How do I gear down in a turbo car?
Discussion
Hi all. I have a N/A car (mk2 golf gti 8v) and a turbo car ('08 scirocco 2.0 TSI-manual not dsg). I tend to have a lot more fun in the golf when going out for a jolly but I'm just wondering about the comparison of changing down the gears in both cars (particularly from relatively high speed).
Lets say for instance I'm approacing a roundabout on a clear main road/dual carriageway doing 70+ mph and want to maintain pace for as long as safely possible before having to slow down to negotiate the said obstacle.
In the golf I find it easy to change down by giving some revs while neutral when the clutch is down before dropping to the next gear so the revs match, resulting in a nice smooth gear change without any unnecessary jerking followed by the ensuing engine braking as desired.
When in the rocco if I try and employ this it just results in me giving the revs while neutral with the clutch but the turbo then adds more revs than I intended which results in me dropping to the next gear and actually accelerating (the opposite effect to what I want).
I would much appreciate any advice. Hopefully I have described my predicament clearly enough.
Many thanks
Matt
Lets say for instance I'm approacing a roundabout on a clear main road/dual carriageway doing 70+ mph and want to maintain pace for as long as safely possible before having to slow down to negotiate the said obstacle.
In the golf I find it easy to change down by giving some revs while neutral when the clutch is down before dropping to the next gear so the revs match, resulting in a nice smooth gear change without any unnecessary jerking followed by the ensuing engine braking as desired.
When in the rocco if I try and employ this it just results in me giving the revs while neutral with the clutch but the turbo then adds more revs than I intended which results in me dropping to the next gear and actually accelerating (the opposite effect to what I want).
I would much appreciate any advice. Hopefully I have described my predicament clearly enough.
Many thanks
Matt
Glosphil said:
You change down to maintain pace? Why?
Yup, not understanding why some anticipation and lifting off won't achieve the desired effect.Leaving that aside, best thing is to understand revs in gear x & impact of the turbo (is it peaky & top end - not something often levelled at VAG turbo applications).
I hear you OP but just to warn you there is advanced and "advanced" what you want to do whilst being skilful isn't advanced in terms of Roadcraft or IPSGA as you're selecting a gear before removing speed so basically you're doing:
Information (spot the R/A)
Position (hopefully this speaks for itself)
Gear (take lower gear and hope it's clear)
Speed (only slow down if absolutely necessary)
Accelerate
I totally get you and that's EXACTLY what I use to do.
I don't now but that's beside the point.
So, onto your question
. I'm not really understanding how the turbo is adding extra revs but I appreciate if it does you'll get the opposite effect of what you intended. It honestly sounds like you just need more experience in matching engine revs to road speed or just stick with the high gear until you know the R/A is clear then take a lower gear and skip out the need for the engine braking. If you take the latter approach you could always consider heel and toe to add back in the "racing driver" element .
Information (spot the R/A)
Position (hopefully this speaks for itself)
Gear (take lower gear and hope it's clear)
Speed (only slow down if absolutely necessary)
Accelerate
I totally get you and that's EXACTLY what I use to do.
I don't now but that's beside the point.
So, onto your question
. I'm not really understanding how the turbo is adding extra revs but I appreciate if it does you'll get the opposite effect of what you intended. It honestly sounds like you just need more experience in matching engine revs to road speed or just stick with the high gear until you know the R/A is clear then take a lower gear and skip out the need for the engine braking. If you take the latter approach you could always consider heel and toe to add back in the "racing driver" element .There is no doubt that most turbo cars have a dulled throttle response off boost compared to a normally aspirated or supercharged engine, the usual answer is to try a much harder prod on the gas for the down change, but for a very short duration, which will get the response you need, without the over rev.
Developing this further is the whole process of minimising lag, and to do that my old Integrale would require you to approach the roundabout on the brakes, do the down change timed so that the clutch is up at the end of deceleration (which is when you need power, not before), then immediately transfer the left foot to the brake and stand on the gas with the right to relight the laggy turbo, then the (rapidly increasing) power is metered out to the wheels through the brake pedal while the boost comes up with the gas pedal held to the floor. if timed right you can ease off the brake and proceed rather swiftly through the apex of your roundabout exit without having to wait for the turbocharger to join the party!
Developing this further is the whole process of minimising lag, and to do that my old Integrale would require you to approach the roundabout on the brakes, do the down change timed so that the clutch is up at the end of deceleration (which is when you need power, not before), then immediately transfer the left foot to the brake and stand on the gas with the right to relight the laggy turbo, then the (rapidly increasing) power is metered out to the wheels through the brake pedal while the boost comes up with the gas pedal held to the floor. if timed right you can ease off the brake and proceed rather swiftly through the apex of your roundabout exit without having to wait for the turbocharger to join the party!
