Mid-engine, Rear- engines superior for aero?
 

I was thinking the other day, since the grille on cars is a aerodynamic nightmare, wouldn't cars with rear engines be better, since a front grille is not needed?
Discuss...

i think a better way to look at it is the location of the radiator which is what allows the engine coolant to release heat.

The grille is only one part of the whole picture but yes superior aero is more easily achievable with the engine mid or rear mounted. Then again you could say the same for 2 doors versus4 doors versus wagons.

Citroen managed very respectable Cd numbers from their cars which were mainly 4 doors and front engined and front drive as well.
Check the CX , GS models for the 4 doors and the SM model for the 2 door.

Pete.

I think Tourigjm hit the nail on the head. You could theoretically design a front-engine car with the same Cd as a low drag rear engine setup, by using active cooling inlets/radiators on the side of the vehicle, and waste heat ejected into the low pressure wake. Of course the plumbing/ducting would be a nightmare for the front engine version.

Another advantage to rear engine placement is you can adopt a 100% smoth undertray since there is no hot exhaust pipe running down the center of the vehicle that needs to be left exposed.

front/rear
 

RiseAbove,in the phil knox aerodynamic photo albums,under Book Illustrations,second row from bottom of 1st page,is an illustration of Walter Korff's zero-drag,cooling system design.It's used in race cars,and a good model for ecomodders.---------------------------------------------------------------One thought with respect to rear engine cars,is center-of-gravity,with respect to aerodynamic center of pressure,something critical to a vehicle's directional stability.Conventional wisdom suggests that you always want the center of pressure behind the center of gravity,which yields high speed terminal oversteer.For front-engine cars,especially front-wheel-drive cars( like the Citroen as mentioned),this is especially easy to accomplish.Moving the engine to the rear can introduce terminal understeer at high speed,and as the front of the car yaws downwind,it catches even more air,increasing the yawing moment,with potentially fatal results.--------------------------------------------Modern monster mpg concept cars with rear engines, were lightweight two-strokes,which helped address the weight bias issue,and will probably never see production.Its true that the rear layout can provide an edge with respect to cooling,however,it may not necessitate moving the engine,only the cooling system as done with Ford Probe concepts,or just idealizing the front system to Korff's recommendations.

My exhaust pipe isn't exposed, its covered by a smooth aluminum sheet. I have designed it so there is an airflow running down the exhaust pipe's tunnel for cooling the pipe and the cat.

yer over- and under-steers are ternt around.

Having had several rear-engine vehicles, I can say I like the handling dynamics of them- nice, feather-light and responsive steering, not to mention superior traction. From a strictly utilitarian standpoint, though, it is better to have the trunk in the back, both for super heavy and oversize loads. And they are more sensitive to crosswind gusts.

[QUOTE=aerohead;52060]RiseAbove,in the phil knox aerodynamic photo albums,under Book Illustrations,second row from bottom of 1st page,is an illustration of Walter Korff's zero-drag,cooling system design.I

The label actually reads "ideal low drag cooling system." I used to be inspired by the North American Mustang aircraft, on which it was claimed that the radiator enclosure had negative drag - sort of like a hot-air jet engine. However, the Voyager team did their own testing, and could not get the cooling drag to be less than 20% of the total on their whole aircraft. One has to assume that they were competent researchers.

The front end provides the most direct flow to the rad, and does not have to disturb the rest of the shape. There may be some existing cars that could be improved by relocating the rad and ducting to the rear in a combined effort to solve other problems - it is not that difficult - VW did it on the wasserboxer Vanagon, in the other direction.

However, I agree with Mr. Lee - a front engine is good for stability, which becomes much more important on a light, streamlined car.

terms
 

Apologize if I goofed on terminology! How I understand the stability issue is: at road speed,on slick or icy roads,if you get popped with a frontal quartering,or side gust,its best to have the rear tires break traction first,as the car will tend to "weather-vane",turning into the wind,cancelling the yawing moment produced by the gust,while the driver applies opposite lock to correct the" oversteer".---------------------- Should the center of pressure lie ahead of the center of gravity,if popped by the same quartering or side gust,if the front were to brake away first(understeer),the car's front would catch more air,amplifying the yawing moment,tending to compete with the driver's attempts at steering corrections.In the past,when fins were added to race cars,I understand that this modification was to ensure that the C.P. would be firmly behind the C.G.-------------------------- Please help me out on this one,'cause a lot's at stake,and I don't need to be advising people with dyslexic notions.Thanks ,Phil.

