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Old 09-30-2007, 08:59 PM   #16
T.Dot_E30
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Quote:
Originally Posted by Soldo View Post
it's okay, but anytime you skip gears you'll put wear on your syncros.
Its not the skipping gears that does that, its the stress from the tranny having to match the speed of the car by forcing the engine to rev. syncronosing the gears.

Done right, it shouldn't be a problem.

Just don't drop it into second doing 120+, your engine won't like 10k rpm.
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Old 09-30-2007, 09:07 PM   #17
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Quote:
Originally Posted by T.Dot_E30 View Post
Its not the skipping gears that does that, its the stress from the tranny having to match the speed of the car by forcing the engine to rev. syncronosing the gears.

Done right, it shouldn't be a problem.

Just don't drop it into second doing 120+, your engine won't like 10k rpm.
You're right! The shop i used to work at told me that, but they said since there isn't much stress when your changing gears accordingly it doesn't wear the syncros.

So lemme ask you this, rev matching still makes the syncros work, right!?
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Old 09-30-2007, 09:41 PM   #18
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So lemme ask you this, rev matching still makes the syncros work, right!?
They work everytime you change gears,...they just don't have to work as much when the engine speed is close to where it should be.
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Old 09-30-2007, 11:43 PM   #19
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Originally Posted by Meegis View Post
You're all asking the wrong questions....



How did the S4 do?

lol the s4 driver couldnt drive for shit man, he was beside me, we both took off pretty even but he dropped back by like 4 cars when he changed gears, so thats was it, i hit the brakes after because there was a car infront of me and it seemed to me like the race was done, but the guy in the s4 decided to blow by me like a loser after the race was aleady done, i hate when ppl do that, i m curious to see how i would do against one with a driver that can actually drive, my brother has a 2.8 and i can take that no problem but an S4 should be able to take a 328 with ease right?
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Old 10-01-2007, 08:29 AM   #20
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Originally Posted by T.Dot_E30 View Post
They work everytime you change gears,...they just don't have to work as much when the engine speed is close to where it should be.
The engine speed doesn't matter if you're not double clutching. The syncros are designed to speed up or slow down the input shaft of the transmission, nothing else. They're just cone clutches (usually brass) that help engage the dogs. That's why it's a terrible idea to shift without clutching on syncro gearboxes - if you're off by even a little bit, those little clutches have to slow down or speed up your engine and they are not designed to do that. And if they wear out, you won't be able to get into gear at all. I'd personally love a straight cut non-syncro box in my track car some day.

If you down shift and revmatch, all you do is make the clutch do no work, the syncros won't know the difference. For upshifting, you can make a difference by shifting quickly, so the input shaft only slows down enough to match the new gear speed and the syncro doesn't have to do any work.
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Old 10-01-2007, 08:44 AM   #21
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i shift mine without the clutch all the time.. as long as you rev match you're fine.. It's also a great way to test a transmission when buying a new car.. take it through all the gears without using the clutch.. if it doesn't grind up/down shifts then she's been well taken care of
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Old 10-01-2007, 08:56 AM   #22
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The syncros are designed to speed up or slow down the input shaft of the transmission, nothing else.
Really, so syncros have nothing to do with synchronizing the gears so they mesh cleanly?


The input shalf has gears on the end of it, that meshes with the gear you select, which in term meshes with the gears on the output shalf.

We're saying the same thing.
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Old 10-01-2007, 10:30 AM   #23
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i shift mine without the clutch all the time.. as long as you rev match you're fine..
No you are not. You will never match the revs perfectly and you are abusing your syncros every time you do this. I know it doesn't feel like it to you but that's because for now, they are helping you out. In time you won't be able to get into gear at all, clutch or not - the same mechanism that is designed to help you engage the gear will prevent you from doing it. The reason you can get away with clutchless shifting on a non-syncro box is because the windows for the dogs on the gears are wider than they need to be to allow some error, and there are no syncros to wear out to fix your inaccuracy.

