Questions re: Tender & Helper Springs? DIY Tenders? - 3000GT/Stealth International Message Center

DoctorDex · 11-22-2007, 05:16 PM

I am going to be installing some ground control coilver conversions on my 3000GT VR4 and I know some of you will scoff at the idea, however, I'm on a tight budget. What I'm wondering is has anybody subsituted in their own combination of main spring and tender spring? Or has anybody used progressive eibach springs?

On Jeff Lucius's GC install page he recommends using:

6" length/2.5"I.D./500lb/in in front and 8" length/2.5"I.D./360lb/in in the rear.

So, in choosing tender springs, should the height of the tender spring + main spring = 6" in front and 8" in the back? If so, then that creates a problem. The shortest 2.5" I.D. main spring eibach makes is 6".

I know some people have complained these height of springs loose contact with the top of the strut base when the wheels are at full droop (off the ground). Could this be fixed by using tender springs, or would I need to have helper springs as well?

Any help would be greatly appreciated.

Highboosted · 11-23-2007, 07:05 AM

OK, I think I need to explain the difference in tender springs and helper springs.

Tender springs have almost 0 spring rate, all they are supposed to do is keep a little compression on the main spring to keep it from unseating at full extension. Notice these are flat, because they are fully compressed all the time.

Helper springs have a significant spring rate, around 1/4-1/2 the main spring rate (or whatever required to be able to support the weight of the car without compressing fully). Turns a single rate spring into a sorta progressive setup, while limiting the progressive rate's tendancy to be a bit "unpredictable" or "unstable" on the track. These are more round, but should still have flat tops and bottoms of coils because they should "bottom out" alot.

Now thats covered, we can move on. If your getting tenders, then you do not subtract the height of the spring, because they are fully compressed normally and only have a thickness of like 1/2 inch. If getting helper springs, then you do need to subtract the height of the new spring. The important thing to know is how much adjustment room you have with GC's (I don't know), I can assume you have plenty, so I'd use at least 6" springs with helpers anyways. You want the longest spring you can use.

Another point. Check Sprint Springs, they are well known in the racing community for quality and have a HUGE selection, including 4 inch springs if you really want them.

DoctorDex · 11-23-2007, 03:47 PM

Quote:

Originally Posted by Highboosted

Tender springs have almost 0 spring rate, all they are supposed to do is keep a little compression on the main spring to keep it from unseating at full extension. Notice these are flat, because they are fully compressed all the time.

Helper springs have a significant spring rate, around 1/4-1/2 the main spring rate (or whatever required to be able to support the weight of the car without compressing fully). Turns a single rate spring into a sorta progressive setup, while limiting the progressive rate's tendancy to be a bit "unpredictable" or "unstable" on the track. These are more round, but should still have flat tops and bottoms of coils because they should "bottom out" alot.

I'm pretty sure its the other way around. Tender springs have a significant spring rate and helpers have very little spring rate. See here: http://www.e30m3performance.com/tech...ings/index.htm

Quote:

Originally Posted by Highboosted

Another point. Check Sprint Springs, they are well known in the racing community for quality and have a HUGE selection, including 4 inch springs if you really want them.

Thanks for the suggestion. I'll check it out.

Highboosted · 11-23-2007, 06:08 PM

Quote:

Originally Posted by DoctorDex

I'm pretty sure its the other way around. Tender springs have a significant spring rate and helpers have very little spring rate. See here: http://www.e30m3performance.com/tech...ings/index.htm

Figures that I'd have it backwards, happens all the time.

11-22-2007, 05:16 PM	#1 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 Trader Rating: (13)	Questions re: Tender Springs with GC Groundcontrol Coilover Conversions I am going to be installing some ground control coilver conversions on my 3000GT VR4 and I know some of you will scoff at the idea, however, I'm on a tight budget. What I'm wondering is has anybody subsituted in their own combination of main spring and tender spring? Or has anybody used progressive eibach springs? On Jeff Lucius's GC install page he recommends using: 6" length/2.5"I.D./500lb/in in front and 8" length/2.5"I.D./360lb/in in the rear. So, in choosing tender springs, should the height of the tender spring + main spring = 6" in front and 8" in the back? If so, then that creates a problem. The shortest 2.5" I.D. main spring eibach makes is 6". I know some people have complained these height of springs loose contact with the top of the strut base when the wheels are at full droop (off the ground). Could this be fixed by using tender springs, or would I need to have helper springs as well? Any help would be greatly appreciated. __________________ '91 VR4 - Modlist: DR650R turbos, Snow stage 2D alky kit, DSM SMICs, blowthrough ported LT1 MAS, Dejon Tool intakes & y-pipe, Blitz DSBC Spec R, HKS SSQV BOV, PTE 580cc injectors, Dual feed fuel system with Aeromotive FPR & filter, Hotwired Supra pump, ek2mfg plenum spacer, HKS DLI, MSD Wires, Apex'i S-AFC II, MAFTranslator, Turbobob ECU, Scanmaster III, LC-1 WBO2, ESP downpipe, Vac/EGR delete, Gutted precats and test pipe, Maximal solid mounts, 300m 18 spline output shaft, Centerforce Dual Friction clutch, RPS flywheel, GC coilover conversions with helper springs, Powerslot slotted rotors, Goodridge SS brake lines, Hawk pads (front), Stillen metal matrix pads (rear) Last edited by DoctorDex : 11-26-2007 at 11:04 AM.

11-23-2007, 07:05 AM	#2 (permalink)
Highboosted king of ghetto Join Date: May 2004 Location: St. Louis Drives: '94 Stealth Turbo Trader Rating: (28)	Re: Questions re: Tender & Helper Springs? DIY Tenders? OK, I think I need to explain the difference in tender springs and helper springs. Tender springs have almost 0 spring rate, all they are supposed to do is keep a little compression on the main spring to keep it from unseating at full extension. Notice these are flat, because they are fully compressed all the time. Helper springs have a significant spring rate, around 1/4-1/2 the main spring rate (or whatever required to be able to support the weight of the car without compressing fully). Turns a single rate spring into a sorta progressive setup, while limiting the progressive rate's tendancy to be a bit "unpredictable" or "unstable" on the track. These are more round, but should still have flat tops and bottoms of coils because they should "bottom out" alot. Now thats covered, we can move on. If your getting tenders, then you do not subtract the height of the spring, because they are fully compressed normally and only have a thickness of like 1/2 inch. If getting helper springs, then you do need to subtract the height of the new spring. The important thing to know is how much adjustment room you have with GC's (I don't know), I can assume you have plenty, so I'd use at least 6" springs with helpers anyways. You want the longest spring you can use. Another point. Check Sprint Springs, they are well known in the racing community for quality and have a HUGE selection, including 4 inch springs if you really want them. __________________ Compressed version: LEXAN WINDOW GROUP BUY!!!!!!!!!!!!!!!!!!!!!!!!!!!! "If the wings are traveling faster than the fuselage, it's probably a helicopter and therefore, unsafe." "Helicopters dont fly, they beat the air into submission." "Basic Flying Rules; Try to stay in the middle of the air. Do not go near the edges of it. The edges of the air can be recognized by the appearance of ground, buildings, sea, trees and interstellar space. It is much more difficult to fly there." "Flashlights are tubular metal containers kept in a flight bag for the purpose of storing dead batteries." "If something hasn't broken on your helicopter, it's about to." "Progress in airline flying: now a flight attendant can get a pilot pregnant." Aircraft Mechanics are Plane Nuts

Sponsored Links
3000GT/Stealth International Message Center Advertisement