Optimal speed/rpm to change gear?

[chirag1988]

Hi guys, as the Z is my first high performance car, I wanted to ask some advice as to when is the best time to change gear when driving normally (i.e. around town, or just local).

 

I've been used to the norm of 2nd as soon as you start moving, 3rd when you hit 20mph, 4th when you hit 30mph, 5th at 40mph and 6th at 50mph.

 

Is this the norm with these cars or is there a more efficient way of driving?

[Ekona]

To save fuel? Change up around 2500.

 

For fun? Change up a fraction before you nudge the limiter.

 

Your current method is probably about as close as you'll get if you just want to save fuel, it's not much fun though!

[Commander]

To save fuel? Change up around 2500.

 

For fun? Change up a fraction before you nudge the limiter.

 

Your current method is probably about as close as you'll get if you just want to save fuel, it's not much fun though!

 

+1

[maddog1982]

I change gear when the bird says were going a bit quick arnt we? I like to change 4k upwards as I cant hear what shes saying after this point

[cs2000]

I tend to shift below 3.5k rpm when im just "driving", I actually have my shift indicator set at 3,500. Sky's the limit when im not however (just don't let the limiter kick in.)

[chirag1988]

Thanks guys - fuel saving is when i'm just popping down the road, but definitely let it rip when I see open road in front of me

[JetSet]

Between 2.5 and 3k, even using just 3k you'll out accelerate most things. On the Wales run I was using 4.5k and rarely getting above 4th gear but at the end of the weekend my overall long term economy had actually gone up 0.1 mpg (according to the computer)

 

 

Pete

[Stutopia]

Is bouncing off the limiter a big no no? Not that I do it, I'm just curious to learn what exactly happens when you do, and why it's bad.

[GMballistic]

Is bouncing off the limiter a big no no? Not that I do it, I'm just curious to learn what exactly happens when you do, and why it's bad.

It's there I believe to stop you over revving the engine and if you hit the limiter once or twice (accidentally) I wouldn't have thought it would do a lot of harm although it isn't really doing you any good either.

Every car has a peak power level at specific rpm so any higher rpm and your not gaining anything as the power curve drop's off. All imo ~ correct me if I'm wrong.

[Floydbax]

IMO hitting the limiter regularly will not harm the engine if it is well maintained. Nissan set it there for obvious reasons, it is possible to remove the limiter and get a few more revs out of the engine probably without doing any damage (again - if the engine is well maintained).

[Tricky-Ricky]

I have always driven using the engine tone to guide me, mind you I have been riding and driving for a long time,

If driving for economy to me its a case of matching the speed I want to maintain with a reasonable RPM without laboring or over reving the engine, and the engine note and feel tells me when to change gear,

similar for making quicker progress, but hanging on to each gear until the engine reaches its peak torque in each gear, no point in taking it to the red-line if its already on the downward slope of the torque curve

Edited December 19, 2013 by Tricky-Ricky

[Stutopia]

Interesting. I can appreciate it's to protect the engine and, as you say Tricky Ricky, if peak power/torque has been achieved then it makes perfect sense to shift up - as you're on a hiding to nothing. Anyone know if it is a soft (computer controlled) or hard (mechanical gizmo) limit? I'm guessing if it can be removed then it's an ECU setting (so soft). If it's mechanical I'd love to know how it works.

 

Everyday is a school day.

[Tricky-Ricky]

The limiter is electronic and can be removed using Up-rev software, its a soft cut also, there is no point removing the limit unless the engine is being tuned IE lumpy cams which will push the power band further up the RPM range.

[Spatt]

What is the peak performance rpm for shifting then? Seams to pull and pull to me but then ive gone from a 1.1 to this haha

[GMballistic]

What is the peak performance rpm for shifting then? Seams to pull and pull to me but then ive gone from a 1.1 to this haha

Haven't you spotted the shift light yet then in the 350?

 

 

Mine is set up at the factory setting for a DE engine still of 6600rpm as the one above.

