mr vs fr drivetrains

[honhon]

just wondering what the disadvantage/advantage of an mr is for drifting.

[cfrost]

just ur FR, MR has too much weight in the back and will spin around on you easier

try not t complicate it---if you're building a car for drifting make sure its FR

[hachiroku-fc3s]

http://www.driftcentral.com/forum/showthread.php?t=3187

Check out the link. Quite a bit of info on this subject.

[honhon]

thx for the replies. i think i got a general idea more. mrs oversteer easily but are hard to drift with?

[hachiroku-fc3s]

No, they understeer. How did you get oversteer easily but hard to drift with?! That would be a nose-heavy FR. Ok, basically, if you follow that link. Don't read anything that Atlantian posted, or do read it but know that it's all wrong. I still have no idea how you came to that conclusion

[cfrost]

I'm sure he just worded it oddly..

when mr cars oversteer they spin super fast and they're hard to stay head of

[honhon]

i never really came up with any conclusions, and i'm just taking guesses based on what i'm reading/skimming thru(it is a lot of reading and usually takes time, and it's hard to tell what's correct without experience)

[atlantian]

Mid engined cars have more grip, but when they let go, they swing around in a more violent manner. Front engined cars have less grip but are more manageable when they starts to oversteer.

Think of the different grip signatures on the two types of cars as rubberbands. A mid engine layout would be represented by a surgical tube. A front engine layout will be represented by a thin rubber band. You will have to try harder to snap the surgical tubing but you will hurt your hand very badly when you do. On the other hand, a rubber band can be snapped with reletive ease, but when the rubber band snaps and hits your hand, you will not be bruised badly.

Mid engined cars do understeer because the center of the mass is farther back on the car. If you accelerate hard, you will have less steering control then if you accelerate hard on a front engined car. On the other hand, this is only as concerning as brake lockup understeer, you just need to tap the brakes as you enter a corner, it should be a habit.

[eomund240]

Mid engined cars have more grip, but when they let go, they swing around in a more violent manner. Front engined cars have less grip but are more manageable when they starts to oversteer.

Think of the different grip signatures on the two types of cars as rubberbands. A mid engine layout would be represented by a surgical tube. A front engine layout will be represented by a thin rubber band. You will have to try harder to snap the surgical tubing but you will hurt your hand very badly when you do. On the other hand, a rubber band can be snapped with reletive ease, but when the rubber band snaps and hits your hand, you will not be bruised badly.

Mid engined cars do understeer because the center of the mass is farther back on the car. If you accelerate hard, you will have less steering control then if you accelerate hard on a front engined car. On the other hand, this is only as concerning as brake lockup understeer, you just need to tap the brakes as you enter a corner, it should be a habit.

You're partially right. It all depends on weight distribution and rotational inertia.

Generally most fr cars have about 65-70% of their weight in the front. This allows for 2 symptoms. If the vehicle is somewhat underpowered, the vehicle will suffer from a pushing understeer, where if it's overpowered, the light rear end can result in it being spin happy. A lot of it depends on suspention settings, and technique as well.

What make an FR layout so suited for drifting is that heavier fron end however. Because of the weight being over the steering and the rear being lighter, the front, controling part of the car has more inertia than the rear. What this means is that because the rear of the car is lighter, it's easier to manipulate, change direction, speed up and slow down in a controlled manner.


Now this brings us into 50/50 weight distribution. There's arguments in preference between a front weight balanced car and 50/50. When it come to actual racing, 50/50 provides more neutral handeling. I personally don't care for 50/50 in racing myself. The problem with it, at least from what I've experienced, is you're either having a slight understeer or snappy oversteer.

Because of the weight being dead center of the car, when the vehicle starts to slide it rotates on it's center and counter steering causes it to snap back fairly violently, many times causing an over correction. Now some people prefer this setup, but I don't.


Rear weighted vehicles are a different story all together. Remember how I mentioned rotational inertia? Well it has a huge effect on rear weighted cars. Just to clarify, 90% of midship layouts have the weight more set over the rear tires. For most racing circumstances Mid and even Rear engine layouts are prefered. It provides good traction over the rear tires, generally runs a lower center of gravity and provides a somewhat neutral handeling in the corners. Even sliding can be some what easier with a rear weight layout because of the extra traction.

The problem you're dealing with however is that extra weight or extra inertia takes more energy to stop. What this means is up to a certain point, mid engines slide halfway decently. But beyond a certain angle, the inertia in the rear end will over take the control and cause a spin.


Everything in driving is physics. And understanding those physics can really help you get a solid grasp in what a vehicle's doing and how it's reacting.

