Weight bias ratio, is it always better to have 50:50 even for a fwd car?

[Jingers]

I know for cars 50:50 is one of the best weight bias you can have.

However doesthis apply for fwd cars? Our itrs have weight bias of approx 70:30 what would happen if you made it 50:50? Would it be better? Would it be worse?


I am in two minds about this, the above leads me to think the more even the balance the better, but then, the original weight ratio must have some reasons too if it came out of the factory this way. discuss?

[Noel]

Apart from drivetrain differences.

The better question is, have you driven a 50:50 weight distributed car the way you would with a 70:30 car? Some drivers can harness the differences in weight distribution while others work strictly better with what they're comfortable with. There isn't a "one school of driving style/technique", weight bias and distribution is specific in catering to such.

Check some 50:50 or close to such specs cars - Your AW/SW MR2s, AP S2000s. Most owners either complain it's too tail happy, hard to drive/maximize performance whilst racers/hard driving enthusiasts speak otherwise. The level of driving skills play the essential role vs. throwing weight bias around.

Total balance can be achieved on multi-weight bias platforms. The meaning of total balance would be better wrapped up as "achieving all rounded complimenting modifications" not outright strength in one particular attribute.

[Page]

I was woundering about this the other day...
I am guessing here but i would say that a 50:50 car would handle good on corners that aren't sharp as the car has plenty of time to "settle" into the corner and use it balance to the max.

Having a car that has most of its weight over the front wheels would make it good for sharp quick corners i guess. As i said i really dont know i am just guessing

[STEVtEc]

having a ff layout limits hondas ability to change the weight distribution, i think if honda had a feasable way of reducing the difference front to rear it would have done it.

having a front(or rear) heavy car is a comprimise on the cars total balance, ie spring/damper rates have to be increased, anti roll bars stiffer etc, all to mask the cars inherent design fault.

Just as a side note, when the 350z was being developed the engineers decided to make the front a little bit nose heavy (53:47 i think) to help increase turn in performance.

[Noel]

You need real experience here, no guessing or theory chit-chat is going to be accurate or remotely close to how it feels or handles. Check my comments above.

[narada]

I dont think an FF car would ever really perform well with 50:50 just due to the fact that there is a concentration of weight at the front of the car to begin with. If you balance the weight out, youll have to add the same sort of weight to the rear of the car which will most likely cause a "pendulum effect" to your handling - it just creates unnecessary momentum on the rear of your car

Its like how taking your spare wheel out the back of the car can improve your cars handling. Its just added weight behind the rear axle.

and because your front wheels are doing all the pulling, adding weight to the rear will just take weight off the front which wont aid in traction.

all you need to make a fast FF car is stiff suspension! stiff rears to stop squatting and aid traction and stiff front to stop your rear wheels lifting off the ground under deceleration and turn in.

which is probably why FF racing cars dont make good street cars..

[Jingers]

but does this stiff is better apply to everywhere? Even on a bumpy circuit? Interesting points raised

One thing interesting the opposite of our cars layout is obiviously the RR layout. Ie porsche. As in the engine is rightontop of the drive wheels.

The porsche in its latest incarnation is loaded with 38:62 weight bias and even more interestingly when its braking the weight bias shifts to 50:50.

Err wat happens when we fully brake? 90:10? LOL

[narada]

but does this stiff is better apply to everywhere? Even on a bumpy circuit? Interesting points raised

One thing interesting the opposite of our cars layout is obiviously the RR layout. Ie porsche. As in the engine is rightontop of the drive wheels.

The porsche in its latest incarnation is loaded with 38:62 weight bias and even more interestingly when its braking the weight bias shifts to 50:50.

Err wat happens when we fully brake? 90:10? LOL

probably =D




Trail braking into the corner shows how much you need stiff front suspension as well as rear.. if i could keep that rear tyre on the ground i would have more corner speed!

but yeh on bumpy circuits obviously you need softer suspension generally.. always compromising..

thats why FF cars are generally ghey when it comes to racing =D.. MR will always be the best!

[lovesil]

but does this stiff is better apply to everywhere? Even on a bumpy circuit? Interesting points raised

One thing interesting the opposite of our cars layout is obiviously the RR layout. Ie porsche. As in the engine is rightontop of the drive wheels.

The porsche in its latest incarnation is loaded with 38:62 weight bias and even more interestingly when its braking the weight bias shifts to 50:50.