[Ekona]

What is the peak performance rpm for shifting then? Seams to pull and pull to me but then ive gone from a 1.1 to this haha

As close to the limiter as you can get.

[cs2000]

Peak performance (in terms of torque) from my searching in a Rev-Up is 4,800RPM and 4,700 in a DE car.

 

But, kind of what Dan says, peak performance (in terms of speed) would be 1RPM away from the limiter!

[Spatt]

Riiight... yeah I had it in my head when you see these torque graphs that after the drop off you should shift but it seams to still pull away nice after. I do some gt5 (ps3) online so often wondered if shifting early makes more speed but it doesnt really. And yeah I've seen the shift light but never at max throttle. .. still scares the '@#$ outa me. I still dont know what my car will feel like dropping the clutch in first to take off or what a full throttle gear change feels like

[GMballistic]

Riiight... yeah I had it in my head when you see these torque graphs that after the drop off you should shift but it seams to still pull away nice after. I do some gt5 (ps3) online so often wondered if shifting early makes more speed but it doesnt really. And yeah I've seen the shift light but never at max throttle. .. still scares the '@#$ outa me. I still dont know what my car will feel like dropping the clutch in first to take off or what a full throttle gear change feels like

Something like this;

 

[Spatt]

Hahaha. Nice one I cant wait

[GMballistic]

Hahaha. Nice one I cant wait

Must be insane going straight from a 1.1 to the Zeds 3.5L.

 

Be careful out there & have fun Spatt.

[Tricky-Ricky]

I am not saying that there is anything wrong with holding onto gears until the red-line if the engine is still pulling hard, as momentum starts to play a part in things once you get the speed up, and on a track its almost imperative,

but on the road your not looking for ultimate speed, so ragging the engine in the lower gears will not always make for the rapid progress your after,

it really depends on how well the gear ratios are matched to the engines torque/power, as the old saying goes BHP is how fast you go and torque is how quickly you get there,

holding onto RPMs to the red-line will certainly make for abysmal MPG though.

[AMT]

Spose' it depends on how you like to drive, if its you're first performance car you might find the Zeds quite torquey. You're ears might tell you to change sooner than you need. I often find, even when going to overtake etc I only head up to 5 and end up changing. It doesn't always or mostly need the full whack. (7.5 on my HR). As EKona said though, normal 'fuel conserving' driving 2.5 and the Zed can change up from any gear at low speeds too with the torque.

Edited December 20, 2013 by AMT

[Chromatic]

TLDR at bottom

 

Interesting topic..

 

There isn't any Hard and fast (Shift at X rpm in 1st, Y rpm in 2nd, and so on..) rule for this car. For a few reasons..

 

1) The DE is a different beast than the HR.. Shift points are going to vary due to the HP/Torque bands in both.. In an HR you will generally want to shift at a higher point than a DE.. but not drastically so.

 

2) People have stock cars,.. or modified cars. This changes the hp/tq

 

3) People just differ on driving style,.. and opinions of what "feels" right.

 

Here's my thoughts on the matter. I hesitate to put any specific RPM points because we all have Z's.. but my 350Z is not like everyone else's.. and yours isn't either. Even if we all had stock 350Z's and they ALL had the exact motor they would still differ a bit.. but THAT would make it easier.

 

Anyhow,.. If you maintain your engine well,.. and it's , well, in good shape (IE: Not 200k+ miles.. and needs to last you as your daily driver)... Then when At the dragstrip or autocross track (or private roads.. really? ) -- Then I maintain that since the 350's make Horsepower and Torque fairly high in the RPM band compared to say a muscle car or typical V8,.. That you should shift at *just* under redline for your model.

 

My redline is 7,500 -- Your's may be 7,500, 7,200 (Nismo GT), 7,000, or lower.. --

 

Now, is this the EXACT point where your car is making the most horsepower and torque? No.

 

Well isn't that the idea of shifting? To shift at the highest Horsepower or Torque? Sort of.

