Technical question

[mr-ramsbottom]

Hi need advice before my next step of making a mod ,.. I've uploaded a picture for the Porsche 911 RSR 17

Could someone tell.if the 8500 rpm maximum setting for this car is all that is needed to maintain maximum speed and acceleration ?

Would i be right in thinking that as long you always apply 8500 rpms to this Porsche you'll always speed up quicker because your less likely to wheel spin or lose traction ? When changing through the lower gears ?.

Ive been trying to maintain 8500 rpms when accelerating but you can accelerate the rpms higher but it's difficult to always keep the accelerator on the 8500 rpm point between gear changes.

For instance if you just keep your foot on the brake and keep the car still and accelerate but don't make the car move, you'll notice that 8500 rpm point is just below full throttle. I'm hoping to make a mod I can adjust for each car. So the accelerator can't go beyond that point, or maybe I'm barking 😊

 

[LSFDRX]

I'm not sure what you're asking. It is impossible to keep an engine at 8500rpm unless you have a transmission that allows for it, like a CVT.

The power band might also not be peaked at 8500rpm, and the engine may make more power at lower RPM.

The pic you posted just displays the cars rpms at a given speed, so for each of those gears you will be at X speed at 8500rpm.

If you lower the top speed (final drive ratio) your car will accelerate faster and have an "easier" time turning the wheels at the expense of top speed.

 

[mr-ramsbottom]

I'm not sure what you're asking. It is impossible to keep an engine at 8500rpm unless you have a transmission that allows for it, like a CVT.

The power band might also not be peaked at 8500rpm, and the engine may make more power at lower RPM.

The pic you posted just displays the cars rpms at a given speed, so for each of those gears you will be at X speed at 8500rpm.

If you lower the top speed (final drive ratio) your car will accelerate faster and have an "easier" time turning the wheels at the expense of top speed.

Throttle control It's something I'm working on at present, I really feal good force feed back through the wheel when I keep the throttle at only 30 percent for 1st gear then go up in inclines of 15 for each a additional gear so 45 percent for second 60 for 3rd an so fourth.

I have a big screen so I'm able to stick lines on the accelerator indicator on my screen to train,

But when i do it right I get really good acceleration through the gears and beat my lap times. But also I get really good feed back through the wheel, as in I actually feel the cars acceration through the wheel,

 

[eran0004]

8500 rpm is probably the shift point recommended in the game.

If you limit the throttle so you never go past 8500 rpm then theoretically you might go a little bit faster in first gear since you do limit the wheelspin a bit. But you'd still have a ton of wheelspin. For the other gears you'd not really see any effect other than that you'd limit the top speed of the car (in the event that it's limited by the gearbox rather than by aerodynamic drag).

It sounds like what you want is a form of traction control, to reduce the throttle when you have wheelspin. Have you tried the traction control aid that's available in the game?

 

[Meythia]

Could someone tell.if the 8500 rpm maximum setting for this car is all that is needed to maintain maximum speed and acceleration ?

There is a bit of math behind it, that fortunatly has been put together on a very gt-dedicated website:

Lab / Optimal Upshift RPM

GT ENG!NE / Gran Turismo Sport Database website

gt-engine.com

Though it refers to GT Sport, the same goes for GT7

 

[mr-ramsbottom]

8500 rpm is probably the shift point recommended in the game.

If you limit the throttle so you never go past 8500 rpm then theoretically you might go a little bit faster in first gear since you do limit the wheelspin a bit. But you'd still have a ton of wheelspin. For the other gears you'd not really see any effect other than that you'd limit the top speed of the car (in the event that it's limited by the gearbox rather than by aerodynamic drag).

It sounds like what you want is a form of traction control, to reduce the throttle when you have wheelspin. Have you tried the traction control aid that's available in the game?

Hi I think your understanding me a little better 😊. Your half way there.

It's not just limiting the throttle im trying to rev match with the rpms, as in increase the revs to match the rpms,

Such as getting up to 8500 rpms in first gear. Then when you change to second gear there is no need to be in full throttle you can actually release the throttle a little bit at the moment of gear change, then increase the throttle again you can literally do this for each gear 😊 and actually gain time by doing it especially in lower gears.

The problem im having is I cant always release the the throttle back to precise point, so I'm working on a mod for this that is going to be installed on my pedals. It's still in design at the moment just on paper.



But I'm still a little confused with exactly what the lower points on the picture I posted for gears are

So for.instamce 6th gear has a higher point than 5th and 4th and so fourth.

There is a bit of math behind it, that fortunatly has been put together on a very gt-dedicated website:

Lab / Optimal Upshift RPM

GT ENG!NE / Gran Turismo Sport Database website

gt-engine.com

Though it refers to GT Sport, the same goes for GT7

Hi thanks it looks a good read I'll digest it more some later 😉

I've just finished making a play seat stand, I used my garden deck chair and cut the stand out so it bends round the of the frame of the chair so it doesn't move now upon acceleration and braking. Best part is it only cost me 20.00 and it's most comfortable play seat I've ever had, and it can be put away in 1 min and set up in 1 min to.

Now I'm designing my pedal mods 😊

 

[eran0004]

It's not just limiting the throttle im trying to rev match with the rpms, as in increase the revs to match the rpms,

Such as getting up to 8500 rpms in first gear. Then when you change to second gear there is no need to be in full throttle you can actually release the throttle a little bit at the moment of gear change, then increase the throttle again you can literally do this for each gear 😊 and actually gain time by doing it especially in lower gears.

The problem im having is I cant always release the the throttle back to precise point, so I'm working on a mod for this that is going to be installed on my pedals. It's still in design at the moment just on paper.

Okay, so you're trying to match the revs of the new gear when you shift up?

You can calculate the new engine speed by v1 = v0* (r1/r0), where v0 is the engine speed when you shift gears, v1 is the new engine speed you want to aim for, r0 is the gear ratio of your current gear and r1 is the gear ratio of the gear you're changing into.

For example

v0 = 8500 rpm
r0 = 2.556
r1 = 1.983
v1 = 8500 * 1.983/2.556 = 6590 rpm

So when changing from 1st to 2nd gear at 8500 rpm, the new engine speed will be 6590 rpm.

 

[Niko-H]

But I'm still a little confused with exactly what the lower points on the picture I posted for gears are

So for.instamce 6th gear has a higher point than 5th and 4th and so fourth.

Just to add -
I believe that picture simply visualizes the engine RPM behavior through each gear.
Looking at @eran0004's explanation:

Okay, so you're trying to match the revs of the new gear when you shift up?

You can calculate the new engine speed by v1 = v0* (r1/r0), where v0 is the engine speed when you shift gears, v1 is the new engine speed you want to aim for, r0 is the gear ratio of your current gear and r1 is the gear ratio of the gear you're changing into.

For example

v0 = 8500 rpm
r0 = 2.556
r1 = 1.983
v1 = 8500 * 1.983/2.556 = 6590 rpm

So when changing from 1st to 2nd gear at 8500 rpm, the new engine speed will be 6590 rpm.

If you shift at 8500, you'll be in 2nd gear from 6590 RPM to 8500 RPM.
Then using the same calculation for the 2->3 shift: 8500 RPM * 1.604 / 1.983 = 6866 RPM
In other words, you have a higher engine speed when you hit 3rd gear, so that might be why the bars get shorter or have higher points - they represent the RPM range for that gear.

6th gear goes above 8500 RPM in that picture to visualize running the engine to the redline because you can't shift up again.

But since there's no scale or units (aside from 8500 rpm), I don't know if you can gain anything useful from it.