If I needed to have work done to the actual differential, then yeah: no need to pull it apart. I was thinking about back when I was making small adjustments to mine that didn't affect clearances, etc. I could have the diff out, adjusted (plates swapped, etc), and reinstalled in just a few mins. It's very satisfying for me to remove/adjust/install such a critical part on my own. I always thought there would be some voodoo involved and was out of my scope of practice. Turned out to be REALLY easy Though, I was intimidated the first time.

 

getting the diff back up and in is the hardest part for me, lining up everything right to bolt in while on my back using the jack to wiggle it around.. but, if i can do it, anyone can lol

 

I've been lucky. I jack it up a bit, attach the drive shaft and axles, then it jacks right into place for me. I lign up all bolts, hand-tightened. When I'm happy, I torque everything. It's been very compliant, so far.

 

He didn't go into too much detail but stated that I should re think the stiff rear spring and that I should try different things to figure it out on my own rather than follow "old information off of evolutionm". He wasn't being super negative or anything just seemed to in a round about way not agree with the stiff spring rates that are commonly recommended on this forum.

My thought is to not to get into over thinking it. Hell I haven't even ever adjusted my dampers since they were set by PSI after the re valve. I haven't made any adjustments other than tire pressures at the track.

 

An old school guy told me the same. Recommended 8/10 to save tires and going stiffer wasn't worth it. I ran that forever but bumped up to 9/10 to reduce some front end roll and tripoding. I'm very happy and was going to try 9/11, but decided to leave the 11s on the shelf because the car drives perfect, IMO.
I can't think of anything I'd rather the car do, right now.

 

imo the old school st* spring rates like 12/16 are flat out crazy for street tires, let alone to track a car

 

I've always had "controllable" oversteer with the stock 10/8 setup. What would be the benefit from swapping them to 8/10 or even 9/10? Would that make the car more neutral?

 

I went from 10/8 (unknowingly) to 8/10 - made the car much looser.

 

It's all so confusing to me but maybe that's because I have Super A D D. I would think the objective is to increase grip where there is less rather than decrease grip where there is more to make the car faster. There is a whole science to this that I will probably never understand and it will likely be my biggest set back at improving. I just want to drive the car faster everywhere :P

 

I am on 11/12 and have the clutch restack done. I find it to be a very neutral setup but can still get the rear end to kick out when I want.

 

ironic since i'm the OP, but my rear end doesn't kick out on power, at least on track. in what situations is the rear end actually kicking out for you now?

I definitiely get some yaw moment out of the rear on power through corner, but not power oversteer. it's rare for taht to actually happen, was more common when i had more power

 

Its mostly in 2nd gear when it happens. Will do it in 3rd too if I am really pushing it. But it can be on a small turn or a big turn. Just give it some gas coming out of the turn and it will go sideways. Its not violent, but the rear end will kick out on demand. I am most likely making less than 400 whp so its not an issue of too much power. I have a 24mm rear sway on the middle setting too. Still stock front bar.

 

interesting. I can get the car to do braking drifts but on power is a different story. i'm on the 26mm rear bar, middle setting, but I think im going to go back to the stock FSB.

 

Nope, sorry. Ya'll are wrong. More rear spring, much much more than you're running. If you want the car to turn you need to work the outside rear as much as possible. This isnt about balance, this is about maximum front grip. You can easily get the balance back with rear camber, lower rear pressure, toe-in, or more rear aero. But if you want to get faster lap times your front needs to work better.

Run the math even with the old standard ratio of 2.2hz front and 2.5hz rear. Up that to 2.8hz front (about where you are with 12k springs) and you'd run 3.2hz in the rear. Which would be 18k. 50% more rear spring than front. And these numbers would assume the car is more or less load balanced on the tires.

There are other interesting dynamic things that happen because we have such a big difference in weight on each end and tires supporting so much less in the rear. Turns out if we have 50% more weight up front we probably need about 50% as much tire in the rear. Hmm, how do we get that

I run 1.8x the rear spring as the front. I could go with 2x rear spring probably. Its AWD, get the thing to rotate and turn as hard as possible, do the other tricks to get the stability back.

 

Something else to think about (sorta sucks to hide this info deep in this thread but oh well...) Ive spent a lot of time talking with people around grids and talking about tire pressures in what people do and how they got there. It was also brought up in an RRAX thread a while ago and lines up very well with what the nationally fast guys have found that works for them.

Corner weight * 0.04 as a starting point for pressure. Obviously this gets swayed a bit when things are out of the norm like too much/little tire for the wheel. But in my 15 years this seems to be solid.

So, On my car, roughly 900/575 lbs, would then need 36/23. Yet I run 36/38-40. Why so much rear, to get rotation mostly but what happens when the car fully unloads the inside rear? Where does that weight go. A majority of it is on that outside rear tire but some of it on the inside front. Even if the tire isnt hanging, the mass being suspended in the rear is on that outside rear.

Following along with that, its not just the tire holding that mass (not force, actual mass of the rear of the car). The rear spring outside spring is doing the work to control all the rear of the car and inside spring is mostly along for the ride. Soooooooo, In my experience after having fought it, the rear needs a ton of spring to get it to turn harder and keeping rotating.