 

Here's the deal. -- Let's take a look at a 350Z, VQ35HR motor with intake, testpipes and exhaust dyno graph..

 

 

You see you can pick your poison here.. Do you want to shift at Max Torque? Or do you want to shift at Max hp? They do not meet at their max's respectively.

 

Neither really..

 

To shift at the optimum for this car (in the Gear this was dyno'd on) you would want to shift ideally right at 7,000 rpm. (You could argue 6k as well.. and it would be worth testing at a drag strip.)

 

This is where both Torque AND Horsepower are high,.. and there is a bit of room not to bump the rev-limiter (although for a car like this the Rev-limiter is often bumped up.. with tune).

 

Now,.. for a DE it would be similar, but different.. same principles apply. A Rev-up motor the same "idea".

 

Now, my thoughts are to shift at about 500 "ish" RPM under your redline. So for me that would be 7k,.. It's technically even better in some arguments to shift right AT Redline... so in my car I would shift at 7400-7500.

 

People will argue,.. but at the redline area you have lost horsepower and torque so you are wrong!

 

Well, that's true,..but why would one shift a little higher?

 

Where do you think the engine RPM is going to fall in the next gear on the HP/TQ curve/band ? Yes sir, .. it will fall closer to the peak hp/tq areas of the RPM band the higher your shift.

 

Let's say you shifted an HR motor at 6k,.. Well you typically aren't reaching maximum hp/tq with the/that shift and the engine is going to invariably drop X revolutions per minute in the next gear which is going to slot you down the power band ,.. which that amount of time to get back up in the best part of the powerband is hurting your performance.

 

So shifting on an HR at 7000-7400ish is not a bad thing. The horsepower and torque drop, yes.. but they only drop by 10-20hp at most,.. and your gain of being higher in the power band for the next gear is going to be greater than that 10-20hp loss from extending it hundredths or tenths of a second.

 

Many people tend to think of performance cars reaching their peak HP/TQ at X RPM then for whatever reason in their minds 100 rpm past that is = to 0 (zero) hp/tq. This is where I think people tend to get confused a bit until they start looking over Dynographs and understanding curves.

 

Same goes for DE, or Revup -- It's just lower.

 

The 350Z power band both for tq and hp is very good. By good I mean it follows a nice upward curve through the midrange and top end.. So "generally" as you climb in RPM so is the power of your Car. This makes it somewhat simple to figure out the shift points.

 

Some cars have peak power at say 4800rpm,.. but may rev to 6000 .. You wouldn't want to push it all the way out to 6k on such a car.. as the HP/TQ drop off would be hurting you more than you would gain on the positioning of the powerband for the next gear.. Sounds sort of complicated but it isn't.

 

That is the beauty of our VQ engines.. they were designed with one of the best horsepower and torque curves you could ask for, stock.. and they generally keep this curve as you add performance parts to them.

 

Long story short: -- Shift 100-600'ish before your redline.

 

Now,.. if you wanted to get absolutely precise with this.. you would HAVE to go get your car dyno'd in every single gear.. and get the precise hp/tq curves for YOUR car for each gear ratio. And you would come out with an exact say: 1st (6800), 2nd (6500), 3rd (6900), 4th (7350), and so on..

 

But we are talking milliseconds difference here. To be honest, most of us aren't good enough drivers to be able to take advantage of such precise shift points.

 

So the EASY way is to take the car to about 300-500 below redline on every single shift (when trying to maximize performance on a drag strip).. Set your shift light to where it first blinks at that range, so you can use the visual queue until you become intimately familiar with the sound of your engine at such high rpm ranges.

 

In the end you want to drive by sound, not by looking at anything. You DO get used to how your engine sounds at fairly precise RPM's.

 

This is all only practical for Straight line, drag strip type of runs.

