handy several times when I had clutch failures and needed to get the car home (no tow truck required!), and needed to shift fast on steep scary roads, or in snow covered roads where slow shifting allows you to loose too much speed between shifts.

It just takes practice, practice, practice. It will become part of your muscle memory and you will be able to do it without any thought or effort.
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Re: Heel Toe and Rev Matching

Post by drege »

Oh for sure, my audi had no clutch when I got it, for several weeks and my cherokee had a clutch issue that plegued it for over 2 months and 1600 miles (turned out it was a broken throughout bearing arm from past owner replacing the slave cylinder with one with improper travel distance)
I was the same way, I power shift normally in a stick shift, its first nature, but not with these turc's, I'd rather replace a fast worn clutch from 2x use than transmission internals.

Witch reminds me, I need to rig up my Neutral safety switch/kill switch this weekend.
See someone try and steal it with that hidden in the car.
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Petros
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Re: Heel Toe and Rev Matching

Post by Petros »

I have found the Tercel clutch to be fairly durable. Factory quality clutch last well over 100k miles, even when abused like in my neigborhood (several miles of steep, rough gravel roads up to 20 percent grade, bump start most mornings going down the same hills). I have heard of some people that treat the clutch very gently getting 200k miles out of them, considering how small they are that is remarkable.

So, I would rather wear out the clutch than the transmission. You can buy clutches all day long in any city in north america. not so with transmissions, or transmission parts!
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Re: Heel Toe and Rev Matching

Post by ARCHINSTL »

DITTO Petros' and drege's advice on clutch wear v. transmission wear!
My OE clutch is nearing 193K and is still OK-ish, even if it takes a tad of slipping on hill starts to get going (of course, I always use the handbrake while starting on hills).
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dlb
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Re: Heel Toe and Rev Matching

Post by dlb »

ARCHINSTL wrote:(of course, I always use the handbrake while starting on hills)
ditto. this is an excellent, underused technique.
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irowiki
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Re: Heel Toe and Rev Matching

Post by irowiki »

The manual even says to use the parking brake on hills!
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Tercel__jon
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Re: Heel Toe and Rev Matching

Post by Tercel__jon »

Id say I use heel and toe every time I drive. Its quite fun and makes the car feel sportier then it is. Id say 90% of my downshifts use double clutching with rev matching with the rest at least just a rev match. Id rather swap out the clutch then hurt my poor trans. When cold, I cant shift from 1st to 2nd. Its not happening unless you float the gears. I dont like doing that when its cold, and Its rare that Ill do it when its warm. Id rather just pull off in 2nd.

Ill admit, it took me a while to get the Heel n Toe with double clutching downshifts to be almost seamless, but its amazing when you let out that clutch and theres no rise in rpms, or jerkiness. That just started happening last week, and I makes me feel awesome when it happens.
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Re: Heel Toe and Rev Matching

Post by irowiki »

What does float the gears mean?
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Re: Heel Toe and Rev Matching

Post by ARCHINSTL »

From eHow:

Floating
Floating the gears refers to the method of shifting without using the clutch. The clutch is only used for coming to and starting from a dead stop. Shifting is accomplished by feel and engine rpm. You use the clutch to begin moving, then, when you want to shift, you begin to put pressure on the stick shift, let off the accelerator pedal, pull the stick out of gear and move it into the next one as the engine rpm drops. It takes “feel” to accomplish this, and you have to either have or develop a knack for it. Downshifting is accomplished in the same manner, except as you shift into the lower gear, you have to increase engine rpm. Improper implementation of this method can result in damage to the transmission, driveline or rear axle.
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drege
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Re: Heel Toe and Rev Matching

Post by drege »

Yea, my boss is an old hippy that used to drive old busses, like old trucks [that] didn't have synchros, you had to wait till the transmission stopped spinning before you could shove the selector into the new gear (upshift with rev drop, or downshift by rev matching)
So truckers fast learned that they could skip the clutch (and the wait time on the spinning gears) and "float" them, a deft driver could shift seamlessly through to final drive, this any one can do, it takes a little more skill to know your rig well enough to know where your top end of each gear will catch the input shaft teeth perfectly.
You pro powershifters know all too well the sounds and feelings of failure and mechanical degradation of missing your target RPM.

My boss suggested I do this with the transmission it came with when I told him synchros for 3rd and 4th were gone, he just couldn't understand why I refused to do it even though the transmission was basically trash when I got it. {also it didn't work, sometimes I could catch 3rd, 4th I only got once, and I REALLY forced it}

But i'll give you that, the tercel feels so sporty! I often times shift so fast the transmission can't keep up and I still end up grinding the gears
It takes more fossil fuel resources to produce new vehicles than it would take to maintain and fuel any 70's or 80's vehicle for a million miles.
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