Roll Bars and Weight Transfer

[saxophonias]

actually I meant the 96-97 ej9 having no front swaybar as you told, not the 1998 and on.

[archyman]

Got u now:)
Great Article Owen, you've explained things well and fully, because there are many factors involved.For me its a pleasure attending this forum also because the people here try using their heads properly.
For me personally front understeer is better controlled with the use of a front ARB than without (FWD cars).
Equalizing the forces between both front wheels will bring some non-neutral cornering but not as much as the benefits. In my opinion ARB's are put exactly to prevent body roll and therefore understeer because body roll introduces weight transfer, thus reduction of total grip (bodyroll brings camber difference also).
Well i may just be wrong haha, but pls correct me:)

[mynameisowen]

Archyman just to clarify here, weight transfer (as in the force on each tyre) which causes understeer/oversteer is not caused by bodyroll. It is a function of the speed and corner radius. Body roll is an affect of weight transfer and is controlled by chassis/spring stiffness and torsional rigidity. That is a common misconception! Body roll is the visible effect of weight transfer but a car with no roll will still have weight transfer!

So no takers for helping my project for our cars! I am surprised!

[archyman]

Is then the ARB actually a way to increase the stiffnes of the chassis wich affects body roll?
I even think that the reason the've fitted ek9 with so many swaybars, frames and etc is to be able to fit the car with stiffer suspension, and prevent damage to chassis during racing. Because the stiffer the suspension the harder the chassis takes forces..and this could lead to critical change in suspension geometry, wich is bad, dont u think?:P
I'll be glad to help everyway i can, waiting for the full list man;)

[BETEK]

I will talk more practically for what I saw in my car, civic ej9 with oem front ARB 22mm.

1. When I had OEM suspension the car used to be understeer. (not equal spring rates)
2. Then I swapped KONI sport-yellow shock absorbers with EIBACH springs the car again used to be understeer. (not equal spring rates)
3. Then I swapped KONI sport-yellow with integra type-R springs the car changed to be little bit oversteer. (equal spring rates)
4. Then I add EK4 vti rear ARB 15mm, the car became to be neutral on corners. (equal spring rates)
5. Then I changed oem ej9's front ARB with EK4 vti front ARB 26mm, the car became again understeer but in some high speed situations the understeer becomes oversteer . (equal spring rates)

What I learned was that: with harder front springs from rear ones the car is understeer.
If the springs rates are equal and with front ARB then the car is oversteer. But if we play with ARBs diameter or spring rates we can change the car's reaction at cornering.
As much we raise the rear ARB diameter or spring rates the car reduces the understeer and we reach the hard controled oversteer
So, if the front-rear ARBs diameters are close each to adder the car tents to be neutral if the springs rates are equal (front-rear axle).

From above suspension history I like number 4 (front ARB 22mm - rear ARB 15mm and equal spring rates) neutral reaction.

[BETEK]

And to add an argument in my above element is that Integra type R DC2 has front ARB 24mm, rear one 23mm and equal spring rates that makes the car to have neutral reaction at cornering.

[mynameisowen]

Nice examples Betek

I think your results corroborate the stuff I wrote above but once I do the analysis I mentioned above we will know for sure (it takes into account spring stiffness).

Tomorrow I will post a list of stuff I need help with, mostly measuring bits of the suspension and ARB's (especially the ARB's since I don't have any myself). Keep your eyes open on this topic and my newbie topic!

[saxophonias]

Very interesting. My history with my suspension set up is the following (ej9 14inch wheels (185/60) 4door 22mm front swaybar)

1. Bilstein Sprint shocks with HnR progressive springs (3mm lower, i think the spring rates must have been around 3.5K)
slighter improved traction but better feeling. The balance was the same (understeer, hard to oversteer)

2. As above but with energy suspension busings
feeling improved more, the rear was more stable and the steering more responsive

3. As above but 2cm lower than rear
The worst I could do. Worse steering (lighter) and more prone to snap oversteer

4. Buddy Club +N coilovers 12K 8K rear 185/55/14 tyres
Day an night compared to the previous, track feeling, more responsive, more accurate, less understeer, but you needed to be cautious, with lift offs and corner braking

5. As above with 26mm swaybar front and 24mm rear (ASR kit)
almost no body roll, reduced slip angles, agile but mainly oversteerish again

6. As above increasing the height (almost 2cm) and have it almost lined it up front to rear. I think this is the best set up so far. Confident with the front and rear, the rear will help you turn and correct your line with less turning. Of course when lift off the rear will turn, when brake hard the rear will turn too. So you need to turn with the throttle and then it is neutral as hell.
Still I should say that my car was extremely low (messed the roll center) and not lined up properly (height difference). If I had 195/50/15 I think it would be ideal as the car would increase in height a bit more. So my verdict is that you get some soft coilovers (softer than mines) and you swap the big swaybars combo and then it is just perfect

[mynameisowen]

Thanks for the input, Please check newbies topic for measuring requests!

viewtopic.php?f=3&t=139&p=13468#p13468

[mynameisowen]

Betek has provided a great deal of information but I still need the rear ARB dimensions and another set of complete dimensions from someone else as a double check.

Thanks for the help