Going for square setup

[Splatter]

Hi, About to go for square tire set up with Dunlop Direzza ZII in 275/35-19. Any suggestions on suspension set up?? Getting tires down here in Chile is usually mail order only, so was delighted to find a Tuning shop that is offering Dunlop tires a steep discounts for track. As it is, the tires dont arrive for 5 weeks.... but the price is good.

Am a little worried about having excessive over steer. Could I get away with a soft setting like 3 on the rear? Or would I need to install a adjustable rear sway bar. If I grabbed a set of 10in rears would that even out the balance??

The car is a DD and the roads to get to the tracks here make California roads look great!

 

[darreng505]

Is the car lowered?

You will probably need to disable traction control and stability control if you have significant front grip. Everything off. I experienced some interference from stability control at high speeds with slight bends in the road or elevation changes - and I mean dangerous interference (i.e. computer braking), but at the time my car was lowered quite a bit and running r compounds square.

If your car isn't lowered you should be able to tune away any oversteer with the dampers.
If your car is lowered, you may need all adjustable components to re-create a proper balance specific to your car (and you will be increasing the handling quite a bit down this road).

You can use a softer setting on the rear to counter oversteer up to a point.

 

[Splatter]

Thanks! No the car is not lowered yet, Thinking of the Steeda Boss springs or the Ford racing Boss set. As it is I hit the tranny cooler, so I can not go too much lower.

 

[isrboss]

Go for the Dunlops and get a 22mm rear sway. The FRPP tranny cooler scoop blows, get the Shelby instead.

 

[65sohc]

The Boss Track Attack cars use the square setup (BFG sport Comp-2 tires) with stock Laguna Seca suspension. Dampers set on 5. Handling is fantastic.

 

[Splatter]

What size where they using of the BFG comp2?? Way cheaper tire!!

 

[65sohc]

I think they are 275/35-19. I put a set on my son's STI and my SL500. I'm happy with them.

 

[Dean95CobraR]

I run a square setup with the Steeda Boss springs. I have the fronts set at 5 and the rears at 3. Perfectly balanced. I bought an adjustable rear bar and it is still setting in the box.

 

[isrboss]

I run a square setup with the Steeda Boss springs. I have the fronts set at 5 and the rears at 3. Perfectly balanced. I bought an adjustable rear bar and it is still setting in the box.

Because when you put the Steeda springs on you substantially raised the front spring rate, and kept the rear near the same (Steeda 225lb front, 195lb rear). That bar is still useable, because all tracks will like either a tight or loose balance. Are you just running one track with your Boss? Steeda was aware of the ridiculously huge rear sways on the Boss and set spring rates so you would be balanced toward slight understeer without removing the huge rear sway. If you would have been on the stock tire staggered setup, so you did the best thing and just went square, imo.

If OP wants to just install 275's on all corners the cheapest way to get a tighter balance would be to go 22mm bar in the rear and tune from there. I prefer to add grip first then work on dialing out understeer.

 

[M3hunter]

How did it went with your dunlop direzza z2 275/35r19 squared setup? I'm planning to go in the same direction with those tires for my '11 GT Brembo package, I wonder if the Z2 Star Spec are better or is the same? Any lap time compare of both tires?
On your set up, I think that Strano's adjustable swaybars will be great. I have them, they will help you set up your car for best handling, very well made