[shapptastic]

I just had a DE event at Lime Rock, first time I had ever been there. I have done a few DE event prior to this, but this was the first time I felt like I might break my car because of my lousy driving skills. The first two turns on the track are two right turns. On my way back to the start of the track, there is a long straightaway. This is where I typically redline it in 3rd and shift to 4th. The problem I have is once I get to the point where I need to brake going into the first turn, I drive like I usually do on the road. This means braking with clutch in, slowing it down enough until I can put it in 3rd without needed to blip the throttle. My instructor told me to brake hard, then go clutch in --> 3rd -> clutch out quickly and everytime I did that I got the squeak of the synchros (mostly because I can't heel toe). In order to avoid completely ruining my clutch at my next event, anyone have any suggestions for either other ways to approach the turn(maybe downshift after the apex?) or is this a case of needing to learn and practice heel toe? As it is, I'm driving the track basically like an automatic (in 3rd the whole time). Any suggestions for ways to improve?

Thanks!

[DallasBoosted]

You need to learn to heel/toe or just brake early, then take your foot off the brake, blip the downshift then get on the gas in the corner.

Don't just drop the clutch in gear without rev matching, you'll lock up the rear tires.

[HP Autosport]

Originally Posted by shapptastic

I just had a DE event at Lime Rock, first time I had ever been there. I have done a few DE event prior to this, but this was the first time I felt like I might break my car because of my lousy driving skills. The first two turns on the track are two right turns. On my way back to the start of the track, there is a long straightaway. This is where I typically redline it in 3rd and shift to 4th. The problem I have is once I get to the point where I need to brake going into the first turn, I drive like I usually do on the road. This means braking with clutch in, slowing it down enough until I can put it in 3rd without needed to blip the throttle. My instructor told me to brake hard, then go clutch in --> 3rd -> clutch out quickly and everytime I did that I got the squeak of the synchros (mostly because I can't heel toe). In order to avoid completely ruining my clutch at my next event, anyone have any suggestions for either other ways to approach the turn(maybe downshift after the apex?) or is this a case of needing to learn and practice heel toe? As it is, I'm driving the track basically like an automatic (in 3rd the whole time). Any suggestions for ways to improve?

Thanks!

My question to you is do you heel toe properly? BMWs are setup in a way that when you 'heel toe' you aren't using your heel at all. The brake pedal sits up pretty high so even under extreme braking, unless you have an impossible foot, you can't rotate to use just your heel.

What you want to practice on the street is rev-match downshifting. To achieve this you want to do the follow: Have about half of your right foot on the brake and half of it hovering over the gas pedal...

1) Brake (which should bring the right side of your right foot very close to the gas pedal)
2) Depress clutch
3) Slip gear into neutral (when gear is in neutral, blip the throttle with the right side of your right foot, all while the left side of your right foot is continually depressing the brake)
HINT: The amount you 'blip' the throttle will depend on braking. The harder you are braking the less you have to blip because your RPMs will be dropping quickly. This is ALL about feeling your gear ratio and practicing.
4) Shift into lower gear
5) Release the clutch

So overall just practice on the streets. I ALWAYS rev-match downshift (unless there is a cop around). It is quite rewarding once you get the hang of it.

Let me know if you have any further questions.

-Mike

[paddy335]

What the previous guys said. There is no need to be rough on the clutch. The bulk of your braking should be done before you downshift.

Nice description of 335i-specific heel-toeing by HP Autosport. Maybe we should rename it 'ball of foot rolling'. Doesn't have much of a ring to it though. I always rev match whether on street or track, even when there ARE cops around

Racing shoes/boots aid heel-toeing, they are built up on the outside of the foot.

Off topic I know, but I'd also ask why you want to go to redline in third.....your way out of your optimal hp/trq point by redline in the 335i. It's just putting unnecessary strain on the engine for less gain than an upshift a bit earlier.

[3002 tii]

LRP is a really FAST track with not many hard braking zones. It's a true momentum track. Turns 1/2 are going to be your classic double apex and you should really trailbrake into that first turn. The only area I need to heel toe is the left hander from 4th to 3rd. But as others said, learn to heel toe on the street and I totally agree with Harold... BMW's pedal placement makes a little difficult to H/T. Consider looking at pedal extensions for the gas so you can hit both pedals at the same time. I also agree with Harold in that before you even get on the topic of H/T, are you properly revmatching on the street? That's the first step when doing H/T...

[IN54NITY]

Mike (that's not Harold!) is spot on. Do eeeet everyday going to work, getting milk, etc. Don't try on doing it quickly at first, that comes later, instead work on being smooth, and then really smooth, and smoother still! Warning, you'll be about as smooth as a 15 year old driving for the first time in driver's Ed. Do it long and well enough and you'll notice the difference a full tank of gas makes over even a 1/2 a tank with the difference in brake pressure required. (Extra credit: add double clutching, though it's not needed in our cars but still fun to do. I have it so engrained it's hard for me to single clutch.)

