When people "magazine" race cars, they are always comparing 1/4 times, but what is the significance of 1/4 speed?

For example, lets say you have two cars; car A and car b.

Car A does the 1/4 in 14.2 secs, but traps at 102 mph.

Car B does the 1/4 in 13.8 secs, but traps at 98 mph.

Does this mean that Car B gets to the end of the 1/4 first but Car A is catching up?

 

This means the car got a better holeshot and got to the end quicker.If the cars had the same mile an hour,then you would see who was quicker!

 

Yes in some cases it does mean the car that ran the slower 1/4 is catching up. Many AWD cars such as the WRX and the S4 are capable of running the same times as the z. If you look at the trap speeds on them they are consistantly lower. Take a look at the 0-100 speed and compare that.

 

a few friends of mine are trapping at 107-108 and are only hitting low 13's because of traction problems. i have the same problem in my crx.

 

...if the reaction time is the same on both car A lost .4 tenths of a second...this is common on cars that get out of the hole quick such AWD there traps tend to be lower....

 

R/T has nothing to do with trap speed or E/T so I guess I dont know what your trying to say. Everybody just forget about R/T it has no bearing what so ever on your times. Im right in assuming nobodys bracket racing right?

Gearing has a lot to do with trap speed versus E/T in most cases mph is more indicative of greater power and E/T is more indicative of setup.

 

i thought he's saying how would the race go down...the 14.2 could win if he leaves first by .4001 w/o a redlight...

put it to you this way...depending on so many factors it could like the 13.8 at 98 car is pulling away from the 14.2 guy the whole time... the only thing that would allow us to really tell you how it'd look is to assume both cut perfect trees .500 (sportsman)

 

Reaction time does play a part in racing, however it doesn't effect E.T. or trap speed. So yes TypeR you are correct, since in the example both cars were racing each other.

But a lot of people thing that once the light goes green the clock starts and that isn't true. It is once you car breaks the light beam. meaning the car has to start moving first. You can sit still for 2 hours and still run the same E.T. and MPH as if you cut a .500 light.

 

Bleh.
Trap speed is the best indicator of power, and acceleration.
Although it can be effected by bad shifting, and is slightly effected by 60ft.

 

The car with more trap speed have more chance to win in the street. In my opinion the trap speed is more important that the 1/4 mile time, for street racing of course!

 

Was reading the latest article on the RX-8 and I thought of this thread.

Checking the stats for the Z vs the RX8 in this particular mag (I know, I know - Magazine racing) shows that the Z and the RX both have a 1/4 mile time of 14.4 secs.

The trap speed however was quite different. The RX trapped at 95 mph while the Z trapped at almost 100 mph. Am I right in assuming that the Z stronly pulling away from the RX at the end of the 1/4?

 

no...that would mean if they both left at identicle times that the Z was behind the whole time only to come on in the last few hundred feet, to end up with the same time

 

Your correct the Z was behind but gaining ground that explains its higher speed with the same time, even though they crossed the 1/4 at the same point the Z was going faster.

 

That's what I thought. The Z starts off behind but catches up to the RX so that at that 1/4 "instant", the cars are side by side. However, the Z is going 5 mph faster so in the seconds after the Z is pulling away from the RX-8.

Out of curiosity, I did a quick conversion. 5 mph translates into 7.3 ft/sec, which is basically half a car length per second. After 4 seconds the Z is 2 cars lengths ahead, assuming the same speed differential.