I've never seen a cross wind that will actually screech my tires sideways causing me to correct. The oversteer/understeer characteristics of a street vehicle are determined by the weight distribution and wheel alignment. 99% of new cars are front engine because all that weight at the front causes the front to break away first so the car ploughs when the driver panics and slams the breaks and cranks the wheel. It is easier to survive a front-on collision, that is why they do this.

I went for a few ride-alongs in a friends MR2 at autocross and he was always battling oversteer becaues the rear end has more sideways momentum in a turn making it more likely to break traction.

As for the original topic, you could make one hell of a sleek frontal shape, top, bottom and sides if there were no ducts there for cooling or intake. A RR car definately has more aero friendly potential. I can't think of a high-speed supercar with the engine up front.

this is something i have thought about quite a bit, the engine placement is not that important really its more to do with engine design and placement of the radiator.

A flat 4 such as in a subaru or porsche allow for a lower profile to the car. subarus
with flat 4s upfront can achieve a very low bonnet line.

There is nothing at all to say that a front mounted engine has to have a radiator mounted at the front and have the hot aor swilling around the engine bay it is just just the way it has always been done. there are several other ways to look at it.

a standard setup air comes in at the front through the radiator, once through the radiator the air is expanded so it just has to exit where it can out of the engine bay. so to refine this you could have ducting incorporated into a bellypan that ducts the hot air under the car and exits at the rear of the car. At the same time the air could pass over the exhaust and cat to help cool it killing 2 birds with one stone

The other is to actualy have the radiator mounted at the back of the car. you have to remember that a radiator dose not have to take the form of what we have always known with little fins. It just has to have the correct surface area to cool enough so the radiator could actually be incorporated in to the whole rear end of the cars body pannels, or a rear wing fin anything the imagination can come up with obviously there
are issues to work our with the car at idle with no air flow but if you set yourself a harder challenge in the first place you come up with better answers to problems
a smaller pipe bore would be more logical if running pipe down the length of a car, .

Then there is another idea i had and one i have spent some time looking for infomation on thermal jets to work out the feasibility of my theoretical concept

Instead of having a radiator made up of fins it could be made from micro bore metal piping, so the air flows in at the front gets expanded in the pipes and the micro pipes then get channeled down the car to the rear end because you will have fine thermal jets theoretical the jets could be used to change the dynamic of the wake at the back. Eather acting as a thermal cushion for the colder air to ride on or by spiraling the jets to create a worm air vortex

The 911 constantly out preforms cars with equal power and its always put down to handling but its would seem obvious to me that the hot engine at the back actually has a big factor in this. After all an engine is expanding air to shift the pistons its just thermal expansion of air and water vapor. as an engine wastes most of the potential energy of the gas put into the car in heat-loss and noise it seems logical to put the waste heat to good use, i have more ideas on that but i will keep that for another topic

good weight distribution can be achieved with rear mid of front engines its just down to good design.

edit..

Just noticed 'Body integrated radiator method, requires no grill or openings...' looks to have some of the same ideas so i am going to go read it now

Porches win because they are extremely well engineered, highly refined cars with excellent weight distro (in all planes). If the heat produced thrust, you'd just start rolling when you let off the break, no?

I think this body-panel cooling concept is a little silly. If you took all the fins on my rad and spread them out into a sheet, you'd have a HUUUUGE area.

Oh yeah, and you don't have to have some non-conventional rad to have it in the back, that's what fans and ducts are for.

Korff
 

[QUOTE=Bicycle Bob;52205]------------------------------------- (reply=aerohead)

The issue of CG vs CP was important enough that Hucho devoted a good portion of an entire chapter on it.Evidently,crashes,if not fatalities are associated with high speed aerodynamics,as played out in events since the 1920s,when streamlining took off.Perhaps it would be prudent to take each vehicle on a case specific basis.When L.J.K.Setright road tested the Citroen CX,in the 1980s,he claimed that the front-engine/front-drive layout was the defining criteria for the cars rock solid stability,even at top speed,with crosswind.

