tav 2 question

[Poboy kartman]

Something with that math doesn't seem right sid. I cant see a 400lb kart with a clone doing the equivalent of a 10s 0-60 time.

Wha a a a t? OK -apples and oranges I get...... but you totally lost me.....A 10 second 1/4 mile car makes almost ALL of it's power at high rpm. It has a lot of weight to get moving.......IDK- ........

 

[exenos]

Wha a a a t? OK -apples and oranges I get...... but you totally lost me.....A 10 second 1/4 mile car makes almost ALL of it's power at high rpm. It has a lot of weight to get moving.......IDK- ........

I'm not talking 1/4 mile. The top speed or 70km/h in the picture that sid posted seems right, but the 7s to get there seems too fast.

 

[itsid]

Something with that math doesn't seem right sid. I cant see a 400lb kart with a clone doing the equivalent of a 10s 0-60 time.

well the math is perfectly okay I'm afraid..
But ATM it's nothing but simplified math unfortunately
(no drag, no wind, no friction not even road inclination)
for a TC it's a third max torque,one third mid and one last third min torque to find the average acceleration (2.6m/s² in this case)
I know that's just a fictional ideal but it's a starting point without a dyno test
(I will shift the values according to more real life TC behaviour after I have some tests)

Based on the minimum needed torque (tiresize and weight) to get the kart moving it should at least help to get an idea.

[for comparison]
with a cent clutch it'd be 1.69m/s² and 10.65 seconds to reach 64.63 km/h (40.16mph)
on a 18" wheel driven 200kg kart
-same math- different torques and single gear ratio
[/comparison]

But you're right at 2.6m/s² it'd be 26m/s after 10 seconds theoretically (93.6 km/h or 58mph)
and that is NOT going to happen!
But the problem isn't the existing math, but the missing additional information,
like the TC shift sequence which is nothing but wishfull thinking ATM and of course wind resistance (well all friction to make it short) which is already an issue at the speeds we're looking at,
and I'm not actually taking that into account at all right now
(I will ... later)
So yeah, it looks wrong or let's say surreal, because the math is in fact correct

'sid

 

[happy_8637]

when it warms up here cause this mornin its -6 F i will try the gps and see what i can hit..mph wise with and that will get me closer to know what to do thanks for all the info

 

[exenos]

I'd try it now, cold air = denser = more power

 

[itsid]

I'd try it now, cold air = denser = more power

dense air = more oxygen per combustion
AND
more wind resistance

Funny side note (Off Topic I'm afraid )

I played around with some numbers for rolling and wind resitances
taking average coefficients from the net
ending up with a factor of 0.45something for wind (took 0.5 to ease the calc)
and 0.19something for the rolling resistance (took 0.2 here)
for a 200kg Kart at a speed of 20m/s (72km/h like in the previous result.. again easy math to calculate the numbers in my head)
I ended up with a minimum power of 4.8kW (or ~6.5HP!)
to maintain said speed on a level asphalt road.
Now let's talk about coincidence


'sid

 

[exenos]

So really, taking into account the huge losses incurred by the cvt system 60km/h seems reasonable.