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Old 12-28-2022   #1
Norwegianmopar
 
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Join Date: Mar 2018
Location: Norway
Posts: 345
Default DRM coilovers & spring rates

Many of you guys have this coilover kit on your cars and from what I understand various spring rates are used according to preference.

My question is what your experiences are regarding spring rates, what do you recommend and why so.

Doing all the bushings and shocks etc anyways and think I want to ship over this kit too in the container. Our car is a 94 ZR-1.

Brackets from Carter is also on the list but is there anything else to think about (besides the lathe job on the rings) if installing this kit?

Thanks and Merry Christmas to all of you [emoji318][emoji319][emoji1762]

**I can add I have emailed Randy (DRM) too but appreciate personal experiences shared here also**

https://www.dougrippie.com/c4-corvette-coilover-kit

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Roy Martin

1994 ZR-1 #112 Admiral Blue/Black
Dana 4:10
Aluminum flywheel
Corsa exhaust
Watson headers
Haibeck chip
470 HP/399 RWHP

1991 ZR-1 #400 White/Red (SOLD)
Dana 4:10
Powder coated engine
Haibeck performance chip
Borla exhaust

Last edited by Norwegianmopar; 12-28-2022 at 07:05 AM.
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Old 12-28-2022   #2
AndrewL
 
Join Date: Dec 2020
Location: Sydney, Australia
Posts: 73
Default Re: DRM coilovers & spring rates

I have 425 and 325 pound springs on my car. That's what was on the car when I received it. With the FX3 set on tour I don't like how the car feels, vague and floaty. In Sport the ride and response is tightened up and it's fine for driving on my local roads which are a combination of good roads and crappy potholed surfaces. I've not done hard nearing the limit) cornering so can't comment on that.

I've barely run it in the performance setting so can't comment on that.

I have poly bushings all round as well.

My car is moderately lowered as well. I'm happy with the setup I have and am not inclined to mess with it.
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Old 12-29-2022   #3
Mikey
 
Join Date: Jul 2020
Location: Nashville TN
Posts: 304
Default Re: DRM coilovers & spring rates

I can't fully comment since my car was equipped already when I purchased it. So I don't have any experience with the stock setup for direct comparison for example. I'm also not exactly sure what spring compounds I have, can't find any visible markings, but they are a kind of metallic dark blue color in case color coding means anything. Doug Rippie's website doesn't seem to have options for spring rates.

What I will say is keep the FX3 adjustable shocks with the coilovers. My car in tour mode is quite compliant and soft ride (with considerable sacrifice in handling - can feel the roll and sub-optimal levels of mechanical grip). If not doing any spirited driving and just a true Sunday cruise with the wife, she is happiest in this mode.

Sport and Performance settings are progressively better with whatever springs I do have. I'll say sport is my go-to for spirited, not pushing it driving. For highly spirited and/or track, I am happy with my springs and full performance FX3 setting as far as grip and response. Best of any C4 I have ever driven (my first was a base '94 383ci LT1 car with ZR-1 base suspension components installed for springs, shocks, brakes and ARBs).

so bottom line, whatever springs you choose, keep FX3 adjustable shocks!
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Old 12-29-2022   #4
Norwegianmopar
 
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Default Re: DRM coilovers & spring rates

"so bottom line, whatever springs you choose, keep FX3 adjustable shocks!"

I have bought new FX-3 shocks and a complete SuperPro bushing kit and will also replace the u-joint as well as new brakes, stainless brake lines and oil cooler lines etc.

Our goal is to try to get the driveability as good as new or even better because we want both comfort and control. New custom built wheels and new tires are also parts of the revamping we have planned. The coilovers will improve both the looks and the performance.

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Roy Martin

1994 ZR-1 #112 Admiral Blue/Black
Dana 4:10
Aluminum flywheel
Corsa exhaust
Watson headers
Haibeck chip
470 HP/399 RWHP

1991 ZR-1 #400 White/Red (SOLD)
Dana 4:10
Powder coated engine
Haibeck performance chip
Borla exhaust
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Old 12-29-2022   #5
GOLDCYLON
 
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Join Date: May 2007
Location: Peoria, AZ
Posts: 9,153
Default Re: DRM coilovers & spring rates

I've done this twice here are my recommendations


Total Poly Body bushing kit (Prophane kit)
Poly Sway bar links and end links etc etc
Guldstrand Front Sway bar relocation kit (Carter200 makes these as well)
Upper and Lower Ball joints (moog)
DRM Front coilovers with Hyper Coils 425 Spring rate fronts
DRM Rear coilovers with Hyper coils 275 Spring rate rears
Rear dog bones replaced with Heim joint links. The standards dog bones will not fit due to the springs.

Car handles well with stability, Does not wander. Very satisfied with the result. And no FX-3 lights. This build is solid.
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GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's)

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91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat

90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat

11 RED/GREY CTS-V
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Old 12-29-2022   #6
AndrewL
 
Join Date: Dec 2020
Location: Sydney, Australia
Posts: 73
Default Re: DRM coilovers & spring rates

Quote:
Originally Posted by Mikey View Post
I'm also not exactly sure what spring compounds I have, can't find any visible markings, but they are a kind of metallic dark blue color in case color coding means anything.

Thes spring rates are etched into the top of the spring. These are mine before I had them sandblasted and powdercoated because they were looking worse for wear.
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Old 12-29-2022   #7
GOLDCYLON
 
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Location: Peoria, AZ
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Default Re: DRM coilovers & spring rates

Quote:
Originally Posted by AndrewL View Post
Thes spring rates are etched into the top of the spring. These are mine before I had them sandblasted and powdercoated because they were looking worse for wear.
That's where mine are as well. They are not visible when installed but clearly marked on the top of each spring. Chances are if you bought your car from any member in this community this information has been shared for about 20 years on the optimal spring rates. 425/275
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GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's)

GOLDCYLON - 11 CTS-V


Arizona State Director




91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat

90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat

11 RED/GREY CTS-V
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Old 12-30-2022   #8
XfireZ51
 
Join Date: May 2007
Location: Chicagoland, IL
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Default Re: DRM coilovers & spring rates

I am running 425/300 Hypercoil springs on mine. My FX3 shocks also have the
Maracca(sp?) valving. I would also recommend Poly bushings all around. I would also add, that the No Flex chassis stiffening system helps reducing chassis flex and that translates into the car handling flatter and with a feeling of more grip in combination with the Michelin PS4S.
I pretty much use Performance as an FX3 setting unless my gf is with me. I put it in Tour then.
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Old 12-30-2022   #9
GOLDCYLON
 
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Join Date: May 2007
Location: Peoria, AZ
Posts: 9,153
Default Re: DRM coilovers & spring rates

Quote:
Originally Posted by XfireZ51 View Post
I am running 425/300 Hypercoil springs on mine. My FX3 shocks also have the
Maracca(sp?) valving. I would also recommend Poly bushings all around. I would also add, that the No Flex chassis stiffening system helps reducing chassis flex and that translates into the car handling flatter and with a feeling of more grip in combination with the Michelin PS4S.
I pretty much use Performance as an FX3 setting unless my gf is with me. I put it in Tour then.
I had to look it up as well Dom "Moraca Valving" is the correct name.
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GOLDCYLON - 91 ZR-1 #2014
GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's)

GOLDCYLON - 11 CTS-V


Arizona State Director




91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat

90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat

11 RED/GREY CTS-V
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