Is it bad to use the power limiter?

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phil1012
Is it better to buy power parts that get you as close to X PP as possible, or is it just as good, or even better to add extra power and use the limiter to bring it back down to your PP goal?

When using the power limiter, the peak horsepower is lower than it is if I tune to the same PP using less limiter. I don't know how PP is calculated, but from this observation it seems like power is probably factored in by integrating the power curve rather than taking the peak value.

I think the power limiter just flattens anything above a certain point on the curve. Obviously it would not be good to flatten the curve below the point that the RPM drops to when shifting up, but could it be beneficial to have a partially flat curve above that point?

I know if peak power is reduced, the potential top speed would be reduced. I am mostly asking about tuning for circuits where you would be accelerating and using more range of RPM.
 
Is it better to buy power parts that get you as close to X PP as possible, or is it just as good, or even better to add extra power and use the limiter to bring it back down to your PP goal?

When using the power limiter, the peak horsepower is lower than it is if I tune to the same PP using less limiter. I don't know how PP is calculated, but from this observation it seems like power is probably factored in by integrating the power curve rather than taking the peak value.

I think the power limiter just flattens anything above a certain point on the curve. Obviously it would not be good to flatten the curve below the point that the RPM drops to when shifting up, but could it be beneficial to have a partially flat curve above that point?

I know if peak power is reduced, the potential top speed would be reduced. I am mostly asking about tuning for circuits where you would be accelerating and using more range of RPM.

Every car and situation can be different, but as a general rule of thumb you pretty much hit it on the head with this:

"I think the power limiter just flattens anything above a certain point on the curve. Obviously it would not be good to flatten the curve below the point that the RPM drops to when shifting up"

You can usually achieve a flat power curve in the usable rev range with less than 10% power limiter and it will only cost you a couple of HP most of the time, but the added benefit of a flat power curve more than makes up for it IMO. Heavy detuning, greater than what is necessary to flatten the curve in that 1000-1500 rpm rev range you are targetting, will cost you more and more HP. Detuning from 490PP with the Engine Limiter will cost you much more HP for example, than removing parts to get down to say 455PP and then using the EL to flatten the curve slightly.
 
If you use nitro on the car Do NOT use power limiter. in 1.03 (i haven't tried 1.04 yet) the nitrous would become unusable. Majority of the time i would suggest just removing the catalytic converter its roughly 5PP.
 
Are we tuning for torque or horsepower? I ask because this discussion came up a few days ago and someone mentioned the torque seems to rise or stay at the same level even with turbo equipped but horsepower drops(when using the power limiter). All the while the power curve flattens but the torque benefit remains. If one of you are the one who knows about this, I'd be grateful.
 
the chart in gt6 is not to any kind of scale, it is pretty much useless and to assign RPM/HP/TQ points is pretty much futile. to get any kind of a useful chart you have to take what little info PD gives us, extrapolate it into excel and make your own chart. you will then see how what I'm about to go on about makes sense. maybe i'll elaborate more on this in a later post.

in PP racing, excessive use of the power limiter is *BAD*. what excessive is will vary from car to car. a car with a very peaky power curve can use more power limiter than a car with a flat power band. However, I can't think of a tune right now where I limit more than 5% and most of the time I'm at 97.5-98.5% or higher.

why is excessive power limiting bad? you have to remember that HP is a just a calculation of torque over time. Thus, when you limit HP, you are also limiting torque. you may or may not be reducing *PEAK* torque depending on how much you limit, but you *are* reducing torque in the RPM range you race in. torque (& gear ratios) is what moves (accelerates) cars, not HP.
 
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torque (& gear ratios) is what moves (accelerates) cars, not HP.
HP moves the car plenty. If you have a HP curve, you can ignore torque completely.

The power limiter should be avoided when possible because it will lower your usable HP. Johnny's graph is good to look out. If your gearing is spaced such that after a downshift, you're at 3600 RPM, using the powerlimiter will slow you down because the area under the HP curve above 3600 RPM will decrease. In general you won't care about what happens before 3600 RPM because you would could just downshift at that point. A possible exception would be cars with very long shift times.