I didnt at any point say the heat would produce thrust and in any case even if it did it would only be proportional to the speed of the air so when braking the air flow slows.
it would only cause the car to have problems if there was a forced propulsion like a jet,

The aston martin v8 vantage was developed with the goal of being faster than the 911 it was endlessly tested on the nurburgring with that goal it has more power than the 911 and its a very very highly developed yet its still not as fast as the 911. Now i am not saying that the sole reason for that is having a rear radiator but i am sure it is a contributing factor, hot air is less dence so it changes the dynamics of the wake behind the car, drag coefficient is one of the most important aspects of a fast car so it stands to reason that if there is something causing less drag its going effect the cars speed.

i know you dont have to have a non conventunal rad but you need space to mount one and somewhere to suck the air in so from a design point of view its would be wiser to stray away from the slab stile radiator.

i dont think its a stupid idea having a radiator built into body pannels, you are thinking in the conventual sence of how a car is designed but if the car is actualy designed with that aspect in mind its not too hard to implament. it may not be the sole radiator on the car there could be small heater matrix size rads with vents from the rear wheels, vents reduce the air friction on the wheels anyway so again it would not be a bad idea. if engine pistons cylinder and heads where ceramic coated along with the exhaust manifold less heat would need to be removed from the block in the first place
as heat would not transmit as well through the metal components. That then cuts the thermal differential the components are subject to resulting in a much longer wearing engine and its is a very good way of getting the most energy you can from the detonation.

I feel I have to disagree with much in this post Matt... I'll break it down into smaller chunks.

first off, while you are partially correct that in a street vehicle (indeed even race vehicles to a large extent) over and understeer are determined by weight distro and wheel alignment, you are overlooking an equally important (perhaps even more important) aspect of the equation: suspension setup - in particular the relative stiffness of the sway bars front to back.

Second, 99% of new cars are front engine/FWD (just call them FF and be done... FR would be front engine/rwd, MR is mid/rwd etc.) not because of steering characteristics, but because it is easier to design (and cheaper to build) them that way, and also allows the manufacturer to maximize a given vehicle's utility so it can appeal to as many potential buyers as possible. let's face it: MR configurations have very low useable interior volume when compared to FR's (hence why that layout is generally reserved for high-performance vehicles), and FR's are inferior to FF's although not by as large a margin.

I also have to take issue to your characterization of understeer as being preferable to oversteer. there is a saying you might be familiar with:

oversteer makes passengers go 'holy $h!T!!!' while understeer makes drivers go 'holy $h!T!!!'.

A small caveat here... understeer *is* preferable to snap oversteer, but a smooth and gentle oversteer is *far* preferable to any understeer, regardless of the drivetrain layout of the vehicle. a properly setup suspension will always tend towards oversteer. as an example, all of my scariest moments in cars have been during understeer events, where my car threatened to slam into a wall or launch itself into the air towards the outside of a curve (many ramps around here have large curves with no railing on the outside radius). every time I have experienced oversteer it was such a non-event that my heart didn't even bother to beat faster.

there are a number of variables there to consider... what year is the MR2? (the 1991 and 1992 SW20 models were prone to snap oversteer because of their suspension setup, which was nerfed by toyota for the 1993 and later models). also, oversteer should be seen by an autocrosser as something to be used and not fought - when the back breaks loose, drift it. that or your friend had something setup in a non-optimal way - it could have been as simple as using the wrong tires for that surface that day. certainly there are other avenues of investigation that I am not mentioning. if the MR2 in question suffered from understeer, your friend would have had a hard time being competitive - and might not have been able to stay on the course.

RR cars with engines any larger than the original VW beetle and of course the 'thing' have severe handling problems - a serious tendency towards snap understeer in particular.

^^^ excellent post^^^
You are definitely correct about the oversteer vs. understeer. A tendency to oversteer allows the driver to rotate the car around the corner better and is preferable to understeer. Although it takes a lot more skill to drive a car like this at the limit and be as fast as possible as compared to a tight setup where anybody can just lift off. Just watch the videos of senna driving the nsx around suzuka-beautiful trail braking oversteer.
Porsches are not known for perfect handling, they tend to suffer from turn-in understeer and then snap oversteer if completely lifted off the gas. The heavy rear end is great for braking and is probably the only real advantage of a rr setup.

ah yes... understeer is scary. thing is I just dont see why many people buy into the idea that understeer is more forgiving, when the very definition of understeer is the complete and total loss of steering effectiveness. this is doubly bad in a FF type car, where understeer results in both a loss of steering AND propulsion AND over half the braking power simultaneously. suprisingly enough however the solution to both over and understeer is pretty simple: MORE power (ie NOT more brakes, because braking in a curve is likely what caused the problem in the first place. drifting a car during oversteer really isnt hard at all, because you still have the ability to control steering, the majority of the braking and power... matter of fact a car in oversteer is actually nowhere near it's true handling limits, while a car in understeer is far beyond its' limits. what bites people about it is the fact that it this is all somewhat counter-intuitive.

