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Revs / Power Bands, Etc


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#16 Ronnie Nilsson

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Posted Aug 31 2015 - 10:50 AM

Sorry John, I probably didn't explain fully.  Both 2nd and 3rd were maxing out too early, hence I gave both more leg room. :)

#17 Pete Gaimari

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Posted Aug 31 2015 - 11:02 AM

View Posttwinpotter, on Aug 31 2015 - 09:57 AM, said:

Sorry for been a heathen here. Don't know how to explain this and wether its relevant but here goes.
Firstly when changing up a gear how far away can you be from the redline in that particular gear and still achieve a smooth change without lifting off throttle. I believe if you change too quickly without lifting off you can damage engine as well as going too far into redline for a long period?
I say this and this is the bit that maybe not relevant but in a modern F1 racing sim with modern gearbox and flip gear change on steer wheel I read a bit about this games set up tips. Sorry forgot game title.
But the basic statement if I remember was obviously set your top gear so you hit top end of that on the longest straight before corner. Also when going through gears it is better to not change right at top by redline but a fraction or so before as hitting powerband bang on Will give you bigger drop off especially going to next gear. In other words you can keep a smooth momentum and optimize your speed,performance and track time?

TP:

Shifting the Lotus 49 in GPL is not like shifting modern cars in other same with paddle shifts. Those are taken full throttle, because they have a throttle cut on them.

In GPL we need to lift for shifts. At least you should be. If you bring the rpm to 9000 it will never go past that for a shift. The tel-tale red needle shows that. As a matter of fact the red needle will tell you if you screwed up during a race. The goal after a race is to have the red needle right on 9000rpm. Then you know all your upshifts and downshifts were correct for the whole race. You might have short shifted, but you never exceeded red line.

#18 twinpotter

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Posted Aug 31 2015 - 11:28 AM

I first played gpl and always went right up to max range in each gear.But realized you can still change slightly before that without lifting,but if you change too early without lifting you get the engine squeal/scream and endanger you blowing the motor.
So on any track are you trying to go to full max range in all gears on any part of the track.Is that impossible and not feasible or is it better to drop of revs at times(depend on track/straight/corner) to adjust gear change so you are finding the correct gear and traction for the situation you are in?

TP:

#19 Pete Gaimari

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Posted Aug 31 2015 - 11:49 AM

I short shift maybe 4-5 times on all the 11 original tracks. That's 4-5 times for all the tracks. It's usually always to get the power down quicker. As an example. Going into the 2nd Lesmo at Monza. Just as I hit the apex I shift from 2nd to 3rd so I can come off the turn at full throttle. if you do it right it will show in faster lap times. At Monza again i'll short shift up to 3rd half way through Parabolica to get the power down.

When you hold full throttle for your shifts that's speed shifting. Even though you're doing it before redline. I could never do that. It's unrealistic, and couldn't be done in the real car. It sounds horrible too. Lift, use the clutch, and shift. Much better, and how it was done in 67. Unless you had a huge supply of transmissions, and didn't mind breaking all the time. :)

#20 John Woods

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Posted Aug 31 2015 - 02:10 PM

Everything that follows is a question and a guess:
:)

A car does not have to be at full throttle to be enjoying maximum acceleration on/within the power band?
It is possible to short shift and speed shift, (not letting off), if engine is not taken to max RPM?
(Mid/high RPM speedshifts).

Not sure, (forget, been too long), isn't the default shift time .22sec?
So five extra (theoretically unnecessary) shifts at the Ring = 1+ seconds of lap time, no matter what technique?

Speedshifting isn't faster because of shift technique being quicker, (because same time is added no matter how fast the shift), but rather because of less loss of momentum (perhaps) and more time in the higher gear = more top end on down the road?

Speedshifting even without realistic mode will break a car if RPM drop is too much.
Anything over 800rpm is dangerous, but not always a disaster.
A speedshift with a 1400rpm drop will probably twist something up instantly.

An 800rpm drop means wasting a lot of time in the lower gears.
Lower gears need to take big leaps forward.
They need to be as tall/long as possible.