Short version: As far as raw acceleration goes, the goal is to maximize the area under the HP curve between the RPM's that your gearing will have let your engine operate in.
 
HP moves the car plenty. If you have a HP curve, you can ignore torque completely.

The power limiter should be avoided when possible because it will lower your usable HP. Johnny's graph is good to look out. If your gearing is spaced such that after a downshift, you're at 3600 RPM, using the powerlimiter will slow you down because the area under the HP curve above 3600 RPM will decrease. In general you won't care about what happens before 3600 RPM because you would could just downshift at that point. A possible exception would be cars with very long shift times.

Short version: As far as raw acceleration goes, the goal is to maximize the area under the HP curve between the RPM's that your gearing will have let your engine operate in.

we're saying the same thing

except you cannot ignore torque, ever, because it is a part of HP with no torque, you have no HP. the only way to increase HP without adding torque is to add more time (RPM). we're very limited in what we can do in that regard in GT6.

so to change your post:

Short version: As far as raw acceleration goes, the goal is to maximize the torque curve between the RPM's that your gearing will have let your engine operate in.

as far as the gt6 graph, if you take the numbers from the game and plug it into a chart along with some formulas in a excel you will see how inaccurate the rpm/hp/torque relationship is.
 
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we're saying the same thing

except you cannot ignore torque, ever, because it is a part of HP with no torque, you have no HP. the only way to increase HP without adding torque is to add more time (RPM). we're very limited in what we can do in that regard in GT6.
From the driver's perspective, no. Yes, HP and torque are related, but that's why you can ignore one for the other. HP accounts for torque. It then makes itself more convenient because it doesn't care about gearing.

so to change your post:
I wouldn't, it would only complicate things.

as far as the gt6 graph, if you take the numbers from the game and plug it into a chart along with some formulas in a excel you will see how inaccurate the rpm/hp/torque relationship is.
If true, this is important.
 
the chart in gt6 is not to any kind of scale, it is pretty much useless and to assign RPM/HP/TQ points is pretty much futile. to get any kind of a useful chart you have to take what little info PD gives us, extrapolate it into excel and make your own chart. you will then see how what I'm about to go on about makes sense. maybe i'll elaborate more on this in a later post.

in PP racing, excessive use of the power limiter is *BAD*. what excessive is will vary from car to car. a car with a very peaky power curve can use more power limiter than a car with a flat power band. However, I can't think of a tune right now where I limit more than 5% and most of the time I'm at 97.5-98.5% or higher.

why is excessive power limiting bad? you have to remember that HP is a just a calculation of torque over time. Thus, when you limit HP, you are also limiting torque. you may or may not be reducing *PEAK* torque depending on how much you limit, but you *are* reducing torque in the RPM range you race in. torque (& gear ratios) is what moves (accelerates) cars, not HP.
Problem is, your assertion that, "torque (& gear ratios) is what moves (accelerates) cars, not HP", doesn't play out in GT especially when using a PP limitation as the OP is suggesting. A higher torque and flatter torque curve usually penalizes you under the PP system, increasing your PP with little return on the track. I've tuned quite a few cars at 450PP and most of the fastest ones have lower peak torque and a peaky torque curve. Cars with flatter torque curves don't accelerate any better and usually suffer on the top end due to a lack of peak HP. And generally speaking again, the peakier an HP curve is, and the closer it is to redline, the happier I am.
 
johnny and exorcet in the end, we are saying the same thing in a different way. :)

when i get some more time, i'll see if i can draw up an example of a car tuned to a certain PP using all parts with limiter vs less part and little or no limiter. it will serve to things, illustrate how inaccurate the gt6 chart is and illustrate how we are saying the same thing.
 
why is excessive power limiting bad? you have to remember that HP is a just a calculation of torque over time. Thus, when you limit HP, you are also limiting torque. you may or may not be reducing *PEAK* torque depending on how much you limit, but you *are* reducing torque in the RPM range you race in. torque (& gear ratios) is what moves (accelerates) cars, not HP.
I completely get what you are saying and I understand the argument of HP vs torque from both sides. I am of the opinion that it is sufficient to ignore one completely, since each can be derived from the other, and that HP is the easiest one to use because you don't have to calculate anything with transmission. Although, I don't think this debate is quite relevant to my question. After all, increasing HP with parts and then reducing it with the limiter is also going to increase and then reduce torque. The HP curve is the one directly affected by the limiter, so it makes even more sense to ignore the torque curve in this situation.