[will.c]

Yep, you gotta learn it. It's pretty essential in tracking a manual car. Otherwise you'll be slow, inconsistent, and more importantly, more prone to wear & tear and damage.

Another thing I noticed when I tracked my 335 was that I didn't get much faster by redlining. So I always short shifted around 5.5-6k, and it still pulled well b/c of low end torque. (AND it kept the temps lower, which is a delicate aspect of these motors.) As such, I didn't really feel the need to downshift in many of the turns. I mean, of course it depends on the track/corner, but saving half a sec on upshifting vs keeping in higher gear might be worth an experiment on corner-by-corner basis for these cars.

[CJ421]

Originally Posted by will.c

Another thing I noticed when I tracked my 335 was that I didn't get much faster by redlining. So I always short shifted around 5.5-6k, and it still pulled well b/c of low end torque. (AND it kept the temps lower, which is a delicate aspect of these motors.) As such, I didn't really feel the need to downshift in many of the turns. I mean, of course it depends on the track/corner, but saving half a sec on upshifting vs keeping in higher gear might be worth an experiment on corner-by-corner basis for these cars.

Agreed, I shift at 5-6k on track. The 335 runs out of steam 6k+.

If you can learn to heel-toe on the street, you can do it on track, where it's easier because the revs are higher.

Remember, perform your shift at the end of the braking zone just before you enter the turn. And if you're going down two gears, just skip the middle one e.g. 5 > 3.

[DallasBoosted]

Definitely shift at 5500-6000. If you're going to be in 4th long at all, shift lower, 5400-5500.

[macmacaman]

There is a sticky on optimal shift point, but there doesn't seem to be any agreement on methodology. Is there a way to go from torque-rpm curves to take into account gearing to figure out the optimal shift point? It seems like to me that you could go from the torque-rpm curve of a motor, apply the gearing to figure out torque at the wheels, and choose your shift points to optimize wheel torque.

Has anyone done this? Is there something that I am missing or not understanding?

[paddy335]

It's an incredibly subjective issue I suppose, because there are so many factors involved over and above hp and trq.

Best way is to try and measure different change points by experimenting with lap times. All other things being equal of course.

[macmacaman]

Originally Posted by paddy335

It's an incredibly subjective issue I suppose, because there are so many factors involved over and above hp and trq.

Best way is to try and measure different change points by experimenting with lap times. All other things being equal of course.

It seems to me that it should not be subjective. After all there's only one thing accelerating the car, and that's wheel torque. Or is there something about driving style that I am missing in this? Perhaps timing of the gear shifts and the lost torque while out of gear?

[The HACK]

Originally Posted by macmacaman

It seems to me that it should not be subjective. After all there's only one thing accelerating the car, and that's wheel torque. Or is there something about driving style that I am missing in this? Perhaps timing of the gear shifts and the lost torque while out of gear?

You're right that it shouldn't be subjective, but you're wrong that it's wheel torque that accelerates the car. It's actually torque X gearing multiplier.

This topic has been debated ad nauseum, with a ton of mis-information out there. The simple answer is, you want as much power delivered to the wheels for as long as possible. And most cars are designed to deliver the majority of their power at or near redline, and even on cars that see significant drop-off in power at or near redline, they're designed to deliver MORE power sooner in the next gear, or at least closer to peak power RPM, for longer, if you shift into the next gear at or close to redline.

So even if someone argues, well, the engine isn't making more power after, say, 5,800 RPM so there's no need to shift at 6,500 RPM? Wrong. There's plenty of good reason to shift at 6,500 RPM. One being the NEXT gear you will start closer to max power engine speed rather than trying to spool up that magical HP for another 800 RPM.

It's the area under the power curve through the gears that gives you the maximum acceleration.

Here's a good brain teaser for you. The 335D produces SIGNIFICANTLY more torque than the 335i. Yet is significantly slower to 60 mph and 1/4 mile. Think about that for a minute.

[SRanch335i]

slip on vans....essential

[paddy335]

Originally Posted by macmacaman

It seems to me that it should not be subjective. After all there's only one thing accelerating the car, and that's wheel torque. Or is there something about driving style that I am missing in this? Perhaps timing of the gear shifts and the lost torque while out of gear?

I am talking about all the other factors that may influence when you change gear: track condition and surface and temperature, tyre condition type and pressure, corner type, road camber, available traction, do you have a LSD or not, what kind of tune you have on your engine, where your peak trq and hp are - the list goes on and on and on....

Even in F1 it is subjective, just listen to drivers disagreeing with engineers about what the best way to drive a track is.

