Shock Hawk

Intro:
Shock Hawk here. I'm getting my WS6 in the next 1-3 months and the first thing that I want to bolt on is a new rear. I'm hoping to do a Ford 9". The reason for this is that I plan to eventually run 550hp/tq. That'll probably tear the 10 bolt to pieces within a week with that kind of power (not to mention stock hp w/ M6 and drill mod). A 12 bolt will get the horrible whine that everyone talks about. The 9" is probably perfect, especially since I "jack rabbit" off the line a bit and am known for drifting a bit.

Goal:
My longterm intention is to have a car for autocross. Not a full blown race car, but a dd that can show off a bit on the track. I don't plan to win any races in it. I also might do some light drifting if I have a tire sponsor (not likely) or I'm about to buy new tires anyways.

Problem:
Here's my problem: the extra unsprung weight is not good for the handling, so I hear. The 9" is 25lb extra (I think). I'll have a hollow sway bar out back (-5lb) and probably some racing wheels when on the track (-16ish). The racing wheels are for the track only and it'll be close to stock weight. Off the track, I'll have my WS6 wheels and so I'll be 20lb over, more if I upgrade the brakes.

Facts:
I'm probably going with a full Strano suspension (not to mention LCA's, PHB, TA, etc.). I've read that you can control the unsprung weight with your shocks (compression dampening). I'm probably going for Konis. I want all good quality products, no half-assing it. Budget is not a problem within reason. I like the sound of the Konis and I was wondering if I can adjust them to counteract the extra unsprung weight. I'm going to suspect that you can only adjust rebound dampening on SA shocks. Thus I'd probably be looking at Koni DA's.

Question:
Could anyone tell me if Koni DA's could counteract this unsprung weight and by how much? Is there a better shock? Is there another way to reduce weight? Is this wishful thinking? Thx for reading the whole thing (or not).

DONAIMIAN

iTrader: (18)

pm sent

Shock Hawk

bump for opinion

DuronClocker

iTrader: (25)

Go Koni SA's. I have them on my car with the 9" and they deal with it fine. Ride quality is definitely affected with the heavier rear end and the 17's, but its still more than daily-driveable. The DA's offer a compression adjustment, but nobody ever uses it. They usually set it on the lowest setting, which makes them equivelent to a Koni SA. Some people even complain about the Koni SA's being slightly stiff on compression, but I'm very happy with them.

The rebound adjustability will be very good to have with the 9" and heavier wheels. Change springs when you do the shocks though. I didn't like how my stock springs felt on the Koni's. Definitely better all around with Strano's springs.

Shock Hawk

Thx, anyone else have an opinion or experience? Someone suggested that I try Penske 8100 shocks. Anyone have any experience with those either?

I'm going for better than stock. I want something that feels really good and will do very well on the slalom. Competition quality would be desirable, but I understand that the extra unsprung weight is a handicap.

JD_AMG

Honestly I think its going to be pretty difficult to auto-x/road race with a 550hp/tq car and a 9" rear end. Thats a whole lot of power to be trying to put down around turns...

subtlez28

iTrader: (15)

Not my area of knowledge...I actually have a couple hy-jack questions.
1. Your post says the 9" is 25lbs heavier. Is that accurate? Is 25lbs that big a deal?
2. I Know they make aluminum center sections for 9"s. How much weight do they save?
3. Isn't another prob w bigger rear ends the increased ride height due to bigger axle tubes?

I suppose these questions kind of belong in another section, but they seem relavent to this thread...

Shock Hawk

How much hp/tq is ideal for autocross? Also, if you have too much, isn't being light on the pedal a great way to limit the power (not pulling as much)?

I don't think there would be increased ride height. As long as the input pinion bisects the axles and you have the same wheels/tires and the room under the car for it, it shouldn't effect ride height at all.

Unsprung weight, if not controlled, makes the car feel like it's bouncing a bit after a bump (or so I hear).

JD_AMG

Im no expert, but there really isnt an "ideal" amount of power, but near stock power should be more than enough.

Shock Hawk

Lets focus away from the power, I don't plan to touch it for about 3-5 years. I'll wait until my rebuild (probably at 200k) to upgrade the engine.

