My remedy to nosediving.....

[J. Clarkson]

So I went on my merry way and rebuilt my old faithful car I had in GT3.

A nice black Evo 6 GSR '00 Premium.

Upped the power a bit, suspension, brakes, etc.

The first race which had a bit of elevation saw my Evo nosedive as soon as I braked hard coming downhill.
As seen here, but not as dramatic.



So my remedy was to add some weight and shift it to the back.
I also adjusted the brake balance, so that the car brakes more at the back.

Is this the correct way to remedy this or are there other options?

 

[FussyFez]

High front compression and high rear extension should help. I like to run balanced spring rates with a stiff rear arb and soft front arb to help with turn in and remedy understeer because of the damping settings dedicated to controlling body movement.

IMO

 

[donpost]

Are you saying A) your rear tyres actually lift off the floor, or B) just that the car dives too much under braking for your liking? If B), see Fussy's post. You could also stiffen the front springs if you want.

If it's A), the problem is caused by forward weight transfer under braking being greater than weight on the rear end of the car (is this even possible IRL?). The only solutions are to reduce the amount of weight transferred forward, or to increase the amount of weight on the rear wheels to begin with.

Increase amount of weight on rear wheels to begin with:
- Ballast in the back (as you've noted)

Reduce amount of weight transferred forward:
- Lower ride height
- Use lesser tyres so you cannot decelerate with as much force.

 

[Motor City Hami]

High front compression and high rear extension should help.

I agree. I would add to some of the things mentioned:

Reduce amount of weight transferred forward:
- High front compression and high rear extension
- Can move some ballast to the rear
- Higher rear brake balance
- I would add a change to higher ride height, maybe even higher ride height in the front and lower rear. I am starting to believe that when we lower ride height, it also shortens the shock travel. Higher front should provide more shock travel and lower rear should give shorter travel. If that theory is correct, the car should fly and land more flat. I am not near the PS3 to test this, but just a hunch.

 

[Voodoovaj]

I would add a change to higher ride height, maybe even higher ride height in the front and lower rear. I am starting to believe that when we lower ride height, it also shortens the shock travel. Higher front should provide more shock travel and lower rear should give shorter travel. If that theory is correct, the car should fly and land more flat. I am not near the PS3 to test this, but just a hunch.

Your hunch is on the money. The springs will work just like the coil overs on a Baja truck/buggy. The more travel they have, the more time the suspension has to deal with weight.

The only contradiction I would add is that I strongly doubt that the shocks (dampers to some) work like a real life shock. By that I mean, in real life, the oil/gas opening that controls damping are uniform for the most part. In other words, 1 click opens or closes the damping by the same amount and changing the springs will need an increase or decrease in damping accordingly. Everything I have seen in the game would indicate that the in game dampers are force multipliers so, so 1 click in the game will add the same amount of damping regardless of the spring rate. ...which actually doesn't contradict your advice at all

 

[FussyFez]

I agree. I would add to some of the things mentioned:

Reduce amount of weight transferred forward:
- High front compression and high rear extension
- Can move some ballast to the rear
- Higher rear brake balance
- I would add a change to higher ride height, maybe even higher ride height in the front and lower rear. I am starting to believe that when we lower ride height, it also shortens the shock travel. Higher front should provide more shock travel and lower rear should give shorter travel. If that theory is correct, the car should fly and land more flat. I am not near the PS3 to test this, but just a hunch.

I feel honoured that you agree with me. I've followed your tuning guides for years now.

I'm trying to control nose dive in an attempt to neauturalise turn in understeer on my S13 track setup. I know it's not stopping endos, like what the OP is asking, but it applies to the same principles.

I mention this because I would be inclined to agree with your shock stroke length theory. I run quite soft springs as I get more feeling for what the car is doing through the wheel , with a stability trade off.

I have noticed much less stability at lower ride heights due to bottoming out, but also the car seems to lose grip over crests in a way that, you can tell the wheels are being lifted from the ground earlier than with the higher ride height.

I think this is related to what I call 'dynamic droop' (as far as I can tell, GT does not simulate static suspension droop, but I haven't tested properly), the wheels can move further from the car without coming away from the floor, because the suspension is already in compression when the car is in a neautral state.


Sorry to thread hijack, and I hope that makes sense.

Just to go back on topic, it seems logical that a lower ride height should put the center on gravity lower and therfore reduce fore-aft roll, but because of the above, I'm not sure if it really is logical, and would therefore agree with your remedy of high front low rear.

 

[Motor City Hami]

changing the springs will need an increase or decrease in damping accordingly

Yes. Excellent point. Adding to the list of advice for the op.

Reduce amount of weight transferred forward:
- High front compression and high rear extension
- Can move some ballast to the rear
- Higher rear brake balance
- I would add a change to higher ride height, maybe even higher ride height in the front and lower rear. I am starting to believe that when we lower ride height, it also shortens the shock travel. Higher front should provide more shock travel and lower rear should give shorter travel. If that theory is correct, the car should fly and land more flat. I am not near the PS3 to test this, but just a hunch.
- Increase springs to be relative to damper position