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MysticGrn07
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Joined: Jun 19, 2009
Posts: 8

PostPosted: Fri Jun 19, 2009 2:52 pm Reply with quote Back to top

have owned a 2009 EX Manual for 7 months. I have driving a manual transmission for that long as well. I took lessons for a month or so before buying the car and am a very satisfied manual owner (gas mileage, fun-factor).

I am still though learning the ropes in optimizing the shifting and am having trouble w/ the first to second shift (there's always this lurch). I suspect this is caused by letting off the clutch too soo, but also I think I may shifting too early.

If I shift around 3500-4000 rpms the lurch seems to go away. It seems unavoidable any earlier. But this approach (from the sounds) seems a bit robust. Any thoughts?
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Misha
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Joined: Aug 02, 2006
Posts: 705
Location: McLean, VA, USA

PostPosted: Fri Jun 19, 2009 3:53 pm Reply with quote Back to top

Hi there MysticGrn07, and welcome to Fun and Safe Driving!

Well, by the sound of it you may have a problem with coordinating the movement of your feet. The idea is to add some throttle by the time of clutch engagement, to match the engine rpm with the car speed.

I would suggest first to take a notice of what approximate rpm you need to target, and then practice.

The easy way to observe the target rpm is to accelerate in second from say 5 mph to say 15 mph and notice what engine speed corresponds to those car speeds. This is probably the range of speeds you would normally shift to second. Note that the higher the car speed at the time of shift, the higher you have to rev the engine for a smooth shifting.

Hope this helps Smile
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MysticGrn07
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Joined: Jun 19, 2009
Posts: 8

PostPosted: Fri Jun 19, 2009 4:41 pm Reply with quote Back to top

(The easy way to observe the target rpm is to accelerate in second from say 5 mph to say 15 mph and notice what engine speed corresponds to those car speeds)


This I will try! That's exactly what I've been trying to figure out and am sort guessing.

Would you mind explaining the final note (engine rev vs. car speed).
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Misha
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Joined: Aug 02, 2006
Posts: 705
Location: McLean, VA, USA

PostPosted: Fri Jun 19, 2009 6:06 pm Reply with quote Back to top

Well, sure I can try Smile

Let's construct a hypothetical example. Say, in second gear at 5mph your engine revolves at 500 rpm. Then at 15 it will be 1500 rpm. So, if you try to shift at about 5 mph, your target rpm would be about 500 rpm (or just idle), at 10 mph - 1000, and at 15 mph - 1500.

During the time shifting takes your car speed will likely decrease some amount, but after some practice you'll adjust for that automatically Smile
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MysticGrn07
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Joined: Jun 19, 2009
Posts: 8

PostPosted: Fri Jun 19, 2009 9:11 pm Reply with quote Back to top

I'll hopefully put this test to practice tomorrow. But I have so many more questions and this seems like a good venue to ask.

When downshifting, I often experience this pressure on the clutch pedal. I have equated this to the engine speed fighting to match the car speed, but my instinct says this isn't helping the clutch. Any thoughts?

Also, when I was learning my friend said to release right foot completely off the gas pedal before putting in clutch. I may be misreading your post, but it seems like you suggest only a partial decrease in throttle, and to increase it when it comes time to engage clutch. What's the deal here?
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Misha
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Location: McLean, VA, USA

PostPosted: Sun Jun 21, 2009 1:16 pm Reply with quote Back to top

Let's try to deal with your questions. Smile

Not sure what exactly pressure on the clutch pedal you are talking about. I never noticed any difference between upshifting and downshifting, and technically I can;t really see what could be a difference. Would you try to elaborate a bit, so I get a better idea of what you are talking about?

Now, talking about coordination between gas and clutch. Yes, you want to release gas completely or almost completely when you are disengaging clutch. The idea is that while connected, transmission and wheels do not let engine to revolve too fast, they sort of create a load for engine. When you are disengaging, you are removing this load, and engine starts to accelerate all by itself, until it hits the redline - providing you did not release the gas.

That is the reason you need to step off the gas when you press clutch. However, you don't have to release gas pedal completely. Ideally you need to have it pressed just enough to rev the engine to match the target speed that we were talking about, like 1000 or 1500 rpm.

