Need help with Power/Torque - How to tune & what to look for.

[Schwadegan]

Hello fellow gtplanet drivers, since 1.06 I've been playing around with some of the new features such as power limiter and the custom gearbox.

My favorite car has 530hp (all upgrades except exhaust and the 1,2,3 stage engines) and a suspension setup I'm fairly happy with. Therefore, due to the lack of multiple setups for each car and the fact that engine stage upgrades are irreversible, I bought a second identical 'test car', with the exception of engine upgrades that is (both cars fitted with their original exhaust).

Since I'm pleased with the 530hp from the original car I used the power limiter to bring the second 'test car' to the same amount of hp. This naturally gave me a bit higher kgfm, which I assume is a good thing?

Then I adjusted the gearbox, I think I only touched the 'Final gear' for now, to make the car reach 300km/h. The first car use this setting since I use it to race on Nürburgring, and 300km/h works well over the last straight.

Now for the acctual question;
Does it actually make a difference in regards of the cars performance to upgrade the engine to about ~610hp then cut it short with the power limiter to 530hp? The only real difference I see is that the car with power limitation has 530hp/6200rpm while the other has 530hp/7300rpm.
And then of course there's the Power/Torque graph, which I understand somewhat, but can't really use since I don't know would be the optimal result.

I've tested both cars rather quickly, and after a few laps it only differed 0,3 seconds that may well have been because of human error.


The car without engine tune and power limiter

The extra tuned car with power limiter

 

[koreanbro]

Looks like your getting max HP at lower RPM and getting more Torq, using Power Limiter! If you notice ar 6200 RPM you max out the car's HP and it will stays same till the engine red line! I would use Power Limiter to take advantage of more Torq! Now adjust gears to match the power output and shifting points!

 

[Rh21]

Yes, the car with more bhp (the one you limited) should be faster because while the original car peaks at 530 hp, the restricted one has 530 hp available for longer. (through a large range of rpm)

FOR EXAMPLE

In the normal car you may shift up and instantly have 400hp which builds to 530hp as the revs increase.
In the restricted car when you shift up u get the full 530hp the the full way through that gear, increasing your acceleration due to a wider powerband.


A restricted car generally has more torque available which increases acceleration throughout the whole rpm range. As a result it easier to tune transmissions for restricted cars.

 

[Schwadegan]

That was fast, I appreciate it!

Looks like your getting max HP at lower RPM and getting more Torq, using Power Limiter! If you notice ar 6200 RPM you max out the car's HP and it will stays same till the engine red line! I would use Power Limiter to take advantage of more Torq! Now adjust gears to match the power output and shifting points!

Thanks a lot. What would be the best way to begin adjusting the gears to the power output?

Yes, the car with more bhp (the one you limited) should be faster because while the original car peaks at 530 hp, the restricted one has 530 hp available for longer. (through a large range of rpm)

FOR EXAMPLE

In the normal car you may shift up and instantly have 400hp which builds to 530hp as the revs increase.
In the restricted car when you shift up u get the full 530hp the the full way through that gear, increasing your acceleration due to a wider powerband.


A restricted car generally has more torque available which increases acceleration throughout the whole rpm range. As a result it easier to tune transmissions for restricted cars.

Thanks for explaining, your example made it easy to understand 👍
How would you go on from this and adjust gears?

 

[Rh21]

No idea, sorry.
I find that I get enough adjustment just using the speed slider though.
It takes a while to setup individual gears for the corners and straights in a specific track and usually doesn't really improve your times that much.

 

[Disavowed]

General rule of thumb, a flatter torque curve means it'll be easier to feather the throttle to control your power coming out of turns. A flat power curve means your car will be able to reach your top speed at a lower rpm.

 

[Schwadegan]

General rule of thumb, a flatter torque curve means it'll be easier to feather the throttle to control your power coming out of turns. A flat power curve means your car will be able to reach your top speed at a lower rpm.

So how do I get about to flatten it out a bit? Purely by adjusting the individual gear ratios?

