HP calculations with time/speed

[A80Avant]

I wonder if there can be a calculation of rough hp or whp depending on time it takes for a car to reach a certain velocity taking into account the weight of the car.
Obviously any such measurement would have lots of other factors in like airdrag,and level of the road doing a run,and etc etc...Hence im saying 'rough' assesment.

It would be interesting,after seeing a video of an RS2 which came with the GT3076R turbo(dont know what hotside yet) and a tubular manifold,reverse inlet from carsten(PKm) and it produces like 500hp.On the video i noticed that it takes roughly 7.2 to 7.4sec to make 60-160Kms run with 2 gear changes(again the time taken to make the changes is also a factor) and it seems that the changes are good,nothing extra fast,nor slow either.

Now if that is the case,and my car is doing a similar run on hot weather @ 7.8 to 8 sec at most(i need to make a clearer video though),with a marginally smaller turbo,rs2 manifold,OEM inlet manifold and more or less the same boost as the above car(1.8bar),it seems a little odd...

I would expect a much better performance from a car that has 100hp more !!

here is the link to the video by the way

http://de.youtube.com/watch?v=0SlhvkAPWfs

[Rusty]

Because peak horsepower is usually only available for a short space of time you can only calculate average power over an allotted time period. The GTech does this but with a much higer sampling rate.

[stiglet]

You also have to take into account the rotational inertia of the power train when accelerating to get an rough hp figure. In 1st and 2nd gear this has a huge effect. Not so much in higher gears. Much easier to just compare top speeds given you are comparing the same model, hence same drag for comparitive purposes.

[A80Avant]

im only comparing 60-160runs on these cars which basically give the same effects on inertia losses as they are the same cars with same gearboxes and generally equipment,if we say that the clutch is in good condition

[Rocco]

i will try to test this 60-160km/h today in my 3b driving in the highway for stay with my girlfriend

my 3b has less weight than your RS2 and less power too.... and different gear ratio

[Audi_CQ]

Looked at an old G-tech readout and my CQ does 60-160 in 6,2s. ~450@wheels with g-tech measured in 3. gear. Weight 1720kg (driver and 1 passanger)

[A80Avant]

so you only had 1 gear change,from 3d to 4th? or was the 3d gear enough to reach the 160km? the RS2 cannot reach the 160kms in 3d gear!

but that is a very good example. 6.2sec on a 450whp car means around 520+ crank so it makes sense.

[Audi_CQ]

so you only had 1 gear change,from 3d to 4th? or was the 3d gear enough to reach the 160km? the RS2 cannot reach the 160kms in 3d gear!

but that is a very good example. 6.2sec on a 450whp car means around 520+ crank so it makes sense.

2 gear changes yes. 6 speed A8 box with same ratios as RS2. Shift at ~7200rpm.

450whp + air resistance + normal dyno loss(tyres and drivetrain) is probably 550+ @crank I quess.