Spring rates opposite ? less in front ?

[EclipseTrbo420A]

I was talking to my buddy, hes really big on AutoX. Anyway I'm buying his Eibach coilover springs that he used with his Ground Control Coilovers. The rates are (2) 450 lbs springs and (2) 275 lbs springs. Now I was talking to him and he was telling me that If I put the 275's up front then I would see some better results for handling. Is this true ? I was under the impression ( after reading here ) that I would want the 450's holding the weight of the motor. Either case this isn't going to get beat on at the track or strip so what would be best for ME, and the best ride with this combo of springs. 450's up front and 275's in the rear or the opposite of that. Thanks alot.

 

[jtmcinder]

275/450 is just too insane to bother doing any of math on. Run them as 450/275 or try to trade the 275s for some 350s or 375s for the rear.

- Jtoby

 

[EclipseTrbo420A]

275/450 is just too insane to bother doing any of math on. Run them as 450/275 or try to trade the 275s for some 350s or 375s for the rear.

- Jtoby

Thanks for the responce. Ill run them 450/275 for now. On another note have you heard of tender springs? I'm sure you have, but what do you think of them? I called eibach to get specs on them and they told me to redirect my call to one of the site that sells their products. I ended up talking to Shox.com and informed me that the tender springs were 100 dollars a piece and they were 2.64 inches long 2.5 inch ID and a rate of 150. and then the shelf adapter was 10 dollars a piece. what do you think of these for a little better ride ? Thanks

 

[stirpicult]

I was talking to my buddy, hes really big on AutoX. Anyway I'm buying his Eibach coilover springs that he used with his Ground Control Coilovers. The rates are (2) 450 lbs springs and (2) 275 lbs springs. Now I was talking to him and he was telling me that If I put the 275's up front then I would see some better results for handling. Is this true ? I was under the impression ( after reading here ) that I would want the 450's holding the weight of the motor. Either case this isn't going to get beat on at the track or strip so what would be best for ME, and the best ride with this combo of springs. 450's up front and 275's in the rear or the opposite of that. Thanks alot.

what type of car does he drive? i know hondas run setups like that. don't do that to your car, though

 

[Todd TCE]

Probably cured his understeer problem though.

 

[EclipseTrbo420A]

Hes got a 98 GSX , now with revalved koni's and 800/6?? set up. Im for sure going to run the set up the correct way, but I would like to purchase some tender springs to help my ride qualty..does anyone know anything about these they think I should know ex. where to get them , how much...stuff like that thanks.

 

[MIdsm]

To calculate the combined spring rate of the main spring and the tender spring add the inverse of their values.

1/Rcombined = 1/Rmain + 1/Rtender

The combined spring rate lasts until the tender spring compresses or it's travel is limited mechanically. Eibach does have a system that's used in F3. It's probably not cheap.

Professional teams use multiple springs to tailor spring rates for various damper displacements. They limit the tender spring travel so that the rate goes from combined spring rate to main spring rate at a calculated damper displacement.

Racecar Engineering had a great article in July 2004 issue.

A street level suspension tender spring would be used mostly to keep springs from falling off perches at full suspension droop (dampers extended). If the car without tender springs gets airborne the main spring may separate from the upper spring perch and when it lands the spring may not land back in the spring perch. Tender spring rate is very low and it's fully compressed when car is at ride height. If the car gets airborne the tender spring extends and keeps the main spring connected to the upper spring perch.

Of course ride quality also improves.

For example with a 600 lb/in main spring and 150 lb/in tendeer spring the combined spring rate would be 120 lbs/in.

600 lb/in main spring and 400 lb/in tender spring would combine to give 240 lb/in.

 

[EclipseTrbo420A]

To calculate the combined spring rate of the main spring and the tender spring add the inverse of their values.

1/Rcombined = 1/Rmain + 1/Rtender

The combined spring rate lasts until the tender spring compresses or it's travel is limited mechanically. Eibach does have a system that's used in F3. It's probably not cheap.

Professional teams use multiple springs to tailor spring rates for various damper displacements. They limit the tender spring travel so that the rate goes from combined spring rate to main spring rate at a calculated damper displacement.

Racecar Engineering had a great article in July 2004 issue.

A street level suspension tender spring would be used mostly to keep springs from falling off perches at full suspension droop (dampers extended). If the car without tender springs gets airborne the main spring may separate from the upper spring perch and when it lands the spring may not land back in the spring perch. Tender spring rate is very low and it's fully compressed when car is at ride height. If the car gets airborne the tender spring extends and keeps the main spring connected to the upper spring perch.

Of course ride quality also improves.

For example with a 600 lb/in main spring and 150 lb/in tendeer spring the combined spring rate would be 120 lbs/in.

600 lb/in main spring and 400 lb/in tender spring would combine to give 240 lb/in.

any idea where to get a set of these ?

 

[jtmcinder]

Whoa! Tender springs (aka helper springs) only have an effect of the effective spring rate when they are not binding (i.e., not fully compressed). The tender springs that most people use fully compress as soon as you put the car on the ground and therefore have no effect on rate. They are just there to keep things lined up when the wheel unloads (such as when you are changing your wheels).

- Jtoby

 

[EclipseTrbo420A]

Whoa! Tender springs (aka helper springs) only have an effect of the effective spring rate when they are not binding (i.e., not fully compressed). The tender springs that most people use fully compress as soon as you put the car on the ground and therefore have no effect on rate. They are just there to keep things lined up when the wheel unloads (such as when you are changing your wheels).

- Jtoby

Thats what I thought till I did alot of research, and it just so happens that tender springs actually do help ride quality. I searched, and found that tender springs actually have a calculation that is

(Spring rate x stock spring rate divided by spring rate + stock spring rate.)

Thats why I have found helper springs for $23.00 a set, and tender springs for $70.00 a piece and you can pick your rate, length and ID.

Its a neat concept, but expensive alike.

Maybe in the future I'll add in a set.