[atlantian]

I think most Gran Touring cars which are front engined sports cars achieve 50/50 for a more neutral handling characteristic for road racing. But these are front mid engined cars.

People want 50/50 weight distribution for road racing because it helps them remain stable and have enough grip on all four wheels to push their cars faster through the corners with minimal oversteer or understeer. So they can control the car's heading in mostly any situation.

Rear placement mid engines are typically more rear heavy, but not as extreme as a rear engined Porsche 911, which has a 35/65 front rear weight distribution. They are used to get more grip off the line and attempt to extend the grip limit of the rear wheels. But the down side is the snap oversteer, which is not as bad as rumors say they are, just takes practice.

I think all I have to say is already stated by eomund.

Edit: By the way, I think that the best format for drifting, based on the virtue of neutral handling, is front mounted mid engine rear wheel drive. Examples would include (but are not limited to): Honda S2000, Dodge Viper, Aston Martin V8 Vantage, Toyota Supra Mark IV, and the Nissan 350Z.

[Soldat]

You're partially right. It all depends on weight distribution and rotational inertia.

Generally most fr cars have about 65-70% of their weight in the front. This allows for 2 symptoms. If the vehicle is somewhat underpowered, the vehicle will suffer from a pushing understeer, where if it's overpowered, the light rear end can result in it being spin happy. A lot of it depends on suspention settings, and technique as well.

What make an FR layout so suited for drifting is that heavier fron end however. Because of the weight being over the steering and the rear being lighter, the front, controling part of the car has more inertia than the rear. What this means is that because the rear of the car is lighter, it's easier to manipulate, change direction, speed up and slow down in a controlled manner.


Now this brings us into 50/50 weight distribution. There's arguments in preference between a front weight balanced car and 50/50. When it come to actual racing, 50/50 provides more neutral handeling. I personally don't care for 50/50 in racing myself. The problem with it, at least from what I've experienced, is you're either having a slight understeer or snappy oversteer.

Because of the weight being dead center of the car, when the vehicle starts to slide it rotates on it's center and counter steering causes it to snap back fairly violently, many times causing an over correction. Now some people prefer this setup, but I don't.


Rear weighted vehicles are a different story all together. Remember how I mentioned rotational inertia? Well it has a huge effect on rear weighted cars. Just to clarify, 90% of midship layouts have the weight more set over the rear tires. For most racing circumstances Mid and even Rear engine layouts are prefered. It provides good traction over the rear tires, generally runs a lower center of gravity and provides a somewhat neutral handeling in the corners. Even sliding can be some what easier with a rear weight layout because of the extra traction.

The problem you're dealing with however is that extra weight or extra inertia takes more energy to stop. What this means is up to a certain point, mid engines slide halfway decently. But beyond a certain angle, the inertia in the rear end will over take the control and cause a spin.


Everything in driving is physics. And understanding those physics can really help you get a solid grasp in what a vehicle's doing and how it's reacting.

I disagree with you on just one point. There's no such thing as an "overpowered car"

Something else to remember, though, is that the car, while drifting (especially while transitioning) is actually pivoting around the front tires, rather than the rear. So for all intents and purposes, the front wheels become the center of the car. A front engine car places the single heaviest piece of weight in the car directly on top of that point, minimizing your rotational inertia.

Think of it this way . . . take a hammer (preferably a small sledgehammer with a wood handle) and grab it by the heavy end. Then swing it around just by rotating your wrist, not with your whole arm. Then, flip the hammer around and swing it by the end of the handle like you normally would and feel the difference in how easily the weight of the hammer stops it's motion and goes back the other way. By moving the center of gravity to the actual point of pivot, you're greatly reducing the energy required to stop the spin and bring it back, resulting in a car that is more responsive.

[eomund240]

Edit: By the way, I think that the best format for drifting, based on the virtue of neutral handling, is front mounted mid engine rear wheel drive. Examples would include (but are not limited to): Honda S2000, Dodge Viper, Aston Martin V8 Vantage, Toyota Supra Mark IV, and the Nissan 350Z.

This is 100% subjective. Many drivers, including some GT racers and D1GP drivers prefer a front weighted setup. It's all up to preference and driving style. Saying one setup is better than the other could be wrong for some one else. Certain setups have their advantages, but in the end it's all about what the driver wants / needs.

[atlantian]

I disagree with you on just one point. There's no such thing as an "overpowered car"

Something else to remember, though, is that the car, while drifting (especially while transitioning) is actually pivoting around the front tires, rather than the rear. So for all intents and purposes, the front wheels become the center of the car. A front engine car places the single heaviest piece of weight in the car directly on top of that point, minimizing your rotational inertia.

