autocrash

dude... most of what you said is true... and I agree with the results of the above situation... but think about it...

More contact = less grip??



Maybe some vehicle dynamics courses are in order... and oregano.. man... you need to spend more time in school.

Now whats that thing called when you go round a circle... I think you were talking about the imaginary force that is opposite to it (hard to tell due to the spelling ) ...right, centripital force... which means that when you are going around a circle, you are accelerating....



...damn, I guess weight distribution duz matter...

Howi

iTrader: (2)

Maybe oregano should not have used the word "better," as it is a subjective term. What he really meant was that the rear end of a FWD would come out easier w/ less weight at the back.
Car manufacturers only strive for 50/50 weight distribution if they're producing a RWD. You will never find a FWD w/ its entire engine and transaxle any where close to the firewall like a RWD.
You might ask what the difference is. Imagine a RWD w/ most of its weight up front. This is a terrible setup becuase:
1) when you enter a turn, you let your foot off the gas pedal and brake. The weight of the car transfers further up front, which can easily initiate a drift.
2) after you initiate the drift, you can not steer the car w/ your gas becuase you have no weight at the back.

This is fine on a FWD, becuase the drive wheels are up front.

Please englighten me as I do not see how an sway bar can increase the contact patch. I believe that the reason why you can increase oversteer by adding a rear sway bar at the back is because the weight transfer will be much quick (similar effect to stiffening up the springs the back of the car), therefore the rear-end will come out much easier.

howi

BDoty311

Why are cars FWD in the first place? Because they are better in bad weather because more weight is over the driving wheels.

So why would a car company try to put more of the weight in the back, it might perform better, but since when is FWD a performance option?

White_FC

FWD aint no performance option, its a COST option, always has been always will be.
Nothing to do with bad wether traction?

Howi

iTrader: (2)

so you need acceleration to keep it going at a constant speed... it's obvious becuase F=mv^2/r. so what? how did you jump to that conclusion?

howi

Terrh

iTrader: (7)

preludes are slow? Man, someone better tell that to the people I autocross with, because preludes almost allways take the top 2 or 3 spots...

mason-rx-7

First of all...

The prelude is overweight.

Secondly...

I really don't beleive that you can have a true sports car unless it is RWD.

Thirdly...

You can make a Honda faster than hell but it is still a FWD economy car (with the exception of the S2000, my friends dad has one and it hits 140 mph with ease).

Fourthly...

VTEC (Variable Timing Electronic Control) is amazing engineering and every car company has tried to copy it.

Lastly...

Mazda's Kick ***...

Howi

iTrader: (2)

I'm with White FC. what are you talking about BDoty311?

Tsunami

I never said more contact = less grip.

BDoty311

Lots of people are scared of RWD in the snow and rain, so they want a FWD car that will do better in bad weather. Thats one reason why FWD cars are more popular.

Tsunami

an anti-sway bar works by tying the bottoms of the suspension pieces together, which in turn lessens body roll and keeps both wheels better planted on the ground, this in turn keeps weight and mass from transfering to the outside when it experiences centrifugal force, thus it doesnt really increase the contact patch, but it keeps the patch planted more firmly on the ground, and keeping more weight over it, thus increasing traction.

also: inheirently in their design tansversely mounted motors cannot be mounted close to the firewall, as there would be no way to access the intake manifold or any of the sensors in the back, while that problem does not exist with a longitudianlly mounted engine because both manifolds and sensors are on the sides, thus can be planted as close as possible to the firewall. A transversely mounted motor cannot be mounted closer to the firewall as then the axles, hubs, and the entire front suspension would be moved further back, giving the car a much shorter wheelbase and thus crappyer handling.

also: Less weight and stiffer springs out back may be perfectly fine for (attempted) fwd drifting and ebrake driving, or for rally driving, as in those conditions it is beneficial for the rear end to sway outside of the front end, while in GRIP racing, it seems much more beneficial to maintain mass in the rear in order to allow the centrifugal force exterted (or seemingly exerted on it, as centrifugal force is an imaginary force) on the rear to aid the car in rotation. It is certainly possible that this weight and centrifugal force is negligible compared to a well tuned suspension, but it makes far more sense to keep it there than to remove it IMO.

andrew lohaus

i definetly agree. i can beat all but the best fwds right of the line but where i realy get them is in not having to shift as much. i beat a prety heavily modified neon on the simple fact that on our way to about 105mph i only had to shift twice (into 3rd) while he had shift 4 times (into 5th). when he was in gear he was seriosly pulling on me but while he was inbetween gears (and not even for that long) i kept on pulling and gaining ground.

andrew lohaus

amen brother. no matter how fast your hon-duh might be, its still a fwd economy car. they never have been, never can be, and never will be true sports cars. so even if one beats you just chew on that.

andrew lohaus

yes this is why corvettes, while amazing handling machines in the right hands, have such a dangerous tendency to sling the *** end out. 60/40 wieght dist.+ gobs o torque=tendency to oversteer. its just the nature of the beast, but id still love to own a vette day, especialy a lingenfelter

Howi

iTrader: (2)

Yes you did, just not in the exact words, here:
sigh... call the honda whatever you want. the truth remains that they are incredibly fast cars on circuit tracks. But you don't care anyways, because you have a 7 and it's a "real sports car." According to your logic, it doesn't matter if a civic whips your *** on the race track, because you have a "real sports car," and your mind can justify that it was actually you who had won, right?

howi

Tsunami

2000 z06 vette as reported by car and driver

53.5/46.5%

Tsunami

nope dont see the words "less grip" anywhere in that quoted statement, because obviously its not true. Regardless of any rebuttle you can make, more mass in the rear=more inertia for the rear=cars tendency to rotate more.

