Speed
- Thread starter johnjoe64
- Start date
H
hiwd
Guest
Get an Apexi RSM, that has a digital speed read out....
Rob Spec C
Octane Boostaholics
If you dont want to spend any money, then you can also make a graph for yourself that will give you an idea using Junior Cert Maths. Theoretically you can take the speed at 2000 rpm, 3000rpm and 4000rpm. You can then make a graph, speed versus rpm, and plot the 3 points. This should give you a striaght line that you can extend as far as you want. If you want to know the speed at 7000rpm, then draw a line up to where it meets your graph line, then draw across to where it hits the speed axis and you will have your speed.
Of course this doesnt take into account friction loss's, any element of clutch slip, wind, uphill, downhill, tyre wear, bigger alloys or anything else that could affect it. The other thing is the allowance on the speedo, if this is constant (say 5mph) then its fine but if its a percentage then you need to know the percentage and account for it in the graph.
To be accurate, you could get an RSM but this doesnt account for tyre wear or bigger/smaller alloys either. The most accurate is probably the GPS tracker, where it just uses the basic distance/time formula and its the most accurate one
Of course this doesnt take into account friction loss's, any element of clutch slip, wind, uphill, downhill, tyre wear, bigger alloys or anything else that could affect it. The other thing is the allowance on the speedo, if this is constant (say 5mph) then its fine but if its a percentage then you need to know the percentage and account for it in the graph.
To be accurate, you could get an RSM but this doesnt account for tyre wear or bigger/smaller alloys either. The most accurate is probably the GPS tracker, where it just uses the basic distance/time formula and its the most accurate one
goldenjohn
Octane Boostaholics
Get a lad on a bike or someit too follow you. Or a car fast enough too keep up with you. 
not that i'm condoning it. 
No money spent that way either.
Make sure that the car is clocked higher than 140 though/
:lol:
not that i'm condoning it. No money spent that way either.Make sure that the car is clocked higher than 140 though/
:lol:
STiBrian
Octane Boostaholics
Like what Robbie says, there are numerous factors that would give you a skewed reading regardless of what method you use, not alone the fact that speedos are known to read anything upto 10% different than actual speed.
The cheapest and most useful tool would be a sat-nav system, you can pick them up for less than 100 yoyo these days & serve a dual purpose
The cheapest and most useful tool would be a sat-nav system, you can pick them up for less than 100 yoyo these days & serve a dual purpose