More power needs stiffer springs, more tire means more lateral grip which can be offset with just sway bars, springs or a combination is the way I look at it. It’s all about controlling the weight transfer ultimately and maximizing the contact patch.

 

Same, thanks for figuring it out, can't wait to see your testing thoughts, both on track and on the street. You have MRC?

Can you list the equipment that finally worked for you and any other install tips?
I'll start
F/R endlinks
Swaybar

 

gtpvette runs the MCS, I run JRI doubles

 

I installed the Eibach rear swaybar on my 23 Z51 yesterday in the softer position and have done 2 test drives on our best curvy roads in the county. I completely agree with what Kracka posted some time ago. - “No abnormal noises on rough roads/aprons/transitions, feels tighter but not too tight, cuts better and rotates nicer! Very happy with the upgrade. The "soft" setting seems ideal with stock tires and front swaybar.” I look forward to track testing probably sometime in February. Well pleased at this point.

 

What do you torque the bolts to on the rear sway bar?

 

43 ft lbs for the bracket,
118 ft lbs for end link

 

Awesome, thanks!

 

Ok, I'm a complete dumbass.........gonna embarrass myself (I do a lot of my own wrenching and am relatively mechanically inclined). I've read all the instructions for the rear install. I can see where the 7mm/15mm/18mm is needed, but can't see where the 8mm comes into play for the end link? Can someone enlighten me on that? Additionally, to get the bar off does the end link just push back easily? Again, sorry for the dumb questions. Thanks.

 

the end of the threaded rod, you can put a socket or wrench on that to keep it from spinning when taking the nut off.

 

Going from memory, the 8mm is to hold the end-link stud from spinning when loosening/tightening the nut against the swaybar.

 

LOL, now I see it......ugh I'm an idiot!

 

I think the stock rear bar is all about dialing understeer to cover liability claims. The old adage: If a car understeers off the road, it's the car's fault, but if the car oversteers off, it's the driver's fault. These days people will sue for either reason.

IMHO, the stock chassis setup delivers amazingly good balance but is tuned for understeer. And yes, it is too soft for aggressive drivers, but keep in mind GM wants to sell C8's to old guys with prostate problems, who just want to look cool with a soft ride. Like you, I'm will be upgrading to a larger rear bar, Z51 spec along with the stiffer springs. Spring rates of the Z51 bar and the car will deliver more response and while being safe from snap-oversteer. If you make a major increase with the rear bar rate, you could end with a very oversteering car: fun, but would require driving with high level skills.

I'm upgrading to the Z51 springs & rear bar, the original front bar is retained. The car will be better balanced, but after 2 days driving a Z51 car at the Ron Fellows Racing School, the car had to be forced to show oversteer. I hope I'll like the Z51 kit in my car.....but might want to go even stiffer with the rear bar.

I did a comparison of rear bars to the standard. For street, I would suggest NOT going stiffer than 275 - 350 lb/in. AFE is obviously focused on race setups
Std = 216 lb/IN
Z51 = 262 lb/in +21%
Paragon = 270-350 lb/in +62%
Eibach = 275 +127%
AFE Control = 600 + 2 x Z51 rate
680 +127% over Z51
780 +160% over Z51
I hope this is helpful....

 

Reducing understeer: Think of the car balanced on a fulcom. With stock bars & springs the front transfers weight in cornering more Efficiently than the rear and thus
is the end to generate Slips angles first. By stiffening the rear bar, the rear tires load "more efficiently" change the "slip angle" equation.

It's all a balancing act of front vs rear tire loading in corners. Race cars are designed & tweaked to get the "Balance" as close to the same at each end (neutral) .

 

You can still get snap-oversteer with the Z51 bars and springs.

 

Thanks for bringing up the topic of Wheel Rate (+ spring + swaybar). The Wheel Rate is the real "tire hits the pavement" focus.

 

Since I didn't experience snap-oversteer, would let me know your situation when it occurred. I would like to be forewarned.
Of course, C8's can be a handful in the wet with so much torque....so I'm not looking to drive mine in the wet....I'll take my 2-ton X3.

 

I also just finished the 2 day level 1 class at Spring Mountain last week. These are great cars, but will understeer at the limit. We were learning to use a slight amount of brake to get the front end to stick. I am used to tracking my Z51 with 265 tires and 5vm aero on the front which both reduce the tendency to understeer so it was an adjustment back into the stock car. I believe my car rotates, or holds the turn in angle better with the Eibach bar. Looking forward to the next track day for sure!

 

They were at the track, and I would say generally it's from trying to carry too much speed into a turn. You'd have to be driving all kinds of illegal to do it on the street.

A couple that come to mind from my last track day at COTA... one was lift off oversteer. I got a point by from the trailing car into turn 6, but the leading car didn't point me by and I had to lift in the middle. Another was turn 19 and I was hard braking and not losing speed fast enough, instead of going off into the nice big, paved runoff area, I turned in and the back end came around. Came into the pits and my pads were pretty thin, so I quit.

I have also driven COTA in a steady rain and the back will slide without even touching the throttle, possibly the back tires hydroplane easier. The fronts can slide too though.

 

Can you also add the hardware you needed to get the adjustable endlinks to work with the aFe bars?

 

Thanks for the comparison list!!!

I'm never good at figuring out sway bar settings, but I'd like to add 2 points from my experience messing it up:
(1) Front and rear bars should be increased in similar ballpark, or else it makes a 'twisting' effect on the car, and upsets handling. It can even introduce the reverse of expected impact if the difference is too much. In this case, if one goes with a stiff bar like AFE at rear, they should also do so up front, and only then consider making marginal changes (with adjustable bars) for balance.

(2) Very stiff bars often improve road course lap time in my experience, even though people say that stiffer bars reduce traction. Again, I don't know exactly why, but it might be the reduction of lag in car responding to directional changes..

Thanks again for the info!