How about instead of trying to catch me in some sort of imaginary slip up, you accept my post for what it was, an informative post that was correcting misconceptions of a fellow Rx7club member.

andrew lohaus

ah true, but after 40 years they finaly decided to go to a rear mounted transaxle on the c5s to offset what i just said. c4s are about 60/40 if not worse because of the conventional engine/trany arrangement. and let me tell you they can sling the rear out like its nobody's buisness. a guy i knew with a c4 would always drive around with the 25 some-odd gallon tank full simply for the sake of having more weight over the rear axle. it didnt even realy slow him down because it would help traction so much.

Tsunami

no there is certianly no debating that

BlackIceGuitar

I wish people wouldn't say that. Veriable Valves don't "kick in" technical the system is engaged from the start. The cam timing simpley changes...

Tsunami

technically you are right, but insted of stirring up trouble lets just say 'kicking in' = switching to high rpm lobes.

Howi

iTrader: (2)

thanks for clearing things up.

I disagree. You can put an engine in a FWD w/ its exhaust ports facing the rear of the car, and the O2 sensor on the down pipe. This has been done.

I disagree again. If you have opened up an transaxle, you would know that the you can design the intermediate shaft to rotate about the input shaft at any angle, and rotate the final fing gear and differential can rotate about the intermediate shaft at any angle. The engine can move back and forth in the engine bay quite a bit without sacrificing wheelbase.


This is what Oregano and I have trying to say the WHOLE time!!! And that is if you put more weight in the front of a FWD, the rear-end will come out easier!! Here's a quote from Oregano:
Howi

Tsunami

regardless of if the engine is turned around and moved closer to the firewall, it still restricts the ability to work on it. Never said it cant be done, of course it can, anything can with money, but with (at a bare minumum) obnoxious repercussions if you want to remove manifolds, or even worse, turbochargers.

Pulling the Ebrake during a turn does not = oversteer, nor does punching the breaks on a dirt course to get the rear come out. I assumed through all the talk of friction and traction that we were talking about grip racing. I believed that we were talking about oversteer/rotation in a grip situation, and as we all hopefully know it is not beneficial to lock up and slide your rear wheels while grip racing. Edit: discontinuing, see my previous post. It explains very logically and clearly.

oregano

iTrader: (1)

"agreed, weight in front does not better the handling of a car" Tsunami

no, it wont. but it will make a FWD car faster. i have experienced it first hand for 2 years and taken the time to draw vector diagrams showing weight transfer on cars of dif. weight distributions. have u?

"The more mass in the front of the car when turning, the more inertia it will have and thus cause a greater force to move the front in a straightline, which will contribute to an understeer situation" Tsunami

Which is exactly what i said, except u left out the part about how the increased mass increases downward force and thus increases friction(traction). these two forces(centrifugal/frictional) increase/decrease linearly at the same rate. ex. 500kg car at 1g of lateral acceleration, with u(friction constant) of x, generates (500*9.8)Newtons of centrifugal force, and (500*9.8*x)Newtons of frictional force. Double the weight, and u can see that the cent. force doubles, as duz the frictional force. Now, we can apply this same method of thinking to weight distribution by dividing the car into 2 axles of different masses. treating each axle as a seperate body. increase the mass of one, and at the same time u will increase its traction proportionally.

"Centrifugal force DECREASES the amount of weight (and mass, in case of body roll) over the frictional service, thus causing a loss of friction (and traction)."

Weight is mass*g. mass duz not dissapear. neither duz gravity. unless the centrifugal force acts upward, it cant decrease the effective weight on the wheels. weight transfer decreases/increases effective weight by acting up/down on the end of the car. the centrifugal force duz not change for a given mass however, since weight transfer duz not affect mass.

"And just for kicks, heres a thought: does a beefier front anti-sway bar cause understeer or oversteer? understeer because it increases the contact patch on the front wheels. A beefier rear sway bar will increase the contact patch of the rear wheels, (and increase its mass), thus increasing its rotational ability."

A beefier front sway bar helps transfer weight to the rear of the car, thus increasing friction at the rear of the car, thus causing understeer.

I hope i have cleared up any misconceptions u may have had about mass dissapearing or centrifugal force acting in a perpendicular direction to the plane of travel.
WERD.

oregano

iTrader: (1)

"Pulling the Ebrake during a turn does not = oversteer"

yes it duz. plz try and tell us otherwise.