Coil Over Spring Rates??

whsjr50 · 08-02-2001, 08:38 PM

I am adding a tubular "K" member and coil overs and new "A" arms with Tociko 5 way adjustable struts. What spring rate would be a good compromise between all out racing and street driving? The rear has a pan hard rod with mega-byte lower control arms and motorsport "C" springs. Any input greatly appreciated.

------------------
1996 Mystic Cobra

whsjr50 · 08-05-2001, 08:51 AM

I guess that unless you belong to the "club"
you don't get replys. I will try scoa, maybe I will get some advise there.

dinomite · 08-05-2001, 10:57 AM

no, people on this board are very open, and helping. the problem is that very few mustangers like road racing, in general they are simple people who can't handle anythin where you have to "turn". therefore, this area of the board doesn't get very many users, and so very few and far spaced replies. i know that there are a few people who frequent this section that could help you out, sorry i can't.

------------------
90LX AOD Convertable: Lakewood control arms, FMS springs.
Best 1/4: 15.277@92.25 (2.27 60')
AIM: dinomite1, roadracestang
dinomite@softhome.net

dinomite · 08-05-2001, 10:58 AM

try asking the company you are buying the stuff from too.

moosejaw · 08-06-2001, 01:51 AM

For front coil overs use 275-350# rate. You could start with 275# and test it. If you feel more spring is needed, up the rate in 25# increments. Different chassis combos will work better with the different rates.

Since the coil over is twice the distance out on the control arm as the stock coil location use the following rule of thumb. To get the coil over rate take the stock location rate (or performance coil) and divide by 2. This is the approximate coil over rating to match. Note the coil overs respond alot differently than the heavier stock location due to lower unsprung weight ( in your case lighter A-arm). Conversely doubling the coil over rate gives an approximate stock location spring rate. This is helpful because everyone advertises rates for the stock location. Stock location rates above 700# are considered race rates. Spring rates above 800# are all out race. Therefore a coil over rate greater than 350# for the front would be considered a race rate that would be rough on the street.

For the best tuning install rear coil overs also. This allows you to set corner weights to compensate for understeer/push or oversteer/loose conditions. Setting up the car correctly can make for really fun on-street and highway performance.

As a side note ensure to get ajustable camber/caster plates and a strong strut tower brace. I recommend Maximum motorsport for both of these items.

Have fun!

Mike

------------------
Live near St.Louis?
Check out Mustang Muscle and Dyno in High Ridge, MO
Check out my ride.

drudis · 08-06-2001, 09:27 AM

Sorry, I had a virus that I cleaned off my home computer, that took out my Windows...

Spring rates in the 275# area might be fine for the street. Thats basically a little more than stock rates. I would start with 300#, on the firm side. Personally I run 8" tall 425# coilovers on the front and 350# (too soft for me) "regular" (non-coilover) rears. THis is for a Griggs tubular front, and my own design t-arm/panhard rear.

------------------
Darius Rudis
Roadracer: Home built t-arm/panhard suspension powered by an S-trimmed motor :-)
My Mustang Page

moosejaw · 08-07-2001, 12:30 AM

Yep, 275# is a little soft. That is what I have now and I need more rate. I don't think I'll get a 425# just yet

Maybe step up to a 350# or 375#. I have 750# on the 740 Volvo with Koni sports.

A little feed back on Griggs rear race shock. It is way to stiff a valving for the street but maybe you would like it. You would love it for the track. I need to revert to the sport shock for the rear.

Mike

------------------
Live near St.Louis?
Check out Mustang Muscle and Dyno in High Ridge, MO
Check out my ride.

whsjr50 · 08-25-2001, 04:25 AM

Thanks for all the help! Sorry for the late response to busy putting my toy together.
Went with 400's in the front. Still looking for a REAR COIL OVER set up any suggestions?

[This message has been edited by whsjr50 (edited 08-25-2001).]

moosejaw · 08-25-2001, 10:12 AM

Yes,
Griggs has a rear coil over setup with two shock options. Like I said above the race shock has extreme damping and not very street friendly. The street shock should be best for us normal folk (not darius

). This shock uses the stock location at the axle and the body for mounting.

