I've been wondering how much help it is to be driving a car that is:

All wheel drive
Rear wheel drive
Front wheel drive

I notice there are very few front wheel drive cars in the top 10 raw times at my autocross events.

What is everyone's experience about how this can affect autocrossing outcomes?

Do you think it's any harder to drive front wheel vs rear wheel drive.

All wheel drive is great but not many have it in my area. Hey that's cheating- sort of.

 

I spent TOOOONNNNNSSSS of money making a 5.0 mustang turn good. It was a great road race car and autocrosser, but for money and time spent the mini pwns my RWD in most cornering situations.

FWD, way easier to drive for me. less of a chance of spinning (my 5.0 was fully built and SCed ((6 psi)) so like 550 WHP isnt easy to handle)


I recently drove a sm class winning (most of the time) wrx sti thats really well set up for road courses, and I was really impressed. it pushed a bit but as soon as you transfer the weight to the rear it rotated and stuck like a champ.

personally I was going for something new to me, and FWD is that and im happy with my switch. high HP is fun, but cornering is better! !!!

 

I believe the Main advantage to Both RWD and AWD in the Autocross arena. Is in the Launch and drag strip areas (any area where coming out of it slowly and you need to stomp on it to get to next section) of an Autocross. in the Launch alone they can get up to 2 car lenght advantage depending on the set up. Which we have to make up in the Flowing technical parts. My best Raw finish so far was 4th and this was in a Rained event. Normal is now 8th - 12th raw. Being beaten by Corvettes, Lotus , Morgan and a Camaro

 

Perhaps the main difference is increased flexibility in driving styles. With RWD you have the option of using power oversteer or lift throttle oversteer, while FWD only allows the latter (I've seen courses setup so tight that big cars like Corvettes had no choice but to use power-on oversteer to avoid trampling cones). RWD/AWD also gives you the option to apply power much earlier (even beginning mid-corner), which would make a FWD car dissolve into understeer.

So there are just more tools in the toolbox. That said, I think FWD is much easier to drive because there are fewer options (and thus fewer ways to screw things up). Anytime the rear starts to get a little loose, you can simply automatically apply more throttle to fix it every time, so in that respect FWD behavior is more consistent.

 

So if the concensus is that FWD is easier to drive then why don't I see that many FWD finishing in the top 10 out of 100 drivers when we have many FWD cars at each event.

"lift throttle oversteer" I have done but only on a long sweeper turn at high speed on a track, not able to get that kind of speed at autocross.

One idea is-

Maybe it is easier to get started doing autocross in a FWD than RWD but once one has mastered driving RWD you can use that to help get around the course faster. The results would still require a high level of skill.

To compete at the same level as the best drivers of the day if one is driving FWD you have to make the least mistakes and be careful not to turn too fast and get into an understeer situation.

The difference in times can be very small. Top 10 places might be separated by only 1 to 2 seconds sometimes 2nd to 10th place only about 1 second over a course that runs 30-36 seconds.

More thoughts on front vs rear drive
http://blogs.drive.com.au/2006/07/is...etter_tha.html

 

At a recent autocross event, we had a team format where three people shared two cars. My Cooper was one of the cars for my team, a friends Miata was the other. So, we had front wheel drive and rear wheel drive.

The two cars were actually very similar in handling. But that's because the Miata had been tuned towards neutral / understeeer and the MINI had been tuned towards neutral / oversteer. About the same power in both cars (1/6 liter engine in each, around 115 hp each). The Miata had better tires, so it set better times. If we had swapped tires, it would have been the other way around.

I also took a fun run in a Toyota MR2 Spyder - mid engine rear wheel drive. Another great car. That one tended to perhaps a little more oversteer, but it was still incredibly controllable.

I don't know that blanket front wheel / rear wheel drive comparisons are valid. Most front wheel drive cars understeer like mad. But not all. Some rear wheel drive cars will oversteer with throttle application, some don't.

The average front wheel drive car is not designed as a "sports car". In rear wheel drive, there's a better chance it will be "sports tuned".

 

I think the reason AWD/RWD cars tend to have faster RAW times is that they can deliver the power to the wheels much better than a FWD car can. You can get on the gas really early, and then stay on the throttle all the way through the corner in a RWD.

This means you can exit the corner compartively faster than a FWD, which needs to be trailbraked into the corner so that it will turn, and then you have to roll onto the throttle gently so as not to smoke the front tires.

And I would contend that corner exit speed is probably 50% of what would make an autocross car "fast".

