customblackbird

iTrader: (15)

installed sportlines 6 months ago and i love them!
the drop is gorgeous and the handling is insane but im gona upgrade the rears for when i drop in my 500hp HSR 383.

what would the diameter and height be for a replacemnt spring? i think i heard someone say they where 14" height and i cant remember the diameter.
im prob gona get a highrate something like 250-350lbs spring rate and then just trim the spring to the ride height i want.

anyone also kno the height of a sportline spring compressed in the car standing still is?? i want the ride height to the be same but with the higher rate spring.

91_5.7_TPI

iTrader: (2)

Man, you run 250-300 lbs rears, and the car will be crazy unbalanced. That's way too much spring. People who lower the PHB and run hard core competitive auto-x don't run springs that stiff. You should do some springrate research at FRRAX and then start coming up with numbers for spring rates.

customblackbird

iTrader: (15)

i just threw that out there... its what ive seen in the mags when i see standard hipo springs. i kno the stock sportlines are like 130lb and the prokit is 160-170lb i think. i just wanted to kno what the demensions where to the rear spring but thanks i'll def check FRRAX...

91_5.7_TPI

iTrader: (2)

I would think something like a 175 lb (the prokit is 109-177 progressive) with stock location PHB would be as much as you would want to run without some very stiff front springs. That combo would require you to run some very good dampners at any rate.
I don't know enough to tell you what uncompressed spring height you'll need to get the ride height you want. You might want to look into a Ground Control or other weight jack set-up so you can effeectivly adjust the height of the spring without adjusting the spring rate.

Here are some set-ups from FRRAX:

Mine:
Eibach ProKit 714 front
36mm hollow front sway bar
KONI Yellows
Hot Part camber plates

109-177 progressive rear
25.4 solid rear bar (haha)
Spohn combo ended PHB
home made aluminum rod/rubber end LCAs (JonA)
Koni yellows, mono-tube

tracbird:

Front:
1000 in lb ground control front springs with weight jacks
35mm Suspension Techniques (solid) front sway bar
Energy suspension lower control arm bushings (I've got the Global West Del-A-Lum bushings here to install over the winter)
Koni SA's
Hotpart camber plates

Rear:
225 in lb rear springs with ground control weight jacks
19mm rear bar (currently on the car for street tire use, I've got one of Sam's 22mm hollow bars here as well as the 25mm)
Hotpart heim/heim LCA's
Hotpart heim/heim PHB
Spohn torque arm (crossmember mounted) and 6 speed conversion crossmember with a front heim joint
Koni SA's (30 series monotube shocks)

StanIROCZ (with usefull rear swaybar info):

This combo pushed BAD. This is what came stock on mine.
34/23 mm sways
750 / stock 107 springs
junk shocks
350 / 700r4

This made the car much more neutral:
34/24 mm sways
600 / stock 107 springs
Koni yellows 1 turn front 2/4 rear
350 / 700r4

This is what I have now and it pushes:
36/24 mm sways
800/200 springs
PHB lowered ~1.5"
Koni yellows 1.5 turns front 3/4 rear
350 / 700r4

Going from a 25mm to a 19 mm bar is a HUGE change. I'd try a 24 mm or a 23 mm bar first.

An 24mm bar is 85% as stiff as a 25. A 23 is 72%. etc

24mm 85%
23mm 72%
22mm 60%
21mm 50%
19mm 33%

My rear bar is way too stiff without lowering the PHB. That's what we were disgussing here. I now have a 24 and 19mm rear bar to try out. I want to find everything in between

customblackbird

iTrader: (15)

wow thanks very useful info

my combo is pushin too i just hear that the prokits rear springs are alot better as far as performance

i got 36mm stock WS6 front swaybar with poly endlinks/sway bar bushings
700lb sportline front springs lowered 1.7"-2"
KYB gr2 struts
poly front control arm bushings
TDS wonderbar
moog inner and outer tierods
edelbrock solid tie rod adjusters

Rear sportline springs lowered 1.3-1.5"
gas a just shocks
24mm stock WS6 sway bar with poly endlinks and sway bar bushings
tublar LCA with poly
adjustable panhard rod with poly
subframes, poly trans mount etc in sig. also got a tunnel mounted tublar torque arm ready to go in.

wat u think? and wat would u change? i know the shocks/struts arent the best but its all i could afford. im thinking of going wit 175-200lb springs for the rear and cut them to length. idk tho the sportlines/struts/shocks made a HUGEEEE difference in the handling and i love it

91_5.7_TPI

iTrader: (2)

I've had poly LCAs and I swapped them out for a set of one's I made that have heavy duty rubber ends on the body and QA1 rod ends on the rear end. I like them alot more than the polyurathane for ride and predictability in exiting corners.
If you start with 170-200 lbs springs and start cutting them, you'll increase the spring rate. There is a thread on here somewhere that will let you calculate how much you will add when you cut coils. I would think if you went with some MOOGs and cut enough (with the right spring rate to start with) you could get where you wanted. You would just have to make sure you got the right springs and cut the right amount.
And depending on if your car tries to oversteer at lower speeds under throttle, I'd consider a smaller rear bar. That's the problem my car has with the 25.4, but I've not tried the 24 yet. It's smaller and the material isn't as stiff, so it might do the trick.

customblackbird

iTrader: (15)

yea i remember that thread well. but if the spring isnt progressive wouldnt the spring rate not change? in my head it would be like cuting the front springs on our cars since they arent progressive u would be simply just lowering the spring height/ride height...i could be wrong it just doesnt make sense in my head lol.

do you kno the spring rates on the rear moogs? i was also thinking of getting a nice set of LCA with spherical ends from UMI i got the adjustable panhard rod with spherical end and its a really nice peice. i was also just thinking of getting a set of aluminum soild bushings from jegs or summit and slapping them on so theres no play.

RacerX13

A coil spring is just a torsion bar wound around an axis. If you visualize it "unwound" like a torsion bar it makes more sense. If you take a torsion bar and cut it shorter it will be stiffer since there is less material to flex, even though the diameter is the same.

91_5.7_TPI

iTrader: (2)

Exactly. Shorten the spring = stiffer spring.

Are you talking about the aluminum bushings in the LCAs? If so, don't do it. You need side to side flex in the LCAs. That's how they were designed to work. That's why poly isn't very good there. A heavy duty rubber (for comfort) or a rod end is best.
Here is a link to my LCAs (and other stuff)

customblackbird

iTrader: (15)

ok i understand now...thanks itmakes more sense. so wats the spring rate on the MOOG rear replacements? and how much should i hack off?

91_5.7_TPI... your camaro looks good. how much did it cost to make the LCA's? i'll prob just get a set from UMI with spherical ends.

91_5.7_TPI

iTrader: (2)

I had a list of all the Moogs on my laptop til it took a dump. I'll have to get it back from my friend. I would think that with the IROCs (can't remember part number), which are the stiffest stocks, that 1 maybe 1.5 coils would be right. I can't be sure, though. You'd have to get BMonteSS in here for that.
Thanks. If it was as fast as it looks, I might have something. I think that they are in the $160-180 range.