[rozca]

(Original post by TheCurlyHairedDude)
There's no such thing as going to fast. Not sure what car you drive, but the average 4 pot car, second gear will go up to 46/47 MPH

Heck even 1st gear goes to 20 mph.

Learn how to change up and down. I'd be slowing down to 5mph to change into first, that's stupid.

lol.

OP, you're going too fast so it jolts and brings your speed down for you (this is bad for the car). Just slow down more, and change gear - you'll notice the engine won't jolt.

[TheCurlyHairedDude]

(Original post by Left Hand Drive)
Are you stupid? Go change from 5th or 4th to 2nd going 40 and your car will engine brake. The reason everyone is saying thats what it is because thats what it is

Nope. I've done track days before, twice. I know how to drive.

Were not talking about engine braking, were talking about the "jolt" and how to eliminate it.

[Nuffles]

(Original post by Left Hand Drive)
Are you stupid? Go change from 5th or 4th to 2nd going 40 and your car will engine brake. The reason everyone is saying thats what it is because thats what it is

If you rev-match properly, it's doable. It'll be noisy and the car will slow up pretty sharpish as you back off on the accelerator afterwards, but it's possible to do it smoothly.

There's a roundabout on my way into town which is pretty small, and the road into it goes over a small hump back bridge before I take the third exit into town. I come along the road in fourth, down to third just before the bridge, and then double declutch into second once I'm on the roundabout and approaching the island, just before I start to turn. I do it this way so I can control my speed with my engine revs whilst also making sure I'm in the right gear to pull away from the roundabout in. If I simply braked and left it in third, I'd have to change into second whilst half way around a very tight roundabout to be able to accelerate away. The other reason I do this is because if I left it until half way around the roundabout to change down to second, this is precisely when I need to swap from indicating right to indicating left to leave the roundabout. I can't do that and change gear at the same time as the stalk is on the left of the steering wheel. More cars should have it on the right really, my Morris Minor did, as did a Honda Civic I drove once. It's much better that way. It makes it possible to change gear and indicate at the same time, which is sometimes a necessity.

[Huskaris]

Definite Engine brake...
Have you ever on a motorway accidentally changed from 4th to 3rd instead of 5th? Same thing... Gears effectively work as a constant brake, hence why some people "coast" by driving with the clutch down whilst going down hill...

[J@tko]

(Original post by Steezy)
I usually take it out of gear completely when I know i don't need to accelerate anymore. Then brake as much as necessary and put it into the correct gear (2nd or 3rd), then accelerate out. It's usually pretty smooth andn saves a tiny bit of petrol each time as the revs go right down when you take it out of gear.

If you leave it in gear you use no petrol whatsoever

[gbduo]

(Original post by zippyRN)
at risk of the wrath or the anti-AD faction ( but hopefully with some support from R0G)

rev matching / sustained revs change will eliminate this , the 'jerk' is because you are effectively using the clutch as a brake , and the engine is spinning to slowly / the car is too fast ...

knowing when it is safe and appropriate to overlap braking and gear changes is something which takes practice and you need to learn to seperate before going back to overlapping ...

heel and toe is a racing technique and has limited applicability to safe and progressive on road driving

Yeh but h&t is good fun though

But I agree, limited use in most cars unless your pedals are set up for it, i.e. the throttle pedal is at the same height as the brake pedal and close together otherwise it is tricky to do anyway. In most euroboxes I have been in, the throttle is about a inch to 2 inches lower than the brake pedal when neither are depressed.

Makes it quite tricky to h&t unless you stamp on the brakes...

PS technically, you are using the compression of the engine as a brake, not the clutch /pedant

[LETSJaM]

(Original post by irate_pirate)
Sounds like engine braking to me - i.e. you're maybe still going a little bit too quickly. Try slowing down a little bit more, changing gear whilst breaking, bring the clutch up slowly. If it feels like it's going to stall then keep the clutch dipped slightly. If you don't need to stop then the momentum + slightly dipped clutch should keep you going. Apply gas as you come out of the corner. Remember to check check check if you're not stopping tho!

I'm still just a learner too tho so...!

This.
I get told to brake more, so the engine doesn't do it for me.

<3 x

[Left Hand Drive]

(Original post by TheCurlyHairedDude)
Nope. I've done track days before, twice. I know how to drive.

Were not talking about engine braking, were talking about the "jolt" and how to eliminate it.

I have too. I was just at knockhill last week. The jolt can be eliminated by slowing down to an appropiate speed for the gear...

[TheCurlyHairedDude]

(Original post by Left Hand Drive)
I have too. I was just at knockhill last week. The jolt can be eliminated by slowing down to an appropiate speed for the gear...

So is that what you do then, slow down to 15mph on the track to go into second Oh wait guys, just changing to second, slowing to 15 mph, cmon....

[Left Hand Drive]

(Original post by TheCurlyHairedDude)
So is that what you do then, slow down to 15mph on the track to go into second Oh wait guys, just changing to second, slowing to 15 mph, cmon....

Nope because I never had to go to second on the track. 4th for every corner apart from the hairpin which was 3rd. I was told to break then go down the gear btw.

Im not saying your way dosnt work its just the awkward way.

[py0alb]

(Original post by Jason2)
When coming to a junction or roundabout and I'm in say 3rd or 4th, I slow to about 20mph then change to second but when bringing the clutch back up the car jolts forward. Anyone know why this is? Do I need gas to ensure smooth re-engagement of the clutch? Its just this is quite difficult when going down an hill and taking the next left 'cause the car goes faster and applying some gas may well make me come into the corner too fast. I can do everything else fine just this is beginning to annoy me.

