True Weight to Power formula, Should I use this?

[Tank-Ceo]

Ok, I am buying my first car in GT5. I lost my account and well i have to start over, so I wanna buy the fastest car and don't tell me which cause im bored.

Ok so, we have the honda civic Type R EK '97 which has 182hp/118lbs torque/1050 kilos

So: 1050kg / 182hp = 7.769, then 1050/118lb of torque = 8.898
Now you add both kg to hp and torque (7.769+8.898) = 16.667 / 2 = 8.3 Average kg/power

Formula: ((Weight/HP) + (Weight/Torque)) / 2 = True Weight to power.

I don't know much about cars, I mean I don't know how much Torque plays a role in it, but would this be a accurate way to tell a cars true power by including the torque, or should I just use (Weight/HP) formula to determine its power. Its not really time consuming since I just have a laptop next to me and input it into spreed sheet that has the formulas all ready.

I guess what im trying to get at is should torque be a consideration when buying a car. Shouldn't that formula average the car out and be faster than cars with a better weight/hp when the weight/truepower average is a better number (well lower kg/power is better)?

 

[Famine]

Ignore torque altogether, for two reasons.

First, horsepower is "amount of torque per second" (literally - 1hp = 550lbft/s). Second, engine torque doesn't move a car anywhere at all - it gets multiplied up through the gearbox, so your 118lbft of torque can be 1,400lbft in 1st gear, or 250lbft in 5th gear.

Torque is only a useful metric when you have two cars of about the same power with about the same gear ratios. Otherwise it's not really a number you can do anything with. Except tow a boat.

weight/truepower

Power is "true power". Power is what torque does. 182hp is 100,100lbft per second.

 

[TenEightyOne]

As Famine said, ignore the torque part of your equation because it's only useful for calculating accelerative potential of a specific object with a specific drivetrain at a specific velocity. Because it only applies to an object in motion you'd also need some fluid dynamic calculations for that to mean anything.

You're much better with a basic power/weight equation. Providing you use the same power units and the same weight units for each calculation you do (although GT5 actually uses a mass unit instead; kg) then you'll be fine. Just don't work some out in bhp and some in kW, you'll be altering ratios on either side of the division and won't get accurate numbers.

 

[Tank-Ceo]

Really, I'd think torque would have a larger role being theres we race on circuits with lots of turns. Having higher torque is good for acceleration. But thanks for the info.

What about a cars height. That has to have some negative effects on the car. Obviously a same spec car that is 1000mm high as the difference will beat a 1500mm car. So how would you incorporate that into my formula (without the torque..

Same thing? Height/horsepower? or an easier one, Weight/Power - Height Formula to see how much hp is lost due to height of a car being held back by air.

 

[TenEightyOne]

For a true formula you need (as you alluded to) to consider the front cross-section, the drag, the mass, the power, the rolling resistance against the mu of the road surface, the drag of the drivetrain, the weight distribution and so on.

For GT5's purposes you'd be best sticking to a simple power/mass calculation!

 

[INSTG8R]

Well if you just look under the Tuning there is a 2nd tab with the HP/Torque with Current Performance. The Power to Weight Ratio is there.
Dunno if that helps you out at all but I use it when I tune and compare my cars when I choose them to race.

 

[alextehkid]

A lower center of gravity will be beneficial. Naturally, a taller car will have inferior handling. The cars you're probably looking at will be in the sport coupe or GT category. The aerodynamic difference and top down centre of gravity of these are neglectible, where the chassis and suspension will have everything to say for the handling of the car. I don't think you can measure this by simply looking at the body of the car. It would have to be tested on a track and compared, and then assigned a value.

Drivetrain would be a more important stat, as well as the front to rear weight distribution. You want a car that is closest possible to 50-50, unless you're driving a Porsc.. uh, I mean RUF..

If you're comparing people carriers and sport coupes, I can't really see the point

 

[Tank-Ceo]

Ok 1 moreee question guys. The bigger displacement the more hp you will get from mods correct?

And, for my first car, should I get a RWD or a FWD as long as I don't use the FF above like 250 hp? This is my first car so I WANT IT TO BE PERFECT lol. Thanks so much for your help guys really.

 

[alextehkid]

You'll also be better off looking at the displacement and aspiration of the engine. Buy something that will crack out as much HP as possible, as power rules all. Like the others said, the car with lowest wheight to power ratio, and best handling, will also be the best car to buy.

