Great 1/4 mile calculator

**Stav** · 16-05-2007, 07:48 PM

http://www.nationaldrivetrain.com/calcs/dragcalc.html

I used this calculator to see how good it was. I had 2 dyno numbers at the same time from 2 different dynos. 131 rwkws and 147 rwkws.i was very confused as to which dyno was correct.Both were dyno dynamic dynos.
My cars weight 3700 pounds with 147rwkws(197hp) estimated my et as 14.78.

The second dyno 131 rwkws (175 horsepower gave me a figure for the 1/4 mile of 15.32. It is highly likely the 131 rwkw figure is wrong.
Plug some figures in and see how you go..

au2sw · 16-05-2007, 07:59 PM

how heavy is a wagon in pounds?

jonbays · 16-05-2007, 08:33 PM

Quote:

Originally Posted by au2sw

how heavy is a wagon in pounds?

Well the brochure I have says 1645kg for may AUII Fairmont wagon and on the weighbridge it was 1650kg so it would appear accurate. Futura and forte would be lighter say 1575 odd maybe?

Here is the fairmont spec sheet

http://www.fordforums.com.au/photos/...cat=500&page=1

MoreHPformyXR6 · 16-05-2007, 08:06 PM

Quote:

Originally Posted by Stav

http://www.nationaldrivetrain.com/calcs/dragcalc.html

I used this calculator to see how good it was. I had 2 dyno numbers at the same time from 2 different dynos. 131 rwkws and 147 rwkws.i was very confused as to which dyno was correct.Both were dyno dynamic dynos.
My cars weight 3700 pounds with 147rwkws(197hp) estimated my et as 14.78.

The second dyno 131 rwkws (175 horsepower gave me a figure for the 1/4 mile of 15.32. It is highly likely the 131 rwkw figure is wrong.
Plug some figures in and see how you go..

Sounds great love to have a go. What's the formula to convert 161.2rwkw to HP? What's the formulat to convert kilo's to pounds I thimk the BA XR6 NA is 1709kg anyone?

Hibbz · 16-05-2007, 08:14 PM

so stav going by that calculator you should be getting close to a flat 14. Are you running at the drags next weekend for aff drags

Jake

Casper · 16-05-2007, 08:14 PM

not even close for my car

b2tf · 16-05-2007, 08:20 PM

wow, 170rwkw equals a 14.05 qtr time. amazing!

**Stav** · 16-05-2007, 08:22 PM

Quote:

Originally Posted by Casper

not even close for my car

No because your dyno is wrong..like one of mine was.

Casper · 16-05-2007, 08:24 PM

Quote:

Originally Posted by Stav

No because your dyno is wrong..like one of mine was.

Even editing it to meet the ET the MPH is totally screwed. I'll stick to calculating ET's by driving down the black stuff really fast

jonbays · 16-05-2007, 08:17 PM

OK i gave it a go.

My wagon weighed in at 1650 on the WSID scrutineering bay so with me in it its 1730KG on the track so that 3806lbs don't know how much lighter the Futura is but 3700 seems light fo race weight to me. Any way power wise pick a number from any one of a million dynos i have beem on say 140kw or 188hp and i get 15.16 @85.94mph?

Since i can be very sure on the weight going backwards from my best time gives me 177HP or 132kw at 15.46 but @84.24mph? I need to have almost 225HP to get the TS that I can get on the track on the calculator. I reckon it means the car is overgearewd which it is of course.

jonbays · 16-05-2007, 08:25 PM

I think its pretty close to be useful if you assume its race weight not just the kerb weight in pounds 2.2 of those for every kilo and that is rear wheel horsepower 1.3 of those for evry kw. It probably also assumes perfect launch and gearing so it would be the ideal not always achievable.

**Stav** · 16-05-2007, 08:27 PM

The mph is out but it is uncanny how it perfectly gave me my real already run et when I plugged in my weight/rpm and power...exactly.

