Team-BHP > Technical Stuff


Closed Thread
  Search this Thread
21,630 views
Old 9th November 2007, 22:51   #46
Senior - BHPian
 
1100D's Avatar
 
Join Date: Jun 2006
Location: Calcutta
Posts: 4,390
Thanked: 4,068 Times

Quote:
Originally Posted by Mayavi View Post
I wrote: Most production RWD sedans are tuned to understeer.


Here is why

....even rear-drive cars sold to average consumers...

I did notice that my coupe understeer's and I have to either slow down or turn the ESP off and accelerate to take the corners. This has been the experience of other C class owners too who drive on stock set-up.
The Keyword here would be cars for the average driver. Thats also what I meant on the quote below.

Quote:
Originally Posted by 1100D View Post
Now in US most drivers do not speed on a turn, they speed on a straight, in this case makes no difference. Moreover most US RWD's pre-charger/300c era were softly sprung, devoid of grip.
My experience may be different from yours on account of my car having the sports suspension setup and no ESP (ESP does a lot of unecessary tricks on you). But have driven a couple of E36's and E34's they too are on the pointy side (although E36 rolls a bit).


Quote:
Originally Posted by Mayavi View Post
where the rear wheels are heading for the weeds, you have to both slow down and counterintuitively turn the wheel in the opposite .
I dont quite agree totally on the slowing down part. One has to modulate the throttle based on the situation.

Last edited by 1100D : 9th November 2007 at 22:57.
1100D is offline  
Old 10th November 2007, 00:01   #47
Team-BHP Support
 
BlackPearl's Avatar
 
Join Date: Aug 2005
Location: Calcutta/London
Posts: 3,604
Thanked: 16,949 Times

then there is left foot braking in fwd which can help to drift a lot and at much higher speeds than that possible with hand brakes.
BlackPearl is offline  
Old 10th November 2007, 01:26   #48
Senior - BHPian
 
1100D's Avatar
 
Join Date: Jun 2006
Location: Calcutta
Posts: 4,390
Thanked: 4,068 Times

Since this has eventually come up, before anybody attempts a LFB turn. One needs to make sure, he/she has had adequate exposure to how the brake pedal feels while being operated by the left foot.

Generally the left leg needs practice to come to terms with the pressure requirements. It is recommended to do straight line braking with the Left foot, for familiarization.
1100D is offline  
Old 10th November 2007, 01:41   #49
Senior - BHPian
 
rocksterraghu's Avatar
 
Join Date: Feb 2007
Location: Bangalore
Posts: 1,240
Thanked: 236 Times

Quote:
Even a M800 can drift on the handbrake, if the brakes are proper. And in my opinion it actually displays a huge control while doing so. Infact handling wise, I dont think any FWD car in India ever comes close to a "proper" Maruti 800.
True. One just has to remember that Maruti 800 is not a very safe car to try adventurous things, that is all.
rocksterraghu is offline  
Old 10th November 2007, 02:04   #50
Senior - BHPian
 
vivekiny2k's Avatar
 
Join Date: Feb 2005
Location: cincinnati, jabalpur,chennai
Posts: 1,264
Thanked: 209 Times

Quote:
Originally Posted by 1100D View Post
I dont quite agree totally on the slowing down part. One has to modulate the throttle based on the situation.
hasn't the situation already been mentioned. rear whels lost traction, car oversteered, driver trying to regain control.

IMHO, the whole reason behind fishtailing is not being able to control the car and steering alternately on either side until balance is regained (or not).

I can see the point that FWD will not fishtail on either side in case of a loss of traction on front wheels.
vivekiny2k is offline  
Old 10th November 2007, 02:40   #51
Senior - BHPian
 
Join Date: Jul 2005
Location: Mangalore
Posts: 1,209
Thanked: 80 Times

Quote:
Originally Posted by SuperSyn View Post
True enough, though I am sure people appreciate the handling of their cars more when driving rather than standing still there seem to be some compromises in road car suspension engineering which makes a more rearward bias desirable.
You misunderstood. I meant that, rearward weight bias can be achieved through control of weight transfer rather than static weight bias, which is what we were alluding to earlier.
ananthkamath is offline  
Old 10th November 2007, 02:42   #52
Senior - BHPian
 
Join Date: Jul 2005
Location: Mangalore
Posts: 1,209
Thanked: 80 Times

Quote:
Originally Posted by vivekiny2k View Post

I can see the point that FWD will not fishtail on either side in case of a loss of traction on front wheels.
I disagree. A FWD can be made to fishtail through incorrect application of throttle and steering inputs, which is most likely what an inexperienced driver will do. Hence FWD can be equally dangerous when pushed hard.