I forgot all about the 911's... yeah their handling is not all that impressive, though the new AWD models have rectified the deficiencies to a great degree.

label
 

[QUOTE=Bicycle Bob;52205]I wanted to mention that in my photo album, the label under Korff's diagram is mine,not Korff's.I used the word "ideal" because I thought any cooling system design that could totally eliminate this component of drag was "ideal".

oversteer/understeer
 

I went back into my library to make sure I was using proper terminology when describing terminal understeer for rear engined,rear drive cars.I believe I chose the correct word.Forgive me while I digress.---------------------------- I the 1930s,40s,and 50s,Mercedes,Jaguar,and Bristol were plagued with crosswind stability and gust issues within their racing programs and higher speed passenger cars,as enabled by better,faster highways.------------------------------------ Kamm's K-cars were notoriously unstable in side gust conditions.It is believed that race driver Bernd Rosemeyer's death was caused by the aerodynamic instability of his Auto Union competition car,whose bodywork deformed and buckled under aerodynamic stresses,creating assymetrical induced lift which pushed it out of control----------------------------------------- In the report on the 275 mph crash of the HONDA Hawk land speed record motorcycle streamliner,it is mentioned that Bonneville racers have died in aerodynamic instability events,at velocities as low as 60-mph.------------------------------ Korff's comments concerning disregard for C.P./C.G. issues,would be analogous to shooting arrows feathers-first.--------------------------------------- My comment about casual remarks about aero-modded rear-engined cars comes from Korff's insistence that C.P. equal, follow the C.G..In a side gust condition,the apparent wind force vector will act on what Hucho refers to as the "lever arm" between CP and CG,and the front of the car can be pushed into a high speed understeer,turning the front of the car off centerline into an even larger cross-sectional area against the the air,in turn,amplifying the yawing moment with potentially fatal consequences.------------------------------- Korff considers the cars to be directionally unstable at high speed,difficult to manage,and a menace to other cars and its driver."C.P. should be at or behind C.G. for high speed stability."------------------------------------- Since,as mentioned,oversteer "freaks out" most motorists,low speed understeer is designed into basically all passenger cars.If the front breaks away,just steer in the direction you want to go,and apply more throttle.------------------------------------------- If you loose the front end at high speed your basically screwed.If you loose the rear,you can apply opposite-lock steering and judicious use of throttle to coax the front end through a curve or back into a lane.-------------------------------------- Parting remark,CP is so difficult to ascertain it requires a windtunnel to determine its location.Our ecomodder friends in Europe,with access to the Autobahn,could be tempted to test the top speed potential of their cars.Since we have no control over the weatheri it's extremely important to understand the forces we're playing with.Lives depend on it.I've done some pretty stupid things and circumstances have played out such that I'm still around.Don't flirt with disaster.If you do,do it where there are EMTs and ambulances.Saving fuel is a noble thing but its not worth your life.

screech
 

I don't think that velocities during autocrossing can approach the velocities I'm concerned with.

understeer/oversteer
 

I understand that oversteer/understeer characteristics for passenger cars are directly related to manufacture's recommended tire inflation pressures.

superior
 

Might want to check out Professor Morelli's CNR "banana-car of the 1970s,developed in conjunction with Pininfarina's wind tunnel.

handling
 

Low speed understeer is considered an attribute by carmakers for the 99th-percentile motorist.If your driving in oversteer conditions,your driving beyond the weather or posted speed.

