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Max Speed and Power on Stock Corolla

jamsbong

By jamsbong
in Corolla / Corolla Sportivo Club

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jamsbong Enthusiast

jamsbong

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This is a technical topic so may not be interesting to some of you.

The corolla is advertised to have drag coefficient of 0.3

What is unknown here is the frontal area.

To work out the maximum speed of the car, we need the drag which is produced by the car at that speed.

Drag=0.5*Cd*density*area*velocity^2

max possible speed is found using this formula:

power = drag x velocity

If I choose the dimension of the whole frontal area (i.e. windscreen and bonnet projected area to the front). then the area works out to be about 2.1m^2.

Using this area, and 75KW power at the wheel => the max speed is only 135km/h...

Obviously that is wrong. I'm sure many of you have pass thru 160km/h.

I re-check my calculations and so on. finally, i've concluded that toyota must have used a different area. so I thought... How about just the bonnet area. which works out to be around 1m^2. and woalah!... max speed of 175km/h.

which exactly corespond to the gear ratio of the 5speed sedan. 175km/h@6000rpm on fifth gear.

So i guess anything faster Will require tail wind or a long down hill... hahaha... :D

This means that the guys at Toyota knew the power at the wheels is 75KW and they didn't bother to make the car comfortable by adding a taller gear (like celica) for highway travels so that the car can be driven at 3000rpm at 140km/h. instead it is 4000rpm at 140km/h which is noisy and inefficient.

I hope this has been enlightening :rolleyes::lol:

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jamsbong Enthusiast

jamsbong

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Negatrons old 1zz Ascent could hit 194 :lol::lol::lol:

Yes. the 194 value is on the speedo. the actual speed is slower on the corolla. at 60km/h your car is actually doing just over 55km/h. at 110km/h on speedo, it is doing 100km/h actual speed.

i suppose is for safety reasons to have "extra" fast speedo. The only other reason could be toyota wants to give you an optimistic speed. hehe... :D but it seems all car makers do it.

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Hexx Community Regular

Hexx

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Negatrons old 1zz Ascent could hit 194 :lol::lol::lol:

Yes. the 194 value is on the speedo. the actual speed may be slower on the corolla. at 60km/h your car is actually doing just over 55km/h. at 110km/h on speedo, it is doing 100km/h actual speed.

Fixed.

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jamsbong Enthusiast

jamsbong

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Negatrons old 1zz Ascent could hit 194 :lol::lol::lol:

Yes. the 194 value is on the speedo. the actual speed may be slower on the corolla. at 60km/h your car is actually doing just over 55km/h. at 110km/h on speedo, it is doing 100km/h actual speed.

Fixed.

I'm only stating facts.

So that means 195km/h is well possible without going downhill or help from wind. assuming you're reading off the corolla's speedo only. That should settle it.....

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MT Grand Master

MT

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i'm in agreement that the stock speedo is completely inaccurate at speeds above 150km/h but below that its pretty dam close.

Corolla rally car in lift in 6th gear the speedo shows off the edge and the terratrip computer which is perfectly accurate is nudging just over 200...

below 150 ish they are pretty dam accurate

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jamsbong Enthusiast

jamsbong

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how much faster is the sportivo? is it close to 210km/h?

Ive had mine at 210 on a ****ty road. 100% Stock.

thanks for that.

It looks like i've underestimated the calculations. can you guys give me the max speed for all the different corolla models? like sedans, hatchs, sportivos, accents etcs?

Not just from one car but as many cars as possible. I want to recalculate this.

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CAP Grand Master

CAP

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This is a technical topic so may not be interesting to some of you.

The corolla is advertised to have drag coefficient of 0.3

What is unknown here is the frontal area.

To work out the maximum speed of the car, we need the drag which is produced by the car at that speed.

Drag=0.5*Cd*density*area*velocity^2

max possible speed is found using this formula:

power = drag x velocity

If I choose the dimension of the whole frontal area (i.e. windscreen and bonnet projected area to the front). then the area works out to be about 2.1m^2.

Using this area, and 75KW power at the wheel => the max speed is only 135km/h...

Obviously that is wrong. I'm sure many of you have pass thru 160km/h.

I re-check my calculations and so on. finally, i've concluded that toyota must have used a different area. so I thought... How about just the bonnet area. which works out to be around 1m^2. and woalah!... max speed of 175km/h.

which exactly corespond to the gear ratio of the 5speed sedan. 175km/h@6000rpm on fifth gear.

So i guess anything faster Will require tail wind or a long down hill... hahaha... :D

This means that the guys at Toyota knew the power at the wheels is 75KW and they didn't bother to make the car comfortable by adding a taller gear (like celica) for highway travels so that the car can be driven at 3000rpm at 140km/h. instead it is 4000rpm at 140km/h which is noisy and inefficient.

I hope this has been enlightening :rolleyes::lol:

I think you need to use the headlight/grille/front bumper area rather than the bonnet for the calculations.

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RME1 Grand Master

RME1

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Yeah I'd back you up Corey.

I'm over physics, bring on economics. Don't we have physics experts on this forum though??? Dylan??

Chemistry mate, chemistry ;)

I'll do an ecomony thread :toast:

Then we can discuss the cost benefit analysis of modifications - payback - comfort vs fuel economy etc etc.

I have data from stock (novemeber ) to modded (currently) since the start of this year :yahoo:

Hopefully we can convince more ppls to go coilovers as it has a direct impact on fuel economy. *all things being equal that is* :whistling:

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jamsbong Enthusiast

jamsbong

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Yeah I'd back you up Corey.

I'm over physics, bring on economics. Don't we have physics experts on this forum though??? Dylan??

Chemistry mate, chemistry ;)

I'll do an ecomony thread :toast:

Then we can discuss the cost benefit analysis of modifications - payback - comfort vs fuel economy etc etc.

I have data from stock (novemeber ) to modded (currently) since the start of this year :yahoo:

Hopefully we can convince more ppls to go coilovers as it has a direct impact on fuel economy. *all things being equal that is* :whistling:

The discussion so far has given me much better understanding on a few things. I've realised that frontal area must have been rather small to achieve the necessary max speed.

In regards to the economy of owning a car. I find the depreciation has to be the most expensive cost. Then insurance especially if my age is young. then service. and finally petrol cost.

I have not changed my tyres or have major repairs yet. corollas are fuel efficient so the impact of fuel prices is quite minimal compared to the other costs mentioned.

I'm actually quite interested getting a ride with coilovers. I want to know if it is really stiff and uncomfortable. or something else. anyone has idea on where to go? i can not ask favors off you people since I live in tasmania. :(

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