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Old 10th January 2005, 17:56   #31
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if you really want to know the true speed of your car at any given rpm, then you gotta use this formula.

(engine rpm) / (gear ratio) / (final drive ratio) * (wheel circumference "in Inches") * (2.54) / (100000) * 60 = vehicle speed in kmph.

Trust me the results will surprise you. So far i've seen a error of just 2%, but that 2% error is inevitable. I'll let you in on a sec, according to calculations the Vtec should do 100.67kmph at 7100 rpm in 2nd gear, take that 2% error and what do you get? 98kmph, exactly what everyone says it does. One reason i can think of why the error occurs is maybe bcoz in reality, when the tyre is pressed against the ground by the car's weight, it's no longer a perfect circle, so the circumference wont remain the same.

2ndly, as the tyres get old they get worn out which actually reduces their overall diameter and circumference, this could be another reason.

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Old 13th January 2005, 16:51   #32
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On the Greater Noida Expressway, driving a Santro with low profilez, 4 people, doing about 143 speedo... I was [rudely] overtaken by a Wagon-R running on LPG and I found it nearly impossible to catch up... my guess is that he was doing about 160 by my speedo. Looked pretty stable from back there.
Are the Suzuki Ignis (JWRC) and the Wagon R related? They look quite similar....
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Old 13th January 2005, 18:08   #33
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Quote:
Originally Posted by Shan2nu
(engine rpm) / (gear ratio) / (final drive ratio) * (wheel circumference "in Inches") * (2.54) / (100000) * 60 = vehicle speed in kmph.
AT 3000 rpm...
in 5th gear... rato : 0.76
Final drive ratio : 4.19

tyre 175/70-13... circumference : 71.1 inches

gives 102.08

My sail speedo reads 100. Nice formula that is.
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Old 13th January 2005, 20:42   #34
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Quote:
Originally Posted by oversteer
On the Greater Noida Expressway, driving a Santro with low profilez, 4 people, doing about 143 speedo... I was [rudely] overtaken by a Wagon-R running on LPG and I found it nearly impossible to catch up... my guess is that he was doing about 160 by my speedo. Looked pretty stable from back there.
Are the Suzuki Ignis (JWRC) and the Wagon R related? They look quite similar....
how did u come to know that it was being run on LPG??...

man... somehow i feel wagonR is a slow city crawler... but on highways.. it just rocks...

P.S. I think Shan2nu would be able to give that answer about Ignis-WagonR relation...
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Old 13th January 2005, 21:18   #35
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Quote:
AT 3000 rpm...
in 5th gear... rato : 0.76
Final drive ratio : 4.19

tyre 175/70-13... circumference : 71.1 inches

gives 102.08

My sail speedo reads 100. Nice formula that is.
It's not just a nice formula, it's based on facts and figures. hehe

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Old 14th January 2005, 15:31   #36
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Yup, Shan2nu, that's a very handy formula you got there... is it applicable to diesel engines as well? Cuz diesels' max torque RPM is usually much lower (for the Indica it's 2500) and the power vs RPM graphs also look quite different.
dceite, I knew the guy in the Wagon R, we had started out togther... he was showing me his LPG kit just before we set out.
BTW another friend's Wagon R had overturned while pulling a U-turn in the city, so I guess you're better off driving it on the higthway LOL
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Old 14th January 2005, 15:56   #37
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Quote:
Originally Posted by oversteer
BTW another friend's Wagon R had overturned while pulling a U-turn in the city, so I guess you're better off driving it on the higthway LOL
MAN................... now i will think twice before taking U turns on my wagon..... God save me.......
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Old 14th January 2005, 21:38   #38
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And I had seen a zen overturn in Noida!! while taking a u turn.... at not so high a speed... I don't know what he must have done!.

Somehow the idea of driving a WagonR at 145+ isn't far from a nightmare!
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Old 14th January 2005, 22:27   #39
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Talking of speedometer errors, are there errors in the odometer? Isn't it easier to see how much time it takes to cover may be half km ? (shd be 10-15 sec for a speed ranging 120-180 kmph)
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Old 14th January 2005, 22:33   #40
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Quote:
Originally Posted by SLK
And I had seen a zen overturn in Noida!! while taking a u turn.... at not so high a speed... I don't know what he must have done!.

Somehow the idea of driving a WagonR at 145+ isn't far from a nightmare!


,
if aomeone can topple a zen ,then he can topple anything.
its just impossible to overturna zen.i have taken turns at ridiculous speeds ,but other than the usual fishtailing or the sideways going(this happens everytime on a right hand turn on the ankola rd) ,nothing has ever happened.
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Old 14th January 2005, 22:39   #41
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????

60km/h = 1km in 1 min
120km/h = 1km in 30sec
180km/h = 1km in 20sec
240km/h = 1km in 15sec
300km/h = 1km in 10sec

.. its not a good idea to trace speedo errors by calculating avg speed/time!...
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Old 14th January 2005, 22:47   #42
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Quote:
Originally Posted by Minardi
Talking of speedometer errors, are there errors in the odometer? Isn't it easier to see how much time it takes to cover may be half km ? (shd be 10-15 sec for a speed ranging 120-180 kmph)

but how will u know that the covered distance is half a km.
and ur speed will never be constant.
odometer errors may be there.assume a 10-15%error in the speedo readings
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Old 21st January 2005, 00:59   #43
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Quote:
Yup, Shan2nu, that's a very handy formula you got there... is it applicable to diesel engines as well? Cuz diesels' max torque RPM is usually much lower (for the Indica it's 2500) and the power vs RPM graphs also look quite different.
Yup this formula will work on any vehicle or machine that uses gears to move.

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Old 24th January 2005, 01:29   #44
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Quote:
Originally Posted by SLK
And I had seen a zen overturn in Noida!! while taking a u turn.... at not so high a speed... I don't know what he must have done!.

Somehow the idea of driving a WagonR at 145+ isn't far from a nightmare!
was this overturn on the DND toll bridge ? ...in mi skool days i used to drive mi dads zen ..it will slide ..oversteer ..tons of underteer..taking high speed turns ...but it never felt like it wud topple even whn i pulled on da e brake at like 90 ks for U turns or 360's ofcourse i cud never control the direction but just for the kicks ( ofcourse on empty roads )..the zen u saw must have blown a tire or hit some debry on the road ..

wagon r however looks as if it'll topple over if the wind blows across too hard ..
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Old 26th January 2005, 00:37   #45
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Quote:
Originally Posted by z klasse
check out these pics.. you can modify.. probably u ll change ur opinion haan.. lol

http://www.team-bhp.com/forum/iipcache/4226.jpg

http://www.team-bhp.com/forum/iipcache/4227.jpg

http://www.team-bhp.com/forum/iipcache/4228.jpg

Nice pics.. Had more but I couldnt find them..


Z Klasse
Dude I would love to buy all the 3 cars in the photograph if Im a post man or courier service man ...which I am not!!!!
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