Nope. Rear engine cars definitely have oversteering tendencies. Think about what "under" and "over" steer really means.

tire pressure is only part of the equation, and not so much as your sources would have you believe. suspension setup is easily as important at all speeds - I believe it is even more so, so long as the tires are in good condition and inflated to within a certain range of psi of each other. for instance, my tc from the factory is recommended to have tires at about 34f/32r. when I increased the pressure recently (my current tires are rated for 51psi), I set it for 48f/45r, in order to maintain the pressure ratio from front to rear within an acceptable relative range.

oversteer can be induced in a number of ways at any speed, but I fail to see how understeer could ever be considered a desirable attribute under any circumstance or at any speed. remember, when a car understeers it is effectively losing all steering control (like I stated previously), as opposed to an oversteer. personally, I am utterly terrified when the front end breaks loose, because at that point the car is going to go wherever the hell it wants, and I have effectively no say in the matter.

remember class... understeer=bad :p

I agree that understeer is bad in terms of maximum performance and speed around a racetrack. But it takes a much more skilled driver to drive a loose car at the limit than it does to drive a tight car at the limit.
This is why pretty much every single road car sold today with the exception of some sports cars and exotics has a tendency to understeer. Sure there are ways to induce oversteer but the engineers design the handling characteristics so that the majority of drivers will only experience understeer. When a driver experiences understeer their natural reaction is to lift or start braking- most of the time the driver then regains control and is safely on their way. When an average/untrained driver is surprised to find their car exhibiting oversteer it is much less likely they will regain control.

oversteer/understeer
 

Hi Frank! I understand where you're coming from,as the Porsche 356,911,912,and Karman Ghias I've driven all had oversteer when at the limits of adhesion.--------------------------------- The thing about what Korff was warning about,which directly effects any of us streamlining,is that since the C.G.of rear-engined and even mid-engined cars can be behind the centerline of the wheelbase,should the C.P. lie ahead of C.G., in a strong wind gust(as Otto might experience if he crosses into Germany from Belgium and goes full speed on the Autobahn) from the side,the car will act like an arrow flying feathers-first,and attempt to switch ends.In such a scenario,with the front coming around to meet the back,would constitute "understeer",of which it might be impossible to recover from,as the front has exceeded the limit of adhesion,and no amount of steering correction or throttle modulation may be enough to recover,with powered rear wheels pushing the car further off course.Remember,I'm not talking about rounding curves at speed,just barreling straight down a superhighway in very strong crosswinds,something that has already claimed lives.

the equation
 

(my response) Understeer is considered desirable by the carmaker,for low speed driving.Oversteer is desired at high speed for the reasons you mention,however is terrifying to anyone not trained in how to deal with it(nearly everyone in the U.S.).----------------------------- My whole point has to do with high speed directional stability which is directly related to C.G. If an ecomodder streamlines their car,such that the C.P. of their car is positioned ahead of the C.G. of their car,in certain situations,they will die.

I spend most of my driveing life on tiny little country roads my car can either understeer or overseer depending on the way it is driven. In the lupo i have to break before a corner and power through it if i break into a corner i will get massive undersear the end up in a hedge its very very scary and once it starts to happen there is hardly anything that will correct it apart from a tree or curb. Overseer is much more predictable if i slow or brake before a corner i can then just power into it, if i start to feel the overstear i know letting off the power will correct it. You can also feather the amount of steer you put into the wheel. So driving into the corner you will almost twitch the steering wheel putting in a bit of steer then backing of then a bit more than backing off. this is ideal on a front wheel drive car you get use to the balance of the car. Its like how you drive a car up on 2 wheels you feel the balance and add the steer in to correct the car from falling back down onto to wheels or in this case spinning out.

On a front engine rear wheel drive car understeer is not as scary as you have the ability to blip the power to get the back end to swing out to correct the lack of steer.

IMO under or over is not better it just depends on the car and the ability of the car and driver to correct it and the driving conditions.

Personally like oversteer for the tight bend british roads i drive on. On long gradual turns oversteer is not as good as g-force is not with you to give the same feed back to calculate how much steer to put in so you tend to overcompensate and it gets very tiring.

YouTube - Top Gear - Oversteer and Understeer

YouTube - What's behind "top gear explain understeer and oversteer"

Understeer is not complete loss of steering. Understeer is when the turning radius of the car is greater than it should be with a given steering wheel angle. The front tires are losing lateral grip in the turn, but there is a spectrum. At its worst, understeer sends the car straight toward the outside of the corner, as described by Equation112.

Oversteer is when the turning radius is tighter than the steering wheel input. The rear is sliding. Somewhat counterintuitively, oversteer spins the car to the inside of a corner.

In general, the drive wheels will determine whether the front or rear slides. FWD understeers, RWD oversteers. This can be complicated by engine placement, which definitely affects turning.

