smoother shifting

remond · Jun 10, 2004, 09:13 AM

is there some sort of key to smoother shifting? this hasn't been a issue in my other cars (due to lack of torque) but some people who ride with me in my evo complain that the shifting is rough. seems like the only way i can get the ride relatively smooth is if i shift before 3000 rpm. the car doesn't lurch or jerk or anything, but whenever i let off the gas and push the clutch to upshift i can see my passengers heads bob forward as if i'm braking hard.

can someone fill me in on how to upshift smoothly through my gears without making my passengers dizzy? it seems to only be a problem when changing 1 -> 2 and 2 -> 3. (this seems to be common in all manual cars i've driven..but in the evo it's more pronounced)

does this have anything to do with wheel/engine speed? i saw mention of that in other threads while i was searching for an answer to this.

TypeIII · Jun 10, 2004, 10:55 AM

In physics, we have position.
Then we have change of position, or velocity.
We also have change of velocity, or acceleration.
Finally we have change of acceleration, or jerk.

You feel that jerk because you go from a positive acceleration to zero (actually it's a very small negative) acceleration, then back to a position acceleration within a very short time. To minimize this effect, you must control that change of acceleration very carefully. If you're accelerating hard, the car is bound to jerk during shifting.

remond · Jun 10, 2004, 01:25 PM

i understand the physics of it.

i was simply wondering if there was some way to minimize the feeling of that change in acceleration other than just driving like a grandma and keeping the rpms low.

basically i want to learn how to make my shifts feel as seamless as possible. while still being able to accelerate moderately fast.

how does an automatic transmission work? how are they able to shift so smoothly even when you're on the gas hard?

stfuad · Jun 10, 2004, 04:10 PM

Hmm I'm not positive, but with automatic transmissions the tourqe converter stays filled and locked (?) as long as your foots on the pedal so there isn't any period of deceleration. Plus since it's controlled by a computer the "shifting" is faster. There's an explanation on howstuffworks.com.

Djkore · Jun 10, 2004, 07:44 PM

well when driving around town but not trying to keep accel high i usually will go until i see im about 2k away from redline and slowly depress the gas till it creeps up slow then shift, slows down the end accel per gear so your shift time (0 accel) is a gradual decline then incline with the next gear *shrug* i drive hard all the time i dont care if my friends break there neck! lol j/k

en1gma19 · Jun 10, 2004, 07:49 PM

it will be smoother if you let the rpms plateau before you shift. instead of shifting while the rpm's are still rising, wait until they level off, and then shift. the key is to keep the rate of acceleration constant. if you go WOT and shift at 4500rpm, it will be very jerky, of course. if you lightly accelerate, and the rpms rise to 5000 and they don't climb anymore, then you're ready to shift. does that make sense?

en1gma19 · Jun 10, 2004, 07:50 PM

you won't get the short "pssh" bov noise, instead it will release the air slowly and kind of mix in with the sound of the turbo, exhaust, etc.....

**urbanknight** · Jun 11, 2004, 12:00 AM

Take some time to play around with the clutch. Smooth shifting comes when you get the timing of the clutch just right in sync with your hand. Not too early, not too late, not too fast and not to slow.

vandammy · Jun 18, 2004, 03:40 AM

hahah rought? i get that alot from my gf. i would say change to a buick or a oldsmobile shock struts absorber or whatever u call it.... i i think the stiff ride make gear shifting more harder because u could feel everymotion... but if u driven anyother sport car who had a stiff suspension u will know they have same probs... just ignore ur friend and be happy to be the one driving! cause i don't feel anything after awhile! hahah

ckl · Jun 26, 2004, 02:10 PM

haha, i got that from my gf too, she always complain that her friend who drives a civic can drive smoother than me, I've explained to her that because I have a stiffer suspension, she said whatever and complain again....

if this is really a problem to you, try to push in and let out your clutch slower, gives more time for the synchros to do its work. This will definitly increase the wear of you clutch, so just choose if you want a smoother ride or if you want to save your clutch

g6civcx · Jun 29, 2004, 04:40 PM

You need to learn revmatching. Read up on it.

Rev up before you release the clutch. Watch your tachometer. If the needle doesn't bounce when you release the clutch, you have successfully revmatched.

If the needle bounces up or down, adjust throttle according to vehicle speed and gear.

evolute · Jul 3, 2004, 01:06 PM

EN1GMA19 SAID "it will be smoother if you let the rpms plateau before you shift. instead of shifting while the rpm's are still rising, wait until they level off, and then shift."

i agree with that - and i've also noticed something else since i've had my boost gauge. if you let off the gas slowly it doesn't take much to get the gauge down to full vaccum, then you shift. not only should the revs be 'plateaued' by that time but you're also not pushing boost anymore. the less force you have pushing you forward, the less you jerk when you shift, and boost definitely pushes you forward - so get off that. from there it's just a little finess with the clutch and you're good.

g6civcx · Jul 3, 2004, 02:16 PM

No no no. It doesn't matter if the rpms plateau, whatever that means.

What matters is how high the motor revs before and after you engage the clutch. If you can hold the RPM to the point where it would had you engaged the clutch, you can literally dump the clutch and the car will not jerk.

It's revmatching.

**urbanknight** · Jul 3, 2004, 02:24 PM

Holding the RPMs would be the same as plateau, although it would be important to learn to the point that you don't have to hold it, because that's costing time. Just like feathering the clutch, you get a feel for it before you can be quick and smooth at it.

evolute · Jul 4, 2004, 12:27 PM

G6CIVICX is right, rev matching is important - something i left out of my post. but if you are still accelerating when you begin to shift, that'll jerk you too, just like not rev matching into the next gear will.

you just have to use a combo of both to be smooth from the start of the shift through to the end.