 

115hp in a 2400lb car may simply not be enough power for RWD vs. FWD to matter whatsoever, if it leaves the power oversteer option off the table. Note it's not that power oversteer may be used to produce a lurid drift, but that it may allow careful modulation to apply more power while in turns without understeering--which can produce higher exit speeds.

By the same reasoning, lift-throttle oversteer isn't necessarily used to swivel the tail around but merely to tighten the line when you find yourself understeering off of it. The throttle is backed off just until the desired result is achieved--not just lifted off

A high powered FWD car forces you to learn patience because you have to wait until it's nearly straight to bury the throttle.

 

Thanks for your thoughtful discussion.

At any performance driving event there are cars that are FWD, AWD or RWD that have engines in the front, middle and rear locations which determine the weight distribution of the car which effects handling characteristics (generally).

FWD- like my MINI about 60:40 weight front:rear
RWD- many times near to or at 50:50 weight distribution

Then we can tune each car with suspension changes to minimize or maximize characteristics such as understeer in FWD and oversteer in RWD either to the point of being as neutral steering as possible or not.

That was a good example about two cars, one FWD and one RWD with similar power but different weight distribution and almost neutral steering/handling. Better would have been to have the "same" tires/wheels. Outcome might be similar.

Another good point was what about power? 115 HP vs 220 HP vs 300+ HP.
What happens as power is increased given the same weight for the car. Some problems are magnified as in torque steer for FWD and even wheel spin and loss of traction with any higher HP car.

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Some Pros and cons about FWD- (from http://en.wikipedia.org/wiki/Front-wheel_drive)

Advantages of front-wheel drive

* Interior space: Since the powertrain is a single unit contained in the engine compartment of the vehicle, there is no need to devote interior space for a driveshaft tunnel or rear differential, increasing the volume available for passengers and cargo.

* Cost: Fewer components overall.

* Weight: Fewer components mean lower weight.

* Improved fuel efficiency due to less weight.

* Improved drivetrain efficiency: the direct connection between engine and transaxle reduce the mass and mechanical inertia of the drivetrain compared to a rear-wheel drive vehicle with a similar engine and transmission, allowing greater fuel economy.

* Assembly efficiency: the powertrain can often be assembled and installed as a unit, which allows more efficient production.

* Placing the mass of the drivetrain over the driven wheels moves the centre of gravity farther forward than a comparable rear-wheel drive layout, improving traction and directional stability on wet, snowy, or icy surfaces.

* Predictable handling characteristics: front-wheel drive cars, with a front weight bias, tend to understeer at the limit, which according to for instance SAAB engineer Gunnar Larsson is easier since it makes instinct correct in avoiding terminal oversteer, and less prone to result in fishtailing or a spin.

* The driver can control the movement of the car even while skidding by steering, throttling and pulling the hand brake (given that the hand brake operates the rear wheels as in most cases, with early Saabs being an exception).

* According to a sales brochure for the 1989 Lotus Elan, the ride and handling engineers at Lotus found that "for a given vehicle weight, power and tire size, a front wheel drive car was always faster over a given section of road." However, this may only apply for cars with moderate power-to-weight ratio. According to road test with two Dodge Daytonas, one FWD and one RWD, the road layout is also important for what configuration is the fastest.

*It is easier to correct trailing-throttle or trailing-brake oversteer.

Disadvantages of front-wheel drive

* Torque steer is the tendency for some high power front-wheel drive cars to pull to the left or right under hard acceleration. It is a result of the offset between the point about which the wheel steers (which falls at a point which is aligned with the points at which the wheel is connected to the steering mechanisms) and the centroid of its contact patch. The tractive force acts through the centroid of the contact patch, and the offset of the steering point means that a turning moment about the axis of steering is generated. In an ideal situation, the left and right wheels would generate equal and opposite moments, cancelling each other out, however in reality this is less likely to happen. Torque steer can be addressed by using a longitudal layout, equal length drive shafts, half shafts, a multilink suspension or centre-point steering geometry.

* Lack of weight shifting will limit the acceleration of a front-wheel drive vehicle. In a vehicle, the weight shifts back during acceleration, giving more traction to the rear wheels. This is one of the main reasons why nearly all racing cars are all- or rear-wheel drive. However, since front-wheel drive cars have the weight of the engine over the driving wheels, the problem only applies in extreme conditions.

