Discussion
Depends where and how you're driving!
For normal roads you shouldn't need to, I rarely do. However, my style is that of IAM and I don't use every gear on the way down, just match the revs carefully and take time over the change ("onethousandone-onethousandtwo") to smoothly ease it in.
On a bike gearbox, for example, I've found it always necessary to select a gear with the revs dropping though.
For normal roads you shouldn't need to, I rarely do. However, my style is that of IAM and I don't use every gear on the way down, just match the revs carefully and take time over the change ("onethousandone-onethousandtwo") to smoothly ease it in.
On a bike gearbox, for example, I've found it always necessary to select a gear with the revs dropping though.
It's always wise to match the revs, if you are tanking it, otherwise you can end up just braking with the rears. This will have the same effect as just pulling on the handbrake. 
I do it as a matter of course, but more because I learnt to drive on a car with a crash box and no syncromesh.
The only time that I really notice the need in everyday driving is when approaching something like a roundabout and you are braking on a curving approach.
If you it a patch of diesel in the wet at the point of change you can be glad that you weren't doing any engine braking.
Years ago I exited a large roundabout coasting backwards at 20mph due to this. lesson learnt. The look on the face of the chap following was priceless as I executed an unwanted but gracefull 180, coasted off the junction backwards, indicated and turned off into a sideroad. I couldn't have executed such an impressive manouvre if I'd practiced for a thousand years.
An extra benefit to doing this is the fact that you soon learn to change gear without having to use the clutch which I do a lot of the time due to a grim knee injury.
>> Edited by Horse_Apple on Monday 5th July 10:01
I do it as a matter of course, but more because I learnt to drive on a car with a crash box and no syncromesh.
The only time that I really notice the need in everyday driving is when approaching something like a roundabout and you are braking on a curving approach.
If you it a patch of diesel in the wet at the point of change you can be glad that you weren't doing any engine braking.
Years ago I exited a large roundabout coasting backwards at 20mph due to this.
lesson learnt. The look on the face of the chap following was priceless as I executed an unwanted but gracefull 180, coasted off the junction backwards, indicated and turned off into a sideroad. I couldn't have executed such an impressive manouvre if I'd practiced for a thousand years. An extra benefit to doing this is the fact that you soon learn to change gear without having to use the clutch which I do a lot of the time due to a grim knee injury.
>> Edited by Horse_Apple on Monday 5th July 10:01
engine braking in a powerful (and light) RWD car can cause the rear wheels to momentarily lock up (or rapidily slow).
This is due to the engine braking power being able to overcome the traction of the road surface.
Two ways out of this are;
1. "Heel and toe" to blip the throttle on change downs whilst braking. Builds the revs of the engine up to match the wheel revs and prevent the sudden change which cause loss of traction.
2. Dont engine brake. Use the brakes only coming into a corner. When to select the correct exiting gear and de-clutch is something that Im still learning though so I combine this with heel and toe at present.
If you ever go to any GT races (or other RWD racing) stand near the end of a long straight coming into a tight corner. At the braking point you wont often hear any of the cars change down. They'll just apply the brakes. You may then hear a change down just before the corner or, if the driver as the car in exiting gear ready, you'll hear no change down at all.
This is due to the engine braking power being able to overcome the traction of the road surface.
Two ways out of this are;
1. "Heel and toe" to blip the throttle on change downs whilst braking. Builds the revs of the engine up to match the wheel revs and prevent the sudden change which cause loss of traction.
2. Dont engine brake. Use the brakes only coming into a corner. When to select the correct exiting gear and de-clutch is something that Im still learning though so I combine this with heel and toe at present.
If you ever go to any GT races (or other RWD racing) stand near the end of a long straight coming into a tight corner. At the braking point you wont often hear any of the cars change down. They'll just apply the brakes. You may then hear a change down just before the corner or, if the driver as the car in exiting gear ready, you'll hear no change down at all.
I always use the heel and toe technique when changing down through the box as it make for much smoother progress. I read about the possible locking of rear wheels in the Griff Bible but it wasn't until I went onto the track that I found out just how much of an effect it can have!
I spun when going from 4th to 2nd and not matching the revs and it was caused purely because the rear wheels locked up and made the car swap ends in no time at all. S
t me right up it did!
I've now been taught to use the heel and toe technique and by matching the revs before engaging the clutch on downshifts, you''ll be able to balance the car much better for faster cornering!!
Cheers - Chris
I spun when going from 4th to 2nd and not matching the revs and it was caused purely because the rear wheels locked up and made the car swap ends in no time at all. S
t me right up it did! I've now been taught to use the heel and toe technique and by matching the revs before engaging the clutch on downshifts, you''ll be able to balance the car much better for faster cornering!!
Cheers - Chris
Blipping on downshift is a good practice to get into, and as has been said in a powerful car like the Griff you can easily swap-ends.
