Suspension Upgrade

[tonycharger72]

Im planning on doing some minor suspension upgrades and was wanting to get some opinions,

 

This is what im planning on doing,

 

Upgrade to 1" front sway-bar,

Replace Steering-Rack Bushes,

Re-located lower control connection on engine crossmember,

Go to adjustable shocks on all four ends,

Get new springs and drop the car about an 1", will get slightly stiffer front springs and keep the rears at their stock spring rate,

 

My car is a daily driver, so dont wanna turn it into a go-kart, just wanna improve car handling and minimise oversteer,

 

What do yall think?

[Savage42]

Well, if you go with a bigger front bar w/o upgrading to a matching rear bar, along with stiffer springs in the front and not in the rear, it will push (understeer) like a pig!! Virtually all aftermarket springs design them with some understeer, which is safer for the average driver. A big bar will add to that problem. No need to relocate the control arm mounting points unless you really lower the car more than several inches. Adjustable shocks and rack bushings are a good thing. Hope that helps.

[tonycharger72]

I've changed wheels to 17"by7" with 205/40-17 tyres (i couldnt physically fit any larger tyres at the front without hitting the spring perch) from 14"by6" with 195/70-14 and the car now feels different,

 

The effort required to make the car turn has decreased,

And

The car dosent feel as stable, for example - when im going around looping long corners i feel as if i cant give it as much gas as before, feels like the ***-end is on the brink of sliding out

[johnc]

The car dosent feel as stable, for example - when im going around looping long corners i feel as if i cant give it as much gas as before, feels like the ***-end is on the brink of sliding out

 

Go to a local autocross and find out what the car's actual limit is. Unless you've spent some time on a track or at an autocross driving over the limit, what you're feeling might well be far from the rear end breaking loose.

 

The mods you mention are fine but I think your tires have a sidewall that's a bit too short. For some reason, and I've talked with Hoosier, Kumho, Penske, and Koni reps, the 240/260/280 handles better with a sidewall aspect ratio not lower then 45. There's a level of compliance that a taller tire sidewall provides that the Z seems to need. You can compensate for it with double adjustable shocks.

 

Without this compliance the Z tends to skate in the corners and people often confuse a skate problem with understeer or oversteer.

[tonycharger72]

Well the tyres i had on before were the 195/70-14's on the stock 14" by 5.5" rims and the car felt so much more secure when going around corners at high speed,

Been checking out all the tyre calculator sites and the rolling-diameter of the wheel with tyre is roughly 1.2" smaller than it was before,

 

Its weird, i go around a short corner hard..........the tail slides for a sec, rights itself and im outta the corner, foot has been flat to the floor the whole time

 

Its probably like you said johnc, i've tried to lose the rear end but the car's rear end dosent actually swing out, just "skates" across the road, rights itself and away i go

 

But going around longer looping corners dosent feel as good, with foot flat to the floor i feel like if i dont back off, it wont be to long before my ***-end slides out

[johnc]

But going around longer looping corners dosent feel as good, with foot flat to the floor i feel like if i dont back off, it wont be to long before my ***-end slides out

 

If you are able to lift your foot off the throttle in a long corner and not spin, you're still a little ways from the limits of the car. A 240Z at the limit will spin if you lift off the throttle. Its not a snap spin or anything mean, but the back end will lose traction from the weight transfer forward and you better be ready to catch it and reapply some power.

 

Again, go to an autocross or an open track day and learn what the car feels like at the limit.

[tonycharger72]

I will mate, thanks for the advice,

 

BTW, love your name mate