Weight Balance

Seduce XR6 · 19-09-2011, 10:34 AM

Might sound like a silly question though I will ask it anyway as am sure somebody on here would know the answer, lets see who really is the Ford Guru on AFF

What is the weight balance on a FG I6 Falcon as in front to rear etc?

I would guess they are front heavy at around 65% front 35% rear, any takers?

SteveJH · 19-09-2011, 04:02 PM

Quote:

Originally Posted by Seduce XR6

Might sound like a silly question though I will ask it anyway as am sure somebody on here would know the answer, lets see who really is the Ford Guru on AFF

What is the weight balance on a FG I6 Falcon as in front to rear etc?

I would guess they are front heavy at around 65% front 35% rear, any takers?

Not me, but i doubt the weight distribute is that far to the front. How much do the spare and IRS weigh?

MAD · 19-09-2011, 04:35 PM

Which gearbox?

FalconXV · 19-09-2011, 04:45 PM

55.5% front : 44.5% rear.

Seduce XR6 · 19-09-2011, 04:53 PM

ZF Box, thanks guys I did not think it would be that far to the front (65/35) specially on the NA 6 however I thought me saying 65/35 might just make some more keen to tell me I was wrong & thus give me an answer lol

So assuming he is right FalconXV gets the prize which is simply a ty from me & Recognition as being a Ford guru

Seduce XR6 · 19-09-2011, 04:56 PM

So next question would be how much weight would you need to transfer to the rear to make it 50/50 & could that even be done?

And will the upcoming 2 Litre have a better balance?

MAD · 19-09-2011, 05:09 PM

50/50 isnt always the best. The way it transfers the weight, under different conditions, is more important.

Hally · 19-09-2011, 05:14 PM

two fat blokes in the back seat?

XR6_661 · 19-09-2011, 05:17 PM

Quote:

Originally Posted by Hally

two fat blokes in the back seat?

That'll do.

Seduce XR6 · 20-09-2011, 05:57 AM

lol so where can I hire a couple of Sumo's?

SteveJH · 20-09-2011, 05:59 AM

Quote:

Originally Posted by Seduce XR6

So next question would be how much weight would you need to transfer to the rear to make it 50/50 & could that even be done?

And will the upcoming 2 Litre have a better balance?

Moving the battery to the boot would have to make it pretty close.

And most likely.

jpd80 · 20-09-2011, 06:20 AM

The I-6 versions are most likely 55% F 45% R but the iron block 5.4 Boss probably changed that to more like
60% F 40% R which is similar to a FWD Cars weight balance and probably why the V8s used to feel a touch nose heavy...

SteveJH · 20-09-2011, 07:08 AM

How much does a typical lead-aid battery weigh? If you moved it to the boot...multiply that by 2 and you get the rearward weight shift.

Would have to be about a 50kg net change?

sudszy · 20-09-2011, 08:51 AM

Quote:

Originally Posted by Hally

two fat blokes in the back seat?

If we take the 55.5/45.5 numbers at face value, thats about 935/765 on a 1700kg Falcon.
To be 50/50, 85kg would have to go from directly above the front wheels to directly above the back wheels.......or put about 2 x 85kg in the back seat, yep two fat blokes.

Yep, you can move lighter things further past the axles to achieve the same effect, but that can affect the dynamics in other ways.

Really though the cars are setup pretty well, if they started at 50/50 empty they'd end up horrible once you've put the driver in and with any sort of a load in the boot or rear seat.

aussie muscle · 20-09-2011, 09:55 AM

Quote:

Originally Posted by Hally

two fat blokes in the back seat?

reminds me when i had to fat blokes get in my valiant. they both sat on the passenger side, and the weight changed the handling of the 25 yo suspension that the car wouldn't drive straight!

dimka100 · 20-09-2011, 11:13 AM

While generally speaking 50/50 Front to Rear weight distribution is a good thing, it’s not always the best outcome the engineers are trying to achieve. When it comes to car handling the car’s static (stationary) weight distribution is not as important as the actual weight distribution when the car is moving. For example:

When the car is braking the weight distribution will always move Forward (i.e. front biased)
When the car is accelerating hard the weight distribution will always move backwards (i.e. rear biased)
When the car is turning the weight distribution will move to the front and the cornering side, and then progressively balance back to the centre while moving rearwards as the car begins to accelerate out of the corner.

That shift in the vehicles mass will generate additional pressure on the tyres hence increasing grip, which will help when braking, accelerating, and cornering …

Many racing cars are actually setup to not be perfectly equal while stationary, however when driven at their expected speed they will achieve the required weight distribution for ultimate performance in the required circumstances

XR6_661 · 20-09-2011, 11:15 AM

Quote:

Originally Posted by Seduce XR6

lol so where can I hire a couple of Sumo's?