I can't talk from experience of the Griff (pick mine up in a week, and only driven one for 1/2 hour or so), but in my current car I do it out of habbit.
Even in a less powerful car that the wheels won't lock up, you are putting stress on the engine mountings (then engine will rock back-and-forth under the sudden stress). It's just nicer on the engine generally, plus it sounds great
Also, probably not as important in a Griff due to the low-down torque, but for example in my current Japanese car, when overtaking I have to change down to overtake to get into the power band. A blip whilst changing down ensures you don't lose speed due to engine-braking before getting on the power.
Heel-and-toe is the next step, but my current car doesn't afford the space for my size 12's to do this. Hopefully the Griff will!
I can't talk from experience of the Griff (pick mine up in a week, and only driven one for 1/2 hour or so), but in my current car I do it out of habbit.
Even in a less powerful car that the wheels won't lock up, you are putting stress on the engine mountings (then engine will rock back-and-forth under the sudden stress). It's just nicer on the engine generally, plus it sounds great
Also, probably not as important in a Griff due to the low-down torque, but for example in my current Japanese car, when overtaking I have to change down to overtake to get into the power band. A blip whilst changing down ensures you don't lose speed due to engine-braking before getting on the power.
Heel-and-toe is the next step, but my current car doesn't afford the space for my size 12's to do this. Hopefully the Griff will!
Agreed - always always always match revs on a downshift in your TVR. In ideal conditions when you are driving gently you will be fine without it, but unless it is second nature you won't do it under pressure when it matters the most. The rear wheel slide that occurs when you needed to match revs and didn't, is one of the hardest situations to recover from and for most people is basically not recoverable.
gingerprince said:
Heel-and-toe is the next step, but my current car doesn't afford the space for my size 12's to do this. Hopefully the Griff will!
Don't count on it - having adjusted the brake pedal right down and the accelerator right up, I still can't flick the accelerator whilst braking. Seperate braking/blipping it has to be...]
Some (obviously) manage to get their pedals set OK for heel and toe though, I just assume my feet are too big.
Does anyone actually do a full double de-clutch while heal and toeing? i.e. Pausing momentarily in neutral and letting the clutch up while blipping the revs.
I've always thought this was the proper way to do it so that you spin the layshaft in the gearbox up to speed. However a friend recently told me that he just blipped the throttle with the clutch depressed.
I do it all the time so I'm pretty quick at it but it must be quicker to do it the easy way.
Ian A.
I've always thought this was the proper way to do it so that you spin the layshaft in the gearbox up to speed. However a friend recently told me that he just blipped the throttle with the clutch depressed.
I do it all the time so I'm pretty quick at it but it must be quicker to do it the easy way.
Ian A.
That double de-clutch thing is a waste of time in my opinion. Admittedly I don't know exactly what benefit it has over heel and toeing regarding saving wear and tear on components etc etc. All I know is it's a lot of hassle!
This caused a bit of an argument once between me and the missus, who incidentally works for the police and has completed their 3 week driving course enabling her to drive the car in an emergency. During the course, she was taught that in an 'emergency', the quickest and safest way to approach corners is to use the engine to slow the car down (no touching the brakes), double de-clutch before the corner and then you can go round it as quickly as possible.
I told her when she was on the course that I didn't think that was the quickest way to get somewhere, why not use the brakes for example? So I told her to ask her instructor about using the heel and toe technique. Apparently he said that it was not the safest thing to do on the road and was more suited for the race track!
Personally I still think it's a load of rubbish!
This caused a bit of an argument once between me and the missus, who incidentally works for the police and has completed their 3 week driving course enabling her to drive the car in an emergency. During the course, she was taught that in an 'emergency', the quickest and safest way to approach corners is to use the engine to slow the car down (no touching the brakes), double de-clutch before the corner and then you can go round it as quickly as possible.
I told her when she was on the course that I didn't think that was the quickest way to get somewhere, why not use the brakes for example? So I told her to ask her instructor about using the heel and toe technique. Apparently he said that it was not the safest thing to do on the road and was more suited for the race track!
Personally I still think it's a load of rubbish!
IPAddis said:Ian, if you are lookibg to rev match then do it whilst the clutch is depressed, you don't need to spin the gears, if you are double-declutching then ye syou need to momentarily engage the clutch to spin the cogs. Rich...
I've always thought this was the proper way to do it so that you spin the layshaft in the gearbox up to speed. However a friend recently told me that he just blipped the throttle with the clutch depressed.
All very confusing this, but I for one will certainly be trying to learn the heel & toe method after experiencing a couple of tail waggling downshift brown adrenalin moments about a foot and a half from the wall at Rockingham :gulp:
Do I need to adjust my peddles? If so...what should I be aiming for?
Do I need to adjust my peddles? If so...what should I be aiming for?
catretriever said:
Do I need to adjust my peddles? If so...what should I be aiming for?
Whatever is comforatable for you.