 

When you are using the Z for it's true built purpose.. autocross (a real track with curves) you won't be shifting like you would trying to save milliseconds on an 8th mile, quarter mile, and so on time. You will shift at points dictated by your experience and conditions, other cars around you, the track, turns, straighaways, etc...

 

For everyday driving shift where you want. I personally shift under 3k with normal driving,.. these cars are VERY torquey (if that is a word). So you can be at 1800 rpm and the car will PULL in a gear. That's torque you are feeling if you've wondered the difference in Torque vs HP. Most other "V6's" aren't like our Z's.. they aren't like the VQ35XX engines. At 1800 rpm the engine is at extremely low torque and thus feels like it is dieing on you.. And you can really feel this in 4 cylinders, where even your everday shift points aren't practical to shift below 2200 if you "want" to. Make sense?

 

I've seen people say they like to shift in "normal" driving at 4500 rpm.. That's quite high to me,.. but to each their own. It's not uncommon for most to shift around 3k (give or take) in everyday driving (in these cars).

 

TLDR: On a drag strip (shift 100-500 rpm below redline) -- On a true racetrack (other conditions/factors will dictate your shift points for you) -- Normal driving that's your call.. there is no optimum, except for fuel economy and for best fuel economy stay somewhere in the 2200-3000 rpm range on shifts.

Edited March 18, 2014 by Chromatic

[GIXXERUK]

TLDR at bottom

 

Interesting topic..

 

There isn't any Hard and fast (Shift at X rpm in 1st, Y rpm in 2nd, and so on..) rule for this car. For a few reasons..

 

1) The DE is a different beast than the HR.. Shift points are going to vary due to the HP/Torque bands in both.. In an HR you will generally want to shift at a higher point than a DE.. but not drastically so.

 

2) People have stock cars,.. or modified cars. This changes the hp/tq

 

3) People just differ on driving style,.. and opinions of what "feels" right.

 

Here's my thoughts on the matter. I hesitate to put any specific RPM points because we all have Z's.. but my 350Z is not like everyone else's.. and yours isn't either. Even if we all had stock 350Z's and they ALL had the exact motor they would still differ a bit.. but THAT would make it easier.

 

Anyhow,.. If you maintain your engine well,.. and it's , well, in good shape (IE: Not 200k+ miles.. and needs to last you as your daily driver)... Then when At the dragstrip or autocross track (or private roads.. really? ) -- Then I maintain that since the 350's make Horsepower and Torque fairly high in the RPM band compared to say a muscle car or typical V8,.. That you should shift at *just* under redline for your model.

 

My redline is 7,500 -- Your's may be 7,500, 7,200 (Nismo GT), 7,000, or lower.. --

 

Now, is this the EXACT point where your car is making the most horsepower and torque? No.

 

Well isn't that the idea of shifting? To shift at the highest Horsepower or Torque? Sort of.

 

Here's the deal. -- Let's take a look at a 350Z, VQ35HR motor with intake, testpipes and exhaust dyno graph..

 

 

You see you can pick your poison here.. Do you want to shift at Max Torque? Or do you want to shift at Max hp? They do not meet at their max's respectively.

 

Neither really..

 

To shift at the optimum for this car (in the Gear this was dyno'd on) you would want to shift ideally right at 7,000 rpm. (You could argue 6k as well.. and it would be worth testing at a drag strip.)

 

This is where both Torque AND Horsepower are high,.. and there is a bit of room not to bump the rev-limiter (although for a car like this the Rev-limiter is often bumped up.. with tune).

 

Now,.. for a DE it would be similar, but different.. same principles apply. A Rev-up motor the same "idea".

 

Now, my thoughts are to shift at about 500 "ish" RPM under your redline. So for me that would be 7k,.. It's technically even better in some arguments to shift right AT Redline... so in my car I would shift at 7400-7500.

 

People will argue,.. but at the redline area you have lost horsepower and torque so you are wrong!

 

Well, that's true,..but why would one shift a little higher?

