AWD vs RWD
08-12-2011, 12:06 PM
#31
Wash Rinse Repeat
Thread Starter
Join Date: Feb 2006
Location: Michigan
Posts: 6,312
you are correct IMO
and also IMO the person that told you that you were wrong doesn't know what the hell he's on about.... lol
if he offered some legit info to this thread I wouldn't be so harsh as this is just a simple discussion, but jesus christ
and also IMO the person that told you that you were wrong doesn't know what the hell he's on about.... lol
if he offered some legit info to this thread I wouldn't be so harsh as this is just a simple discussion, but jesus christ
Last edited by Morbid Intentions; 08-12-2011 at 12:09 PM.
08-12-2011, 02:06 PM
#32
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
A car's handling is more about suspension, load transfer, alignment, traction etc. In FWD and AWD cars the steering wheels in the front have power, so they can effectively "pull" the front of the car where they point when you steer. With RWD the front of the car is just reacting to the resistance created by turning the wheels and trying to track along the path of least resistance.
With RWD though, the power out back and resistance up front can cause oversteer with power application, which can be beneficial in bringing the rear in line with the front more quickly. It helps with quicker turn-in when steering. It's also why a lot of high performance and race cars are set up with a suspension balance that favors oversteering slightly. Quicker response but they're easier to lose control of.
In FWD or AWD you don't have a power biased rear trying to push past the front, since the front is pulling the whole vehicle, so you tend to get a car with less oversteer characteristic, and often understeering. It's more forgiving since the steering wheels are powered and drag the whole car along, so it's harder to lose control of in a turn(there's not a power/resistance imbalance). As a result, FWD and AWD is more forgiving and the powered front wheels can help compensate for inadequate ability to control a car in a turn. This causes people to think they handle better, when the reality is that average Joe is going faster through a turn with FWD/AWD because it compensates better for his ****ty driving.
RWD lets you use the throttle to help steer the car with the power, and control how it lines up, especially as you come out of a turn. But, in the end, handling is more a factor of weight, suspension etc etc. Depending on how power transfer is managed in AWD, you can get an AWD and RWD car to handle the same. The difference is that all things being equal, AWD will be a heavier vehicle, and RWD will be more able to "kick" the back end out or around.
There's also alignment problems with AWD and FWD. Because RWD is ALWAYS pushing the front wheels/suspension, the control arms etc are always trying to pull back towards the rear of the vehicle. The alignment accounts for that....and under acceleration, braking or cruising, the suspension is always loaded in that same direction. In FWD and AWD though, the power in the front wheels PULLS the suspension under power towards the front of the car, but under braking, PUSHES the suspension towards the rear. As a result of being loaded in 2 directions, you can't get an optimal alignment for all situations, you have to account for movement in multiple directions.
So FWD and AWD may have a static setup that favors more toe-out for example, so when under power you have slight toe-in as the suspension flexes forward and it gives good straight tracking under power, but when you brake and the suspension is pushed rearward you get toe-out(more than the static setup). You then end up with a car that tracks straight under power but can be slightly unstable tracking under hard braking. The extra toe-in under power also means the car will have less turn in and more understeer as you power through a turn. So then if you set it for neutral or slight toe-out under power, you have quick turn in and better tracking while powering as you turn....but it's even worse tracking under braking. Or if you set it for toe-in under hard braking it will track straight under hard braking, but will have a crapload of toe-in under power and have slower steering response and likely generate a ton of understeer when you power in a turn.
The frontward and rearward movement of the FWD/AWD suspension can also have negative impacts on the Ackerman angle, since it will vary from braking to accelerating. Which will change the turning radius and tracking/stability characteristics of the car depending on whether you brake and turn, accelerate and turn etc. And depending on how the suspension is designed, it may change the caster as well.
There's actually a LOT of engineering and design challenges to overcome when trying to develop FWD/AWD suspension systems. RWD setups are a lot simpler with fewer problems to overcome and a more consistent operational situation to account for.
