Realtalk Q45! I just picked up a set of unrevised 350z springs. I also just bought a set of Stillen Sways. I plan on installing these next week when my sways arrive.

Currently I own a G coupe with sport suspension. I was wondering how my handling is going to be effected after the installation of the:

springs
sways
new .5 drop

For those of you who took my route, how was your handling and ride/comfort effected? What things did you notice as improvements? What things can you say were negatively effected by running this setup?

 

If you want better handling, better tires, sway bars, struts (you want a lot more rebound, but less bound), and a good alignment (good, not factory spec) are a must. These are the key components for traction, and you can't improve handling without traction. Springs and a drop mean nothing here. How soft or stiff a spring is only dictates how much road feel the driver will get. And on top of that, you're adjusting the center of gravity for the worse by dropping the car.

After that, start looking into chassis reinforcing parts. Front strut bars are usually pretty useless unless it's a 3-point strut bar connecting to the firewall. But a standard strut bar with fender braces will work just about as well. Tie bars are great, cheap chassis products and are very effective for better response. A full cage is even better than all the parts combined. Also, don't neglect the tie rods and tie rod ends.

Just remember that the chassis can never be too stiff, while the suspension can. Some might argue that some suspensions won't work well with strut bars, etc... because the car is too stiff - that just means the suspension has too much bound, which means it just sucks. And keep in mind that while you want to eliminate a lot of the sway, you don't want to eliminate all of the sway... your car still needs to be able to transfer weight from one side to the other.

Oh, and keep in mind that most coilovers raise the bound as well as the rebound and the adjustments control both the same... I'd actually suggest struts and springs rather than coils, but you won't get ride height adjustability.

 

HMMM. thanks for all the input guys....

 

When you lower the body by 1" you lower the center of gravity by less than 1". But just for drill assume 1" so about 4 - 5% this is divided by track width [~60"] to calculate the change in weight transferred to tire in a turn. The change is 22" /60 or 1/3rd of the 5% change in CG or ~~ 1.8% weight change on the tire at 1.0G load thus results in about half that or 1% change [improvement] in tire slip angle.

Just for drill assume 1000 pounds static weight on a [each] front tire rolling straight ahead, in a 1.0 G turn approximately 360 extra pounds are added to one tire and removed from the other.
Changing the tire load by 7 pounds is not very significant.

The improvement in slip angles is roughly half the reduced weight on tire %wise. A TRICK is to increase the load index [fit a stronger tire] as this will reduce the slip angle more.

Most new cars from factory have weaker tires on front [to increases understeer] and safety. Increase load index on front tires by a few hundred pounds and feel the results.

Sway bars try to retransfer some of this weight transfer BACK to the lightly loaded side as the body rolls and springs compress and bar twists.

The point is removing 100 pounds of weight above the springs is worth 3-4 times more than lowering 1.0".

 

Eh? Lehman's terms please!

 

tires with a stiff side wall, are sweet!

 

But don't stretch your tires to get a thinner, stiffer sidewall please. Besides the fact that it's dangerous, it's worthless if you don't have stiffer suspension bushings first.

 

I have the above (in bold) and I'm running 245 40 19's all round. The ride is taught but still not bad. It corners like a beast now. I can storm in to a corner, do my braking, set the line and just floor it thru the turn now. It's a blast.

I still want to add a front strut bar to see if it makes much of a difference.

 

alright... i know the springs for sure are going to be...

350z Tein s-techs.... any input?

shocks may be HPs or dspecs... (unsure if it HP are strong enough for the drop)

and adjustable sways...

 

How do you have your sways set up?

 

One step above med in the front and hard in the back.

Someone recomended 4 turns back from full dampening on the D-specs and that was just right.

 

Awesome! I'll see if I have to make any adjustments as I'm running 255s rear and 225s front. Might have to adjust the rear one notch stiffer or maybe soften up the front one notch.

 

Yeah, it handles very neutral now. Hardly any yaw in hard turns, I just love it now. All I need is about a 100 more hp and it would be perfect.

 

I'm going to have to disagree with you there. Higher spring rates change your roll stiffness as well, which has an enormous effect on how your car handles mid corner, especially if you tune the front and rear different amounts. Roll stiffness dictates how much lateral weight transfer you have through the roll center of the suspension. Changing the spring rates will also affect the amount of lateral weight transfer you get through body roll. Moving the center of gravity down will also lessen the amount of lateral weight transfer through body roll as well, by making the car roll less. Lowering the CG will also not affect ride quality at all.

 

I'm almost done with my suspension project. As of now, it handles extremely well. I have yet to drive another car (non-G35/350Z) that is up to par with mine

So far I have HKS Hipermax III Sports coilovers, Hotchkis Sway Bars, SPC Rear Camber kit, along with decent rubber (245/275 on T1R's...getting better tires as soon as these wear out). My car is significantly dropped (almost no wheel gap) and the car isn't even aligned [yet]. I plan on getting it aligned and corner balanced at west end to finish it off.

I really wish I could stiffen up the chassis with the GTSpec bars, but the brace is a no-no on a dropped car and my exhaust wouldn't allow the other bars to fit.