DIV 1 rally/track suspension setup

[NoHachi]

If those are truly your springrates then there's your problem.. Extremely oversteer biased. You'll need one hell of a front sway bar to balance them out. But it would be better to add one kg/mm to the fronts and the sway bar.

As you probably know, if you are at equal freqs front-rear then you have no grip left in mid corner and corner exit to accelerate. Since there is still aero, tire and slip angle drag the car will start to decelerate.. Try to aim for at least 60% front roll bias.

I also seriously doubt that 4/4 is 1.9Hz. 1.9Hz is Lotus Elise territory and works very well on any asfalt. 1.8Hz saw an MX5 to sub 8min laps on the nordschleiffe.

[ditn]

1.7 is arround 5.5/4 if it is linear

I will be doing tarmac only so the tarmac spec will be the best


are those the grp4 rear bilstein dampers?
http://www.ebay.co.uk/itm/Escort-Mk2-Rea...43a40f153d

so for front i will need another strut to accept the grp 4 bilsteins?
http://www.grp4fabrications.com/product_...cts_id=493

and the rest i will need to ask

[totta Crolla]

I have a set of those GP4 front uprights.
You can get the inserts in different ratings and lengths.
I use 300 / 70 (long) for tarmac coupled with 190lb front springs.
You will need special topmounts as the Bilstein insert uses a larger
diameter thread.

[NoHachi]

No pics of the modifications made?

I would like to run something similar, but with 40mm pistons

[ditn]

Interesting to know
could you give a bit more information on what else you needed to change

so front
GP4 front uprights (what are the different characteristics between 300/70 and 260/60?)
springs
special topmounts,would those by any chance be those
GRP4 Fabrications "NEW " RUBBER ROLLER TYPE TOP
Toyota GRP4 Front strut tube needed?

rear
Rear Bilstein Turreted Shock Absorbers

[NoHachi]

ditn Wrote:GP4 front uprights (what are the different characteristics between 300/70 and 260/60?)

300s are for 10% stiffer wheel rates/springs. You need to ask them if they can modify your pair to keep the stock perches.

ditn Wrote:springs
special topmounts

You can modify some existing ones to fit..what do the regs say about top mounts?

ditn Wrote:Toyota GRP4 Front strut tube needed?

nopes

[Eircamae86]

http://www.grp4fabrications.com/index.php?cPath=42

Im going for some in the new year for gravel.

[Dino86]

NoHachi Wrote:If those are truly your springrates then there's your problem.. Extremely oversteer biased. You'll need one hell of a front sway bar to balance them out. But it would be better to add one kg/mm to the fronts and the sway bar.

As you probably know, if you are at equal freqs front-rear then you have no grip left in mid corner and corner exit to accelerate. Since there is still aero, tire and slip angle drag the car will start to decelerate.. Try to aim for at least 60% front roll bias.

I also seriously doubt that 4/4 is 1.9Hz. 1.9Hz is Lotus Elise territory and works very well on any asfalt. 1.8Hz saw an MX5 to sub 8min laps on the nordschleiffe.

OK, I will check the spring rates again. Might be wrong calculation because it handles OK.
Are you in this topic talking about spring rates or wheel rates? Maybe I missed it

Frequency is around 1.9 I guess.
NoHachi, you wrote in your suspension topic:
* Toyota AE86 5.8/4.5 ~ 2.3hz front, 2.1hz rear (me and Ivan)
* Toyota AE86 3.5/3 ~ 1.8hz front, 1.7hz rear (best street setup?)

Means, 1.9Hz fits in with around 4kg??


Honestly Nordschleiffe is difficult to compare to other tracks. Setup is way softer than other tracks (I ran 24hrs race and setup was totally different to other race-tracks).

In rallying, especially on low grip, and tight corners, steer in is important for me. Mid corner and exit are often covered in sand and dirt (only if you pass the first leg with startnumber 1 ) So I want to have the car turned-in earlier. (like Scandinavian flick)
If not, at low speed, it will understeer in the corner. (most stupid rally accidents on you-tube are caused by this )

Anyway, I do not want to hijack this topic with my setup but I will definatly "steal" some of your advice here
:wink:

[ditn]

Discussion is good,this way i am learning
I hope to get a bit more information today

so then front
GP4 front uprights (what are the different characteristics between 300/70 and 260/60?)
springs
GRP4 Fabrications "NEW " RUBBER ROLLER TYPE TOP or midify current

rear
Rear Bilstein Turreted Shock Absorbers

What does perches mean?
As long as it looks normal i dont think they can anything of it
I can't find any info about it.

[NoHachi]

Perches.. the thing the springs sit on. Normally the gp4 struts are coilover prepared with threaded strut bodies.

The rubber roller tops are for a Escort mk2 I think..