Can a time slip tell more then just 1/4m
- Thread starter ricardoa1
- Start date
mywhite89
Registered User
All you need to know is the weight of the car and the trap speed and some of those online calculators can give you a decent estimate. I beleive it is all just an estimate though, and can be off by a decent amount.
Chris
fastsc92
Registered User
Those calculators are fairly accurate given ideal conditions...
On my PLX logger I can calculate HP using a 2-axis accelerometer. This way I can datalogg realtime HP and torque that is utilized. I use similar parameters as those calculators:
Weight in lbs
MPH (converted to ft/s)
Acceleration (G-Force, not ft/s^2)
the equations then simplifies down to HP=MPH x G's x Weight/804.6
then you can calculate Tq from HP using RPM's and the constant 5252.
On my PLX logger I can calculate HP using a 2-axis accelerometer. This way I can datalogg realtime HP and torque that is utilized. I use similar parameters as those calculators:
Weight in lbs
MPH (converted to ft/s)
Acceleration (G-Force, not ft/s^2)
the equations then simplifies down to HP=MPH x G's x Weight/804.6
then you can calculate Tq from HP using RPM's and the constant 5252.
XR7 Dave
Registered User
The data can be used to help you narrow down some things but there are always limits.
For example, I ran 12.09 @ 114 in my car. Given perfect traction and a good launch 114mph is good for an 11.95. This tells me that my launch was pretty good but not perfect. Now on a car with an auto set up for drag racing that same 114mph is good for an 11.75.
That is useful information but it doesn't tell the whole story. Just because your car makes a particular power number doesn't mean you'll get it down to the pavement in a quarter mile. During the above run my car was making 440rwhp+ @ 6200rpm but I was shifting at 5500rpm so my actual max power was more like 415rwhp combined with the fact that I was running 3.27 gears which put me well down in the power band crossing the finish line (4500rpm) and I was actually only getting an average of about 390rwhp to the ground.
You can also compare your 1/8 mile #'s with your 1/4 numbers to see if the car is pulling like it should on the top end. Sometimes you'll see a great 1/8 mile followed by a lackluster 1/4 time. This typically indicates either a mismatch of gear ratio's or a tuning issue.
So the numbers can help you figure things out but they will not tell you the whole story.