No need for that mate, go pick up a couple of fat chicks. It's like fishing with dynamite.

sudszy · 20-09-2011, 12:24 PM

Quote:

Originally Posted by dimka100

When the car is braking the weight distribution will always move Forward (i.e. front biased)

in most cases yes, but if the C of G is at axle height(which is effectively how formula one is setup) there will be no "weight" transfer effect.

dimka100 · 20-09-2011, 12:31 PM

Love F1, tyres in F1 make a huge difference to the setup and most of the suspension movement is actually in the tyres LOL also aero adds massive weight to the car and it can generate 5G under braking

MAD · 20-09-2011, 12:51 PM

Quote:

Originally Posted by sudszy

in most cases yes, but if the C of G is at axle height(which is effectively how formula one is setup) there will be no "weight" transfer effect.

That's actually not correct. The CoG is still above ground level (the point of contact of the tyres) so there will still be a weight shift under braking, accelerating, and cornering.
Body roll and pitch is affected by the difference in height between the CoG and the Roll Centres.

GTP-814 · 20-09-2011, 12:55 PM

Quote:

Originally Posted by Seduce XR6

lol so where can I hire a couple of Sumo's?

Look on any public transport system & you will find a coulple of heavy weights

sudszy · 20-09-2011, 01:16 PM

Quote:

Originally Posted by MAD

That's actually not correct. The CoG is still above ground level (the point of contact of the tyres) so there will still be a weight shift under braking, accelerating, and cornering.
Body roll and pitch is affected by the difference in height between the CoG and the Roll Centres.

Have to respectfully disagree there, any rolling/pitching is proportional to how far the C of G is above or below axle height. If the C of G is below axle height the front of the car will move upwards during hard braking that is caused by braking via wheels.
Though during cornering I do agree, the height of the c of G is an issue irrepsective of axle height as even a slight bump can cause roll while cornering and pitch the c of G over axle height, my comment was prefaced for braking.

MexicanBatman · 20-09-2011, 01:22 PM

fat blokes are 85kg now?

WOW

sudszy · 20-09-2011, 01:36 PM

Quote:

Originally Posted by MexicanBatman

fat blokes are 85kg now?

WOW

LOL, thought that may get a reaction, ave male height = 178cm in Aus, at 85kgs that a bmi of 27, = fat bloke. (yes i appreciate there are muscle bound types(afl players) who arent carrying an ounce of fat, that might fit those numbers, but they are the exception)

MAD · 20-09-2011, 01:39 PM

Quote:

Originally Posted by sudszy

Have to respectfully disagree there, any rolling/pitching is proportional to how far the C of G is above or below axle height. If the C of G is below axle height the front of the car will move upwards during hard braking that is caused by braking via wheels.
Though during cornering I do agree, the height of the c of G is an issue, my comment was prefaced for braking.

Even if the CoG was at axle height, there are two lines of force in play; road-tyre-contact and CoG. If they are not inline with each other, there will be a moment created. Ergo a weight shift will occur.

The two examples (pitch;braking/accel & roll;cornering) are one and the same. If it is true, as you've said, and there will be no pitch under braking if the CoG is level with the axles, then there could be no roll because the CoG is still level with the axles.

sudszy · 20-09-2011, 01:42 PM

Quote:

Originally Posted by MAD

Even if the CoG was at axle height, there are two lines of force in play; road-tyre-contact and CoG. If they are not inline with each other, there will be a moment created. Ergo a weight shift will occur.

The two examples (pitch;braking/accel & roll;cornering) are one and the same. If it is true, as you've said, and there will be no pitch under braking if the CoG is level with the axles, then there could be no roll because the CoG is still level with the axles.

Yes, that is correct, but check my edit above.

geckoGT · 20-09-2011, 01:50 PM

The Op asked about finding out weight distribution specs, I am thinking this has gone a little bit OT.

MAD · 20-09-2011, 01:53 PM

Quote:

Originally Posted by sudszy

Yes, that is correct, but check my edit above.

My statements above apply to a perfectly flat, and smooth, surface.
There is a whole lot more to suspension setup than I know, but for this example it's a very simple physics problem.

While I still think this is sort of on topic. We should probably leave it at that.

Go have a read of some suspension setup books and see for yourself, that pitch/roll is caused by the forces induced by the tyre contact patch and the CoG. How those forces are used, is a funtion of the suspension design.

Seduce XR6 · 20-09-2011, 08:56 PM

Quote:

Originally Posted by SteveJH

How much does a typical lead-aid battery weigh? If you moved it to the boot...multiply that by 2 and you get the rearward weight shift.

Would have to be about a 50kg net change?

Yes I was thinking exactly the same, ty for the input

Seduce XR6 · 20-09-2011, 09:05 PM

While I can almost understand all that tech speak it does leave me a little lost though taking 1 part of it which I feel is relevent to myself & my reasons for asking is that if you have that many kilos of extra weight on the front would that not under hard braking make the extra weight more of an inluence than it would be under normal driving conditions thus making the not so bad balance as some have said rather bad?

As in a multiplier effect of sorts?

Moving the battery into the boot in one of those battery boxes sounds good though would you then lose some effect of the alternator as the cables would be much longer than they were under the bonnet?