Quote:
Originally Posted by T.Dot_E30 View Post
Really, so syncros have nothing to do with synchronizing the gears so they mesh cleanly?


The input shalf has gears on the end of it, that meshes with the gear you select, which in term meshes with the gears on the output shalf.
No they don't and no it doesn't. The gears are always meshed (unless you want to talk about 80 year old transmissions). The only thing the syncros do is syncronize the speed of the half shaft (and lay shaft if you want to get all anal) so the dogs can engage with the already meshed gear.
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Old 10-01-2007, 11:26 AM   #24
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Well I have been shifting my T5 in my mustang for the past 100k with no clutch and still no issues.. I put 80k on my white e36 with no issues.. I only do it when shifting around 3-4k rpm driving conservatively.. I always use the clutch when driving spiritedly. With the abuse they take driving spiritedly they are more likely to blow from missing a gear or the torque before my synchros wear out.. but i know what you're sayin...
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Old 10-01-2007, 11:30 AM   #25
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No they don't and no it doesn't. The gears are always meshed (unless you want to talk about 80 year old transmissions). The only thing the syncros do is syncronize the speed of the half shaft (and lay shaft if you want to get all anal) so the dogs can engage with the already meshed gear.
No it doesn't as in your telling me this input shalf doesn't have gears on the end of it that mesh with the other gears within the transmission?

I don't see how each gear is always meshed, they are turning at different speeds and would each turn the output shalf at different speeds, when are are not in use I cannot see how they would all be connected, turning the output shalf at the same time. Even if they are, atleast one gear needs to mesh with the selector rod chooses a gear.

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Old 10-01-2007, 11:33 AM   #26
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I'm sure shifting without the clutch does wear your synchro's, however, if you do it well, although you probably wont get it quite bang on, it will be close enough such that it minimizes the wear on your synchro's.

i shift without the clutch every once in a while when i'm too lazy to move my left foot.
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Old 10-01-2007, 11:41 AM   #27
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Originally Posted by T.Dot_E30 View Post
No it doesn't as in your telling me this input shalf doesn't have gears on the end of it that mesh with the other gears within the transmission?

I don't see how each gear is always meshed, they are turning at different speeds and would each turn the output shalf at different speeds, when are are not in use I cannot see how they would all be connected, turning the output shalf at the same time. Even if they are, atleast one gear needs to mesh with the selector rod chooses a gear.

You just posted a diagram showing all gears meshed... I'm not sure what your confusion is. I never said they are turning the output shaft at the same time, please re-read. Engaging a gear and meshing it are not the same thing (since circa 1929).
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Old 10-01-2007, 11:45 AM   #28
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I'm sure shifting without the clutch does wear your synchro's, however, if you do it well, although you probably wont get it quite bang on, it will be close enough such that it minimizes the wear on your synchro's.

i shift without the clutch every once in a while when i'm too lazy to move my left foot.
Please don't confuse minimized with minimal. No matter how close you get it, if you're not exactly right, that little difference is not a question of changing the momentum of two relatively small sticks and a clutch disk but rather changing the RPM of an engine. That is a load the syncros were never designed for and they will fail many times faster than if you simply use the clutch and let them do the job they are designed for. It's the difference between a transmission that lasts 500k+ withour a rebuild, and one that doesn't go into gear at 200k.
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Old 10-01-2007, 11:46 AM   #29
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Just to illustration what i mean.



Quote:
The cone on the blue gear fits into the cone-shaped area in the collar, and friction between the cone and the collar synchronize the collar and the gear. The outer portion of the collar then slides so that the dog teeth can engage the gear.

Every manufacturer implements transmissions and synchros in different ways, but this is the general idea.
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Old 10-01-2007, 11:49 AM   #30
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You just posted a diagram showing all gears meshed... I'm not sure what your confusion is. I never said they are turning the output shaft at the same time, please re-read. Engaging a gear and meshing it are not the same thing (since circa 1929).
Sorry, I thought engaging meshing was the same thing....but either way engage a gear should need some Synchronizing .
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