Here's my theory:
I need to adjust the compression dampening (on the DA). According to DuronClocker, the softest setting makes them similar to the SA's. If I use a firmer setting, it should dampen more weight. That would mean that if I'm running an extra 20lbs max on a rear end that is probably over 100lbs stock (including brakes and wheels), then I should have no problem controlling that extra unsprung weight (the extra weight is small in comparison to the overall weight). Can anyone help my theory?

DuronClocker

iTrader: (25)

Compression dampening will make them stiffer upon hitting a bump/irregularity in the road, which will shock the car more. Softer is better here (to an extent of course). You're really looking to control the outward extension of the shock in this case, which would be the rebound dampening adjustment

Shock Hawk

Ok, so I'm backwards. Would it work if I did the rebound dampening instead?

DuronClocker

iTrader: (25)

Yes, which is why the SAs will work fine for you

eLTwerker

Even Strano has said that Koni DAs are somewhat of an overkill.

Shock Hawk

My question is if the DA's would be able to control the extra weight since you can adjust the rebound dampening on it. I would like it to feel like the stock rear with the Koni SA's.

eLTwerker

ask trackbird or Strano

coolformula

iTrader: (21)

Does the 9inch way more than just 25 pounds more? Konis SA will be good, your adding weight not good, but you have to a have a rear taht can handle the power!

chupr0kabra

iTrader: (10)

I've got a Moser 12-bolt. A couple things I've learned from personal experience on this subject.

1. Your ride height will change. The axle tubes are bigger, thereby moving where the spring mount plates are. It's about 0.5" higher in the back now than it was with my stock 10-bolt.
2. There are a few ways to counter the increased weight.
   1. Lighter wheels. I've read that 1 lb on the wheels is like 7 lbs anywhere else on the car. I'm not sure how accurate that is, but it makes sense, since your wheels are the first things motivated by the drivetrain. Any good engine builder will tell you lower rotational mass (i.e. crankshaft, pistons, connecting rods) will result in an engine that spins up faster, and wheels are rotational mass.
   2. Lighter (hollow) swaybars. It's only a few pounds, but every little bit helps.
   3. Aluminum center section. I did a lot of reading/research before I made my decision to get a 12-bolt. Had I gone with a 9-inch, I would have gine with the aluminum center section. I chose the 12-bolt to retain ABS.
   4. Adjustable shocks. Compression adjustment will likely help, but it's still unsprung weight.
3. You have to ask yourself what you want to do with the car. Why are you getting a 9-inch? Is it because you plan to drag race? If so, great, but you have to know there will be a sacrifice in handling. From what I've read, a lot of the auto-x guys run Torsen differentials in 10-bolt rearends. If it's not going to be a quarter miler, why get a 9-inch?

I'm not telling you "don't get a 9-inch". They're great, pretty much bulletproof, and there are tons of options out there for them. I upgraded my rearend to a 12-bolt because I have future plans to make more power and wanted a little added insurance. My goals with the car are to have a street-friendly, comfortable ride, with the option to go to the 1/4 mile occasionally. When I first got the 12-bolt, I was unhappily surprised at how much it affected my handling. I was able to overcome the problems with a few adjustments to the shocks (I adjusted my Koni SA's a little bit firmer (rebound)) and going from (heavy) 17x11 ZR1's to (much lighter) 17x9.5 Fikse FM/5's. My ride comfort is now back to where it was before I upgraded the rearend, which is exactly where I wanted it to be.

Maybe this thread will help: https://ls1tech.com/forums/suspension-brakes/697206-unsprung-weight.html

Good luck!


-Mike

sapper_daddy

iTrader: (12)

Man I've made posts like this before and I don't want to tell you how to spend your money at all. You said you aren't going to do any motor upgrades for what 3-5 years? Are you sure you want to spend that kind of cash on a 12 bolt or 9"? That rear is good for some power PLUS if you want to get to 550 HP you are going to have a hard time getting there even with all bolt ons because those setups rob some power. My thing is if you are staying on the street you have some bigger fish to fry.....just my opinion, take it with a grain of salt.

Shock Hawk

I just want something that'll perform much better than stock at the slalom and something that I can't brake. I've heard of guys braking their 10 bolts with stock power and I'm stupid enough to do it. I just want to get something that won't brake. I also want it to handle really well. My big question on this post is "how do I get the 9" to feel like a 10 bolt with Koni's?"