Example: My own Jetta. If I start accelerating out a corner hard, the car starts understeering. Alarmed by this, if I let off the throttle, all the weight transfers to the front, and the rear end becomes light. Result: Snap Oversteer. I get even more alarmed by this, and I give opposite lock. The car has, however, stabilized itself, and starts coming back to line. But the opposite lock overcompensates and the back starts swinging in the other direction. Result: Fishtailing. See what I mean?


Which is why weight transfer is much, much more important in the overall balance of the car rather than which wheels are driven.

Last edited by ananthkamath : 10th November 2007 at 02:48.
ananthkamath is offline  
Old 10th November 2007, 03:00   #53
Senior - BHPian
 
vivekiny2k's Avatar
 
Join Date: Feb 2005
Location: cincinnati, jabalpur,chennai
Posts: 1,264
Thanked: 209 Times

Quote:
Originally Posted by ananthkamath View Post
Hence FWD can be equally dangerous when pushed hard.
may be i am wrong, but my brain still thinks FWD has to be pushed HARDER to be equally dangerous.

well, actually mayavi was favoring understeer, regardless of which set of wheels is driven. I should have noted.
vivekiny2k is offline  
Old 10th November 2007, 07:21   #54
Senior - BHPian
 
DirtyDan's Avatar
 
Join Date: Jul 2007
Location: Dharamsala, H.P
Posts: 2,074
Thanked: 1,554 Times
Definitions

Understear: car hits tree with front end
Overstear: car hits tree with back end
high Horsepower: car hits tree very, very hard
alcohol: tree hits car very, very hard
DirtyDan is offline  
Old 10th November 2007, 14:24   #55
BHPian
 
2fast4u's Avatar
 
Join Date: Mar 2005
Location: pune / Bahrain
Posts: 488
Thanked: 7 Times

Quote:
Originally Posted by 1100D View Post
I dont quite agree totally on the slowing down part. One has to modulate the throttle based on the situation.
in addition be in the right gear.
2fast4u is offline  
Old 11th November 2007, 03:13   #56
BHPian
 
oversteer's Avatar
 
Join Date: Aug 2004
Location: KA-03
Posts: 69
Thanked: 0 Times
Say What?

Quote:
Originally Posted by BlackPearl View Post
then there is left foot braking in fwd which can help to drift a lot and at much higher speeds than that possible with hand brakes.
Very interesting... Could someone throw more light on this (or point me to the right post) please?
I mean... I'm going, I turn, touch the brake pedal with my left foot, and I'm assuming counter-balance the throttle with my right foot... but in order to achieve what, exactly? I mean, how do I get the car to "drift" and brakes not to "burn"? (Disclaimer: I'm not being sarcy here, just curious!)

Quote:
Originally Posted by 1100D View Post
Infact handling wise, I dont think any FWD car in India ever comes close to a "proper" Maruti 800.
I second that. You get fantastic feedback from the car, unpolluted by "electronic noise" (from the EPS etc)
oversteer is offline  
Old 11th November 2007, 12:17   #57
BHPian
 
hyper123's Avatar
 
Join Date: Jan 2005
Location: Bangalore
Posts: 321
Thanked: 2 Times

check this out.
Autocar UK:
hyper123 is offline  
Old 11th November 2007, 21:11   #58
BHPian
 
oversteer's Avatar
 
Join Date: Aug 2004
Location: KA-03
Posts: 69
Thanked: 0 Times

Thanks, hyper123. Makes sense now!
This raises another interesting point, though: differentials. Are the differentials in RWDs and FWDs typically different, in a way that would allow the driver to distinguish one from the other?
oversteer is offline  
Old 11th November 2007, 22:55   #59
Senior - BHPian
 
Join Date: Sep 2007
Location: New Delhi
Posts: 3,095
Thanked: 303 Times

Quote:
Originally Posted by oversteer View Post
Are the differentials in RWDs and FWDs typically different, in a way that would allow the driver to distinguish one from the other?
No. They cannot be. Laws of physics dictate that part.
anupmathur is offline  
Old 11th November 2007, 23:00   #60
Senior - BHPian
 
v1p3r's Avatar
 
Join Date: Feb 2005
Location: BLR / DXB / LON
Posts: 5,334
Thanked: 6,893 Times

Quote:
Originally Posted by oversteer View Post
Thanks, hyper123. Makes sense now!
This raises another interesting point, though: differentials. Are the differentials in RWDs and FWDs typically different, in a way that would allow the driver to distinguish one from the other?
The connection between the diff and the wheels differs from FWDs to RWDs though.
v1p3r is offline  
Closed Thread

Most Viewed
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Copyright ©2000 - 2024, Team-BHP.com
Proudly powered by E2E Networks