Accuracy of "1/4 Mile E.T. Calculators" ?

You know . . . The ones where you enter your car's weight ( with or without driver ? ) and either your Torque or HP, either at the Flywheel or Rear-Wheel numbers.

QUESTIONS :

(1) Do they only rely on Peak Torque or Peak HP ?

(2 ) How accurate are they ?

(3) Are there any "online calculators" that would let you enter data from a Dyno Chart, all throughout the RPM range ? ( It would be really cool if you could also enter transmission gear ratio's and ring & pinion ratio and run it through all of the gear changes, too ! )

 

Desktop Dyno 2003 has #3 built in.

 

Will it allow for a simulated combination to be "run through the gears", all through the RPM range, by inputting Torque & HP numbers at various RPM levels ?

In other words, will it allow you to "virtually drag race" the entire combination ?

 

Well, yes and no. DD 2003.
It's an old program, so how detailed do you expect it to be?
But it's free, so download it and have fun.
You input your engine parameters into DD2003 and then they transfer to Drag2003 where you can do that simulation.
I have the program, the head flow files, and the engine files. But you can no longer email them because email now blocks those type of files.

Of course there are now newer and more detailed and accurate programs, but you will pay $$$ for them.

 

There is another way . . .

https://wetransfer.com

 

Some are pretty accurate, usually et is alittle quicker than actual since most cars are not set up perfectly to use its power. A well optimized drag car might get closer.

its good enough for an estimate if you know your hp and weight

 

I was thinking of using it to optimize cam event choices and gear ratios ( transmission & rear end gears ), by being able to "virtually drag race" the vehicle, up through all gears, using Torque & HP data throughout the RPM range.

 

None that i know of do that. They seem to work off a peak hp value.

you could try to take average hp across the curve that is used for a track pull and use that as the estimate. Higher average hp should run the fastest. Then again it depends on rpm too, two motors that have same average power but one makes that power at a higher rpm will have a slight advantage at the track.

this would assume you have a very good engine simulator to get power curves based on small changes in cam events. Desktop dyno is not it lol. Think engine analyzer pro or better

Use peak power to determine what mph to expect in the 1/4 and then use your power curve rpm range and tire sizes to get gear ratio and optimal shifts based on trans gearing and dyno chart average power. It can be done i guess but seems like a lot of work for marginal accuracy at prediction

 

Thanks . . . Not the answer I was hoping for, but it was the one I expected, based on comments here and searching the internet.

 

http://www.gearcal.com/

 

Thank you for the link . . . Very Interesting !

 

You’re welcome

 

cool. I just played around with that gearcal.com site a bit, swapping from a 3.55 gear to a 3.91 in the next few weeks.
thanks for posting it

 

neat graphic. fer all the arm chair hotshoes remember that the desktops always make assumptions about traction, -- which is the key to obtaining time.....

 

No ones arm chair racing.

 

I put my Hp and time into the 1/4 mile calculator and it said I suck and should let somebody else drive.

Well, nobody is talkin' time slips either, so.....