[volkl23]

I am still trying to get down the 1st to 2nd gear shift at WOT so that it's silky smooth (read: no bucking), but it has proven harder for me than I first though. I'm theorizing that there are 3 points where this bucking feeling originates...

1. When I am WOT and near 6500rpm and let my foot off the gas completely, it feels as if I've run into a brick wall. The sudden deceleration is immense. This may be a stupid question, but is this sudden deceleration bad for the engine or any part of the driveline? It just seems so violent when I let my foot completely off the gas.

2. I'm guessing the second part of the bucking feel results from my clutch action and gas coordination. I notice that if I release the clutch too quickly, i also get this violent bucking motion. Is this the same as dumping the cluth at 6000rpm from a stop, but while moving?

3. Gas pedal. I think this ties in with point 2, but sometimes, not neccessarily during the 1-2, but maybe 2-3, 3-4, after I release the clutch completely and then WOT, I get this slingshot bucking feeling. It's hard to explain, but it feels like getting rid of slack. Am I waiting too long to gas or gasing to hastily? I'm sure that this is not a good thing. I've noticed I can remedy this a little by stepping on the gas before I completely release the clutch (near the end of engagement).

Can all the wise gurus here explain all this to me and suggest what I can do to prolong the life of my STi (I don't drive hard every day, just once in a while).

[drdome99]

i'm not a guru by any means but just from my experience with 1-2 shift it seems like the faster I shift 1-2 the smoother it is... which as you explained could be because I'm shifting before too large of an RPM drop.

[renichms]

Shift faster. At the drag strip, I don't let off the gas at all.

RN

[Slowride]

Originally Posted by volkl23

1. When I am WOT and near 6500rpm and let my foot off the gas completely, it feels as if I've run into a brick wall. The sudden deceleration is immense. This may be a stupid question, but is this sudden deceleration bad for the engine or any part of the driveline? It just seems so violent when I let my foot completely off the gas.

That's just engine braking. It's not detrimental, but it does mean you're shifting too slow or deliberately. Engaging the clutch and letting off the gas should be simultaneous and rapid. An upshift should be three steps:

1) Press clutch and release gas at same time.
2) Shift.
3) Release clutch and press gas at same time.

If you're making steps 1 and 3 into two steps each, you're doing it wrong.

2. I'm guessing the second part of the bucking feel results from my clutch action and gas coordination. I notice that if I release the clutch too quickly, i also get this violent bucking motion. Is this the same as dumping the cluth at 6000rpm from a stop, but while moving?

I don't see how you can release the clutch too quickly unless you're sliding your foot off the pedal. I really can't imagine how you're getting bucking at this point in an upshift.

3. Gas pedal. I think this ties in with point 2, but sometimes, not neccessarily during the 1-2, but maybe 2-3, 3-4, after I release the clutch completely and then WOT, I get this slingshot bucking feeling. It's hard to explain, but it feels like getting rid of slack. Am I waiting too long to gas or gasing to hastily? I'm sure that this is not a good thing. I've noticed I can remedy this a little by stepping on the gas before I completely release the clutch (near the end of engagement).

Hmm...again, no clue. Where do you live? Maybe you need someone to ride along with you. Are you ever smelling burnt clutch smell?

[sciolist]

I'm not a guru either, but I'll offer a few suggestions:

You're going to get some bucking if you snap your foot off the throttle in 1st at redline with any car that has any kind of power, just ease it off a bit slower. Smooth = fast.

Generally speaking, the key to a smooth downshift is to get the rev's matched up. It's probably better to err a little on the high side with the engine speed, and let the car pull the engine speed down (perfect match is best). Holding engine speed and rev mismatch constant, lower gear = more violent reaction.

The turbo's power delivery is a bit more spikey than an N/A motor's, especially in second. I think you have to deliver throttle a bit slower immediately after the upshift, just as the turbo begins to build boost, then mash it - kind of like catching a wave.

Just like in surfing or gymnastics, you are trying to interface two (or more) forces of different magnitudes. This has to be accomplished smoothly so that power can be taken from the initial to the final state "on the fly". There are very brief windows of opportunity at the points of interface. In sport climbing we refer to this as the "deadpoint". Kinda like what (I think) they call "hang time" in basketball.

I'm by no means an expert in the context of driving, but my advice is to dial in your technique at about 5/10 so it's very smooth, then gradually make it faster. Don't try to make it 10/10 at first. You have to train yourself to be sensitive to all the transitional movement that's in play.

Hope that's not too esoteric.

[nhsilversti]

my theory:

first gear is so fast that you are feeling the loss of acc. when pushing in the clutch. try and acc. to 6500 rpm in first push in the clutch and dont shift, feel the brick wall effect.

when you do shift to 2nd from a high rpm, it will "buck" slightly until the boost builds and pulls hard again.

ted

[mx_9]

What Slowride said. I looked into this a few weeks back and that was my conclusion as well. Look at it this way...during normal driving when you hit second gear you slip the clutch a bit as you apply throttle..right? You just need to practice doing this quickly.

[crashsti]

yes, practice, practice, practice. i learned on the STi and i asked everyone i knew who drove stick for advice. that and as time went by i would try slight variations in my technique. if something was'nt working i would try it in a slightly differant manner next time out. i've gone from god awful, clunking, downshifts to the silky smooth, you don't even notice ones.

[jwainwri]

I have a stock STI with 1300 mi.
I was playing with my shifting from 1st to second at WOT. I was shifting as quickly as possible at 6700 or there about and noticed the revs drop once I engaged second to 5000. I shifted slower and the revs were matched and the shift was smoother. This definetly did not feel as fast.

Should I change my shift point, just let the syncros work, or work on matching my revs?

[jrich523]

Originally Posted by renichms

Shift faster. At the drag strip, I don't let off the gas at all.

are you flooring it? i would think this would get you to red line REAL fast..

also.. as most people have said.. RPM matching.. just keep an eye on your RPMs and speed as you drive.. just need to learn it.. it will become second nature.... im getting there