engine limiter or tune down?

[Tower Turn 13]

Obviously the engine limiter gives a car a very odd looking torque/power curve, but I'm certainly not knowledgeable enough to interpret the differences. So my question is if I'm spec racing is it better to use the limiter or to naturally tune the car as close as possible to the required hp? It looks like the torque power band is at less than 1000 rpm which is very odd with the limiter, and goes substantially down from there.

What is the difference between an overpowered car with an engine limiter and one that naturally meets the hp requirement? Which is more effective for racing?

 

[mafia_boy]

It's better if you tune it closer to it's required hp. By limiting the motor, you push the peak points for hp & torque down and in some cars it can cause a huge difference in performance as you die in the top end from the lack of torque since it's been limited down. Just grab a high hp car, look at where the peak power and peak torque markers are (for example, xxxHP@8000rpm max power, xxxKgfm@5500rpm max torque), then push the limiter to 50% and see the change occur where the torque and power peaks are, usually it's a lot lower. Since most racing occurs in the high rpm range, it makes it a fruitless exercise in power limiting. Only power limit if you must. 👍

 

[Tower Turn 13]

Thanks! This could make a huge difference in the series I'm participating in as I've always limited down 👍

 

[Adrenaline]

While Mafia makes a 'visual' point, I've seen nothing to back it up, tests or otherwise.
That's not to say I disagree... I'm indifferent at this time.
I've often wondered myself, but never cared enough to actually test it.

Mafia's point is that when you read the data it says "Max power 900hp @ 9000rpm.
Power Limiter to 50% and now it reads "Max power 450hp @ 5500rpm.

Now, one assumption, in this case Mafia's, is that you've changed your 'peak power' to a much lower rpm range, but, I'm not sure I buy it, until proven. Just because it says 'max power @ 5500, doesn't automatically mean, you aren't still making that power at 6000, 7000, 8000 or 9000. Oddly enough, I think drag racing would be the best way to prove the outcome. Same cars, same tune, same HP, but one use the limiter, one without.

Yes, clearly you're making 'max power' at 5500rpm now, but you're also making 'max power' at 9000rpm as well. That's what a flat power curve gives you; max power over a plateau. So while it 'visually' appears to be a disadvantage, logically, it doesn't actually make sense that it should be one. The graph data is simply programmed to calculate max power at RPM, and it appears as if it targets the 'earliest' point of a peak.

So, let me reiterate for those who will insist on throwing stones. I am indifferent. I don't know which is true, but until someone proves it one way or the other, I won't blindly accept either outcome.

Now, on the other hand, on topic of what you're asking....
For PP rooms, removing parts, and avoiding the power limiter, will give you more HP than using purely the power limiter. It's usually not much, but there's no reason not to take the extra 5-15hp if it's there!

 

[mafia_boy]

While Mafia makes a 'visual' point, I've seen nothing to back it up, tests or otherwise.
That's not to say I disagree... I'm indifferent at this time.
I've often wondered myself, but never cared enough to actually test it.

Mafia's point is that when you read the data it says "Max power 900hp @ 9000rpm.
Power Limiter to 50% and now it reads "Max power 450hp @ 5500rpm.

Now, one assumption, in this case Mafia's, is that you've changed your 'peak power' to a much lower rpm range, but, I'm not sure I buy it, until proven. Just because it says 'max power @ 5500, doesn't automatically mean, you aren't still making that power at 6000, 7000, 8000 or 9000. Oddly enough, I think drag racing would be the best way to prove the outcome. Same cars, same tune, same HP, but one use the limiter, one without.

Yes, clearly you're making 'max power' at 5500rpm now, but you're also making 'max power' at 9000rpm as well. That's what a flat power curve gives you; max power over a plateau. So while it 'visually' appears to be a disadvantage, logically, it doesn't actually make sense that it should be one. The graph data is simply programmed to calculate max power at RPM, and it appears as if it targets the 'earliest' point of a peak.

So, let me reiterate for those who will insist on throwing stones. I am indifferent. I don't know which is true, but until someone proves it one way or the other, I won't blindly accept either outcome.

Now, on the other hand, on topic of what you're asking....
For PP rooms, removing parts, and avoiding the power limiter, will give you more HP than using purely the power limiter. It's usually not much, but there's no reason not to take the extra 5-15hp if it's there!

Totally saw where you're coming from there Adrenaline. That's the reason why I mentioned the torque in the equation at the same time. The power will have this power peak hold for over 2000-3000rpm, but look at what's happened to the torque. The peak torque is lower, operates at a lower rpm peak and then after it hits peak torque, the torque graph looks like it took a fall off a cliff!! Perfect case in point, look at the Eclipse GT '06s I've done. Both are based off the same car, but the power limiter came into play and changed the whole dynamic of the car with the 500PP version.

But yes, try it out for yourself, you'll see what I mean. 👍

 

[Sail IC]

Interesting topic. Below is based on extensive racing in different engine configuations, and some specific testing. First, there are three ways to run an engine.

1, Broken in with frequent of oilchanges. This gives max HP/Torque at 100%.

2, One oilchange or very old oil. This gives less HP/Torque at 100%. If you take a broken in engine and run it without changing oil the HP will go down until it reaches a lowerest value and after a while it will stop decreasing. This is the same as just doing one oilchange (no more) on a new car.

3, Never do an oilchange on a new car. This will give the lowest HP/Torque at 100%.

Add to above different configurations of engine stage and turbo upgrades and there are many engine configurations to chose from. Also, in the game the engine take no harm by not doing oilchanges.

When chosing a configuration, I most often find running the engine limiter at 90-95% to be the best. Then peak HP is flat in the usable rev range and max torque is high up in the rev band. At 95-100%, peak power HP is only available at one specific RPM and in the usable rev range you will not always have max HP available. When running at low-90% the HP curve looks good, but the torque is not available in the usable rev range.

When racing at an max HP regulation ( don't do that often), go for a flat HP curve and highest torque configuration. In most cases you want to try to run your engine with stage/Turbo upgrades and if needed old or no oil configurations. In many cases you will run your engine limiter a bit lower at 85-90%, but not lower as it pushes down the max torque to much in the rev band.

A max PP regulation gives more options. The PP value is calculated from max HP and torque, and its better to try to find a configuration giving a higher HP to the cost of max torque. It gives most often the best overall acceleration and highest top speed but more importantly an easier to drive car and lower tirewear. Depending on the car/PP, its often best to stay away from stage/turbo configurations if the regulation PP can be reached at 90-95% engine limiter. If upgrading, do stage 1-2-3 rather than turbo as they give more added HP and less added torque.

Above is based on what worked best for me doing many races. The only test I sometimes do is to take then engine configuration I think is the best and then run it in practice mode at Suzuka and save the best lap. Then I take another engine configuration (ie car), load the previously best lap, and observe how it does against the ghost after passing the start line. The differences are not that big but often noticable.

To do above, you will have to buy several of the same car and configure them differently to find out what will be the best race car. Some might feel that above is not realistic, but in my experiance, regulations have to be set as; if it cannot be policed its allowed. To think that all racers will follow non policable rules never work 100%.

Be interesting to see other findings by other people on this forum.