I also heard Central Coast Mustang has a rear kit also. I saw their axle mount setup and I think it adds to many levers (read torque moment) to the shock assembly. Could make it prone to failure in an extreme situation.

When you change to the coil over you can change your lower control arms to a style that does not have a spring perch. This means less unsprung weight. So when you buy your torque arm or 3-link and panhard bar

you can remove your uppers and have a lighter rear end.

Mike

------------------
Live near St.Louis?
Check out Mustang Muscle and Dyno in High Ridge, MO
Check out my ride.

drudis · 08-27-2001, 09:08 AM

Just be careful when getting rear coilovers, about the lower control arm.
Aftermarket lower control arms (tubular) will NOT have sway bar mounts. So you will need aftermarket swaybars.
The cost of coilover hardware, plus coils, plus shocks, plus lower control arms, plus aftermarket swaybar... OR, adjustable lower control arms and coils (what I did).

OR the expensive way:

------------------
Darius Rudis
Roadracer: Home built t-arm/panhard suspension powered by an S-trimmed motor :-)
My Mustang Page

[This message has been edited by drudis (edited 08-27-2001).]

moosejaw · 08-29-2001, 02:29 AM

My lowers from Griggs, without spring perch, had a sway bar mount for the stock bar. Not like the stock bar has enough roll rate anyway. But the mount was there. You can see them in picture #2 on my ride (they are backwards in the photo)

. See my posts above for a link.

Mike

[This message has been edited by moosejaw (edited 08-29-2001).]

Skankin · 08-31-2001, 03:54 PM

Actually the coil-over difference is a factor of 4! (for the front).

Torque = force * distance

Force = (spring constant) * compression

The compression is proportional to the radius. ie. circumference = 2pi*r

So, Torque = k (dist) * compression

Since you're doubling the leverage & the compression, it's equivalent to 4X that of the stock location. (Actually is something like 4.1 because the springs aren't vertical... so they're compressed even more than what the arm movement would indicate).

So a 250# coil-over is similar to a 1000# spring in the stock location. Fortunately, the unsprung weight is reduced and the spring's motion becomes the same as the strut's, so the ride is a little better.

So with coil-overs, you have to take the square of the ratio.

------------------
'89.5 5L LX, hatch, Medium Canyon Red, 155K Km (No winters), 5sp, 3.08, GT interior, a/c, Alpine CD, K/N, Crane PS91, Walbro 190 LPH, March Pulleys, Mr. Gasket 180 therm (HP balanced), 3 core rad, MarkVIII fan, Variflow controller, Polygraphite front bushings, FMS-5300B springs, 6 KYB's, 73mm Calipers, Maximum Motorsport 4pt chassis brace, Western Motorsport Racing's Sub-frame connectors. Re-ringed bottom end, conv. motor mounts, melling oil pump, FMS-C50 waterpump, GT40P heads (blended, polli

turbolx · 09-01-2001, 04:16 PM

Hrmm... just saw this thread...

FYI, I'm running MM 350#/in front coilovers on my LX and it's a daily driver. The ride is not what I would call too harsh for the street, even over MI's crappy roads with the Tokico's set on "3". Since I too run a TA/PB rear suspension, my rear spring is a 390-430#/in variable rate.

IMHO, the 275#/in front coilover is too soft for agressive handling on the street, but fine for a street/drag strip car.

------------------
Greg Banish
President, Detroit Speedworks, Inc.
'93 LX Turbocharged Road Racer
'00 Bad-Ass F150

08-02-2001, 08:38 PM	#1
whsjr50 Registered Member Join Date: Dec 2000 Location: Ypsilanti, Michigan Posts: 5	Coil Over Spring Rates?? I am adding a tubular "K" member and coil overs and new "A" arms with Tociko 5 way adjustable struts. What spring rate would be a good compromise between all out racing and street driving? The rear has a pan hard rod with mega-byte lower control arms and motorsport "C" springs. Any input greatly appreciated. ------------------ 1996 Mystic Cobra

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
What spring rate should I get for rear coil overs	ciara	Windsor Power	0	12-24-2003 07:29 AM
coil over spring rate?	ciara	Windsor Power	2	11-25-2003 08:10 AM
convertible spring rates?	93GTDIN	Windsor Power	3	12-18-2002 11:14 AM
Coil Spring Question??	RMARIANI	Windsor Power	1	01-29-2002 10:02 AM
Eibach Drag Spring Rates	COG3164	Windsor Power	1	12-11-2001 06:21 PM

08-05-2001, 08:51 AM	#2
whsjr50 Registered Member Join Date: Dec 2000 Location: Ypsilanti, Michigan Posts: 5	I guess that unless you belong to the "club" you don't get replys. I will try scoa, maybe I will get some advise there.

08-05-2001, 10:57 AM	#3
dinomite The Dude Join Date: Feb 2001 Location: Arlington, VA Posts: 1,262	no, people on this board are very open, and helping. the problem is that very few mustangers like road racing, in general they are simple people who can't handle anythin where you have to "turn". therefore, this area of the board doesn't get very many users, and so very few and far spaced replies. i know that there are a few people who frequent this section that could help you out, sorry i can't. ------------------ 90LX AOD Convertable: Lakewood control arms, FMS springs. Best 1/4: 15.277@92.25 (2.27 60') AIM: dinomite1, roadracestang dinomite@softhome.net

08-05-2001, 10:58 AM	#4
dinomite The Dude Join Date: Feb 2001 Location: Arlington, VA Posts: 1,262	try asking the company you are buying the stuff from too.

08-06-2001, 01:51 AM	#5
moosejaw Registered Member Join Date: Apr 1999 Location: St.Louis,MO Posts: 274	For front coil overs use 275-350# rate. You could start with 275# and test it. If you feel more spring is needed, up the rate in 25# increments. Different chassis combos will work better with the different rates. Since the coil over is twice the distance out on the control arm as the stock coil location use the following rule of thumb. To get the coil over rate take the stock location rate (or performance coil) and divide by 2. This is the approximate coil over rating to match. Note the coil overs respond alot differently than the heavier stock location due to lower unsprung weight ( in your case lighter A-arm). Conversely doubling the coil over rate gives an approximate stock location spring rate. This is helpful because everyone advertises rates for the stock location. Stock location rates above 700# are considered race rates. Spring rates above 800# are all out race. Therefore a coil over rate greater than 350# for the front would be considered a race rate that would be rough on the street. For the best tuning install rear coil overs also. This allows you to set corner weights to compensate for understeer/push or oversteer/loose conditions. Setting up the car correctly can make for really fun on-street and highway performance. As a side note ensure to get ajustable camber/caster plates and a strong strut tower brace. I recommend Maximum motorsport for both of these items. Have fun! Mike ------------------ Live near St.Louis? Check out Mustang Muscle and Dyno in High Ridge, MO Check out my ride.

08-06-2001, 09:27 AM	#6
drudis Moderator Join Date: Dec 1999 Location: Livonia, MI, USA Posts: 1,194	Sorry, I had a virus that I cleaned off my home computer, that took out my Windows... Spring rates in the 275# area might be fine for the street. Thats basically a little more than stock rates. I would start with 300#, on the firm side. Personally I run 8" tall 425# coilovers on the front and 350# (too soft for me) "regular" (non-coilover) rears. THis is for a Griggs tubular front, and my own design t-arm/panhard rear. ------------------ Darius Rudis Roadracer: Home built t-arm/panhard suspension powered by an S-trimmed motor :-) My Mustang Page

08-07-2001, 12:30 AM	#7
moosejaw Registered Member Join Date: Apr 1999 Location: St.Louis,MO Posts: 274	Yep, 275# is a little soft. That is what I have now and I need more rate. I don't think I'll get a 425# just yet Maybe step up to a 350# or 375#. I have 750# on the 740 Volvo with Koni sports. A little feed back on Griggs rear race shock. It is way to stiff a valving for the street but maybe you would like it. You would love it for the track. I need to revert to the sport shock for the rear. Mike ------------------ Live near St.Louis? Check out Mustang Muscle and Dyno in High Ridge, MO Check out my ride.

08-25-2001, 04:25 AM	#8
whsjr50 Registered Member Join Date: Dec 2000 Location: Ypsilanti, Michigan Posts: 5	Thanks for all the help! Sorry for the late response to busy putting my toy together. Went with 400's in the front. Still looking for a REAR COIL OVER set up any suggestions? [This message has been edited by whsjr50 (edited 08-25-2001).]

