Stiffer Springs = Oversteer
#32
Front and rear drop links are good. Engine and trans mounts are good.
R888s, 32-34 front hot and 34-36 rear hot.
Going to double check the spring rates on the front (confirmed the rears).
I wonder with the KW V3s if some how the gas pressure chambers (one to all of them) are not correct, or missing pressure altogether
Last edited by 996TWINS; 04-23-2013 at 10:33 AM.
#35
TC Design.
http://www.tcdesignfab.com/
Let If you want your car to handle similar to mine. Let him know you want similar settings to Enrique's car. great great rotational ability.
http://www.tcdesignfab.com/
Let If you want your car to handle similar to mine. Let him know you want similar settings to Enrique's car. great great rotational ability.
#36
Assuming your tire circumferences are not a miss matching causing PSM to kick in at odd times, I'm betting a mismatch in spring rate ratios f to R causing a ride height issue making the rake angel unacceptable.
This has nothing to do with corner balancing. A sharp suspension tech may pick up on it comparing total front to total rear weights as compared to the total or a check on your caster angle. The difference in the latter may be too subtle though. Also your compression and rebound dampening may not be matched to your spring rates.
Logic tells me your front rates may be too stiff. Good luck!
This has nothing to do with corner balancing. A sharp suspension tech may pick up on it comparing total front to total rear weights as compared to the total or a check on your caster angle. The difference in the latter may be too subtle though. Also your compression and rebound dampening may not be matched to your spring rates.
Logic tells me your front rates may be too stiff. Good luck!
#37
Thanks for your offer. This will get sorted out.
That is what I am leaning towards. Did not get a chance to check the front springs last night.
Last edited by 996TWINS; 04-23-2013 at 12:04 PM.
#38
IF i recall correctly. I have 650 front spring rate and 1020 or 1050 rear spring rate.
The car ATM with a new alignment is very neutral for my style of driving....I do not have my front splitter on though. I suspect once my front splitter on it will be neutral but bias to oversteer which is what i prefer.
I know Dez ( heavychevy) has commented in the past that a mismatch spring rate so far apart causes a lot of oversteer....but my driving suits it... so perhaps that is why i cannot tell ? ... that is my only guess at this moment.
The car ATM with a new alignment is very neutral for my style of driving....I do not have my front splitter on though. I suspect once my front splitter on it will be neutral but bias to oversteer which is what i prefer.
I know Dez ( heavychevy) has commented in the past that a mismatch spring rate so far apart causes a lot of oversteer....but my driving suits it... so perhaps that is why i cannot tell ? ... that is my only guess at this moment.
#39
N/mm X 5.71= lbs/in, correct?
I will check the front springs tonight.
Last edited by 996TWINS; 04-25-2013 at 05:57 PM.
#40
You may want to get your alignment checked again.
On some car with the escentric bolt, the alignment will slip during hard cornering causing the alignment to be off. I'm not sure what the torque specs are on the 911, but sometimes they are much higher than the typical tech will tighten them by hand.
As soon as you go into a turn aggressively and accelerate hard, the rear toe will be off again, as it was previously.
Get your alignment rechecked. If it's off again, make sure they look up the factory torque specs and torque the ecentric bolts appropriately.
Later, Steve
On some car with the escentric bolt, the alignment will slip during hard cornering causing the alignment to be off. I'm not sure what the torque specs are on the 911, but sometimes they are much higher than the typical tech will tighten them by hand.
As soon as you go into a turn aggressively and accelerate hard, the rear toe will be off again, as it was previously.
Get your alignment rechecked. If it's off again, make sure they look up the factory torque specs and torque the ecentric bolts appropriately.
Later, Steve
#41
Last night I finally got to check out the front springs, which are 685.
So the fronts at 685 and the rears at 970 are in balance (200-300).
Looks like the car is going back to the shop who did the original install.
#42
Good luck,
Steve
Last edited by Steve Jarvis; 04-26-2013 at 11:59 AM.
#43
Looks like I found the problem, the bumpstops up front are too long. With little travel of the shock available, since it sits lower than stock it bottoms out, and the spring rate goes to ∞.
You were correct!
My shop will take care of this next week and set my car up at a nearby track
You were correct!
My shop will take care of this next week and set my car up at a nearby track
Last edited by 996TWINS; 04-25-2013 at 11:16 PM.
#44
A 300 lb difference in front rear will be more prone to oversteer than understeer. If its not an alignment issue I would try playing with the rake. Do you have a side profile shot of the car sitting still? Is the understeer slow and progressive or does it snap sideways? If its slow, then likely setup involvex. If fast more than likely toe related.
900 lbs is too stiff for no real downforce and on r888's. Your car cannot set properly and grip.
Enrique your car is very tail happy because of that enormous spring rate gap. Thats nuts.
I would set everything to the middle setting and start over by adjusting rake first. You can do this on your own at the track but if you dont know how to having a knowledgable mechanic with you will do. Start by lowering the rear 1/2 to 1 turn. But try and work on the end with the issue first if you can. If it gets close then play with rear sway and then shock settings.