* In some towing situations, front-wheel drive cars can be at a traction disadvantage since there will be less weight on the driving wheels. Because of this, the weight that the vehicle is rated to safely tow is likely to be less than that of a rear-wheel drive or four-wheel drive vehicle of the same size and power.

* Traction can be reduced while attempting to climb a slope in slippery conditions such as snow or ice covered roadways.

* Due to geometry and packaging constraints, the CV joints (constant-velocity joints) attached to the wheel hub have a tendency to wear out much earlier than the universal joints typically used in their rear-wheel drive counterparts (although rear-wheel drive vehicles with independent rear suspension also employ CV joints and half-shafts). The significantly shorter drive axles on a front-wheel drive car causes the joint to flex through a much wider degree of motion, compounded by additional stress and angles of steering, while the CV joints of a rear wheel drive car regularly see angles and wear of less than half that of front wheel drive vehicles.

* The driveshafts may limit the amount by which the front wheels can turn, thus it may increase the turning circle of a front-wheel drive car compared to a rear-wheel drive one with the same wheelbase.

* Due to the combined stress of steering and power, the front tires have a tendency to wear more quickly when compared with rear-wheel drive vehicles.

 

RWD will always make for a better autocross car. But obviously, if you have too much power, that can make it more difficult to drive. But the same can be said of an overpowered FWD car.

Lack of power in either a FWD or RWD car makes the car easier to drive because there's one less thing to worry about (throttle).

FWD cars can hang with the RWD cars when the grip is higher (hot weather or concrete surfaces). But in low grip situations, the FWD cars really struggle to get off the corners.

I know about this first hand having switched from a Miata to the Mini. Honestly, I'm trying to figure out how to get back into a RWD car. The two main things I don't like about autocrossing a Mini are:
1) FWD (see above)
2) Front strut suspension (the car needs more camber and caster....the camber curve sucks compared to a Miata or other "sportscar")

But don't get me wrong, the Mini is a fun car! It's only when you get to compare side-by-side with other true sports cars that you realize it's deficiancys. It's MUCH more practical than the Miata! That's for sure!

 

Excellent comments.

Each driver's skill level or style might also be better match or in sync with FWD vs RWD. Some prefer oversteer tendency to understeer and know how to cope with it power or not.

Personally I think it's much harder to drive well with more than a little added power. Base or midded MC is fine and MCS mid modded to 230 HP is fine but 300+ HP in any FWD would be a bit more touchy.

Then there is the course itself, which varies from location to location, sometimes smooth and flat, sometimes more grippy or not. Weather's a factor with rain or with temperatures thoughout the year.

I've noticed that in my area the quickest RWD car besides the Miata are-
Honda S2000, Camaro and the 240Z. MR2 does well. Besides our MINIs there is one Civc CRX and sometimes a WRX STi that finish high.

I would expect in other areas to see BMW M3, AWD subarus, Pontiac Solstice, Lotus Elise, or Corvettes to do well. Alot depends on tires and driver skill.

 

coming for an autocross-ing 2000 audi a4 1.8t quattro i must say that it was much faster thru hairpins than many other cars. i have noticed taht thru such turns other higher powered cars with rwd/fwd tended to oversteer and 'drift' around almost, where as 85%-100% throttle in my car around a hairpin produced no over/understeer and just powered straight thru. my$.02

--E

 

All season tires were just no good at all for my MCS at the autoX today. The front tires spun in the air whenever the turbo kicked in in the 2nd gear. Too much torque for the light car with too little traction. I am never autoXing again until I can put some R-comp tires on the MCS.

 

The R56 has tons of lower rpm torque so-

Yes, use the grippiest tires you can find (wider is good too)
Make good use of your gears and get out of first early
Make good use of second because you still have to feather the throttle enough not to get wheelspin which happens almost too easily even with R compound tires (depends on which tires and what track surface).

Personally I think soft rubber would be best but the availability of tires for the R56 are rather limited if you use 17" wheels, might be better if you use stock 16" or if possible 16x7.5 or wider rims and Hoosier A6 or Kumho V710 tires not Avon Tech Ra. Or if you are on a track then Toyo Ra or the new BF Goodrich R1 tires.

All season tires are meant for the street to handle all season driving.

If you like street tires then maybe
Bridgestone Potenza RE01-R or
Falken Azenis Rt-615 or
Hankook Rs2 Z212

 

I guess I was hammering it too much. With my former Z3 I could not spin the wheels like my MINI did today. Won't it rub if I go with 7.5" width? What tire dimensions? 215? 225?