Speedshifting only slows things down in lower gears, as all that is happening is lots of high RPM shifting going nowhere fast. In lower gears, the idea is to make the most use of the full range of each gear and, more importantly, get to the next higher gear as quickly as possible. In other words, upshift into the bottom of the next gear's power range.

A transmission geared for 1000rpm drops can be short-shifted up to the bottom of the next gear's power band without reaching max RPM first and average lap time will improve because the car will reach a higher top speed before braking due to being in a higher gear a longer time. More distance will be covered at the end than any time lost at the start.

Just my theory, based on the "laws of marginal returns," the fastest average lap is the result of accelerating in the highest possible gear from the bottom to the top of its 90 percent max power range more of the time than not, and has not a lot to do with speedshifting.

Speedshifting works, if at all, when shifting in higher gears, (3rd/4th or 4th/5th with Lotus). If geared properly, (not too little RPM drop/not too much), you will feel the car make a little jump forward that does not happen when not speedshifting.

My theory is this force is being transferred from the lateral clutch, because it seems the effect is more pronounced when the shift occurs during a flatout turn, like when going from 4th to 5th on the outside at Ascari.

Wuhooo!

There's an unbelievably long thread around here about shifting.
:D

Edited by John Woods, Aug 31 2015 - 02:23 PM.


#21 Pete Gaimari

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Posted Aug 31 2015 - 03:15 PM

Speedshifting is wrong in so many ways in a sim. It's great in games. :P

#22 John Woods

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Posted Aug 31 2015 - 05:26 PM

From page 22 of Steve Smith's Four Wheel Drift:

"To Clutch or Not to Clutch:

The use of a clutch is new to auto racing sims, although most experienced players probably won’t recognize its absence as an aid (although I guess you could think of its presence as a “reality enhancement”).
Thirty years ago, a driver only needed the clutch at the start of a race, to get under way, after which a “crashbox” (a manual transmission without synchromesh) could be shifted all race long by just matching the engine speed to the speed of the gears (easier than it sounds)."

#23 Pete Gaimari

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Posted Aug 31 2015 - 06:17 PM

Not true. You forget i'm from that era.

Just one example.

https://www.youtube....h?v=JJDkZYhJR1E




Clutch, or no clutch they didn't speedshift as the term is used in GPL. Which means full throttle shifts.

Edited by Pete Gaimari, Aug 31 2015 - 06:21 PM.


#24 Pete Gaimari

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Posted Aug 31 2015 - 07:34 PM

A post by the son of the present owner of  the R2 Lotus 49. The same one I posted a video in another thread.





My Father owns the car now. This is chassis R2/11, which was Jim Clark's car for the Dutch Grand Prix in 1967. It was the car's first race, and Clark's first time racing the car (he hadn't even driven it before the race weekend), and he blew everyone else out of the water. An incredibly important part of Formula 1 history as this was the first F1 car to use the engine as a stressed chassis member. It was also the first race car to have sponsorship/sponsorship colors.
I wish Road and Track would have picked a driver who had ANY experience using an H pattern box, because according to R&T, Rossi has literally none. The ZF box that the 49 uses is very delicate and prone to breaking. It broke on my dad at the Historic Monaco Grand Prix twice. The key is to pause between coming out of gear and selecting the next gear.
<a class="expand" style="color: rgb(51, 102, 153); margin-right: 3px; padding: 1px;">[–]Ayrton Sennamattverso 6 points 2 years ago



Changing gear properly in that car would require significant use of the double-declutch and heel-and-toe techniques. Clutch in to shift to neutral, clutch out, back in, select gear, out again, while matching revs with your toe and braking with your heel.
It is the opposite of easy. It's also why most drivers these days have no idea how hard it used to be. I've wrecked the gearbox of more than one modern car trying to learn the techniques and I still haven't got it down. I can only imagine how short a time a classic Lotus's gearbox would last if you didn't know exactly what you were doing

Edited by Pete Gaimari, Aug 31 2015 - 07:35 PM.


#25 John Woods

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Posted Sep 01 2015 - 07:43 AM

From Road & Track magazine website:
(article on history of Hewland)

At Lola's request, Hewland modified a VW Beetle's magnesium-case four-speed for strength and service. It also provided for a custom dog-clutch (read: unsynchronized) geartrain. The result was a five-speed manual that let you blitz through shifts without the clutch and allowed for complete ratio swaps in 20 minutes.

