Anyone else dab the gas on an upshift?

Ken

Ken

Ken

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Joined
28 Apr 2004
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1,067
Hi,

I can't stand unsmooth gear changes whether I'm the driver or passenger.

When in traffic, I shift early early before the torque is available. For example, when I'm in third which would be around 19 mph, I would shift into 4th at around 28 mph. This guarantees a smooth ride.

Now shifting early means I miss out on the torque band. So going round a country road or accelerating into a motorway or entering a dual carriageway I like to give it some.

I stay in each gear for longer for maximum acceleration but because of this, the speed is too fast for the next gear but to slow for the gear after that. Let me explain. Say I was in 3rd, I'd be flooring it to about 45mph, at which point 4th would be best to get maximum acceleration but 5th would be too weak.

Now to the point of this post.

Shifting into 4th from 3rd doing 45 mph would jerk the car as the revs matches the car speed obviously. What I do is dab the gas to the right number of revs so that 4th engages smoothly.

Does anyone else do this?
 
You're in 4th at 28? What car have you got?

You can get smooth changes whatever speed you change up at, if you know how to drive.
 
Ken said:
Shifting into 4th from 3rd doing 45 mph would jerk the car as the revs matches the car speed obviously. What I do is dab the gas to the right number of revs so that 4th engages smoothly.

Does anyone else do this?
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You need to shift faster. Change gear fast and without dabbing the throttle and it will smooth out. If dabbing the throttle means it gets smoother, you must be taking so long to change gear the engine revs have dropped below that required for the next gear, and so need to be brought back up. You'll get a perfectly smooth shift if you engage the gear at the point where the engine revs have naturally dropped to that of the next gear.
 
The most common mistake people make driving modern diesels is to shift too early or sit in too high a gear. You want to be changing gear so that the next gear up drops you to a least 1800RPM which is around peak torque for most TD's. Whilst they will pull from lower it doesn't do them any good, and you'll use more fuel with lots of throttle in 4th than you will staying in 3rd when you want to increase speed. You don't want to be cruising much below the peak torque figure either.

If the car is jerking noticably shifting from 3rd to 4th at 45mph then your car has some sort of problem with the clutch or gearbox, or you can't drive.

You may sometimes need to rev match on the way down the box, but you shouldn't need to on the way up.

I quite often miss gears in my car, usually 3rd to 5th or 4th to 6th when pressing on. There is no need to use 6th gear below 60mph, I generally only use it about 70mph as its not exactly noisy in 5th at that speed.
 
Ken said:
Say I was in 3rd, I'd be flooring it to about 45mph, at which point 4th would be best to get maximum acceleration but 5th would be too weak.
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Yeah, flooring it :confused:

If I was accelerating onto a motorway/dual-carriageway, 3rd would see me up to 70-75MPH at least.
 
Indeed - and 4th to get max acceleration at 45? Erm. I have never had the 'pleasure' of driving a diesel but I am guessing modern diesels aren't that short geared.
 
at 45 in my diesel fiesta (not a modern engine admitingly - tddi), I'll have just changed into 3rd....(as to not hit the limiter)
 
paradigm said:
Yeah, flooring it :confused:

If I was accelerating onto a motorway/dual-carriageway, 3rd would see me up to 70-75MPH at least.
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Same here. If I was accelerating on a slip road 45mph would be 2nd - 3rd not 3rd - 4th. Your not using enough of the revs, so when selecting next gear, the revs are too low for the speed.
 
Using a bit of gas for an upshift is part of the advanced driver training, aim being to provide a nice smooth change are arguably less wear on clutch/drivetrain.
 
The gear you need at different speeds varies wildly between cars, so you can't really generalise.

Blipping the throttle to match revs when changing gears is a recognised driving technique. Before Synchromeshes it was the only real way to do it.
 
Mr Jack said:
The gear you need at different speeds varies wildly between cars, so you can't really generalise.
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True but how many cars give max acceleration at 45, in 4th - not many I'll wager :) 99% cars will be 3rd or 2nd.
 
You must spend a hell of a lot on petrol... and you must drive pretty slow if your in 4th at 28mph... whats the lagg like? hehe
 
Simon said:
Using a bit of gas for an upshift is part of the advanced driver training, aim being to provide a nice smooth change are arguably less wear on clutch/drivetrain.
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When i did the IAM course they taught me to up the revs on down shifts to make smoother changes, and match the revs with the speed, but when changing up the gears there is no need to increase the revs.
 
Simon said:
He spends nothing on petrol ;)
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pffft, ok for some... including me at themoment as i dont drive yet hehe.but when im in the learner car i drive pretty ok with gear changes, sept the car is a ***** to shift gear in...
 
James07 said:
pffft, ok for some... including me at themoment as i dont drive yet hehe.but when im in the learner car i drive pretty ok with gear changes, sept the car is a ***** to shift gear in...
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You missed the point ;)
 
chrislusty said:
When i did the IAM course they taught me to up the revs on down shifts to make smoother changes, and match the revs with the speed, but when changing up the gears there is no need to increase the revs.
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This is what I was thinking. By all means blip the throttle on downshifts, but upshifts? Surely there is no need, unless you double declutch and need more time.
 
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