 

[Rh21]

You can't, you have to tune the transmission to suit the torque curve from the engine, not the other way around.
The only way you can alter the shape of ur torque curve is by tuning the engine or adding/changing turbos

 

[Schwadegan]

Oh, I see. Thanks yet again, all of you, for your help!

 

[itstheDRE4M]

The "best" way is to use all of the maximum RPM increasing bits (race exhaust, cat, ECU) and avoid engine tuning, intake mods, and turbo/superchargers unless absolutely necessary to get the PP up to wherever you need it. Less torque = you can run higher power output = faster. Having about 1500rpm of constant peak power is extremely useful and will pull much harder than 5-6hp more at peak and 10hp less on either side of it.

--Explained by Roj from a previous post.

 

[charliec]

The "best" way is to use all of the maximum RPM increasing bits (race exhaust, cat, ECU) and avoid engine tuning, intake mods, and turbo/superchargers unless absolutely necessary to get the PP up to wherever you need it. Less torque = you can run higher power output = faster. Having about 1500rpm of constant peak power is extremely useful and will pull much harder than 5-6hp more at peak and 10hp less on either side of it.

--Explained by Roj from a previous post.

I'm not sure I follow. If you were to max our your engine and then reduce it via the power limiter, you'll probably be making peak power sooner and over a larger range of RPMs.

Also, you say "Less torque = you can run higher power output = faster" which I'm not sure I follow either. Engines produce torque, power is the application of torque over time (RPMs). They're linked (HP = (RPM*tq)/5252). Reducing torque at any given RPM will also reduce power at the same point. Engines with low torque can still have high power outputs because they can rev high, but I'm not sure that having 300HP at 8500RPM will be faster than 300HP at 6500RPM if both can make that peak power over the full length of their powerband.

 

[Disavowed]

charliec is right. Peak power means nothing without a fat torque band. Torque will allow you to reach peak power faster. Torque is what determines how fast your car can accelerate given enough traction of course while HP determines your top speed. Do all the engine mods you want but if you look carefully at your powerband, you'll note that the basic shape hasn't changed much (especially the torque band).

The power limiter is very poorly implemented in GT5. It basically makes your engine's powerband look like a diesel engine. Using the power limiter is not like a using a restrictor plate IRL.

 

[Rh21]

The "best" way is to use all of the maximum RPM increasing bits (race exhaust, cat, ECU) and avoid engine tuning, intake mods, and turbo/superchargers unless absolutely necessary to get the PP up to wherever you need it. Less torque = you can run higher power output = faster. Having about 1500rpm of constant peak power is extremely useful and will pull much harder than 5-6hp more at peak and 10hp less on either side of it.

--Explained by Roj from a previous post.

This is completely wrong!! Torque is the force that makes your car accelerate so you definitely do not want to decrease torque.
And by the way all parts/mods that increase hp WILL also increase torque.

 

[VTiRoj]

The "best" way is to use all of the maximum RPM increasing bits (race exhaust, cat, ECU) and avoid engine tuning, intake mods, and turbo/superchargers unless absolutely necessary to get the PP up to wherever you need it. Less torque = you can run higher power output = faster. Having about 1500rpm of constant peak power is extremely useful and will pull much harder than 5-6hp more at peak and 10hp less on either side of it.

--Explained by Rotary Junkie from a previous post.

Fixed for you.

The quote was taken out of context anyway. RJ was explaining how to get the most power under a PP limitation, not horsepower. Say you have a 500PP limit, you'll get more power out of the car if you follow RJ's method, than if you just bolt on everything and then rely on the power restrictor to bring the PP down.

Please read quotes before you use them, guys.

 

[Disavowed]

Ok, now that made more sense. Thanks!

 

[Schwadegan]

I've worked on a few different settings today, further playing with the individual gears and tweaking the LSD. The car is now about five to ten seconds, give or take a few, faster around the Nürburgring than before!

 

[CloneHead]

This should be a sticky thread.

 

[shirakawaa]

The power limited version in your case has always more torque (and therefore power) than the less powerful, not limited version. These are the two engines compared with the same scale: