Coilover springs rates - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

10' Camaro SC · 03-16-2016, 02:18 PM

I have BC racing coilovers and found out that they are 8kg front (448bs/inch) and 12kg rear (672bs/inch).

BC told me they can reduce the rear spring to a 10kg which I feel would be much better because I think it's to stiff with all the poly bushing/arms/sway bar I have.

I also have a supercharger which is probably another 150 pounds in the front and BC said they can upgrade the front spring to a SWIFT spring.

Should I stay with a 8kg front spring rate, reduce or increase the spring rate.

The car is mostly a daily driver and looking for more comfort but occasional aggressive driving.

sting808 · 03-16-2016, 09:52 PM

Depending on your definition of comfort and agressive driving, I would go softer on the front and maybe 10kg on rear. Pedders XA coilovers came with 8 and 10. I tried 10kg up front but ended up with 350lbs/ft. Front ride became softer and better for autox. I run a 27mm solid front bar with a 32mm rear hollow fe4 style. Also have a KB 2.8 and DeWitt radiator. Bought 8" coils and needed to raise the strut a bit to keep the height the same due to the softer spring rate.

If you're interested, I still have my Pedders 10kg front coils laying around. Can't remember the height, but same DiA and BC made Pedders coilovers. Will let it go cheap. Or check Summit Racing for 2.5" springs. PM if interested. I went with Draco springs for fronts.

No matter what anyone says, stiffer rates are more harsh and less OE comfort. OE fronts are larger DIA 150lbs/ft.

FunkedOut · 03-16-2016, 11:58 PM

some numbers to look at:

SS (including 1LE): 165/370
Pfadt drop springs: 210/395
Z/28: 305/610
RideTech: 275/500 (can be ordered differently)

(Front/Rear - lbs/in)

10' Camaro SC · 03-17-2016, 07:43 AM

Quote:

Originally Posted by sting808

Depending on your definition of comfort and agressive driving, I would go softer on the front and maybe 10kg on rear. Pedders XA coilovers came with 8 and 10. I tried 10kg up front but ended up with 350lbs/ft. Front ride became softer and better for autox. I run a 27mm solid front bar with a 32mm rear hollow fe4 style. Also have a KB 2.8 and DeWitt radiator. Bought 8" coils and needed to raise the strut a bit to keep the height the same due to the softer spring rate.

So it looks like you went with more of a 6kg spring of front? It was required to go from a 7" to a 8" spring? I'm not sure if the supercharger weight really matters. Sounds like going to a 10kg spring up front is overkill/to stiff.

If you're interested, I still have my Pedders 10kg front coils laying around. Can't remember the height, but same DiA and BC made Pedders coilovers. Will let it go cheap. Or check Summit Racing for 2.5" springs. PM if interested. I went with Draco springs for fronts.

I was gonna go the SWIFT route because BC offers that option. From what Iv'e read it people said they ride softer, less coils & more stroke at the same spring rate.

No matter what anyone says, stiffer rates are more harsh and less OE comfort. OE fronts are larger DIA 150lbs/ft.

I would agree with that. I kinda question why coilovers go so stiff on there springs unless there trying make that much of a difference at the track even tho some of these kits are more of a "street" version.

10' Camaro SC · 03-17-2016, 07:47 AM

Quote:

Originally Posted by FunkedOut

some numbers to look at:

SS (including 1LE): 165/370
Pfadt drop springs: 210/395
Z/28: 305/610
RideTech: 275/500 (can be ordered differently)

(Front/Rear - lbs/in)

I could do 6kg (336) front & 8kg (448) rear but I don't know if that's to soft...

I would have to check with BC if 8kg in the rear is even possible.

sting808 · 03-17-2016, 07:52 AM

Went with Draco since DSE uses them. Also, decent price with shipping. Ridetech uses hyperco. All of the Manufacturer's has their reduced coil, optimized spring travel versions. I just got the Pedders 6"(?) 10kg per Pedders 4 years back. Switched to softer springs a couple year ago. Played around with different rates to see how they worked with my setup. 10" soft rate springs(150-200) will need a compressor to install.

10' Camaro SC · 03-17-2016, 07:58 AM

Quote:

Originally Posted by sting808

Went with Draco since DSE uses them. Also, decent price with shipping. Ridetech uses hyperco. All of the Manufacturer's has their reduced coil, optimized spring travel versions. I just got the Pedders 6"(?) 10kg per Pedders 4 years back. Switched to softer springs a couple year ago. Played around with different rates to see how they worked with my setup. 10" soft rate springs(150-200) will need a compressor to install.

