Does 1g = 1g = 1g? - Toyota Yaris Forums

LtNoogie · 03-05-2010, 09:43 PM

I have some data that shows I pulled 1g during a sweeping turn at the last autocross.

I was wondering if the radial acceleration is affected at all by any specific details about the body in motion such as weight or is it purely determined by speed and turn radius?

In other words, do a 250 lb man and a 125 woman experience 1g if they both follow the exact same trajectory at the same speed?

Thanks

127.0.0.1 · 03-05-2010, 10:43 PM

1g = 1g = 1g

LtNoogie · 03-05-2010, 11:17 PM

Thanks

advocate · 03-06-2010, 05:06 PM

Quote:

if they both follow the exact same trajectory at the same speed?

Indeed they would but it would take different amounts of force in order to make both follow the same trajectory and speed.

In order to generate gee force you need to generate acceleration. This acceleration needs a driving force. The acceleration of an object is based off of its change on velocity versus time. It would require more force to make a heavier object accelerate at the same rate as an object that's not as heavy.

Cosmonaut · 03-07-2010, 01:20 AM

being a dynamics student i am obligated to contribute. Force= Mass x Accel
so the 250 lb man and the 125lb woman will experience the same accel but will experience the "force" differently.

yaris-me · 03-07-2010, 03:42 AM

We are talking about centrifugal force. 1g for a 250 lbs man is 250 lbs. 1g for 125 lbs woman is 125 lbs. The 1 g would occur with the same trajectory and speed.

Jason@SportsCar · 03-07-2010, 10:54 AM

A “G” is no different than HP or PSI, it is just a measurement, and will always be the same. However, there can be variables in what you may have seen, and just like with reading HP the equipment makes a difference.

A spike in your G trace over the course of a turn can simply be a bump in the track surface. Only pay attention to sustained numbers, a brief spike does not mean your car can generate those numbers. A cheap G meter, one that works only via accelerometers can be easily fooled; body roll will make it read artificially high. A GPS only meter can also be off, as the inexpensive ones refresh too slowly to get an accurate number. The best type of meter is one that combines accelerometers and GPS with a 5hz or more sampling rate, 10hz is better. The two measurements keep each other in check, and the software will generate the number based on the data from both sources.

Also keep in mind the lot in Fontana is not flat, so you will see numbers that are better in one direction. El Toro is a much better place for testing and getting this type of data.

Don’t get hung up on achieving a high G number, that is like bench racing dyno numbers, it may look cool on paper but does not mean you have a fast car.

justjesus · 03-08-2010, 12:21 AM

As Jason noted above, it could be a spike. BUT, I just read that part of the manual last night, and will get an average sustained G number for ya, Long ;)

And the instrumentation I'm using is sampling at 5hz (sorry! i have a tight budget)

03-05-2010, 09:43 PM	#1
LtNoogie View User's Garage Drives: '08 Bayou Blue LB AT Join Date: Oct 2008 Location: West Hills, CA Posts: 2,517	Does 1g = 1g = 1g? I have some data that shows I pulled 1g during a sweeping turn at the last autocross. I was wondering if the radial acceleration is affected at all by any specific details about the body in motion such as weight or is it purely determined by speed and turn radius? In other words, do a 250 lb man and a 125 woman experience 1g if they both follow the exact same trajectory at the same speed? Thanks __________________ aFe Intake \| Blitz Supercharger \| Megan Header \| TRD Exhaust \| NST Pulley Set TRD Shocks/Struts \| Tanabe NF210 Springs \| TRD Sway Bar \| Motegi TRAKLITE wheels \| Kuhmo Ecsta XS R1 Concepts slotted rotors \| Carbotech 1521 brake pads \| stainless steel brake lines \| Seibon vented carbon fiber hood

03-05-2010, 11:17 PM	#3
LtNoogie View User's Garage Drives: '08 Bayou Blue LB AT Join Date: Oct 2008 Location: West Hills, CA Posts: 2,517	Thanks __________________ aFe Intake \| Blitz Supercharger \| Megan Header \| TRD Exhaust \| NST Pulley Set TRD Shocks/Struts \| Tanabe NF210 Springs \| TRD Sway Bar \| Motegi TRAKLITE wheels \| Kuhmo Ecsta XS R1 Concepts slotted rotors \| Carbotech 1521 brake pads \| stainless steel brake lines \| Seibon vented carbon fiber hood

03-07-2010, 01:20 AM	#5
Cosmonaut The Last Baron View User's Garage Drives: 09 Polar White HB Join Date: Jun 2009 Location: Sanentoneyow, Tecksis Posts: 280	being a dynamics student i am obligated to contribute. Force= Mass x Accel so the 250 lb man and the 125lb woman will experience the same accel but will experience the "force" differently. __________________ Sanction this outbreak, a Virus conspires. Single sparks are Spectral Fires! \| UR 19mm sway \|

03-07-2010, 10:54 AM	#7
Jason@SportsCar Drives: 2015 H Production Yaris Join Date: Oct 2009 Location: Debary, FL Posts: 1,953	A “G” is no different than HP or PSI, it is just a measurement, and will always be the same. However, there can be variables in what you may have seen, and just like with reading HP the equipment makes a difference. A spike in your G trace over the course of a turn can simply be a bump in the track surface. Only pay attention to sustained numbers, a brief spike does not mean your car can generate those numbers. A cheap G meter, one that works only via accelerometers can be easily fooled; body roll will make it read artificially high. A GPS only meter can also be off, as the inexpensive ones refresh too slowly to get an accurate number. The best type of meter is one that combines accelerometers and GPS with a 5hz or more sampling rate, 10hz is better. The two measurements keep each other in check, and the software will generate the number based on the data from both sources. Also keep in mind the lot in Fontana is not flat, so you will see numbers that are better in one direction. El Toro is a much better place for testing and getting this type of data. Don’t get hung up on achieving a high G number, that is like bench racing dyno numbers, it may look cool on paper but does not mean you have a fast car. __________________ 2005-2008 SCCA Solo BS National Champion 2017-2018 SCCA H Prod National Champion Last edited by Jason@SportsCar; 03-07-2010 at 03:37 PM.

03-05-2010, 10:43 PM	#2
127.0.0.1 Banned Drives: '10 Yaris5drHB+99 4runner LTD Join Date: Sep 2009 Location: NE Posts: 672	1g = 1g = 1g

03-07-2010, 03:42 AM	#6
yaris-me Learn to Relax Drives: 2007, Meteorite, LB Join Date: Dec 2008 Location: Anaheim, CA Posts: 2,070	We are talking about centrifugal force. 1g for a 250 lbs man is 250 lbs. 1g for 125 lbs woman is 125 lbs. The 1 g would occur with the same trajectory and speed.

03-08-2010, 12:21 AM	#8
justjesus View User's Garage Drives: 2008 Liftback Join Date: Oct 2008 Location: Orange County Posts: 962	As Jason noted above, it could be a spike. BUT, I just read that part of the manual last night, and will get an average sustained G number for ya, Long ;) And the instrumentation I'm using is sampling at 5hz (sorry! i have a tight budget)