Thats Sonata Slow Rental Car...

[Danny]

The 06 Sonata sure is a pretty car.

 

[Tornado]

Honestly, though, I'm certain that the camera is off. 147mph? My recent turbocharged European sedan's speedo doesn't even go past 140. I'd buy 127, and maybe 137 but 147 is out of this world.

My Mom's P-Body Shadow did a GPS-proven 127, and it only had 100 BHP 2.5L I4.

 

[YSSMAN]

While I have my doubts as to the veracity of any speed-camera reading, I don't doubt that 147 mph is possible in a modern FWD V6. That's why a lot of them have 130-135 mph speed limiters. I'm just surprised it's taken so long for someone to do this... and get caught.

Well, consider that the FWD Chevrolet Impala/Monte Carlo SS with the 5.3L 303 BHP V8 tops out at 154 MPH (governed). The V6 version? Barely goes north of 120 MPH, and it has about the same ammount of power as the Hyundai as mentioned.

 

[Tornado]

Well, consider that the FWD Chevrolet Impala/Monte Carlo SS with the 5.3L 303 BHP V8 tops out at 154 MPH (governed). The V6 version? Barely goes north of 120 MPH, and it has about the same ammount of power as the Hyundai as mentioned.

Yeah, but the 3800 is a pig of an engine, and the Hyundai is no doubt a smoother car (not to mention lighter).

 

[Famine]

Well, consider that the FWD Chevrolet Impala/Monte Carlo SS with the 5.3L 303 BHP V8 tops out at 154 MPH (governed). The V6 version? Barely goes north of 120 MPH, and it has about the same ammount of power as the Hyundai as mentioned.

Gearing and aerodynamics.

The numbers say that the Hyundai has just about enough power to overcome the drag at 147mph, IF its gearing will allow it to get there. My particular FWD V6 car has 138hp and does 141mph, limited by both 'box and aerodynamics (it runs out of gearbox at the exact same time it runs out of power).

 

[Danoff]

Because most cars can't reach the limit of their speedometer.

Hehe. I drove a 1971 VW Beetle whos speedometer topped out at 90 mph. It's cool to watch it start to wrap around the bottom. Note: I accomplished this while going down a steep hill, in case anyone starts with the drag/hp calculations.

 

[1X83Z]

Gearing and aerodynamics.

The numbers say that the Hyundai has just about enough power to overcome the drag at 147mph, IF its gearing will allow it to get there.

My problem with your numbers - and you didn't post the calculation you used to get them - is that they don't take any factors but aerodnyamics, the speed, and the power into account, completely abandoning weight and, indeed, gearing. My biggest problem, though, is that they can't account for the tires, which aren't rated to go anywhere near that high - the tires on that vehicle are 215/60R16s, which, if I understand the ratings correctly, aren't intended to beat 105mph.

 

[daan]

the tires on that vehicle are 215/60R16s, which, if I understand the ratings correctly, aren't intended to beat 105mph.

The R16 means its a radial tyre that fits 16 inch wheels. You haven't listed the speed rating there.

Speed Rating Miles/Hour Kilometers/Hour
N 87 140
P 93 150
Q 99 160
R 106 170
S 112 180
T 118 190
U 124 200
H 130 210
V 149 240
Z 150+ 240+
W 168 270
Y 186 300

http://www.blackcircles.com/general/speedrating

Is the fact that a car can go faster than it's tyres speed rating OK in the US? I know that in the UK, if my tyres aren't speed rated for my car, then my insurance can be invalid. So I have to buy at least a V (149mph) rated tyre, even though my record speed would be covered by an H, and its highly illegal to be going at that speed anyway.

 

[Famine]

My problem with your numbers - and you didn't post the calculation you used to get them

I didn't post the calculation? What's this post all about then?

Rolling resistance (at any speed) in lb = 0.0135 x Vehicle weight (lb)
Air resistance in lb = Coefficient of drag x Frontal Area (sq.ft) x 0.00256 x speed (mph) x speed (mph)
Total resistance in lb = Air resistance + Rolling resistance
Power required at wheels to overcome resistance = Total resistance in lb x (speed (mph) / 375).

is that they don't take any factors but aerodnyamics, the speed, and the power into account, completely abandoning weight and, indeed, gearing.

Abandoning weight? What's this line all about then?

Rolling resistance (at any speed) in lb = 0.0135 x Vehicle weight (lb)

Total resistance in lb = Air resistance + Rolling resistance

And no, they don't take into account the gearing. That's why I clearly stated:

In this case, assuming that the Hyundai can reach 147mph at all with its gearing (ratio, final and wheel), the Hyundai probably will be able to reach 147mph just with its engine power, dimensions and weight.

Which, you'll note also includes the word "weight".

My biggest problem, though, is that they can't account for the tires, which aren't rated to go anywhere near that high - the tires on that vehicle are 215/60R16s, which, if I understand the ratings correctly, aren't intended to beat 105mph.

I don't need to take the tyres into account for the calculation. The calculation is for "aero speed" - the maximum speed the vehicle can reach with it power, dimensions, Cd and weight. In this case the "aero speed" is, roughly 147mph. If the gearbox will allow it to reach 147mph then the car will be able to reach 147mph.

As for the tyres, its rated top speed is 137mph. This means that, by LAW in the UK (though I'm not sure about the US), it must wear V-rated tyres - tyres rated above the vehicle's top speed - which are also, handily, rated up to 149mph.

215/60R16 means that they are radial tyres with a cross-section of 215mm, a sidewall of 60% the tyre's width (129mm in this case) and an internal diameter of 16 inches. No speed rating is referred to.

For example, my own tyres are 225/45ZR15 - 225mm wide, 101mm sidewall, 15 inch internal diameter, 150mph-rated radial tyres.


This is irrelevant to aero speed.


Besides, do you know what happens when you take tyres over their maximum rated speed? I'll give you a clue - the words "absolutely" and "nothing" come into it for a full 25% above the rated speed.