 

I've driven the R56 MCS at autocross on R compound tires and spun the wheels in 2nd easily. I can't do that with my R53 MCS with Quaife in 2nd with R compound tires.

I think R56 MCS drivers will have to learn how to make the best of ample torque and a lack of camber and lack of grip even with LSD. Ease onto the throttle, ease on the brake so not to loose too much speed and rpms. Smoother input/transitions on sharp turns and better weight distribution on all tires. You'd have to do all those things anyway to do better.

Stock wheels are 17x7 with +48mm offset and 205/45-17 tires.

17x7.5 is possible but that would mean no longer legal for stock class autocross. Go to STX if street rubber or DSP if R compounds on wider rims.

17x7.5 with +42 to 45 offset. Stock sized tires are good or smaller like 215/40-17 or even 205/40-17 if the load rating is at least 84. 215/45-17 is a bit taller than stock height so less clearance and small risk for rubbing under load or with dips on the road. Usually rubs in the back on the inner plastic wheel arch. 225/45-17 is too tall at 25".

 

I have a set of R-comp tires 225/50/16. I was told 16x6.5 will fit on those. However, I think 16x7 will be a better fit. Do the tires have the right dimensions for my MINI btw? Or should I just sell them?

 

Lets stay on topic for this thread.

"RWD vs FWD- ease of driving at autocross".

Your question has already been answered on another tread where you asked about autocrossing with 16" rims.

225/50-16 is well suited for 16x7 to 16x8 rim. It will your car but it is taller than stock tire diameter.

 

I have autocrossed the mini twice now since I have bought it. It handles well for a stock car, and maybe it seems a little easier to drive because its low power FWD. My SM2 M Roadster on the other hand is a completely different experience. Its raw, exhilierating, and I always know I could do more.

When I have FWD or AWD guys auto-x my roadster, they always comment that it was just more exciting and raw than their cars.

 

How long did you autocross your M roadster and what were your results?
How many Seasons? How many drivers per event in your class and overall?

Do you have a 2007 MCS?

For the older MCS R53 if you add lots more power with a turbo kit it doesn't make autocross easier, it makes it harder to handle the extra power and get around tight corners. There is probably a sweet spot in power with 115 HP in an MC being too low and 200 HP in an MCS being not quite enough but 300 HP is a handful and not really helping in the right way.

 

I have run the roadster for 4 years now, progressing from BS to ASP to SM2. The car doesn't have forced induction so its pretty underpowered for SM2. Obvisouly, SM2 is not a big class in most areas. In Ohio, I was winning consistantly, but not much for SM2 competition. I have put up FTD before and for a while had a 320rwhp turbo miata to contend with, to which I lost most, but won a couple. Here in FL I am losing to a built twin screw miata with a great driver. Most events I atteneded were in the 75-100 driver range.

In the last several years I have spent alot of time in other people's cars as well. Most of it in STis and Evos. I've done a couple National Tours and had 1 fairly good one and 1 terrible one. My good one was placing 2nd in SM driving a BSP STi. In the 2006 Southeast Subaru Challenge, I managed to get into the superstar challenge and took 5th pax out of the 135 drivers.

I have auto-xed a '05 JCW a few time and thought the power was good ,but still needed alittle more. The course I am thinking of was a power course set up by Danny Popp (ASP Naitonal Champ at the time). I was driving a JCW with a rear sway and azenis 215 and ended 4.0 seconds behind him on a 55 second course.

I'm currently building a M Roadster (2nd one!) that will be to the limit of the rules and not a street car. Its a 2700#, 3 liter turbo, beast with 18x11 wheels on it.

thats more than enough about me..... sorry if I rambled.

I have a 2004 MC that I have done a couple events in HS on the factory all seasons. I have some used slicks at the house waiting but no wheels yet. Its definately a very different feel than I am used to. I didn't buy the car planning to try to take it to Nationals or anything (and I'm not ready as a driver). I just want to do a few things stock legal and maybe go to a Tour at most just to see how my times are.

Some good friends of mine at TiC (now a forum sponsor) bought a '07 MCS and have been kicking butt in The Cincinnati area in STX on the stock run flats. The HART (Honda of America Race Team) guys are pulling their hair out. They were saying the power is too much for the car on those tires and the car should really respond to the stickier tires.

The rwd thing is a preference for me. I like a powerful and slightly tail happy car. Maybe I will post up a link tonight of me spinning the roadster....