Does it make any sense?
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MysticGrn07
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PostPosted: Sun Jun 21, 2009 8:46 pm Reply with quote Back to top

During a downshift the vehicle feels as if it a gonna launch as I release the clutch. I think its the engine rpms increasing to match the car speed (as one would expect during the downshift). Alternatively, if I brake sufficiently enough before engaging the lower gear the sensation goes away.
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Misha
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PostPosted: Sun Jun 21, 2009 10:01 pm Reply with quote Back to top

Gotcha! Yes, this is exactly what you think it is - fast revolving transmission accelerates the engine. Be careful with that, you can easily exceed the redline this way, because fuel cut would not help here. Always make sure you are not going too fast for a chosen gear. And again, while you are within the normal rpm range for the engine for your target speed, you can always add more gas to raise engine speed to match the vehicle speed. Smile
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MysticGrn07
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Joined: Jun 19, 2009
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PostPosted: Mon Jun 29, 2009 2:43 am Reply with quote Back to top

So I think I have discovered a solution to my first to second shifting. Of course, the target rpm insight you gave before has made a lot of difference as I am paying much closer attention to when the best transitions occur (in terms of maximizing acceleration under normal driving conditions).

My solution has to do with starting from a standstill. I think I may have been releasing the clutch when I engage first gear too soon. And as a result the shift from first the second is a bit shaky (I'm not sure of a good mechanical reasoning for this, but its what I experience). When I hold the clutch at the catch a bit longer and release the clutch above the catch point ever so slightly, the car seems to almost launch. At this point I'm at my target rpm 2500-2700 (around 15-18 mph) and I disengage to switch to second.

Now this seems to have the effect of making the gear change smoother and I no longer get that lurch I mentioned in my first post. Of course I may do something that in the long run may be harmful to the vehicle. My mechanical knowledge is novice at best.

Any thoughts...

Thanks You!
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Misha
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PostPosted: Sat Jul 04, 2009 11:45 pm Reply with quote Back to top

Sorry for delay Mistic, I was out of town.

Well, glad you are making progress, but if I understood you correctly, it seems like you are really hurting your vehicle. If you do not release clutch completely as soon as the car starts moving and you continue to accelerate with partially disengaged clutch, you are going to need clutch replacement pretty soon...

Th point really is in matching speed of engine to the speed of transmission, no more no less Smile
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MysticGrn07
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Joined: Jun 19, 2009
Posts: 8

PostPosted: Sun Jul 05, 2009 12:37 am Reply with quote Back to top

Gotcha! I figured as much...I haven't been keeping with that practice as I realized its still just a timing issue with the clutch and gas pedal. I guess I'm still worried about stalling the vehicle and have a reluctant left foot (speaking of 1st and 2nd gear). I've been practicing barefooted actually to get a better feel of the mechanics. And as I said, its really just mastering the timing. Sometimes I get it, other times I don't get it. But some progress nonetheless. Thanks for the input!
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Misha
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Location: McLean, VA, USA

PostPosted: Sun Jul 05, 2009 5:23 pm Reply with quote Back to top

That sounds much better! Looks like you are on a right track now Smile
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MysticGrn07
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Joined: Jun 19, 2009
Posts: 8

PostPosted: Tue Jul 07, 2009 7:52 pm Reply with quote Back to top

Highway driving:

Say I'm on the highway, which i do much driving on nowadays, and am encountering a slope that 5th lugs on. My instinct is to down shift to forth to help the vehicle up the slope. This maneuver speaks to an earlier post with my issues downshifting: you wrote that it was an issue of matching the engine speed with the now fast revolving transmission, and that I can always add speed to the engine to do this.

My question now is when do I add this speed to the engine. (Is this a double clutching thing). Or can I add the speed to the engine without redlining with a single clutch? That is, is it safe to rev the engine prior to engaging the clutch as I shift from 5th to 4th (or any other down shift for that matter)?
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Misha
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Joined: Aug 02, 2006
Posts: 705
Location: McLean, VA, USA

PostPosted: Tue Jul 07, 2009 9:14 pm Reply with quote Back to top

Yes, you need to down shift in such a case, and it is safe - even if you go to redline - cause computer will limit engine idle speed well before it can become damaging. What I meant when I was talking about the dangers of downshifting is actually engaging the engine with transmission when transmission forces engine to rotate faster than redline. Transmission, not gas pedal. In this case computer can't help, cause even if you cut the fuel, transmission still forces engine to rotate too fast.

And you don't need double-clutching on moderns cars. 18 wheelers is another story, but we are talking cars, right? Smile
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arun
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Joined: Dec 25, 2009
Posts: 100

PostPosted: Fri Dec 25, 2009 8:14 am Reply with quote Back to top

It's a common problem for many people while shifting from 1st to 2nd gear. You can shift to 1st to 2nd gear at around 10kmph. just release the acceleration pedal slowly and viceversa for the cluch pedal and then shift to 2nd gear.
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