Would I be correct in saying that the amount of time taken to accelerate from an RPM range of 6000 to 7000 for example in one gear is inversely proportional to the integral of the power curve in that range?
 
Would I be correct in saying that the amount of time taken to accelerate from an RPM range of 6000 to 7000 for example in one gear is inversely proportional to the integral of the power curve in that range?

:odd: *Pop* Mind = blown.

This is a very interesting discussion. I'm still not sure if there is a consensus regarding the OP's question, is it better to use the limiter or remove parts?
 
:odd: *Pop* Mind = blown.

This is a very interesting discussion. I'm still not sure if there is a consensus regarding the OP's question, is it better to use the limiter or remove parts?

The benefit in detuning using the power limiter is flattening out the power curve at peak power in the usable rev range. Once you flatten the curve to cover the entire rev range (usually less than 5%) you no longer get any benefit from detuning but will begin to lose more and more HP vs removing parts. A couple of illustrations:

This is an RX-8 Type S 07, tuned to perform at 500PP with parts removed to lower it to 455PP with 5% power limiter. Peak HP is 265 and it's sustained throughout the usable rev range. Notice also the torque peak is at the beginning of the normal shifting range and relatively flat:

Windsor-20140204-01785.jpg

This is the same car, tuned to 500PP, then detuned using engine limiting to 450 PP. 23 less peak HP means less accleration and lower top speed. The added flatness to the power curve is of no benefit because you only need about 1000 rpm to operate this car with a 6 speed transmission.

Windsor-20140204-01786.jpg
 
Here is an example of where it seems like using the power limiter could be good.

IMG_0231.JPG


This is BanditKarters tune for the Toyota 86 seasonal that he posted in this thread:
https://www.gtplanet.net/forum/threads/toyota-86-gt-super-lap-active-op.301526/

By simply switching to racing exhaust and lowering the limiter to get back to 450PP you get this

IMG_0230.JPG

Peak power is almost the same, but the curve in the usable range is much flatter.

One thing to note is that in the second picture, the peak power and peak torque are at 100 RPM higher. A loosely related question I might also have is, is it better to use the parts that raise the RPM over parts that dont? If you adjusted the final drive accordingly, wouldn't the second picture be just better?
 
Limited use of the Power Limiter isn't really an issue.
Generally speaking you'll find very little performance differential between say building as close to a given PP and using like 5% power limiter. Indeed on many cars you may need to slightly exceed the target PP then use either the power limiter, ballast or a combination of the two to reach your target or wind up short with just parts.

Between 5-10% power limiter it will be more of a case by case call on what's more effective but you probably still won't see a big difference performance wise.
Past 10% you'll start to get punished by trying to use power limiter. As has been pointed out already you'll start making less HP than building the car closer to spec. Also the excessive use of power limiter will start impacting your torque and you'll start seeing it taking a dive past its peak. That means slower acceleration past peak power and can have serious impact on trying to tune a transmission, especially for automatics which PD has programmed to upshift only at redline.
 
Here is an example of where it seems like using the power limiter could be good.

View attachment 111164

This is BanditKarters tune for the Toyota 86 seasonal that he posted in this thread:
https://www.gtplanet.net/forum/threads/toyota-86-gt-super-lap-active-op.301526/

By simply switching to racing exhaust and lowering the limiter to get back to 450PP you get this

View attachment 111163
Peak power is almost the same, but the curve in the usable range is much flatter.

One thing to note is that in the second picture, the peak power and peak torque are at 100 RPM higher. A loosely related question I might also have is, is it better to use the parts that raise the RPM over parts that dont? If you adjusted the final drive accordingly, wouldn't the second picture be just better?
I haven't tested it on the track in GT6 so I'm going on the assumption it works the same way, but in GT5 it was a definite advantage to adding parts that raised rpm over those that don't, specifically ECU, Racing Exhaust and Catalytic Converter. I try to add those to all cars first and everything else after.
 
