1/4 mile time calculation

[kangavxss]

Does anyone have a formula for working out 1/4 mile times for a modded vxss ( cam, otr, full exhaust, 3.73 diff gears, mafless etc typical mods). I dont live or have access to a drag strip so always wanted to know roughly what my ss would do. I did find an online calculator (Xcceleration) that asked for rwhp (355rwhp - 265rwkw) and weight of car (approx 3300lbs i think) and it gave a time of 12.2 seconds. The calculator doesnt ask if its manual (its an auto) or diff gear ratio ( 3.73) if that has effect on the time. Is the 12.2 about right? I know there are many variables but a ballpark figure is what im after. Also whats the 1/4 for a stock ss. Like to know my mods have paid off...lol.. Thanks for ur help...

 

[Not_An_Abba_Fan]

Still not going to have the same weight as an actual time slip though will it. Can see the conversation now...

"Hey man, took my car to the strip and it did 12.5, here's my time slip. How fast is your car?"
"According to the online calculator it does 12.2"
"....."

 

[AirStrike]

Don't have access to a drag strip?
Adelaide International Raceway
29th of June, only way you'll know what it runs.

 

[Pollushon]

Desktop dyno and drag purport to do this accurately....it's a load of **** IMO.

 

[gm1961]

Hi All

just google / search for online speed calculator
but here is a good site with plenty of links
also you can find excell sheets

The best program to use is 1/4jr & dyno these are older dos programs, for windows you can use dyno 2000
they may turn up on a google search or a torrent, but they are commercial ( bought / paid ) programs , i am just pointing you in the right direction not telling you to do something illegal, there may be limited or trial versions available.

For free online simulators / calculators i use this site with a fair few web pages listed

Wallace Racing - Automotive Calculators

you may also need a metric to imperial calculator, use a online one, but there are some good utilities you can download

But the results are not perfect, instructions are vague, so some may be for rear wheel HP, but dont actually say , others ( usually USA ) like to use engine flywheel HP as a example

So some stats for a VT SS

We know the weight is 1643kg ( hmm my rego papers say my VT SS 304 is 1504 )
so 1643kg = 3662 pounds

We know it is rated 179kw , this is 243 HP ( roughly we use 1/3 to go HP to KW , also as a coincidence we also use 1/3 to go from engine KW to rear wheel HP as driveline loss is about 1/3 , so sort of funny a 180kw engine , should show 180 hp rear wheel dyno as a guide )

the maths in some 1/4 programs came back as follows - best time 14.33 , which is think is a bit high , i dont have any proper trustworthy articles here but i would be suprised that the Gen3 would be a 14.3 car , the 304 to me would be a 15.5 -16.0 car

Power to Weight Ratio: 14.91
60 Foot E.T. : 1.99
1/8 Mile E.T. : 9.04
1/8 Mile Trap Speed : 75.15
1/4 Mile E.T. : 14.33
1/4 Mile Trap Speed : 93
1/4 Mile Trap RPM : 3,985


regards
george

 

[kangavxss]

Don't have access to a drag strip?
Adelaide International Raceway
29th of June, only way you'll know what it runs.

Yeah i know i could go to Adelaide International but weekends see me working most of the time so im out of luck there for the time being..

 

[kangavxss]

thanks gm1961. very informative.

 

[Not_An_Abba_Fan]

I just did the calculation for the VC at Kwinana Motorplex.

Your 1/4 Mile ET is 11.81
Your 1/4 Mile MPH is 117.27

Bit like a happy dyno.....

 

[Immortality]

Hi All

just google / search for online speed calculator
but here is a good site with plenty of links
also you can find excell sheets

The best program to use is 1/4jr & dyno these are older dos programs, for windows you can use dyno 2000
they may turn up on a google search or a torrent, but they are commercial ( bought / paid ) programs , i am just pointing you in the right direction not telling you to do something illegal, there may be limited or trial versions available.

For free online simulators / calculators i use this site with a fair few web pages listed

Wallace Racing - Automotive Calculators

you may also need a metric to imperial calculator, use a online one, but there are some good utilities you can download

But the results are not perfect, instructions are vague, so some may be for rear wheel HP, but dont actually say , others ( usually USA ) like to use engine flywheel HP as a example

So some stats for a VT SS

We know the weight is 1643kg ( hmm my rego papers say my VT SS 304 is 1504 )
so 1643kg = 3662 pounds

We know it is rated 179kw , this is 243 HP ( roughly we use 1/3 to go HP to KW , also as a coincidence we also use 1/3 to go from engine KW to rear wheel HP as driveline loss is about 1/3 , so sort of funny a 180kw engine , should show 180 hp rear wheel dyno as a guide )

the maths in some 1/4 programs came back as follows - best time 14.33 , which is think is a bit high , i dont have any proper trustworthy articles here but i would be suprised that the Gen3 would be a 14.3 car , the 304 to me would be a 15.5 -16.0 car

Power to Weight Ratio: 14.91
60 Foot E.T. : 1.99
1/8 Mile E.T. : 9.04
1/8 Mile Trap Speed : 75.15
1/4 Mile E.T. : 14.33
1/4 Mile Trap Speed : 93
1/4 Mile Trap RPM : 3,985


regards
george

Just like the Moroso calculator, these results are a best case scenario. No road car is going to have perfect traction or gearing etc.

Using those kind of calculators look at the MPH as this won't change much as it takes X amount of power to achieve Y speed. Elapsed time is going to be slower.

 

[st3r3otyp3]

anywhere from 12.5-12.9 Id say don`t get overhyped you may get deflated, where does it make max torque with no converter this is important.