Think of it this way . . . take a hammer (preferably a small sledgehammer with a wood handle) and grab it by the heavy end. Then swing it around just by rotating your wrist, not with your whole arm. Then, flip the hammer around and swing it by the end of the handle like you normally would and feel the difference in how easily the weight of the hammer stops it's motion and goes back the other way. By moving the center of gravity to the actual point of pivot, you're greatly reducing the energy required to stop the spin and bring it back, resulting in a car that is more responsive.

There is overpowered cars, but the horsepower figure at which it is too much is dependant. It depends on the chassis and suspension setup, it depends if it will be able to take all of that power without skidding. For instance the BMW M6, very powerful at 500 bhp, but it is a front engined car and it will not be able to utilize all of that power, so it skids a lot, in fact, it does a lap of the Isle of Man TT course with identical times to the Aston Martin V8 Vantage, which is around 100 break horse power weaker. The Porsche Carrera S on the other hand had 200 break horse powers less then the M6 and did the lap a good 5 seconds faster because it has a lot of grip and can utilize it's power very efficiently.

But on your analogy, you should also factor in traction overload, which happens a lot on American GT cars AKA muscle cars, causing overloading understeer. Honda Civics with the H engine swap from the Prelude also has this problem. When you have front heavy cars, they initiate drifts slightly easier because of the lighter rear end, you are right, but you can not take that attribute to the extreme or else you will end up with a car that understeers a lot. The cars like silvias which are front heavy, are only slightly front heavy.

By the way, eomund, sorry for my miswording. there might not be a "perfect" drift car, but I ment that big heavy front mounted mid engine cars have the most "ponder" time through a skid. Which would allow the driver to feel more in control and at ease.

[Soldat]

There is overpowered cars, but the horsepower figure at which it is too much is dependant. It depends on the chassis and suspension setup, it depends if it will be able to take all of that power without skidding. For instance the BMW M6, very powerful at 500 bhp, but it is a front engined car and it will not be able to utilize all of that power, so it skids a lot, in fact, it does a lap of the Isle of Man TT course with identical times to the Aston Martin V8 Vantage, which is around 100 break horse power weaker. The Porsche Carrera S on the other hand had 200 break horse powers less then the M6 and did the lap a good 5 seconds faster because it has a lot of grip and can utilize it's power very efficiently.

The fact that the suspension/chassis isn't good enough to allow the driver to fully use all of the motor's power doesn't mean that the car is overpowered, it means that the handling isn't up to par. If Al Unser Jr jumped in the M6 you used as an example, took it for a few hot laps and was asked what he thought of it, do you really think he would say "it has too much power"? No, he would say that it's too heavy or that the suspension is too soft.

There is such a thing as "too much power for the driver" or "too much power for the car", but these aren't problems with the motor. They're problems with the suspension and the driver's skill level. So, once again, there's no such thing as an "overpowered car".

And again, you're missing the point. You keep trying to bring up road racing and track times in all of these threads you post in. This is not a road racing forum. We're not talking about lap times between the Aston martin and the Carrera S at a road course and we're certainly not talking about Prelude's with motor swaps. We're talking about what makes a more driver friendly drift car.

[eomund240]

I disagree with you on just one point. There's no such thing as an "overpowered car"

Something else to remember, though, is that the car, while drifting (especially while transitioning) is actually pivoting around the front tires, rather than the rear. So for all intents and purposes, the front wheels become the center of the car. A front engine car places the single heaviest piece of weight in the car directly on top of that point, minimizing your rotational inertia.

Think of it this way . . . take a hammer (preferably a small sledgehammer with a wood handle) and grab it by the heavy end. Then swing it around just by rotating your wrist, not with your whole arm. Then, flip the hammer around and swing it by the end of the handle like you normally would and feel the difference in how easily the weight of the hammer stops it's motion and goes back the other way. By moving the center of gravity to the actual point of pivot, you're greatly reducing the energy required to stop the spin and bring it back, resulting in a car that is more responsive.

Hahaha. That's why I had the overpowered part in quotes. I was trying to find a way of stating a higher horsepowered vehicle as simply as possible.

And your examples on the rotational inertia are decent. I wish I thought of them.

You kind of missed my point on the pivot point though. I don't know if you've ever gone out and tried to drift a miata or RX8 (both are my only experience with 50/50 setups). The problem, that I was having at least, was when the slide would go beyond a certain point, the pivot point would switch from the front wheels to the dead center of the car, causing it to either spin or have an extremely harsh snap in the other direction. My brother (who was the owner of both vehicles) calls it '5th wheel syndrom'. And it's a decent description because it feels like a wheel is in the center of the car causing you to rotate around.

It's kinda freaky feeling to tell you the truth.