With RWD though, the power out back and resistance up front can cause oversteer with power application, which can be beneficial in bringing the rear in line with the front more quickly. It helps with quicker turn-in when steering. It's also why a lot of high performance and race cars are set up with a suspension balance that favors oversteering slightly. Quicker response but they're easier to lose control of.
In FWD or AWD you don't have a power biased rear trying to push past the front, since the front is pulling the whole vehicle, so you tend to get a car with less oversteer characteristic, and often understeering. It's more forgiving since the steering wheels are powered and drag the whole car along, so it's harder to lose control of in a turn(there's not a power/resistance imbalance). As a result, FWD and AWD is more forgiving and the powered front wheels can help compensate for inadequate ability to control a car in a turn. This causes people to think they handle better, when the reality is that average Joe is going faster through a turn with FWD/AWD because it compensates better for his ****ty driving.
RWD lets you use the throttle to help steer the car with the power, and control how it lines up, especially as you come out of a turn. But, in the end, handling is more a factor of weight, suspension etc etc. Depending on how power transfer is managed in AWD, you can get an AWD and RWD car to handle the same. The difference is that all things being equal, AWD will be a heavier vehicle, and RWD will be more able to "kick" the back end out or around.
There's also alignment problems with AWD and FWD. Because RWD is ALWAYS pushing the front wheels/suspension, the control arms etc are always trying to pull back towards the rear of the vehicle. The alignment accounts for that....and under acceleration, braking or cruising, the suspension is always loaded in that same direction. In FWD and AWD though, the power in the front wheels PULLS the suspension under power towards the front of the car, but under braking, PUSHES the suspension towards the rear. As a result of being loaded in 2 directions, you can't get an optimal alignment for all situations, you have to account for movement in multiple directions.
So FWD and AWD may have a static setup that favors more toe-out for example, so when under power you have slight toe-in as the suspension flexes forward and it gives good straight tracking under power, but when you brake and the suspension is pushed rearward you get toe-out(more than the static setup). You then end up with a car that tracks straight under power but can be slightly unstable tracking under hard braking. The extra toe-in under power also means the car will have less turn in and more understeer as you power through a turn. So then if you set it for neutral or slight toe-out under power, you have quick turn in and better tracking while powering as you turn....but it's even worse tracking under braking. Or if you set it for toe-in under hard braking it will track straight under hard braking, but will have a crapload of toe-in under power and have slower steering response and likely generate a ton of understeer when you power in a turn.
The frontward and rearward movement of the FWD/AWD suspension can also have negative impacts on the Ackerman angle, since it will vary from braking to accelerating. Which will change the turning radius and tracking/stability characteristics of the car depending on whether you brake and turn, accelerate and turn etc. And depending on how the suspension is designed, it may change the caster as well.
There's actually a LOT of engineering and design challenges to overcome when trying to develop FWD/AWD suspension systems. RWD setups are a lot simpler with fewer problems to overcome and a more consistent operational situation to account for.
08-13-2011, 01:14 PM
#35
4th Gear Member
Join Date: Nov 2010
Location: Indiana
Posts: 1,717
A car's handling is more about suspension, load transfer, alignment, traction etc. In FWD and AWD cars the steering wheels in the front have power, so they can effectively "pull" the front of the car where they point when you steer. With RWD the front of the car is just reacting to the resistance created by turning the wheels and trying to track along the path of least resistance.
With RWD though, the power out back and resistance up front can cause oversteer with power application, which can be beneficial in bringing the rear in line with the front more quickly. It helps with quicker turn-in when steering. It's also why a lot of high performance and race cars are set up with a suspension balance that favors oversteering slightly. Quicker response but they're easier to lose control of.
In FWD or AWD you don't have a power biased rear trying to push past the front, since the front is pulling the whole vehicle, so you tend to get a car with less oversteer characteristic, and often understeering. It's more forgiving since the steering wheels are powered and drag the whole car along, so it's harder to lose control of in a turn(there's not a power/resistance imbalance). As a result, FWD and AWD is more forgiving and the powered front wheels can help compensate for inadequate ability to control a car in a turn. This causes people to think they handle better, when the reality is that average Joe is going faster through a turn with FWD/AWD because it compensates better for his ****ty driving.