I would like to keep the same spring length that BC has on there standard kit which is 180mm in front & 170mm in the rear. Just trying figure out how soft I can go on the spring rate without other Issues. Leaning more towards comfort but also don't want to kill my performance either.

Right now my ride has to much bounce to it. It could be because it's to stiff or could be that the shocks weren't right when i bought them.

sting808 · 03-17-2016, 08:45 AM

Softer rate springs at same height will sit lower. Need to compensate with coil height and/or strut adjustments.

10' Camaro SC · 03-17-2016, 09:40 AM

Quote:

Originally Posted by sting808

Softer rate springs at same height will sit lower. Need to compensate with coil height and/or strut adjustments.

I'd rather not change the spring lengths. Trying keep this simple lol.

So sounds like 8/10 setup is good. JusticePete suggested a 10/10 for my setup but still waiting on a response why.

FunkedOut · 03-17-2016, 02:49 PM

Quote:

Originally Posted by FunkedOut

some numbers to look at:

SS (including 1LE): 165/370
Pfadt drop springs: 210/395
Z/28: 305/610
RideTech: 275/500 (can be ordered differently)

(Front/Rear - lbs/in)

Look at this list again with motion ratios applied:
(I'm using 2/3 for the rear and 1 for the front)

SS (including 1LE): 165/246
Pfadt drop springs: 210/263
Z/28: 305/407
RideTech: 275/333

The higher spring rate in the rear raises the natural frequency over the front. Equal wheel rates would result in max porpoising (front is at max compression while rear is at max extension & vice versa) when going over a bump. A higher frequency in the rear speeds up the rear reaction so it lines up with the front, keeping the car closer to level as it runs over a bump.
Observe the ratios of front to rear rates and mimic them to capitalize on other's extensive testing unless you want to conduct your own.

10' Camaro SC · 03-17-2016, 03:42 PM

Quote:

Originally Posted by FunkedOut

Look at this list again with motion ratios applied:
(I'm using 2/3 for the rear and 1 for the front)

SS (including 1LE): 165/246
Pfadt drop springs: 210/263
Z/28: 305/407
RideTech: 275/333

The higher spring rate in the rear raises the natural frequency over the front. Equal wheel rates would result in max porpoising (front is at max compression while rear is at max extension & vice versa) when going over a bump. A higher frequency in the rear speeds up the rear reaction so it lines up with the front, keeping the car closer to level as it runs over a bump.
Observe the ratios of front to rear rates and mimic them to capitalize on other's extensive testing unless you want to conduct your own.

Little confused on what your saying lol. I think I understand some of what your telling me. So you agree the 8/10 is better than the equal 10/10?

FunkedOut · 03-17-2016, 05:21 PM

8/10 should be more comfortable on the street, yes.
6/10 might be better still.

VR Baron · 03-17-2016, 08:46 PM

Quote:

Originally Posted by FunkedOut

Look at this list again with motion ratios applied:
(I'm using 2/3 for the rear and 1 for the front)

SS (including 1LE): 165/246
Pfadt drop springs: 210/263
Z/28: 305/407
RideTech: 275/333

The higher spring rate in the rear raises the natural frequency over the front. Equal wheel rates would result in max porpoising (front is at max compression while rear is at max extension & vice versa) when going over a bump. A higher frequency in the rear speeds up the rear reaction so it lines up with the front, keeping the car closer to level as it runs over a bump.
Observe the ratios of front to rear rates and mimic them to capitalize on other's extensive testing unless you want to conduct your own.

Not sure how these numbers work. Pete says the 8 and 10 kg springs are an almost perfect match to the front rear balance and rife motion. Now if that is true, and obviously others use different rates as shown above, translate to 450 and 560 lbs. Take .67 of the rear 560 and you have 375. So I have alot more effectively in front and not rear. I dont have a ny porpoising one way or the other, only movement is the firm spring shock movement over bad roads. May be the valving I have in the supercars negates this, dont know.

FunkedOut · 03-17-2016, 11:47 PM

Pete's logged a couple more hours than me.
I don't claim to be an expert.
I've educated myself a little on the subject and put a lot of faith into what GM comes up with.

Another thing to keep in mind is GM builds street cars, even when they build track cars.
I never read where Pete recommended the 8/10 or 10/10, but he might have been talking race car?

Like I said, I'm no authority. My advice is worth every cent you paid for it.
For every tiny bit I pick up, there's worlds I don't know yet.