[will.c]

Originally Posted by paddy335

I am talking about all the other factors that may influence when you change gear: track condition and surface and temperature, tyre condition type and pressure, corner type, road camber, available traction, do you have a LSD or not, what kind of tune you have on your engine, where your peak trq and hp are - the list goes on and on and on....

Even in F1 it is subjective, just listen to drivers disagreeing with engineers about what the best way to drive a track is.

Agreed.

All the gearing, torque curve, and misc details are more relevant to drag racing or straight line acceleration. I mean, it's definitely good to know the technical stuff and all, but what it really comes down to at a road course is simply what makes quicker lap times.

For just one example out of millions, a driver may choose to short shift into next gear on a particular sweeping "straight" because the higher gear's lower wheel torque helps the driver to maintain stability under full throttle, where as keeping in the lower gear might be more prone to upsetting the vehicle dynamic from minor throttle adjustments. Now if it's Ayrton Senna who can be perfect with the throttle at any given point in that particular sweep, perhaps lower gear is faster for him.

There are sooo many intangible factors, including driving skill, in determining what's faster for that person in that car for that corner on that weather condition, etc. that the driver simply has to try different things and conclude it from lap times & data.

For me, cooling issues, less wear on the engine, and insignificant lap time differences led me to short shift at 5.5-6k. But obviously I'm not so hardcore as to conduct a study on this, so maybe my entire experience is insignificant.

[macmacaman]

I think I may have had a misunderstanding about terminology. When I wrote wheel torque, I thought that meant the torque x gearing = torque applied to the drive wheels (torque transmitted into the tires). From what you wrote, it seems that wheel torque is not torque at the drive wheels, but torque at the FLYWHEEL. Is this correct? Not being an automotive engineer, I think I got a little confused about the terminology.

I understand your point about wanting your next shift to be in the area of the torque/power output curve nearest max power. What is a little confusing to me is that because of the gearing, isn't first gear pretty much always delivering more torque (at the tires) than second gear under all parts of the curve?

Originally Posted by The HACK

You're right that it shouldn't be subjective, but you're wrong that it's wheel torque that accelerates the car. It's actually torque X gearing multiplier.

This topic has been debated ad nauseum, with a ton of mis-information out there. The simple answer is, you want as much power delivered to the wheels for as long as possible. And most cars are designed to deliver the majority of their power at or near redline, and even on cars that see significant drop-off in power at or near redline, they're designed to deliver MORE power sooner in the next gear, or at least closer to peak power RPM, for longer, if you shift into the next gear at or close to redline.

So even if someone argues, well, the engine isn't making more power after, say, 5,800 RPM so there's no need to shift at 6,500 RPM? Wrong. There's plenty of good reason to shift at 6,500 RPM. One being the NEXT gear you will start closer to max power engine speed rather than trying to spool up that magical HP for another 800 RPM.

It's the area under the power curve through the gears that gives you the maximum acceleration.

Here's a good brain teaser for you. The 335D produces SIGNIFICANTLY more torque than the 335i. Yet is significantly slower to 60 mph and 1/4 mile. Think about that for a minute.

[M3E46M]

Originally Posted by HP Autosport

My question to you is do you heel toe properly? BMWs are setup in a way that when you 'heel toe' you aren't using your heel at all. The brake pedal sits up pretty high so even under extreme braking, unless you have an impossible foot, you can't rotate to use just your heel.

What you want to practice on the street is rev-match downshifting. To achieve this you want to do the follow: Have about half of your right foot on the brake and half of it hovering over the gas pedal...

1) Brake (which should bring the right side of your right foot very close to the gas pedal)
2) Depress clutch
3) Slip gear into neutral (when gear is in neutral, blip the throttle with the right side of your right foot, all while the left side of your right foot is continually depressing the brake)
HINT: The amount you 'blip' the throttle will depend on braking. The harder you are braking the less you have to blip because your RPMs will be dropping quickly. This is ALL about feeling your gear ratio and practicing.
4) Shift into lower gear
5) Release the clutch

So overall just practice on the streets. I ALWAYS rev-match downshift (unless there is a cop around). It is quite rewarding once you get the hang of it.

Let me know if you have any further questions.

-Mike

Pretty much dead on IMO. If you brake very hard you don't even need to blip the throttle at all. Here is what I'm talking about:

Brake late, less foot work ,less steering input = faster lap as long as you get all corner entries/exit correct.

[HP Autosport]

Originally Posted by labedra

Pretty much dead on IMO. If you brake very hard you don't even need to blip the throttle at all. Here is what I'm talking about:

Brake late, less foot work ,less steering input = faster lap as long as you get all corner entries/exit correct.

Thanks for the agreement. And BTW, that guys driving technique scares me a little bit... He dove every corner when the driver on the outside would like to apex. I wouldn't be a happy camper if he was on the track with me.

-Mike

[Meeni]

Your instructor is right, follow his advice. Also, do the same on the Road, you should never stay in neutral, ever.