The idea of fine-tuning via cross-settings, ie., using one 'soft' end link hole and one 'medium' middle end link hole, is an interesting idea. Assuming one has the stiffness ratings vs oem for each hole setting, how do you calculate the 'net' bar stiffness increase when cross-setting? Is it a simple average, ie., Hotchkis front bar with one side soft (+9% vs oem) and one side medium (+32% vs oem) or 9 + 32 = 41 divided by 2 = 20.5% increase over stock?

2004 | 6MTs | Diamond Graphite/Graphite
Upstate NY

 

Use the ratio method: the length of the right angle end portion of the bar.............5" with be twice as stiff as 10".

Stiffer than stock by some percentage doesn't help you if you don't know stock stiffness.

Make a jig with stock bar and mounts, a jack, and bathrooom scales to determine how many pounds it takes to twist the bar one inch.

Remember the GOAL is to relate everything to a 1" change in tire height [body roll], where the bar attaches to the lower suspension member is CRITICAL as this determines the bars motion ratio............many bars attach in middle so 4 inches of wheel movement only move bar by 1.0 inch.

A 20mm diameter rear bar [Q45] has 160 pounds per inch of bar stiffness YET when attached to suspension yields only 40 pounds at the tire road interface [resists roll by 40 pounds every inch of roll]. That's with urethane bushings any rubber will decrease the bars effective stiffness at least till the rubber compresses to a semi solid mass.

Same with Springs that mount at an inward angle at the top and don't bolt directly to the HUB.

All about as installed [geometry] not individual external tests.

Generally the oem rear ALWAYS has significantly less roll stiffness [softer springs and bars] than the front because of lighter weight on rear tires.

Remember a stiffer sway bar increses load and thus decreases traction at the stiffer end............except in rain and serious acceleration ----- the rear always has more traction so the rear can stand to give up some to help the front.

Unfortunately what is ideal in dry low acceleration curves can be almost deadly in wet high acceleration curves.

The factory set SAFEISH for wet and non trained drivers who do not road race for a living.

Tires change with wear, temperature, and road surface friction so the " PERFECT POINT" will constantly change.

 

So then after reading all of this. If Lets say you were to go with the Tein H-techs.. (causing a 27% increase to the front) and u set the sways at soft in the front and stiff in the rear.. What does that leave the final result as? You decrease the 27% transfer by how much? How much understeer do u lose?

 

Q45tech - "Stiffer than stock by some percentage doesn't help you if you don't know stock stiffness." Thanks, I learned plenty from your reply, however, I am not tryng to determine the exact stiffness % increase over oem using the diff end link hole combos, rather the approx stiffness % increase between the two Hotchkis settings.

Since we already know the 'claimed' stiffness % increase over oem for each of the Hotchkis settings, it seemed like my calculation above might be plausible for determining an approx stiffness % increase between the different Hotchkis primary and cross settings (not over oem whatever they are). Aren't you, in essence, just 'splitting the % diff' or averaging the two rating %'s when cross-setting?

Regardless, if I determine that soft/front and med/rear settings are not enough to cure my at-the-limit understeer - yet med/front and med/rear is TOO much to keep the azz end in check - it makes perfect sense to try the soft/med cross setting in front and med/rear. And, as long as it gives me the neutral handling characteristics I want, I guess I can get along without the actual #'s alright. ;->

2004 | 6MTs | Diamond Graphite/Graphite
Upstate NY

 

Sway bar setup should be a trial and error affair, start with the mild, test and make changes up from their as required. Your goal is to fine tune into what is best for you.

The OEM torsional deflection rate on the front sway bar is
1100 lbs./ in

The OEM rear bar is 380 lbs/in

Spring rates and wheel rates:
Front 314 spring rate to 248 wheel rate Rear 342 spring rate to 123 wheel rate. (WHEEL RATE is the actual rate of the spring acting on the tire).

"All that's necessary for the forces of evil to win in the world is for enough good men to do nothing.”
Edmund Burke

G35 6mt

 

I've done Loren's 'skidpad test' and still push the oem 215's with Hotchkis bars set at soft/front and med/rear (running circles around a cone in the empty movie theatre parking lot early one am, prompted a visit from the security scooter, lol!). For sure, I'll be changing one side of the front bar to the middle hole and testing again. By the time I get it set right, it will probably be just about time to replace the skinny rubber! Again, the #'s don't really matter much to me, just curiosity of how much stiffer that cross-setting might be relative to the soft/soft front holes. Thanks.

2004 | 6MTs | Diamond Graphite/Graphite
Upstate NY