08-25-2001, 10:12 AM	#9
moosejaw Registered Member Join Date: Apr 1999 Location: St.Louis,MO Posts: 274	Yes, Griggs has a rear coil over setup with two shock options. Like I said above the race shock has extreme damping and not very street friendly. The street shock should be best for us normal folk (not darius ). This shock uses the stock location at the axle and the body for mounting. I also heard Central Coast Mustang has a rear kit also. I saw their axle mount setup and I think it adds to many levers (read torque moment) to the shock assembly. Could make it prone to failure in an extreme situation. When you change to the coil over you can change your lower control arms to a style that does not have a spring perch. This means less unsprung weight. So when you buy your torque arm or 3-link and panhard bar you can remove your uppers and have a lighter rear end. Mike ------------------ Live near St.Louis? Check out Mustang Muscle and Dyno in High Ridge, MO Check out my ride.

08-27-2001, 09:08 AM	#10
drudis Moderator Join Date: Dec 1999 Location: Livonia, MI, USA Posts: 1,194	Just be careful when getting rear coilovers, about the lower control arm. Aftermarket lower control arms (tubular) will NOT have sway bar mounts. So you will need aftermarket swaybars. The cost of coilover hardware, plus coils, plus shocks, plus lower control arms, plus aftermarket swaybar... OR, adjustable lower control arms and coils (what I did). OR the expensive way: ------------------ Darius Rudis Roadracer: Home built t-arm/panhard suspension powered by an S-trimmed motor :-) My Mustang Page [This message has been edited by drudis (edited 08-27-2001).]

08-29-2001, 02:29 AM	#11
moosejaw Registered Member Join Date: Apr 1999 Location: St.Louis,MO Posts: 274	My lowers from Griggs, without spring perch, had a sway bar mount for the stock bar. Not like the stock bar has enough roll rate anyway. But the mount was there. You can see them in picture #2 on my ride (they are backwards in the photo) . See my posts above for a link. Mike [This message has been edited by moosejaw (edited 08-29-2001).]

08-31-2001, 03:54 PM	#12
Skankin Registered Member Join Date: Dec 1998 Location: London, Ontario, Canada Posts: 1,349	Actually the coil-over difference is a factor of 4! (for the front). Torque = force * distance Force = (spring constant) * compression The compression is proportional to the radius. ie. circumference = 2pir So, Torque = k (dist) compression Since you're doubling the leverage & the compression, it's equivalent to 4X that of the stock location. (Actually is something like 4.1 because the springs aren't vertical... so they're compressed even more than what the arm movement would indicate). So a 250# coil-over is similar to a 1000# spring in the stock location. Fortunately, the unsprung weight is reduced and the spring's motion becomes the same as the strut's, so the ride is a little better. So with coil-overs, you have to take the square of the ratio. ------------------ '89.5 5L LX, hatch, Medium Canyon Red, 155K Km (No winters), 5sp, 3.08, GT interior, a/c, Alpine CD, K/N, Crane PS91, Walbro 190 LPH, March Pulleys, Mr. Gasket 180 therm (HP balanced), 3 core rad, MarkVIII fan, Variflow controller, Polygraphite front bushings, FMS-5300B springs, 6 KYB's, 73mm Calipers, Maximum Motorsport 4pt chassis brace, Western Motorsport Racing's Sub-frame connectors. Re-ringed bottom end, conv. motor mounts, melling oil pump, FMS-C50 waterpump, GT40P heads (blended, polli

09-01-2001, 04:16 PM	#13
turbolx Registered Member Join Date: May 1999 Location: Detroit, MI Posts: 252	Hrmm... just saw this thread... FYI, I'm running MM 350#/in front coilovers on my LX and it's a daily driver. The ride is not what I would call too harsh for the street, even over MI's crappy roads with the Tokico's set on "3". Since I too run a TA/PB rear suspension, my rear spring is a 390-430#/in variable rate. IMHO, the 275#/in front coilover is too soft for agressive handling on the street, but fine for a street/drag strip car. ------------------ Greg Banish President, Detroit Speedworks, Inc. '93 LX Turbocharged Road Racer '00 Bad-Ass F150