 

the reason why rear wheel drives always has faster times is because they can get more power to the ground and use it. Front wheel drive has its horsepower limits before they start to lose traction. If a mini has the same amount of horsepower as an s2000 its up in the air, the better driver wins.

 

Rear wheel or not you still have to apply a generous amount of skill to control that power you have.

I drove a Porsche turbo during Test and tune day and recently a Camaro during fun runs and both times had trouble making the correct adjustment for the ample power those cars had. Both times brakes were stronger and power needed to be applied but ever so smoothly to maintain control.

My MINI permits me to stomp on the brake or gas with abandon. Hopefully not so much on the brake as slowing down isn't a good strategy when I don't have ample power to speed up.

I guess it's kinda fun to use a front wheel drive car and try to keep up with rear drive leaders each event. Again, it's going to boil down in large amount to driver skill (applied in generous proportions).

 

I started autocrossing in 1980 in a Scirocco and then went with a Rabbit Convertible just because I wanted a convertible. I autocrossed an old Formula V for a while too. I had fun with the front drivers, but the Mustang and Camaro guys looked liked they were having so much more fun. I bought a Mustang and found out that, yes, yes, they were having much more fun. I owned several 5.0's and autocrossed them all. I had my last 5.0 for over 10 years and it morphed from being a daily driver to a highly modified track car that was just barely streetable. It had some engine mods, but mostly the suspension was greatly changed, full Griggs, K-member, adjustable springs at each corner. I gave up autocross in favor of open track. In Denver SCCA autocross has gotten too serious for my liking, people buying new cars each year to take advantage of stock classes, 250+ entries, running over 8 or 9 hours. Just too much standing around for so little track time, but I digress.

Open track was fun, but a high horsepower, heavy car needs lots of maintenance and that was taking the fun out of things so I sold it. I figured I'd had enough racing for a lifetime or at least a few years.

My wife wanted a MINI since they came out, but I really wanted to stick with something RWD, but I could never fiqure out what to get: Miata - not enough horsepower, RX8 - could use more horsepower and really needs better mileage, S2000 - not enough torque, 350 Z - close, Camaro - dated, too much like a Mustang, Corvette - super cool, but kind of big and heavy, a BMW M3 looked like the best compromise, but they are expensive new and old ones are expensive to repair. So after 5 years of begging I finally caved to my wife and got an 07 MCS. I ordered it with the sport suspension and LSD just in case I decided to autocross again. Love it. It's faster than my Mustangs at this altitude.

I autocrossed it a couple of times at smaller BMW and Porsche Club events. Bone stock with Slipstreams, 215/50/16 BFG KDWs, and what little negative front camber I could get it was a blast. I'm nowhere near knowing the limits yet. I kept hitting corners too hot. I'd start to turn and think I was so far out of shape that I was going to blow a gate, but I never did. I just scrubbed off speed and turned the wheel and damned if that MINI just didn't turn and turn. I never blew any gates. The Mini is so tossable. In many ways it feels like a rear driver. I've found it very easy to rotate the rear - you just have to drop throttle with abandon. Once I get my adjustable 22mm bar on the rear I'm hoping I'll be able to drift it through some corners. I'm trying to keep things simple and not modify myself out of another street car. To that end I've decided to keep the stock exhaust - I like the quiet. I run on street rubber so I don't have to haul around wheels and tires. So far I'm impressed with the sport suspension. I'm just going to add the adjustable rear bar and an adjustable camber plate. Once someone makes a race pad I'll take it to the track. I'm sure that will happen before spring. I don't have enough self control to track on stock pads. If I get back into opentrack I'm sure I'll need a big brake kit. Then of course I'll need another set of wheels and some track rubber, but hopefully that's where I can draw the line.

I miss the sound of a V8 and accelerating full throttle as I drift perfectly into position for the next corner, but that's all I miss about the old Stang.

FYI - a couple I know who is really into autocross - multiple cars, truck and trailer, events every weekend, new car every year if they are running a stock class, etc. etc. They ran an 05 Mini in 06 and said it was hands down the most fun car they ever autocrossed. They wanted to get an 06 with LSD, but couldn't get it in time for the 07 season so they got a really nice modified BMW to run. Obviously they are in to the competition and can put up with 250+ entrants.

I'm in it for the fun factor. Looks like a finally found the right car!

 

i dont think you understand what Im talking about. I was referring to the strictly the mechanics of cars not about driver skill.

I dont know what "abandon" means.