Getting rid of understeer
02-16-17, 08:08 AM
#16
As part of my own personal continuing education effort, I did a little googling exercise and found the following articles. Some of the suggestions have already been mentioned in bits and pieces, but I found them slightly enlightening... at least to my own limited knowledge base.
http://www.drivingfast.net/understeer/
http://www.execstudio.com/tech_suspe...understeer.htm
http://www.drivingfast.net/understeer/
http://www.execstudio.com/tech_suspe...understeer.htm
02-16-17, 10:09 PM
#17
Instructor
Thread Starter
Upgrade to the Lexus GX460. That's how I plan to fix that very same issue.
There's very little you can do with the FWD platform - it will inherently understeer. The h is a little better in this regard than the 350. 350 will fully release the rear axle in the turn, while h will send power to mask some understeering tendencies.
No need for sandbags in the boot either. It will only make the things worse. We already have a battery sitting under the rear seats, which helps with weight distribution.
And please don't yell at Mrs. MellonC. She does exactly the right thing - transfer weight to the front in the middle of the turn to get more traction for the steering and less in the rear to rotate the vehicle.
https://en.wikipedia.org/wiki/Lift-off_oversteer
The WRX STi I had refused to turn. The only way to really rotate it was to go into a turn hot and then slam on the brakes.
There's very little you can do with the FWD platform - it will inherently understeer. The h is a little better in this regard than the 350. 350 will fully release the rear axle in the turn, while h will send power to mask some understeering tendencies.
No need for sandbags in the boot either. It will only make the things worse. We already have a battery sitting under the rear seats, which helps with weight distribution.
And please don't yell at Mrs. MellonC. She does exactly the right thing - transfer weight to the front in the middle of the turn to get more traction for the steering and less in the rear to rotate the vehicle.
https://en.wikipedia.org/wiki/Lift-off_oversteer
The WRX STi I had refused to turn. The only way to really rotate it was to go into a turn hot and then slam on the brakes.
I did change the psi to 36 front and 32 rear (at 50 degree temp). it helps but unless you are pushing it until you are actually squealing your rear tires (on Mulholand Dr for those of you LA area), the lower psi in the rears really don't help much. In other words, I'm still correcting mid-turn and yank the steering wheel even more in the direction of the exit from the turn.
what I'm ultimately learning here is that there is a limit to how much HP and torque you can put into a front wheel drive with a front engine.
02-17-17, 10:40 AM
#18
As with ColAngus, I have yet to encounter understeer to the point it required correction in the midst of a turn, unless I was just not paying attention. When I drive on twisty roads, I use the entire lane, always entering a turn from the outside to the inside approaching the apex. Even if the wheel is not turned enough to continue along the inside of the line, I will not have to correct to complete the turn.
My wife, and all but one woman I have ever ridden with, doesn't understand this. She would rather start in the middle of the lane, correct in the first part of the turn, correct again at the apex, and correct again to stay in the middle of the lane at the end, all the while travelling at 10mph under the recommended speed for the turn. I make her "nervous", she scares the **** outta me.
Honestly, Mellon, according to how you describe your wife driving, nothing you do is going to make a difference when she is at the wheel....
My wife, and all but one woman I have ever ridden with, doesn't understand this. She would rather start in the middle of the lane, correct in the first part of the turn, correct again at the apex, and correct again to stay in the middle of the lane at the end, all the while travelling at 10mph under the recommended speed for the turn. I make her "nervous", she scares the **** outta me.
Honestly, Mellon, according to how you describe your wife driving, nothing you do is going to make a difference when she is at the wheel....
02-17-17, 10:58 AM
#19
OP's idea regarding reverse stagger tire fitment seems to have the best chance
of changing the handling away from understeer. Back in 2008 the Chevrolet Impala SS
was a FWD sedan with a "small block" 5.3L V* stuffed transversely. The torque steer
was manageable but the understeer was unnerving particularly in the rain or snow. It
was fitted with 235/50-18's all around.
The corporate twin was the Pontiac (RIP) Grand Prix GTP had the same motor but
was shipped from the factory with 255/45-18 up front and 225/50-18 in back. Reviews
at the time described the handling as more neutral than the Chevrolet.
of changing the handling away from understeer. Back in 2008 the Chevrolet Impala SS
was a FWD sedan with a "small block" 5.3L V* stuffed transversely. The torque steer
was manageable but the understeer was unnerving particularly in the rain or snow. It
was fitted with 235/50-18's all around.
The corporate twin was the Pontiac (RIP) Grand Prix GTP had the same motor but
was shipped from the factory with 255/45-18 up front and 225/50-18 in back. Reviews
at the time described the handling as more neutral than the Chevrolet.
02-17-17, 11:20 AM
#20
Instructor
Thread Starter
OP's idea regarding reverse stagger tire fitment seems to have the best chance
of changing the handling away from understeer. Back in 2008 the Chevrolet Impala SS
was a FWD sedan with a "small block" 5.3L V* stuffed transversely. The torque steer
was manageable but the understeer was unnerving particularly in the rain or snow. It
was fitted with 235/50-18's all around.
The corporate twin was the Pontiac (RIP) Grand Prix GTP had the same motor but
was shipped from the factory with 255/45-18 up front and 225/50-18 in back. Reviews
at the time described the handling as more neutral than the Chevrolet.
of changing the handling away from understeer. Back in 2008 the Chevrolet Impala SS
was a FWD sedan with a "small block" 5.3L V* stuffed transversely. The torque steer
was manageable but the understeer was unnerving particularly in the rain or snow. It
was fitted with 235/50-18's all around.
The corporate twin was the Pontiac (RIP) Grand Prix GTP had the same motor but
was shipped from the factory with 255/45-18 up front and 225/50-18 in back. Reviews
at the time described the handling as more neutral than the Chevrolet.
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