most important - bhp or power to weight ratio

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joe__kerr
When tuning a car (adding power parts, doing weight reduction etc), what are the important numbers to look at - power to weight ratio, break horse power or other?

Should I be looking to get the lowest power to weight ratio or best bhp? I can't figure out whether to run with a higher bhp at the expense of a higher power to weight ratio or go for the lowest possible power to weight ratio but a lower bhp?
 
unfortunately neither of those is the most important. I've had cars that had incredible power to weight and or more HP than other cars in that class and it didn't matter. It all depends on how PD made the cars.

A great example is 550pp and the Mclaren 12C. You have to drastically limit the power to get it to that level. Other cars like the Gallardo and F430 Scuderia should be much better at that level but aren't because the 12C is just magically better, way better. Some cars, despite the numbers, are just better than others.

So it comes down to total feel and handling of the car above all else. Then HP. Try my cars out as an example. Take my F430 to your favorite track and set a hot lap, then the gallardo at 550pp (the tune is at 600pp). Then drive the mclaren and see how much better and faster it is with a worse power to weight and lower total HP then the other two.
 
ImToLegitToQuit grazie! So there are no real conclusions we can draw regarding which is better? Not even generally? Not comparing car A with car B for the moment and just thinking about how can I max out what I have for X car. An example would be a race with say another ten RX500s @ 500pp:

(A setup)
P to W: 2.78
Bhp: 323

vs.

(B setup)
P to W: 2.94
Bhp: 341


Is it individual to the car then? In the above scenario with say ten RX500s in a race A setup might be faster but with ten Elise 111rs in a race, B setup might be faster?

I think what I'm trying to get at is this; aren't there any basic principals that I can follow or get my head around regarding the above figures?
 
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reefer
ImToLegitToQuit grazie! So there are no real conclusions we can draw regarding which is better? Not even generally? Not comparing car A with car B for the moment and just thinking about how can I max out what I have for X car. An example would be a race with say another ten RX500s @ 500pp:

(A setup)
P to W: 2.78
Bhp: 323

vs.

(B setup)
P to W: 2.94
Bhp: 341


Is it individual to the car then? In the above scenario with say ten RX500s in a race A setup might be faster but with ten Elise 111rs in a race, B setup might be faster?

I think what I'm trying to get at is this; aren't there any basic principals that I can follow or get my head around regarding the above figures?
Click to expand...
I get what your asking. I think that in real life it makes sense that both cars would have similar times because the lighter car would be better in the turns and the more powerful car would be better in the staights. Unfortunately gt6 doeant always accept real life logic very well.

Take the 111r for example.

Car 1: reduce weight to get to 450pp

Car 2: add power to get to 450pp

Car 2 is going to be faster on every single track every time because the 111r is already light. These results are specific to this car though. A similar lightweight car (s2000 comes to mind) might get different results depending on how well it handles and how much grip it has.

Each car has to be approached fresh and be put through different tests just like you outlined above.

I think that for gt6 the MR platform has the fastest cars for each given class. Most of the time the setup that allows you to get on the throttle the soonest is going to be the fastest.
 
reefer
When tuning a car (adding power parts, doing weight reduction etc), what are the important numbers to look at - power to weight ratio, break horse power or other?

Should I be looking to get the lowest power to weight ratio or best bhp? I can't figure out whether to run with a higher bhp at the expense of a higher power to weight ratio or go for the lowest possible power to weight ratio but a lower bhp?
Click to expand...

Power to weight is important for acceleration.
Power is important for top speed.
 
Then add the track into the equation. Is it a tight track with lots of turns and no long straights?

Is it Route X?

HP gets you to a higher top speed, but torque and lighter weight get you to the top speed attainable faster.

Few real race tracks allow you to reach the top speed of your car. That's where gearing comes into play.
 
SmileyOr1
Then add the track into the equation. Is it a tight track with lots of turns and no long straights?

Is it Route X?

HP gets you to a higher top speed, but torque and lighter weight get you to the top speed attainable faster.

Few real race tracks allow you to reach the top speed of your car. That's where gearing comes into play.
Click to expand...

Smiley, this makes a lot of sense and helps a lot. Thanks for that!
 
And sometimes else to consider is the effect the upgrades have the car for your driving style. High torque with a very aggressive style can lead to lost time due to wheel slip so more power with less torque will actually be faster in that situation because of reduced wheel slip.
Torque leads to acceleration, acceleration leads to speed, speed leads to victory!
 
It depends on the car. Some are too heavy at any kg/hp ratio and they are difficult to slow and steer through a tight track. Some are feather light and need ballast to keep them from floating away. Some have lousy weight distribution and require ballast to be shifted to improve handling. Some simply have too much hp and it's too difficult to translate that to the ground.

Also, some improvements are not worth their price in PP boosts. If you're aiming for a particular PP class, all this, and more, must be weighed. See the tuning guide by Motor City Hami in the tuning forum.
 
The most important thing is when your done inputting numbers i regards to completing your tune, in which as opposed to say writing an algorythm for turning to test your new machine on a track.
 
As said above, very light cars benefit more from power overall, except for on the smallest tracks. But mostly, less weight wins. Do some Free Run on SS route X (rolling start for consistency) you'll see keeping a car with relatively normal stats at a certain PP, reducing weight vs increasing power, only towards very high speed (more than you will hit on most tracks) do you get the benefit of more power. Thing is a lighter car will get much more back on every turn of a circuit!
 
Ya not really sure their is a simple answer to this. Others have already pointed out a lot of the variables...here's another one.

Max RPM.

Certain upgrades (engine stages, cpu, exhaust, and catalytic converter) increase the rpm at which the engine readlines.
Depending on how the car is built, this can have a noticable, or negligible effect.

Basically, if the car makes peak power near redline (S2000, ISF...300ZX with high RPM turbo) and is built to spec using minimal power limiter, the increase in available rpm can be useful.

However, if the engine makes peak power early in the rev range, and then dies off due to parasitic losses, the increase in available rpm really does you no good, as the longer you hold a gear, the less power the motor is making (which in turn slows down your acceleration).

Similarly, if your build uses a lot of power limiter, shifting at redline can be slow, as usually, a lot of limiter results in virtually no torque at high rpm. If you flatten the power curve to the point where peak power and peak torque are very low in the rev range, it makes no sense to run the engine near max rpm.

These kinds of cars (muscle cars, Skyline GTRs with mid turbo) generally benefit from a custom transmission which is set up for short shifting (ie, you shift up at or just past peak power, as opposed to going all the way to redline, thus keeping the revs in the powerband).

Hopefully my crappy explination is understandable :lol:
 
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I actually consider one thing first. Weight distribution. Of course i always leave the car lighter than original, but i usually add ballast to improve that.

For example: for cars that are very light (around and under 1000kg) with heavier front or back, i usually add enough weight to make it 50/50 or as close as possible while keeping it a few kg lighter than normal. Then i match the PP limit with power. On the other hand, for heavier/powerful cars, i try to keep at least it's original power, and reduce/redistribute the weight as much as possible.

Weight dist and ratio first, revs/peak power second, horsepower increase third. If you manage to fine tune and balance them all, you would probably find the sweet spot for each car.
 

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