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But if you're good enough at rev-matching and getting the revs right for the next gear it's not hard on your transmission and don't have to worry about double clutching :)

But yes, heel-toe is very important, and I'm still learning it...not easy. Left foot braking is also very important, and also takes some practice.

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Ryan
 

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Well, not to get into a pissing fit, but no...not quite....Double clutching is a way to more precicely rev match, but it is not needed. I can rev-match a car without ever using the clutch, you literally rev the motor to the rpm where going into a given gear and put it in gear, no clutch needed if properly matched. Not the easiest on your synchro's but it is do-able.

Double clutching is a method used to more precicely match revolutions whereby you push in the clutch, take the trans out of gear, let the clutch out, rev to the appropriate rpm, push in the clutch again and select the appropriate gear.

In modern synchromesh transmissions this is not necessary. The synchro's are there to do the synchroizing for you. Simply push in the clutch, pull trans out of gear, rev to appropriate RPM and select gear and let out clutch. If your transmission is healthy with good fluid, and you don't ask too much of it (I.E. trying to select 2nd gear moving at 60 mph with the engine at idle) then you should have no problems.

Actually try double clutching on an Auto-X course, and you'll find you're slower and asking waaay too much of your feet, especially in the corners where you've got to heel-toe your downshifts and still double work the clutch all in time for a corner coming at you at 30 mph with only 30' to react...Doesn't work, and I've yet to see a national level driver try it for exactly that reason :)

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Ryan
 

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Discussion Starter · #44 ·
Oh god please don't ruin my thread.

YOU DO NOT DOUBLE CLUTCH!!!!!

The only time you do is if your synchros are completely shot or you do not have any. If either of those facts are true than you should not be racing but if you were than you need to get off the track. If you are a Professional than you wouldn't even be reading this so this does not apply to you.

To anyone else that does not get paid (or fund a private) to race a motorvehicle......DO NOT DOUBLE CLUTCH.


AND DO NOT RIDE YOUR CLUTCH. Please Samol_hok, learn more before you make any statement.
 

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please thouroughly explain through automotive science y double clutching is bad even in todays modern vehicles

first what does a syncros look like

they are brass rings splined to the selecting helicol gears (or input cluster assembley some FWD applications). Thay have adapting teeth to connect to the sliding sleeve assembly wich is the unit that completes path of power to the out shaft now what matches the speed
it would be a tapered ramp machined in those rings

have you ever overhauled a tranny where you noticed the ramp does not catch thus causing the gears to clash going in

Y? through wear forcing a difference in speed betweed the sliding sleeve assembly and the syncros

ok now how do lessin the oppsing force of the two units in nuetral going into gear
REV MATCH ok your in the proper range now both units are spin at less of a difference oh... whats this liss force meaning more life for the unit

ok now think how do most units defect

1. ABUSE
2.OVER loading
3.contamination

how is lessining the rotational force any of those 3

now please explain to me why through proper automotive science how this wil l cause harm to the unit
 

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Oh god...This thread is officially Hijacked...

First off, please use some proper english...thrying to raed carp that is'nt speled rite is a apin in teh arse!!

Second...from your article...

Your Article said:
But many trucks and some racing cars are still set up with a non-synchromesh gearbox. With trucks, because they have so many gears, it's noticeably more efficient not to have all of the gears in mesh all of the time. So with the "crash-box," you HAVE TO double-clutch, or you will not be able to shift. The same holds true for racing cars—to gain the last couple percent of efficiency, only one set of gears is in mesh at any time, and you have to actually synchronize their speeds or you can't get it in gear. Despite the obvious drawbacks of having to double-clutch, the gearbox is stronger and more efficient than a comparable synchromesh one, and has less tendency to overheat.
Last time I checked...our cars aren't race cars, nor trucks, nor do they have Crash Boxes in them....

Your Article said:
Other reasons for double-clutching: Because it is the right way to operate the clutch.
If you've got a crash box, truck or race car as seen above, sure is!!

Your Article said:
Because it saves wear and tear on your synchronizers in the long run, if you're planning to run your car over 200,000 miles
Guess what, even if you don't double clutch, just change your fluid once in a while and no problems. I've got a '89 MX6 GT that has over 240k on the original tranny, and guess what...It's the smoothest shifing car I own, always has been...Why? It's not abused, and gets maintained...and guess what else...NOBODY has EVERY bothered to double clutch it...

Your Article said:
Because it is fun to do.
Yes, it is sometimes :)

Your Article said:
Because in very cold weather, (-10° F, for example) you may have to double-clutch to shift gears at all, at least for the first few miles.
You live in -10° F weather? If you do, then you better have the proper fluid in your transmission, and still be easy on it the first few mins...and still no double clutching needed...

Your Article said:
One very important reason is that, if your clutch linkage ever fails, you can still shift and get home by double-clutching, getting the engine and gears' speeds synchronized and then just EASING the shifter into the right gear.
Yeah, I kinda mentioned this already...it can also be done without a clutch at all...