I would also reccomend buying a light car with less power, than a heavy car with more.

 

[Tank-Ceo]

So a bigger displacement will gain more hp from mods than a smaller displacement?

 

[alextehkid]

I can't confirm this, but I would think so. Some cars have natural aspiration, and can't be retrofitted with a supercharger or turbo.

EDIT: '07 BMW M3 for instance.
EDIT2: I would perfer a FR or MR car, but you can't go wrong with 4WD.

 

[INSTG8R]

I dunno I mean I just bought a standard Miata 1.8 RS '98 from the used dealership. It is light, FR, decent handling and cheap. You need one for the NR-A Roadster Cup anyway and it can compete in quite a few of the beginning events.

Tho there are a couple of Eunos Roadster's available as well at the Mazda Dealership that are 19k.
But I wouldn't knock your choice on the Civic I have always enjoyed driving that one and I have 2 now one "stock" and one RM'd

 

[Mopatop]

Really, I'd think torque would have a larger role being theres we race on circuits with lots of turns. Having higher torque is good for acceleration. But thanks for the info.

Mostly false, only applies in first gear. As you normally operate in gears and at the top of the engine powerband, power is where it's at. Torque is only important if you're not using your gears properly. That's why having good low end torque in your road car is good, but it means nothing on the track.

 

[alextehkid]

I thought torque was one of the reasons Audi and Peugeot converted to diesel? The Seats racing BMW in the German touring series were also very successfull using diesels..

 

[Famine]

I thought torque was one of the reasons Audi and Peugeot converted to diesel? The Seats racing BMW in the German touring series were also very successfull using diesels..

If you have a higher engine torque through the same gearbox you end up with higher wheel torque and better acceleration - because gearboxes are torque multipliers. But power tells you how the torque is being used - 200hp is 110,000lbft per second, 300hp is 165,000lbft per second and the amount of actual torque is irrelevant.

So a bigger displacement will gain more hp from mods than a smaller displacement?

In terms of the game, no. However, even in the real world, displacement is more about power delivery than power itself.

Take a big, naturally aspirated engine. Say a 6.0 V12, making 500hp. That 500hp comes when you press your right foot down a bit and goes away when you lift it. But it's five feet long, three feet wide and weighs 800lb.

Replace it with a supercharged 5.0 V10. The 500hp still comes when you press your right foot down a bit, goes away when you lift it, but it uses a bit more fuel (superchargers need power to run). It's smaller (4.5 feet long, three feet wide) and lighter (700lb) than the NA V12 though.

Replace that with a twin turbo 3.0 V6. The 500hp now comes a half second after you press your right foot down and when you lift it, it thinks about slowing down, goes "FSSSSHT!" and dumps fuel for fun. On-gas it's slightly more economical than the V12 and is far smaller (three by two) and lighter (400lb) than either previous engine, allowing for more precise weight distribution by careful engine placement and it can fit in a much smaller car.


The peculiarity of the above is that all the engines have the same effective displacement - forced induction flows air at a given rate, effectively increasing the capacity. The 6.0 V12's displacement is six litres, the 5.0 Supercharged V10's is five litres plus a 61ci equivalent charger (for six litres total) and the 3.0 TT V6's is three litres plus a pair of 90ci equivalent turbos (for six litres total). The V12 delivers power on tap, is in the middle for fuel economy but is big and heavy, the V10 delivers power on tap, is least economical and in the middle for size/weight and the V6 delivers power eventually, but is the most economical (on track - less so on the road) and smallest/lightest.

What about a cars height. That has to have some negative effects on the car. Obviously a same spec car that is 1000mm high as the difference will beat a 1500mm car. So how would you incorporate that into my formula (without the torque..

Same thing? Height/horsepower? or an easier one, Weight/Power - Height Formula to see how much hp is lost due to height of a car being held back by air.

You're running the risk of overcomplicating here. However, you're broadly right - a car's frontal area (not just height) and drag coefficient (which isn't in the game) will determine the air resistance. Unless you're looking to spend the whole lap up at the limiter in whatever your top gear is, it's not particularly relevant though. All other things being equal, your 1000mm high car (with some relevant blanks filled in) will need just 52hp to do 100mph and the 1500mm high car will need 73hp to do 100mph. Since you're talking about cars with more than 200hp, it's not a problem - it only becomes relevant at higher speeds.