RWD lets you use the throttle to help steer the car with the power, and control how it lines up, especially as you come out of a turn. But, in the end, handling is more a factor of weight, suspension etc etc. Depending on how power transfer is managed in AWD, you can get an AWD and RWD car to handle the same. The difference is that all things being equal, AWD will be a heavier vehicle, and RWD will be more able to "kick" the back end out or around.
There's also alignment problems with AWD and FWD. Because RWD is ALWAYS pushing the front wheels/suspension, the control arms etc are always trying to pull back towards the rear of the vehicle. The alignment accounts for that....and under acceleration, braking or cruising, the suspension is always loaded in that same direction. In FWD and AWD though, the power in the front wheels PULLS the suspension under power towards the front of the car, but under braking, PUSHES the suspension towards the rear. As a result of being loaded in 2 directions, you can't get an optimal alignment for all situations, you have to account for movement in multiple directions.
So FWD and AWD may have a static setup that favors more toe-out for example, so when under power you have slight toe-in as the suspension flexes forward and it gives good straight tracking under power, but when you brake and the suspension is pushed rearward you get toe-out(more than the static setup). You then end up with a car that tracks straight under power but can be slightly unstable tracking under hard braking. The extra toe-in under power also means the car will have less turn in and more understeer as you power through a turn. So then if you set it for neutral or slight toe-out under power, you have quick turn in and better tracking while powering as you turn....but it's even worse tracking under braking. Or if you set it for toe-in under hard braking it will track straight under hard braking, but will have a crapload of toe-in under power and have slower steering response and likely generate a ton of understeer when you power in a turn.
The frontward and rearward movement of the FWD/AWD suspension can also have negative impacts on the Ackerman angle, since it will vary from braking to accelerating. Which will change the turning radius and tracking/stability characteristics of the car depending on whether you brake and turn, accelerate and turn etc. And depending on how the suspension is designed, it may change the caster as well.
There's actually a LOT of engineering and design challenges to overcome when trying to develop FWD/AWD suspension systems. RWD setups are a lot simpler with fewer problems to overcome and a more consistent operational situation to account for.
With RWD though, the power out back and resistance up front can cause oversteer with power application, which can be beneficial in bringing the rear in line with the front more quickly. It helps with quicker turn-in when steering. It's also why a lot of high performance and race cars are set up with a suspension balance that favors oversteering slightly. Quicker response but they're easier to lose control of.
In FWD or AWD you don't have a power biased rear trying to push past the front, since the front is pulling the whole vehicle, so you tend to get a car with less oversteer characteristic, and often understeering. It's more forgiving since the steering wheels are powered and drag the whole car along, so it's harder to lose control of in a turn(there's not a power/resistance imbalance). As a result, FWD and AWD is more forgiving and the powered front wheels can help compensate for inadequate ability to control a car in a turn. This causes people to think they handle better, when the reality is that average Joe is going faster through a turn with FWD/AWD because it compensates better for his ****ty driving.
RWD lets you use the throttle to help steer the car with the power, and control how it lines up, especially as you come out of a turn. But, in the end, handling is more a factor of weight, suspension etc etc. Depending on how power transfer is managed in AWD, you can get an AWD and RWD car to handle the same. The difference is that all things being equal, AWD will be a heavier vehicle, and RWD will be more able to "kick" the back end out or around.
There's also alignment problems with AWD and FWD. Because RWD is ALWAYS pushing the front wheels/suspension, the control arms etc are always trying to pull back towards the rear of the vehicle. The alignment accounts for that....and under acceleration, braking or cruising, the suspension is always loaded in that same direction. In FWD and AWD though, the power in the front wheels PULLS the suspension under power towards the front of the car, but under braking, PUSHES the suspension towards the rear. As a result of being loaded in 2 directions, you can't get an optimal alignment for all situations, you have to account for movement in multiple directions.