My FR ranger understeers going into corners, but with throttle will severely oversteer because of its poor longitudinal weight balance. My Golf would understeer terribly, which was a tire and possibly suspension issue. Only three times, at my worst behavior, did I ever get it to oversteer. My Passat, with better tires, has a very smooth and controllable understeer. That is the turning radius can be comfortably adjusted with throttle, which made poor weather simple to drive in.

So, I guess my point is absolutes are dangerous to use and all generalizations are false. Back to your regularly scheduled thread.

someone needs to introduce you to the handbrake :)

Obviously any oversteer or understeer arent really economy techniques. If you want economy, go slow through the corners and stay off the brakes, but it is good to know how to control your vehicle in any case.

http://www.youtube.com/watch?v=UyG0mWtcp6Y

I would think understear or overestear could be economical if they stop you from having to either use the brakes and slow way down in the turns or drive the whole time at a less than optimal speed.

What kind of steer do they call it when you lose control and do a 360? When i was a freshman i was driving to college half asleep in my dads car i borrowed. The road had some damp leaves on it. I had the heat on defrost the windows. I started drifting that boat of a car to the edge then realized it and overcorrected the other way and lost control and went into a full spin. I hit the last few guardrail posts and then slide sideways through a bank of mud stoping suprising quickly. Luckily I went after the drop off and before the pole. maybe 10 or 15ft either way. I didnt have a scratch on me. The whole side of the car was dented and scratched, the front bumper was in pieces and the wheel fell off when pulling it onto the flatbed. I was borrowing the car because mine was in the shop getting a minor dent fixed that day. That 98 monte carlo LS was a front wheel drive and handled poorly. I remember my fathers teeny tacoma truck would fishtail when he would drive it in the snow and i remember the truck going into a 360 once or twice in the middle of the road. Other people seemed to like to hit that truck when it was parked in parking lots lol.

Miket: You would be wrong. Oversteer and understeer are ways to scrub off speed; the brake is a much more controllable way to do that. Which also doesn't risk you stuffing the nose of the car into a wall (understeer), or sliding the tail of the car into the wall (oversteer).

Oversteer can be a way to get the car to change directions really quickly, but you lose quite a bit of speed when you use it that way. On pavement, it is pretty much always better to not get one end or the other of the car sliding. (Note: Gravel/dirt/snow can be different; the rally guys always seem to be sideways and it works for them!)

It can be beneficial for MPG to take a turn at a fast speed, because that means you don't have to slow for it so you don't have to regain that speed after you have slowed down. But sliding the car means losing speed, so you do have to use fuel to regain it.


BTW, the 360 you did is called many things, from a "360" to a "spin" to a "loop"; and the "starts to go one way then spins the other way when I tried to fix it" is called a "tank-slapper". They can be exciting, but are usually not so good for the car. If nothing else, you wind up having to do some cleaning of the upholstery. ("First you say it, then you do it!" ;) )

-soD

Google seems to think tank slapper is a term for something that happens on motorcycles.

How could it be more economical ?

Understeers means you run off the road or into the oncoming lane unless it's corrected - typically by slowing down anyway.
Oversteer slows you down because of the extra drag caused by sliding sideways - that is, if it doesn't get you off the road to start with.

If you experience either, you've carried too much speed into the corner and could have slowed down well before the corner - say by coasting - or you could have started with a lower speed to begin with.
That'd have been economical.

I seem to think tank slapper is a term for something that happens on motorcycles.

Some of us car folk have stolen that term pretty shamelessly from the MC crowd. Generally the same thing, over-corrections of increasing magnitude--usually with no good ending.

N.B.--working a car hard enough to spin at 70+ MPH can result in multiple 360s, in both directions!!

-soD

stability
 

If you are to streamline a car the location of the center of gravity is especially important in relation to the center of 9aerodynamic) pressure.
At high speed,and exposed to a side gust,a car should weathervane towards the gust direction,canceling out the yawing moment.
Typically,for streamlining,a front engine with front wheel drive is the most stable.
A rear fin can be a palliative to compensate for an improper CG/CP bias.

You can also affect the self-steering by using suspension geometry. IIRC, in the front you want leading arms to give you the "steer into the wind" effect, while in the rear you want trailing arms for the same effect. The notion is that between the compliance in suspension bushings, flexing of parts, and so on, the arm will pivot roughly where it is attached to the chassis of the car when a side-force is placed on the car.

-soD