From sdt.com:

For a manual car the best method of acceleration is to rev to or just beyond peak power in the gear before up-shifting. After the change the engine will be right on, or just below, the point at which it develops maximum torque. By red-lining each gear the engine sounds like its making extra power but really you are only putting excessive stress on all engine component, wasting fuel and making noise.

Lewis Hamilton on the 2014 car, from BBC

"This year, the torque is much lower in the rev band and there is so much more of it. We also have a lot less downforce.

That means we use the engines very differently - we rev them much less, and we change gears much sooner, so at the same point on the track we're often in a higher gear than last year.

This is called short-shifting, and it allows you better control of the torque of the engine.

If we had as much downforce as last year, we would not have to short-shift as much. But we have lost a lot of grip, especially at the rear, with the restrictions on aerodynamics.

It's really difficult to put into words exactly how you judge when you need to short-shift, because it's all done on feel."

Edited by John Woods, Sep 01 2015 - 07:57 AM.


#26 Pete Gaimari

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Posted Sep 01 2015 - 08:44 AM

John...The Lotus 49 didn't use a Hewland. It had a syncro ZF tranny. Not a dog ring tranny. It needed the clutch for smooth shifting. It was also a sequential tranny that couldn't skip gears on downshifting. Hill hated that, because he was used to skipping gears going into a turn. Jim never complained about it. :)

Lets keep to 67 F1 cars, and the era they were driven. What Hamilton does in a modern F1 car is not relevant to this conversation.

#27 Fat Rich

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Posted Sep 01 2015 - 11:02 AM

Steve Smith's Four Wheel Drift was a good read and a very nice addition to the game, but there's some stuff in it that I don't agree with... and some stuff that Lee's explanations of how GPL's physics code actually works suggest Steve Smith wasn't in possession of the full facts at the time of writing. As for clutches, people made a big fuss that Jim Clark won the '67 Mexican Grand Prix despite his clutch breaking early in the race, drivers could change gear without it but it wasn't something they chose to do.

Personally I often short shift the Lotus 49 as it sometimes has more torque than it has grip, I usually avoid 1st gear completely except for the start of the race, apart from the hairpins at Monaco or similar. Generally I short shift 2nd to 3rd, but hardly ever above that. I always try to avoid "speed shifting" (or flat shifting) although sometimes I miss-time my shift and do it by accident. Although shifting takes approx 0.2 of a second, it's not adding 0.2 of a second per shift to your laptimes.... it would only do that if the car was suddenly totally stationary for each of those 0.2s ;) Let's say you shift up to top gear while doing 145mph, while the clutch is in you'll only slow down fractionally due to wind and rolling resistance.

Edited by Fat Rich, Sep 01 2015 - 11:04 AM.


#28 John Woods

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Posted Sep 01 2015 - 11:54 AM

Some may recall BRR's test at Reims yielded an average point-5 second slower lap time when on the .22 shift delay than when deleting it for purpose of test. So shift-time delay does effect lap time, but not 1:1?
This is the reason for Fairshift?

Pete, just guessing, Hamilton's comments about low end torque and short shifting would apply to any era?

This thread, reading the first post as literally as possible, does not limit the discussion to the Lotus 49 or the 67 season.

Did all 60s era F1 cars use the synchro'd sequential ZF?

Find lots of references to shifting race cars without the clutch, as Steve Smith notes, enough to assume it was very common going all the way back.

Powershifting and speedshifting at the same time, while not possible in Grand Prix Legends without using GPL Shift, seems theoretically possible, or just stupid fun, in "real life."

Like to try it someday with an old VW on snow.

Edited by John Woods, Sep 01 2015 - 12:08 PM.


#29 Pete Gaimari

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Posted Sep 01 2015 - 12:50 PM

Read the last sentence in the first post John.

#30 John Woods

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Posted Sep 01 2015 - 02:29 PM

View PostRonnie Nilsson, on Aug 30 2015 - 01:21 PM, said:


principally


So he didn't specifically exclude an old VW on snow.
:)




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