What we're talking about here is the quality of the throttle response. Your MkII Golf will have a cable operated throttle mechanism with a comparatively simple engine management system that ensures enough fuel when you press the accelerator for a quick, linear response.
On the other hand, when you press the throttle in the Scirroco, the (I'm guessing) drive by wire actuator sends a message to the engine management computer, which then summons a committee to consider the request. After deliberating what it is you're trying to do, taking account of the reports submitted by the very numerous sensors that are monitoring intake temp, ambient temp, coolant temp, CO levels in the exhaust and whether or not there's an 'R'in the month, the committee then decides that you might want to speed up the engine but that you should not be permitted to over fuel and thus produce an excess of evil pollutants.
All of which results in a sluggish and non linear response to your push on the accelerator pedal. It's probably got much less to do with the turbo and more to do with modern engine management systems and their programming to minimise unburned toxins.
On the other hand, when you press the throttle in the Scirroco, the (I'm guessing) drive by wire actuator sends a message to the engine management computer, which then summons a committee to consider the request. After deliberating what it is you're trying to do, taking account of the reports submitted by the very numerous sensors that are monitoring intake temp, ambient temp, coolant temp, CO levels in the exhaust and whether or not there's an 'R'in the month, the committee then decides that you might want to speed up the engine but that you should not be permitted to over fuel and thus produce an excess of evil pollutants.
All of which results in a sluggish and non linear response to your push on the accelerator pedal. It's probably got much less to do with the turbo and more to do with modern engine management systems and their programming to minimise unburned toxins.
DukeDickson said:
Glosphil said:
You change down to maintain pace? Why?
Yup, not understanding why some anticipation and lifting off won't achieve the desired effect.Leaving that aside, best thing is to understand revs in gear x & impact of the turbo (is it peaky & top end - not something often levelled at VAG turbo applications).
Thanks to all who have replied to my topic, very much appreciated. My predicament makes a lot more sense now. Even though having a turbocharged engine is fun and quick, I think I will always prefer the ease and fun of driving n/a. I just need to accept that when I drive either car it will require a slightly different style of driving in order to be safe, have fun and drive with competence.
DubNut1664 said:
If I just stay in 5th gear and brake I will be in the wrong gear when I want to accelerate, therefore need to change down gear whilst braking.
Are you sure? On arriving at a R/B without having changed down, I generally find that there is sufficient time after coming off the brakes to take the gear for acceleration before needing to go back on the gas - which is generally not until I have entered the R/B and started to steer to the right.On the other hand arriving at a bend, you may well want to blend braking into acceleration without a gap for changing down (though be aware that police, IAM and Rospa all recommend completing the braking far enough before entering the bend to leave time and space for changing down before entering the bend). Anyway, if you want to brake up to the point of acceleration the way this is usually done is using Heel and Toe (not clear if that is the technique you are currently using - not going to start explaining the technique here, but must mention the golden rule which is always to make sure your foot is safely on the brake, and to practise in a safe situation). Rev matching using H & T works fine in most turbo cars.
DubNut1664 said:
I don't think you quite got what I meant. What I was trying to say is I want to stay at speed for as long as possible before having to slow down.
Personally, I'm careful about this, because it's easy to under or over brake, resulting in imperfect entry speed for the roundabout. When I did Calofornia Superbike School, it was called "charging the turn" and drilled out of us. Instead, I find the usual "slow in, fast out" race school advice works equally well for road driving too. Entry speed into the roundabout makes little difference to overall pace, whereas exit speed out of the roundabout has more impact. Consequently, I prefer an unhurried approach to the roundabout, which gives ample time and space to get braking and gear changing done smoothly and accurately, followed by a brisk exit out of the roundabout. (Ditto for bends too,)As ever, it's hard to discuss without being in-car. If you're a driving enthusiast, you might enjoy a day with someone like RideDrive.
Cheers
Edited by SVS on Sunday 20th October 07:22
SVS said:
DubNut1664 said:
I don't think you quite got what I meant. What I was trying to say is I want to stay at speed for as long as possible before having to slow down.
Personally, I'm careful about this, because it's easy to under or over brake, resulting in imperfect entry speed for the roundabout. When I did Calofornia Superbike School, it was called "charging the turn" and drilled out of us. Instead, I find the usual "slow in, fast out" race school advice works equally well for road driving too. Entry speed into the roundabout makes little difference to overall pace, whereas exit speed out of the roundabout has more impact. Consequently, I prefer an unhurried approach to the roundabout, which gives ample time and space to get braking and gear changing done smoothly and accurately, followed by a brisk exit out of the roundabout. (Ditto for bends too,)As ever, it's hard to discuss without being in-car. If you're a driving enthusiast, you might enjoy a day with someone like RideDrive.