Thanks in advance for any help.

There are two scenarios when you might change down a gear.

The first one is when you have braked down coming up to a bend/roundabout and you wish to accelerate away in a lower gear. In this case, you should brake, depress the clutch, release the brake, select the appropriate gear, and apply gentle acceleration as you release the clutch. This should give you a nice smooth gear change and a clean acceleration.

The second scenario is when you wish to engine brake as well as foot brake on the way down a relatively smooth speed gradient. For example you might be in 5th gear going at 60, and be approaching a busy roundabout and wish to make the final approach in 2nd gear at 10mph. In this case, you should brake down to about 25mph, depress the clutch whilst continuing to gently brake, select 2nd gear, and lift the clutch slowly at around 15-20 mph, this should match the revs automatically. There is no need for the accelerator in this scenario.


*all values are estimates for example purposes only.

[Steezy]

(Original post by J@tko)
If you leave it in gear you use no petrol whatsoever

Que?

Petrol usage is based on the revs... So if you keep it in gear, the revs stay higher than if you take it out of gear.... So therefore if you take it out of gear you use less petrol...?

Unless I'm being a retard which could be the case.

[A Mysterious Lord]

Essentially your engine was revving too high for the gear you wanted and the speed you needed to be going. I noticed this when I first started driving, I'd be doing 40mph in 4th gear then turn off, changing down to 2nd for the turn. I'd brake, 40, 30, 25, change down... JOLT, because I'd changed down too fast - the engine speed was still on its way down.

When changing down, don't just brake and change down, you need to be matching the engine speed (revs) to the speed you need to be going, not the speed you are currently at.

[jordanelouise]

(Original post by Jason2)
When coming to a junction or roundabout and I'm in say 3rd or 4th, I slow to about 20mph then change to second but when bringing the clutch back up the car jolts forward. Anyone know why this is? Do I need gas to ensure smooth re-engagement of the clutch? Its just this is quite difficult when going down an hill and taking the next left 'cause the car goes faster and applying some gas may well make me come into the corner too fast. I can do everything else fine just this is beginning to annoy me.

Thanks in advance for any help.

This usually happens to me when i'm going to fast for second gear! Try slowing down a lot more before going into second and also bring your foot off the clutch a lot slower! Hope this helps!

[jordanelouise]

(Original post by Steezy)
Que?

Petrol usage is based on the revs... So if you keep it in gear, the revs stay higher than if you take it out of gear.... So therefore if you take it out of gear you use less petrol...?

Unless I'm being a retard which could be the case.

I was always told if you take it out of gear you use less petrol, because your car is just basically rolling? So i don't think your being a retard! haha

[zippyRN]

(Original post by jeddows)
I'm sorry but that's pretty much nonsense. If I braking from 60mph in 5th to 30mph, I'm going to drop it down to 4th, simply because 30mph is too slow for 5th gear in my car. Likewise, if I'm slowing for certain roundabouts or junctions I'll drop it to 2nd so I can accelerate away. The only time you need first is when you're pulling away, or literally crawling in traffic.

Anyway, back to OP, then as everyone else has said, you're probably going too fast for second. Stay in 3rd/4th for longer, or try *slowly* bringing the clutch back up to reduce the jerkiness.
20mph is about 2,000 rpm in 3rd, but it's around 4,000 rpm in 2nd, so if I go from 3rd to 4th normally, the engine is going to have to quickly 'speed up' to match the road speed, causing the jerk.

Jeddows , how long have you been driving ? do you have your cat B licence? what about IAM /RoSPA ? RoSPA Diploma or equivalent ? ADI ? LGV ? PCV ?

[FXX]

(Original post by Steezy)
Que?

Petrol usage is based on the revs... So if you keep it in gear, the revs stay higher than if you take it out of gear.... So therefore if you take it out of gear you use less petrol...?

Unless I'm being a retard which could be the case.

In modern engines, if the car is in gear and slowing down and the accelerator isn't depressed, no fuel will be pumped through. If you flick it into neutral, the engine needs fuel to stop itself stalling.

Of course you need to balance that up with which gear you're in and how much the engine is slowing you down vs knocking down into neutral, but with having it in gear you have more control if there's an emergency situation.

[zippyRN]

(Original post by jordanelouise)
I was always told if you take it out of gear you use less petrol, because your car is just basically rolling? So i don't think your being a retard! haha

never really been the case since the days of directly mechanical driven fuel pumps ...

in a car built in the las 15 or more years you will use more fuel coasting then on the over-run

[J@tko]

(Original post by Steezy)
Que?

Petrol usage is based on the revs... So if you keep it in gear, the revs stay higher than if you take it out of gear.... So therefore if you take it out of gear you use less petrol...?

Unless I'm being a retard which could be the case.

Yeah as FXX said above, if you're driving along with no throttle and the car in gear, the ECU doesn't pump any fuel into the engine, because it doesn't need to. However if you engage the clutch, the engine goes to idle and because there's no connection between the engine and the driven wheels, there's no force to keep the engine going (like there is in the first case) so the ECU has to pump a little bit of fuel into the engine to stop it stalling

[Steezy]

(Original post by FXX)
In modern engines, if the car is in gear and slowing down and the accelerator isn't depressed, no fuel will be pumped through. If you flick it into neutral, the engine needs fuel to stop itself stalling.

Of course you need to balance that up with which gear you're in and how much the engine is slowing you down vs knocking down into neutral, but with having it in gear you have more control if there's an emergency situation.

Define 'modern'.