 

Where do you think the engine RPM is going to fall in the next gear on the HP/TQ curve/band ? Yes sir, .. it will fall closer to the peak hp/tq areas of the RPM band the higher your shift.

 

Let's say you shifted an HR motor at 6k,.. Well you typically aren't reaching maximum hp/tq with the/that shift and the engine is going to invariably drop X revolutions per minute in the next gear which is going to slot you down the power band ,.. which that amount of time to get back up in the best part of the powerband is hurting your performance.

 

So shifting on an HR at 7000-7400ish is not a bad thing. The horsepower and torque drop, yes.. but they only drop by 10-20hp at most,.. and your gain of being higher in the power band for the next gear is going to be greater than that 10-20hp loss from extending it hundredths or tenths of a second.

 

Many people tend to think of performance cars reaching their peak HP/TQ at X RPM then for whatever reason in their minds 100 rpm past that is = to 0 (zero) hp/tq. This is where I think people tend to get confused a bit until they start looking over Dynographs and understanding curves.

 

Same goes for DE, or Revup -- It's just lower.

 

The 350Z power band both for tq and hp is very good. By good I mean it follows a nice upward curve through the midrange and top end.. So "generally" as you climb in RPM so is the power of your Car. This makes it somewhat simple to figure out the shift points.

 

Some cars have peak power at say 4800rpm,.. but may rev to 6000 .. You wouldn't want to push it all the way out to 6k on such a car.. as the HP/TQ drop off would be hurting you more than you would gain on the positioning of the powerband for the next gear.. Sounds sort of complicated but it isn't.

 

That is the beauty of our VQ engines.. they were designed with one of the best horsepower and torque curves you could ask for, stock.. and they generally keep this curve as you add performance parts to them.

 

Long story short: -- Shift 100-600'ish before your redline.

 

Now,.. if you wanted to get absolutely precise with this.. you would HAVE to go get your car dyno'd in every single gear.. and get the precise hp/tq curves for YOUR car for each gear ratio. And you would come out with an exact say: 1st (6800), 2nd (6500), 3rd (6900), 4th (7350), and so on..

 

But we are talking milliseconds difference here. To be honest, most of us aren't good enough drivers to be able to take advantage of such precise shift points.

 

So the EASY way is to take the car to about 300-500 below redline on every single shift (when trying to maximize performance on a drag strip).. Set your shift light to where it first blinks at that range, so you can use the visual queue until you become intimately familiar with the sound of your engine at such high rpm ranges.

 

In the end you want to drive by sound, not by looking at anything. You DO get used to how your engine sounds at fairly precise RPM's.

 

This is all only practical for Straight line, drag strip type of runs.

 

When you are using the Z for it's true built purpose.. autocross (a real track with curves) you won't be shifting like you would trying to save milliseconds on an 8th mile, quarter mile, and so on time. You will shift at points dictated by your experience and conditions, other cars around you, the track, turns, straighaways, etc...

 

For everyday driving shift where you want. I personally shift under 3k with normal driving,.. these cars are VERY torquey (if that is a word). So you can be at 1800 rpm and the car will PULL in a gear. That's torque you are feeling if you've wondered the difference in Torque vs HP. Most other "V6's" aren't like our Z's.. they aren't like the VQ35XX engines. At 1800 rpm the engine is at extremely low torque and thus feels like it is dieing on you.. And you can really feel this in 4 cylinders, where even your everday shift points aren't practical to shift below 2200 if you "want" to. Make sense?

 

I've seen people say they like to shift in "normal" driving at 4500 rpm.. That's quite high to me,.. but to each their own. It's not uncommon for most to shift around 3k (give or take) in everyday driving (in these cars).

 

TLDR: On a drag strip (shift 100-500 rpm below redline) -- On a true racetrack (other conditions/factors will dictate your shift points for you) -- Normal driving that's your call.. there is no optimum, except for fuel economy and for best fuel economy stay somewhere in the 2200-3000 rpm range on shifts.

 

Can you elaborate on this ?