Cheers
Edited by SVS on Sunday 20th October 07:22
I agree with XJ Flyer. Here's how it looks when applied to a roundabout:
Picture courtesy of RideDrive driving tips
Picture courtesy of RideDrive driving tips
SVS said:
I agree with XJ Flyer. Here's how it looks when applied to a roundabout:
Picture courtesy of RideDrive driving tips
That's brilliant I much appreciate the knowledge and expertise on here, thanks a lot!Picture courtesy of RideDrive driving tips
Matt
[quote=SVS]I agree with XJ Flyer. Here's how it looks when applied to a roundabout:
I think the only difference there is that it seems to use the late block change downshift idea rather than braking and sequential downshifts on the approach.In which case the diagram would be along the lines of brake to match the road speed for the next gear down then downshift on a continuous basis until you've reached the right gear for the exit.But the important thing is not to allow enthusiasm to create a situation where you're trying to make up time on the approach and on entry to roundabouts and corners rather than just using optimum exit speeds to make progress.
This is how it looks when it's done with a truck but it's no different with a car in most respects.
www.youtube.com/watch?v=9_9kZB5-MyM
I think the only difference there is that it seems to use the late block change downshift idea rather than braking and sequential downshifts on the approach.In which case the diagram would be along the lines of brake to match the road speed for the next gear down then downshift on a continuous basis until you've reached the right gear for the exit.But the important thing is not to allow enthusiasm to create a situation where you're trying to make up time on the approach and on entry to roundabouts and corners rather than just using optimum exit speeds to make progress.
This is how it looks when it's done with a truck but it's no different with a car in most respects.
www.youtube.com/watch?v=9_9kZB5-MyM
Edited by XJ Flyer on Sunday 20th October 21:57
XJ Flyer said:
I think the only difference there is that it seems to use the late block change downshift idea rather than braking and sequential downshifts on the approach.In which case the diagram would be along the lines of brake to match the road speed for the next gear down then downshift on a continuous basis until you've reached the right gear for the exit.But the important thing is not to allow enthusiasm to create a situation where you're trying to make up time on the approach and on entry to roundabouts and corners rather than just using optimum exit speeds to make progress.
This is how it looks when it's done with a truck but it's no different with a car in most respects.
www.youtube.com/watch?v=9_9kZB5-MyM
As you say, the big difference from the RideDrive diagram is changing down sequentially through the gears. The advantages of using a block change after the end of braking are that you keep both hands on the wheel for longer and until you are going slowly, you only have to think about one thing at once, and you can use the accelerator to match engine revs to road speed with a single smooth braking action and without having to use the more difficult technique of heel and toe to operate brake and accelerator at the same time.This is how it looks when it's done with a truck but it's no different with a car in most respects.
www.youtube.com/watch?v=9_9kZB5-MyM
Edited by XJ Flyer on Sunday 20th October 21:57
What are the advantages of sequential downcchanges for car road driving?
waremark said:
XJ Flyer said:
I think the only difference there is that it seems to use the late block change downshift idea rather than braking and sequential downshifts on the approach.In which case the diagram would be along the lines of brake to match the road speed for the next gear down then downshift on a continuous basis until you've reached the right gear for the exit.But the important thing is not to allow enthusiasm to create a situation where you're trying to make up time on the approach and on entry to roundabouts and corners rather than just using optimum exit speeds to make progress.
This is how it looks when it's done with a truck but it's no different with a car in most respects.
www.youtube.com/watch?v=9_9kZB5-MyM
As you say, the big difference from the RideDrive diagram is changing down sequentially through the gears. The advantages of using a block change after the end of braking are that you keep both hands on the wheel for longer and until you are going slowly, you only have to think about one thing at once, and you can use the accelerator to match engine revs to road speed with a single smooth braking action and without having to use the more difficult technique of heel and toe to operate brake and accelerator at the same time.This is how it looks when it's done with a truck but it's no different with a car in most respects.
www.youtube.com/watch?v=9_9kZB5-MyM
Edited by XJ Flyer on Sunday 20th October 21:57
What are the advantages of sequential downcchanges for car road driving?
Sequential downshifts have the advantage of always being in the correct gear for the road speed therefore less load on the transmission together with the continuous engine braking and more control which you get as you go down the gears in close increments in addition to it usually being easier to match engine speed and road speed in the case of a downshift to a closer ratio than one big step in the case of a block change.In addition to that is the advantage that it's probably likely that the approach speed will be dropped to a lower level on entry than could be the case in someone just braking and then just putting it into whatever gear is required at the end.
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