Here's an example I posted in my Tuning Garage. I believe it's for the 78' Trans Am.

You just raised torque vs hp.
Torque would be smalker than this and have a less important incidence on pp if you left the power limiter alone.
That becoming a advantage depends if the car needs more torque or more power to start with... (under power limiting power is no more equal to torque x rpm - edit woopsie, forget this, this is true again, but max torque doesn't change is its peak is not near hp's peak, judging by @MindsMirror 's pics).
 
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Fixed.
At lower speeds the HP doesn't play that much of a role, but torque does.
On the track operating in the peak power range, I'd rather have that extra 23 hp where I need it, than extra torque where I don't.
 
On the track operating in the peak power range, I'd rather have that extra 23 hp where I need it, than extra torque where I don't.
Of course, we agree that on Road X Torque <<<<<< Power...
On autumn ring mini, that may be different :)
 
Would I be correct in saying that the amount of time taken to accelerate from an RPM range of 6000 to 7000 for example in one gear is inversely proportional to the integral of the power curve in that range?

Almost - it would be the integral of the torque curve. F=ma and all that - torque is the force in that equation.


EDIT: The inaccuracy of the power/torque graphs is very irritating. In Forza I made an app that would calculate the 'optimum' gear ratios and shift points etc depending on a number of inputs - you could quickly and accurately get the data for the graph using replays and telemetry.
 
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I use engine limiter quite aggressively. It works quite well as far as I'm concerned. Here is the engine limiting I used on two tunes for online time trials. I was reasonably successful with both time trials I think.



 
I might regret posting this, lol.

I'm reading the OP, then I'm reading the fifty responses, and I'm confused.

I'm going to try to throw a hypothetical example.
Car is 507pp and the limit of the race is 500pp.
Is the question, "should I use the limiter or remove a tuning part?"

If that's all it is, that's simple. Run laps with both and compare your times, lol.
Assuming that's what the question was, there ya go, lol. Now, MY question is to those who responded so far.

When I use the power limiter, while using high rpm turbo, I don't seem to have any issues. The performance of the car still shows the high rpm turbo. It doesn't 'go away' or become something different, as far as handling goes. It's simply a car with less power and pp. But the effect of the parts is still very apparent.
Is someone saying something different?
I couldn't quite understand a lot of the responses, I am not being a jerk or anything, lol, I'm just curious if any of you know the actual effects of the limiter?
I mean, yes we know lowering it to say, 95%, will lower the pp and the hp. But is that it? Does it do anything else to the car besides just effecting the base raw power?

I'm curious, because of a car I've been working on. Nissan Option Stream, and yes it's a handful. But when I was playing with it, tuning, I lowered the power limiter to make it hit 450pp.
Now, we're talking about a Nissan beast that maxed out has over 900hp, being driven in a 450pp limit race? I did it just for a laugh. BUT, it was awesome. Well, not awesome, but very well behaved. The car is sooooo much more behaved at 450pp then any other pp I tried. Corner in, corner out, pick up, recovers, everything performed better. And no I didn't change a single thing to the tune itself. I tuned it for 600pp, made all my adjustments, and then did the power limiter.
In this case, the limiter took a car with way too much juice, and tamed it into a real beast for 450pp races.

So to reiterate, my question is, with regards to the OP as well, does anyone know of actual detailed responses to the limiter besides pp and bhp?

Sorry about the book, when I type, I type as fast as I talk, and I get carried away easily, lol.
 

I get what your saying, I see what your saying. And thanks for the quick response, lol. But it's not really what I wanted to know. I think I just don't know how to word the question correctly.
I know and see the comparisons to limiter vs. part reduction. That has nothing to do with what I'm trying to find out though.
It's simply, what actual 'things' (lack of a better word) does the limiter do when used, besides lowering bhp and pp?
Does it change the effect of, say, any tuning abilities? (Dampers, ect)
Grip? Over/under steer strength?
Or is it simply just juicing the engine down?
I apologize if I'm not understood, or explaining correctly. This just happens to be something I'm really working on.
Not using the limiter for 90% - 100%, but using it for radical amounts like 55%, ect.
 
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