So FWD and AWD may have a static setup that favors more toe-out for example, so when under power you have slight toe-in as the suspension flexes forward and it gives good straight tracking under power, but when you brake and the suspension is pushed rearward you get toe-out(more than the static setup). You then end up with a car that tracks straight under power but can be slightly unstable tracking under hard braking. The extra toe-in under power also means the car will have less turn in and more understeer as you power through a turn. So then if you set it for neutral or slight toe-out under power, you have quick turn in and better tracking while powering as you turn....but it's even worse tracking under braking. Or if you set it for toe-in under hard braking it will track straight under hard braking, but will have a crapload of toe-in under power and have slower steering response and likely generate a ton of understeer when you power in a turn.
The frontward and rearward movement of the FWD/AWD suspension can also have negative impacts on the Ackerman angle, since it will vary from braking to accelerating. Which will change the turning radius and tracking/stability characteristics of the car depending on whether you brake and turn, accelerate and turn etc. And depending on how the suspension is designed, it may change the caster as well.
There's actually a LOT of engineering and design challenges to overcome when trying to develop FWD/AWD suspension systems. RWD setups are a lot simpler with fewer problems to overcome and a more consistent operational situation to account for.
And shout out to Ackermann geometry lol, had to study that last year.
08-13-2011, 03:35 PM
#36
2nd Gear Member
Join Date: Apr 2009
Location: texas
Posts: 448
http://www.youtube.com/watch?v=gNtTAa0nYfk
idk how to set it up, but copy and paste this link in the tool bar and watch. this cobra gets an amazing launch against a jeep srt 8
idk how to set it up, but copy and paste this link in the tool bar and watch. this cobra gets an amazing launch against a jeep srt 8
08-13-2011, 05:57 PM
#38
6th Gear Member
Join Date: Feb 2007
Location: North Carolina
Posts: 11,302
That whole AWD's plow into corners thing is truth. Me turn da wheel, but it go straight! Seriously, my WRX handled really good until you pushed it, then you could hang it up. The faster you went and the more you throttled up, the worse it would understeer. I'd take a RWD in a heartbeat over a FWD or AWD around cones, (or a drag strip). Having the throttle as an extra steering wheel is a huge plus if you know how to use it. As far as rain, and everyday adverse weather, or lightly modded stop light to stop light stuff, damn right, an AWD is the only way to go.
08-13-2011, 06:01 PM
#39
Wash Rinse Repeat
Thread Starter
Join Date: Feb 2006
Location: Michigan
Posts: 6,312
I think it depends on the driving style too... because if you don't push it going into a corner and then let all hell loose turning in during the apex hugging the inside you will get a sling shot effect ripping you out of the corner faster... so while a properly setup RWD car could take the corner better, afterwards there is a good chance that an AWD car will handle coming out of it better under more load
at least, that's what would make sense to me
at least, that's what would make sense to me
08-13-2011, 07:20 PM
#40
6th Gear Member
Join Date: Feb 2007
Location: North Carolina
Posts: 11,302
I was in a parking lot totally experimenting with my AWD pushing it pretty damn hard just too see how it would react. It plowed and there was no way to correct it other than slowing down or going to a higher gear. Problem I ran into was that while it was understeering, the turbo was also out of breath due to having to keep it redlined to keep it somewhat making the turn. Going to a higher gear would drop the RPM for more boost, but it also dropped the RPM enough to slow the car too much, losing all momentum. A high HP AWD or being able to adjust where the power goes (front or rear) like the STI has would've helped a lot cause I could've kicked the rear out some, counter steered, and possibly have stayed in the same gear until it straightened up, maybe. A rear wheel drive would've stepped the rear out under throttle, and been much easier to steer and stay in the powerband with... to me, but everyone is different and that was just my minimal experience with just that one 225 hp WRX, not a higher HP car like the EVO or STI, much less a high HP AWD. In other words its like Skater stated earlier, it all depends on where the cars are on power, and like you said... how its driven.