Your Article said:
Another reason is that on some old cars, first gear isn't synchromesh, so if you need to shift into first without coming to a full stop, you have to double-clutch. Also, a lot of cars these days are made with weak, chintzy synchros, so they soon wear out, and to drive them gracefully, you need to double-clutch.
In a hurry to get into 1st gear? If so then yes, you have to double clutch...if you don't have synchro's...but guess what...YOU DO!!! Granted double clutching will slip it in nicely, but again, on a race course your best and fastest bet is to simply rev-match...by the time you take the extra .3 second to pump the clutch you're already needing to be in gear and ready to accelerate...sounds nice, but doesn't always work so well...As for 'chintzy' newer car synchro's...See above about my 240k plus mileage MX6 :rolleyes:

And then to top it off, you're referencing a guy writing for an ELECTRONICS website?!?!

Dear god...at least bring someone with some automotive credentials to the table, granted he seems to fairly well know what he's talking about...but really now...How about I start spewing off about TV Tubes...Sure, I know how they work, taken them apart, blown them up, even sold televisions in a high end home theatre store, but do I claim to be an expert on their operation? No, I don't.

In summation...double clutching is NOT necessary, it WON'T hurt anything, it's just not necessary...and in MY experience, I've put well over 200k miles on variuos Mazda trannies, both first and second generation, and even a Ford Exploder with a Mazda transmission...I've broken them stuck them in gear, blown the cases apart, but even through all the racing, all the beating and grinding of gears has there been a synchro failure...No. Not one yet. And I rarely double clutch...

:rolleyes:

And furthermore, tell me this...do you Auto-X, Road Race, or do some other form of racing?



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Ryan
 

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i go to sait for automotive service technology SAIT.ca

wasnt explaining it in clear automotive science enough or should i scan a diagram and hilight exactly what i mean about reducing torsional loading of a opposing forces

hmm lets see studying 1st period including metalurgy adn failure analysis
 

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Discussion Starter · #49 ·
Please stop.

Automotive science is right, double cluthing does save wear and tear. Real life is another story. The wear and tear is negligible. You are more likely to cause more damage with ONE misshift than saving by double clutching a synchromeshed transmission your whole life. Science said that the amount of dirt you breathe in is very unhealthy; but in real life you have to breathe, so you breathe.

If you wanted to put this info as a "ways to prolong the life of a transmission" I would approve. As this is a "racing" thread, double clutching does not help, matter of fact, only times it would help is if yout tranmission is about to go bye bye.

Go ask your instructor if double clutching is necessary on a modern day synchromeshed transmission. Also ask them if it helps anything that has to do with "racing."

So please Samol_hok, just stop.
 

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Oh god...Give it up...how many of these cars have you owned? How many of these cars have you raced? How many of any car have you raced? How many transmissions have you replaced?

I've owned nearly 20 Mazda's in the last three years alone, most of which have been raced at one point or another...If you've got better proof to your side of the equation, please offer it up...because right now you're not convincing me and I sure as hell hope you're not convincing anybody else...

:rolleyes:

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Ryan
 

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NOTE TO NEWBS:

Something as complex as auto-x can't be explained in words. Sure you can read all this stuff all you want, but don't think that just because you read this that you're the best auto-xer around. There's just too many factors. The only way to truly learn how to race your car is to actually race it. This post is just pointers.

If you want to read a guide, go read the blacktop. Nothing more educational then buying a bunch of cones and going to some huge abandoned parking lot and going through the curves.
 

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Oh, it can be explained in words...Tens of authors having writen hundreds of books on auto cross alone are doing it right now...unfortunately it is one of those subjects that is very hard to finish :p

/bringing up the dead...

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Oh, OUCH DUDE!! That's quite funny though, I got a good chuckle from it :lol:

Dude, you're getting Karma for that one :D

And in my defense, most of them were parts cars in the end, or simply sold...or for one or two wrecked...with my sis driving and the other driver's fault...I only blew/broke three or four 8D

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I have the 1gen mazda not the 2gen and im wondering... wouldnt the tire size (205/45zr15) severly change the acuracy of the speedometer? And wouldnt the engine rev a lot higher at hiway speeds? I was going to buy 16's or 17's but keep the stock tire height (decrease sidewall height but increase width a little) or should i stick with 15's?

I bought coilovers for my car (2gen coilovers)....i heard that they fit on the 1gens.... do you know what the correct setting, or close to 'improved handeling' settings would be?
-sorry lots of questions any answers would help....thanks
 

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AFAIK, you'll have a helluva hard time finding a 205/45/15, since Tire Rack returned absolutely no results...Now if you were thinking a 205/50/15, you've got quite a few more sizes to choose from:
http://www.tirerack.com/tires/Compa...20&pagenum=1&pagemark=1&x=98&y=11&RunFlat=All

And yes, it will affect your gearing quite a bit, going from stock 205/60 to a 50 series is a good difference...To give you and idea I went from finishing the 1/4 on stock tires in 4th gear, to finishing in 5th.

Were I you 16's would be a good option, it's a good fit on the 1G's, and looks good with a drop.

As for the coilovers, don't just drop them all the way...if you're going for autocrossing start with a good 1.5" drop around and go from there. Other than that it's hard to tell you what to do without driving the car and knowing the particulars of it's setup. :)

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Ryan
 

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hey thanks for your help, i just got the coilovers in the mail yesterday. I guess i didn't realize how small they are......:shrug: should i install new tie rods and and ball joints and strut mounts too?
 

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Well, if half of the suspention is a part anyway....But if you need more help not directly relating to the thread toss me a PM, I'm glad to help :)

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Ryan
 
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