Because 1st to 2nd represents the biggest change in gear ratio, resulting in the biggest change in lay-shaft speed change, thus the 2nd gear synchros has to work harder than the other synchros in, er, synchronizing.
Try shifting from 2nd to 5th quickly, it also results in a hard shift. Same principle.
At low gear ratios (low gears) any aburpt changes in torque at the "input" end of gearbox get amplified by the gearbox. When these changes in torque emerge at its "output" of the gearbox, they are stong enough to shake the entire car. At high gear ratios (high gears) any aburpt torque changes remain relatively small at the "output" end of the gearbox. They are too small to be able to have any effect on smoothness of the car's motion.
For example, try randomly modulating your gas pedal in 1st gear. The entire car will shake like crazy. You might even get caught in driver-induced-oscillation (be careful). Now try doing the same thing in 5th gear - the car will barely react, no matter what you do with the gas pedal.
The same thing happend when you switch gears. In low gears any imperfections in timing, clutch engagement, RPM matching etc. get amplified by the gearbox and noticeably jolt the entire car. In high gears this doesn't happen.
So... any tips on making the 1-2-3 transition smoother? I noticed that some people "balance" the clutch and gas during the clutch release step while others first release the clutch completely before using the gas again. What is the "correct" or "best" way to shift up?
ym wrote: Thanks MaxRC and Andrey. Very insightful. :-)
So... any tips on making the 1-2-3 transition smoother? I noticed that some people "balance" the clutch and gas during the clutch release step while others first release the clutch completely before using the gas again. What is the "correct" or "best" way to shift up?
Thanks in advance!
When upshifting, you upshift, it is essential for smoothness that the engine RPM hasn't dropped too far before the clutch starts to engage.
Say you are at 4500RPMs in second gear and want to go into third gear, which will drop the engine RPM to 3000 RPMs. I would:
1. Press in the clutch partly. Let go of the gas but leaving a little bit so that the RPMs fall slowly.
2. Quickly move the shifter from 2nd into third. RPM continues to fall.
3. I start letting go of the clutch, at about the point where the clutch starts to engage, I am back on the gas. This takes timing and practice. At this point, your PRMs sthould still be above 3000RPMs, I can usually pull this off by the time the RPM has fallen to 4000RPMs.
4. As I ease the clutch out, I give it progressively more gas, until the clutch completely engages and drags the RPM down.
The clutch should never be allowed to completely engage before you get back on the gas. It will result in a rough shift.
make sure you know exactly where the engagement point is and dont mash either gas or clutch.
ideal shift: notice when you let off the gas and the car is in neutral, revs will drop at a certain speed - the idea is that when you shift say from 2nd to 3rd, as you press the clutch the engine is going at 3,000rpm, and given your speed, when it engages 3rd it will be at (for example) 2,000rpm. what you want to do is change gears in the exact amount of time it will take for the revs to drop from 3,000rpm to 2,000rpm, thereby making the change very smooth (then have the throttle opened the same amount).
you can compensate by either tapping the gas before engaging the gear, or waiting slightly longer before shifting. either way, it comes down to knowing your car and practicing.
It also seems more difficult to push the shifter into position on the 1st - 2nd shift. Is this becasue of some sort of high RPM engine protection mechanism limiting the chance of mishifts into 2nd? I know that first is often hard to get into for this reason.
Also what is the proper way to performance shift. On a 03 civic when I am performance shifting into 2nd at the redline I pop the clutch out rapily to get a faster shift, this causes the tires to squeal for a fraction of a second and the front end also drifts a little sometimes. Is this normal? Should I be taking more time releasing the clutch?
I notice that the clutch dosnt engage right away, like after my foot has left the clutch peddle the engine RPM's are only about half way to match the 2nd gear ratio. I'm guessing that the clutch has a maximum amout of torque that it can handle and my rapid clutch release has caused it to max out to this value.
Is this a safe way to occasionally shift when you want to accelerate fast? I find it kind of fun to hear the tires squeal when shifting.
BTW the best way to make smoother downshifts is to match the RMP of the of the gear your downshifting into with a slight tap on the gas when your in mid shift. Some say it's also better to release the clutch when you tap the gas, just make sure you put in in again when you shift into gear. This makes 2 clutch uses per shift and requires some fast foot work.
Double clutching works well for down shifting into corners, unfortunatly I can do this becasue my foot is too big to press both the gas and break at once in the Civic. I usually floor the gas when double clutching and it just isnt possible for me.
Has anyone with size 11+ shoes managed to heel toe double clutch on a Civic? I'd like to know it's its at all possible.
All great info on shifting, i enjoy blipping the gas just before a downshift to help match and get people looking. The average lay person pays no mind to these types of techniques, so when you do i they think that you are a racecar driver!!
As far as the size 11 foot goes, i am glad to hear someone else with the same inability...i too can't manuever this great shifting technique because of my big a$$ feet in my crx!!
The jdm b16 that i have doesn't enjoy tough downshifts into 2nd or 1 st, especially 1st, that mechanisim previously mentioned is quite noticable and seems to "open" at 1000 rpms. when i come to a stop with clutch out and gently push on 1st gear she pops in easily when rpms are low (1000). i would have to guess that this is also to keep you from blowing the engine since anymore with big disk brake tech and so on that it really isn't necessary anymore to downshift heavily to stop.
p.s. watch out for extra light flywheels that cause major adjustment in shift response. i had a 7.5 lb fly installed over the factory 26 lb one and dear God does it make everday driving an effort...on the flip side all other standard cars seem like cake to drive!!! lol
the heel-toe im still working on. but im getting it, and i have a size 11 foot. i figure i need a pedal set and it will be a little bit easier. i can only do it when im wearing old beatup shoes that flex really easy tho.
Interesting about the fly wheel. I'm guessing that it will get rid of the tire squeal between the first and second shift and make you get into gear faster. It would also be funny to watch others try and drive your car. It should also make the revs go up faster when punching the gas. I usually get boared while doing every day driving anyway so another challenge would be fun.
If you want to be able to shift into first with ease double clutch. its great becuase you save your synchros and it makes for a smooth acceleration. in case you don't know how: say your going 25mph. if you were in 1st (in my car) you'd be at about 5000rpm, so just put the tranny in neutral, let the clutch out, take it up to 5000 push in the clutch and that sob will go right into gear because that's what rpm it would be at if it was in first in the first place.
i still get tire squeal, btwn 1 and 2, but it is brief. it does go into gear faster when dragging and needs to go into gear fast when normal driving to match rpm's. she sure does wind out quick; combo of stock vtec crossover and light flywheel make for a cool near turob'd feel..5k-8k are ultra quick in the first two gears, for that matter 1st is quick all over.
i do miss the built up torque that a shaved or heavier lightened fly would give me, but it is awesome at the track to see a v8 stang or camaro take that monster jump off the line only to get sucked up by my little pearl 88 hf...it really is worth all the bugs, bucks, and hassle whenever their engine is growling like the lion in the jungle and i catch up to em tagging 8k happily in the quarter!!!
I still have many bugs to work out, but my (driver induced) best time has been a 14.9 at 94.7 mph--that is real top end for only a couple mods on 14" steely bald street tires!!! Lol
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