TheSneakiness · 16-05-2007, 08:31 PM

Gave me a lower MPH reading, and my time should be .8 of a second quicker than it is...

Casper · 16-05-2007, 08:31 PM

Given that your wagon and my xr6 are almost the same weight and run identical times.. that would mean almost identical rwkw I guess. I just dont think they are accurate as gearing and torque are totally ignored. Not to mention grip, track conditions and even transmission type

**Stav** · 16-05-2007, 08:35 PM

Quote:

Originally Posted by Casper

Given that your wagon and my xr6 are almost the same weight and run identical times.. that would mean almost identical rwkw I guess. I just dont think they are accurate as gearing and torque are totally ignored. Not to mention grip, track conditions and even transmission type

Hmm maybe its just me that got the perfect et match?

**Stav** · 16-05-2007, 08:42 PM

Quote:

Originally Posted by Stav

Hmm maybe its just me that got the perfect et match?

Nar ..at the end of the day to move a certain weight across 2 fixed point...being the starting line and finsh line requires a certain amount of power.Gearing ,traction and other similar mods change the power delivery. Therefore you have a ceratain amount of power put to the ground to get there in the specified time or et. To get from point a to point b in the same time at same weight then the car across the track must deliver the same average power despite dyno mumbo jumbo differences

au2sw · 16-05-2007, 08:32 PM

ok, using 3800pounds and running my 2 figures (petrol and gas) i get
15.94@81.8mph for petrol
16.35@79.8mph for LPG

**Stav** · 16-05-2007, 08:34 PM

So what are you guys getting down the 1/4 and mph? I already mentioned the mph is incorrect in the calc.

I plugged deathxr power in and it seems to think he can pull a 14.56

jonbays · 16-05-2007, 08:34 PM

Quote:

Originally Posted by au2sw

ok, using 3800pounds and running my 2 figures (petrol and gas) i get
15.94@81.8mph for petrol
16.35@79.8mph for LPG

Those would be honest enough ET's the TS seem low though. Certainly mine ran 16.8 best stock u know!!! : (

jonbays · 16-05-2007, 08:41 PM

yeh its nver going to be right for everyone its a calculator thats all. not bad almost as amusing as a gtech and a lot less amusing than actually running your car down the strip.

Slips rule dyno charts 1/4 calcs gtech asn all that sort of stuf is just F5643

Sourbastard · 16-05-2007, 08:47 PM

theres much more to the 1/4 then power and weight. these calculators are more of a novelty toy for mastabatorial technicians.

jonbays · 16-05-2007, 08:54 PM

Quote:

Originally Posted by sourbastard

theres much more to the 1/4 then power and weight. these calculators are more of a novelty toy for mastabatorial technicians.

Well i wouldnt have put it quite that way but ...

**Stav** · 16-05-2007, 09:05 PM

Quote:

Originally Posted by sourbastard

theres much more to the 1/4 then power and weight. these calculators are more of a novelty toy for mastabatorial technicians.

Thanks for the input mate.That helped the topic heaps.Youve invented new words for the dictionary.

:

Sourbastard · 16-05-2007, 09:20 PM

its true, like it or not, its a fantasy land toy. It cant calculate track temperature, driver ability, suspension stiffness, traction, wind direction, aerodynamics. These details can vary the result hugely.

At best its a magic 8 ball of drag racing.

"Will I run an 11 second quarter?"
"Outlook not good"

au2sw · 16-05-2007, 10:15 PM

trust sourbastard to bring us back to reality

:love it and i vote the mastabatorial technicians wins phrase of the year!!!

:

out: :sm_headba

Futura01 · 17-05-2007, 03:31 PM

i just tried it and got this:

Vehicle Weight (in pounds in me): 3520
Vehicle Horsepower: 196.83hp rear wheels
RPM through lights (finish line): n/a
Tire Diameter (Hght.) in Inches: 16"
1/4 Mile ET: 14.51
1/4 Mile Top End Speed: 89.74
1/8 Mile ET: 9.24