I have truned my brake peddle up side down so it is closer to the throttle pedal. I have also adjusted the brake pedal out so when it is pressed its just a bit further in then the throttle.
All this means I can almost roll my foot on to the throttle but still need to angle it a bit.
No engine braking otherwise the TVR police will come and confiscate your car. Probably one of the biggest reasons for write offs I'm afraid.
Even if you get away with it, a clutch is about 10-15 times as expensive to replace than brake pads.
Heel and toe is fine for the road. You don't have to be on the track to practice it. You don't have to be going fast either.
What is allows racing drivers to do is to trail brake where the braking phase overlaps the acceleration phase so that there is no distinct periods. It all blends (or should) into a very smooth and fast cornering technique with the car balanced. The braking distence is shortened, the power applied earlier and helps overcome understeer. Get it wrong though and it can be a bit messy.
Big discussion in the bible on this and other techniques.
Steve
www.tvrbooks.co.uk
Even if you get away with it, a clutch is about 10-15 times as expensive to replace than brake pads.
Heel and toe is fine for the road. You don't have to be on the track to practice it. You don't have to be going fast either.
What is allows racing drivers to do is to trail brake where the braking phase overlaps the acceleration phase so that there is no distinct periods. It all blends (or should) into a very smooth and fast cornering technique with the car balanced. The braking distence is shortened, the power applied earlier and helps overcome understeer. Get it wrong though and it can be a bit messy.
Big discussion in the bible on this and other techniques.
Steve
www.tvrbooks.co.uk
shpub said:
No engine braking otherwise the TVR police will come and confiscate your car. Probably one of the biggest reasons for write offs I'm afraid.
I'm going to stick my neck out and say that Steve comments need some clarification
I think the comment engine braking here relates to taking your foot right off the throttle at reasonably high revs. That does feel very much like whacking the handbrake on (or would do if Tiv handbrakes were any good
) Obviously an unwise thing to do in slippery conditions. More subtle engine braking is not something to be afraid of and indeed lifting off the throttle in a controlled way is exactly what some situations require. As with all these things it's down to subtlety and finesse so that you don't upset the balance of the car.
I'd say the same of downchanging and as Beano (I think) said earlier - if you ease the change in gradually you will not unsettle the car; hence no absolute requirement for heel and toe.
Just my 2p!
Lifting off is fine and is not engine braking. Use it a lot BTW. The engine speeds drop naturally so there is no mismatch. When the brakes are applied they take the brunt of the forces involved.
No problem except in a lot of cases it is not enough and brakes and gears are needed to prepare the car for a corner or something else.
Doing it gently will work in many cases but the engine braking is very vicious and there will be a time when the surface is slippery or the driver is under pressure where it goes wrong and the car becomes another insurance statistic.
It is a not worth the risk and once H&T is mastered it becomes automatic. My advice is if you drive a TVR, learn H&T before it is too late.
>> Edited by shpub on Monday 5th July 15:09
No problem except in a lot of cases it is not enough and brakes and gears are needed to prepare the car for a corner or something else.
Doing it gently will work in many cases but the engine braking is very vicious and there will be a time when the surface is slippery or the driver is under pressure where it goes wrong and the car becomes another insurance statistic.
It is a not worth the risk and once H&T is mastered it becomes automatic. My advice is if you drive a TVR, learn H&T before it is too late.
>> Edited by shpub on Monday 5th July 15:09
Lifting your foot off the throttle is not what sh is talking about. Its about changing down through the gears to slow the car down.
When you change down a gear with out adding gas you are asking the rear wheels slow down rather a lot.
In an underpowered car the power of the traction on the wheels is greater than the power the engine has so the wheels are forced to gradually slow down.
Due to the fact that you have heaps of torque under the bonnet the car is powerful enough to brake the traction of the rubber/tarmc and slow the wheels quicker than you actually want.
ie: the wheels will be going at a different speed to the tarmac, in otherwords...skid!
If you dont believe it then try it! I have doen it in a safe area so i can see what it feels like incase it ever catches me out.
I have also accidentilly done it but fortunately it was all under control.
I have recently driven other high powered cars it which this happens too, but more of that later (and in a different thread).
When you change down a gear with out adding gas you are asking the rear wheels slow down rather a lot.
In an underpowered car the power of the traction on the wheels is greater than the power the engine has so the wheels are forced to gradually slow down.
Due to the fact that you have heaps of torque under the bonnet the car is powerful enough to brake the traction of the rubber/tarmc and slow the wheels quicker than you actually want.
ie: the wheels will be going at a different speed to the tarmac, in otherwords...skid!
If you dont believe it then try it! I have doen it in a safe area so i can see what it feels like incase it ever catches me out.
I have also accidentilly done it but fortunately it was all under control.
I have recently driven other high powered cars it which this happens too, but more of that later (and in a different thread).
that was almost stereo 
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