Err wat happens when we fully brake? 90:10? LOL

Or maybe try driving a ITR backwards, and one might have the 50:50 weight shift of a RR Porche :P

[Jingers]

[Jingers]

I QUOTE

"
Quote:
Originally Posted by boredfast
so someone tell me how 3 wheeling is a good indication of good suspension geometry?


Ack ... I don't know how to explain it from a technical perspective. From my dumbass perspective I can tell you that having your inside rear wheel up means you've tuned your front suspension so well that even in tight cornering, when suspensions are compressed at their fullest, traction is maintained. In more casually tuned cars, there's a limit to how tightly they can turn before they lose front traction and begin to understeer. The weight of the rear of the car attributes to the resistance that causes the front wheels to lose traction.

However, with correctly tuned cars, the front wheels are able to keep traction even in the tight turns, so that they pull the car around the tight corner at such a fast rate that the rear end rolls so sharply to "catch up" that the inside-rear wheel lifts off the ground.

EDIT: Another way to explain this phenomenon is that in hard cornering, a properly tuned suspension will significantly load the outside rear tire and significantly unload the inside-rear, causing it to lift off the ground.

Being able to maintain excellent traction at full compression with the RSX is an exceptionally hard challenge due to our MacPherson strut design. Unlike wishbone suspensions, which gain negative camber as they compress, the RSX's suspension will lose negative camber if incorrectly configured. Setting your ride height too low (remember my Front LCA Angle thread?) is one way to accelerate this problem."

Of course just like typical internet someone goes along and says that that not necessary the case. Interesting read non-the-less

[BlitZ]

FWD werent designed as 50/50 becuase they couldnt do it, without compromising traction (wheel spin), safety, and speed (weight).

FWD cars are designed to be cheaper to produce and safer for the driver (understeer)...


----------------------------------------------------
traction:- if you make the car 50/50, it would either create less traction over the front wheels (moving engine back towards firewall)...OR Adding additional weight to rear (more to pull, need more traction)

Safetly:- understeer is alot easier to control.. that why most FWD hondas are faster around the track than cars like s2k, 200sx etc etc.. heheh easier to drive... Just pedal to the metal out of a corner

Speed:- FWD have no rear diffs, drive shafts, centre shafts etc etc.... so to get that balance you would most likily have to add more weight.. which makes car slower

[narada]

its true that when the rear inside wheel lifts off the ground your suspension setting probably does give good traction.. mostly because the rear suspension has so little travel compared to the front that youll never be able to "pop a wheelie" meaning the front tyres lose traction

like how a rwd drag car has real soft suspension to aid traction

but traction is different to "grip" in that if you have all four tyres on the ground while cornering, you will ultimately have more grip in the corner which roughly equates to more cornering speed.. 4 tyres produce more grip than 3

this is why FF is such a hard platform to understand and get the most out of.. too much compromise!

[tinkerbell]

my car sometimes three wheels over steep servo driveways...

oversteer FTW...

Blitz - check PM

[GoldCoastDC5R]

I dont think an FF car would ever really perform well with 50:50 just due to the fact that there is a concentration of weight at the front of the car to begin with. If you balance the weight out, youll have to add the same sort of weight to the rear of the car which will most likely cause a "pendulum effect" to your handling - it just creates unnecessary momentum on the rear of your car

Its like how taking your spare wheel out the back of the car can improve your cars handling. Its just added weight behind the rear axle.

and because your front wheels are doing all the pulling, adding weight to the rear will just take weight off the front which wont aid in traction.

all you need to make a fast FF car is stiff suspension! stiff rears to stop squatting and aid traction and stiff front to stop your rear wheels lifting off the ground under deceleration and turn in.

which is probably why FF racing cars dont make good street cars..

I have to disagree with some of your comments. I have found that by rmoving the spare tyre makes the car quite tail happy when high speed cornering compared to having it in.

In addition to this very stiff rear suspension also makes the car tend to be a lot more tail happy. When tracking my car i have the front sussy very stiff with the rear quite a bit softer. This is because of the weight difference of the front and rear half of the car.

You make the rear as stiff as the front and it will become very twitchy and jumpy and on a track with an uneven surface this is a very bad setup. Allowing more travel at the rear, coupled with the lighter half of the car ultimately results in more grip at the rear.... Trust me a car which oversteers at 140kph is not exactly a fun experience.