03-16-2016, 02:18 PM	#1
10' Camaro SC Drives: 2010 Camaro SS 5th Gen 6spd SC Join Date: Jun 2015 Location: Florida Posts: 614	Coilover springs rates I have BC racing coilovers and found out that they are 8kg front (448bs/inch) and 12kg rear (672bs/inch). BC told me they can reduce the rear spring to a 10kg which I feel would be much better because I think it's to stiff with all the poly bushing/arms/sway bar I have. I also have a supercharger which is probably another 150 pounds in the front and BC said they can upgrade the front spring to a SWIFT spring. Should I stay with a 8kg front spring rate, reduce or increase the spring rate. The car is mostly a daily driver and looking for more comfort but occasional aggressive driving. __________________ 10' LS3 Camaro 2SS (blacked out) - Edelbrock Supercharger, ZL1 rims, 275/315 tires, XS Power LT headers, 3" exhaust, twin tips, Edelbrock CAI, ZL1 fuel pump/ADM FPCM, VMax ported TB, JRE fuel mod, TR6ix plugs, ZL1 spoiler/splitter/grille, KW V1 coilovers, BMR sway bars, strut tower brace, trailing arms, toe links, Prothane radius arm & subframe bushings, Slotted rotors, Hawk pads, SS brake lines, HURST short throw shifter, Scosche dash kit, Pioneer 7" radio, backup camera, Dyno - 520 rwhp/tq

03-16-2016, 09:52 PM	#2
sting808 Drives: 2010 SS RS Join Date: Apr 2009 Location: Honolulu, Hawaii Posts: 930	Depending on your definition of comfort and agressive driving, I would go softer on the front and maybe 10kg on rear. Pedders XA coilovers came with 8 and 10. I tried 10kg up front but ended up with 350lbs/ft. Front ride became softer and better for autox. I run a 27mm solid front bar with a 32mm rear hollow fe4 style. Also have a KB 2.8 and DeWitt radiator. Bought 8" coils and needed to raise the strut a bit to keep the height the same due to the softer spring rate. If you're interested, I still have my Pedders 10kg front coils laying around. Can't remember the height, but same DiA and BC made Pedders coilovers. Will let it go cheap. Or check Summit Racing for 2.5" springs. PM if interested. I went with Draco springs for fronts. No matter what anyone says, stiffer rates are more harsh and less OE comfort. OE fronts are larger DIA 150lbs/ft.

03-16-2016, 11:58 PM	#3
FunkedOut Drives: Black 2010 SS Join Date: Dec 2012 Location: FL Posts: 447 View My Garage	some numbers to look at: SS (including 1LE): 165/370 Pfadt drop springs: 210/395 Z/28: 305/610 RideTech: 275/500 (can be ordered differently) (Front/Rear - lbs/in)

03-17-2016, 07:52 AM	#6
sting808 Drives: 2010 SS RS Join Date: Apr 2009 Location: Honolulu, Hawaii Posts: 930	Went with Draco since DSE uses them. Also, decent price with shipping. Ridetech uses hyperco. All of the Manufacturer's has their reduced coil, optimized spring travel versions. I just got the Pedders 6"(?) 10kg per Pedders 4 years back. Switched to softer springs a couple year ago. Played around with different rates to see how they worked with my setup. 10" soft rate springs(150-200) will need a compressor to install.

03-17-2016, 08:45 AM	#8
sting808 Drives: 2010 SS RS Join Date: Apr 2009 Location: Honolulu, Hawaii Posts: 930	Softer rate springs at same height will sit lower. Need to compensate with coil height and/or strut adjustments.

03-17-2016, 05:21 PM	#12
FunkedOut Drives: Black 2010 SS Join Date: Dec 2012 Location: FL Posts: 447 View My Garage	8/10 should be more comfortable on the street, yes. 6/10 might be better still.

03-17-2016, 11:47 PM	#14
FunkedOut Drives: Black 2010 SS Join Date: Dec 2012 Location: FL Posts: 447 View My Garage	Pete's logged a couple more hours than me. I don't claim to be an expert. I've educated myself a little on the subject and put a lot of faith into what GM comes up with. Another thing to keep in mind is GM builds street cars, even when they build track cars. I never read where Pete recommended the 8/10 or 10/10, but he might have been talking race car? Like I said, I'm no authority. My advice is worth every cent you paid for it. For every tiny bit I pick up, there's worlds I don't know yet.