Post your spring rates

dtompsett
Doug Tompsett
Super Moderator
Location: Ontarible, Canadiana
Join Date: 06/21/2007
Age: Midlife Crisis
Posts: 125

Rally Car:
'84 Scirocco Rally car... '88 90q project

dtompsett

Post your spring rates
August 17, 2007 02:31PM

Registered: 06/21/2007
Posts: 125

Trying to get an idea of what people are running for spring rates, and if you know, what your shocks are valved to and what the corner-weight is. Vehicle weights and an estimate of balance would be nice too...

Vehicle, FWD/AWD/RWD
Spring Rate F/R
Dampener type/rates
vehicle weight/balance
other items (sway bars, etc)
brief opinion (too soft, too stiff, harshness on transit, etc)

Please Login or Register to post a reply

Tom B
Tom B
Godlike Moderator
Location: Douche Canoe, WA
Join Date: 02/27/2006
Age: Midlife Crisis
Posts: 780

Rally Car:
VW Golf

Tom B

Re: Post your spring rates
August 17, 2007 06:29PM

Registered: 02/27/2006
Posts: 780

I was at JVL's place on time and he broke out some calipers and figured out the rate of a spring right in front of me....no Idea how he did it...mebe he could refresh my memory So I can figure out what I am running on the rabbit...?

Please Login or Register to post a reply

wildert
Brian Klausen
Infallible Moderator
Location: Denmark
Join Date: 03/21/2006
Age: Midlife Crisis
Posts: 388

Rally Car:
VW Golf GTi 16V

wildert

Re: Post your spring rates
August 22, 2007 12:11AM

Registered: 03/21/2006
Posts: 388

325 lbs/inch front
225-110 lbs/inch progressive rear

VW Golf 2 16V so FWD - not too many mods that should mess up weight distribution (I have no idea what it is)
Running on tarmac with street tires in 195/50-15. Front swaybar removed.

Used to have the normal heavy VW understeer, but removing the swaybar really did the trick. Nice oversteer now when pushed (diff helps), but not something that'll catch you with your pants down.

Brgrds
Brian

Please Login or Register to post a reply

Ascona73
Bob Legere
Professional Moderator
Location: Spofford, NH
Join Date: 03/07/2007
Age: Possibly Wise
Posts: 308

Rally Car:
1971 Opel Ascona

Ascona73

Re: Post your spring rates
August 22, 2007 05:27PM

Registered: 03/07/2007
Posts: 308

Not that it applies to anyone else here really, but here's the setup in my 1971 Opel Ascona. Hasn't been stage rallied, just rallycrossed and ice raced and generally abused...

380 lb front springs - 153 lb wheel rate

140 lb rear springs - 98 lb wheel rate

2013 lb total weight, 51.8% front/48.2% rear (battery relocated to back seat area)

Fox off-road shocks adapted, 5" stroke front and 9" stroke rear, custom valved.

No rear sway bar (removed).

Front sway bar diameter is 22 mm, but it has been softened for greater articulation by milling .250" off the bottom.

It will understeer at slow speeds, but from about 45-50 mph on up it's damn near perfectly balanced. Steering is 2.4 turns via Quaife fast rack adapted from a Manta B, and the rear diff is a 40% ZF with 4.75 final drive. Oh yea, it's rear wheel drive for those who remember what that is!

Bob

Opel is a 4-letter word...
http://www.flickr.com/photos/10498579@N07/sets/

Edited 1 time(s). Last edit at 08/22/2007 05:28PM by Ascona73.

Please Login or Register to post a reply

Dazed_Driver
Banned
Godlike Moderator
Location: John and Skyes Magic Love liar
Join Date: 08/24/2007
Posts: 2,154

Dazed_Driver

Re: Post your spring rates
August 24, 2007 03:12AM

Registered: 08/24/2007
Posts: 2,154

JVL might have used this formula

Spring Rate = Gd^4/8ND^3

G= Torsional Module for steel, 11,250,000
d= wire diameter in inches
N= number of active coils (all but the very ends)
D= Mean Diameter in inches
8= Constant for coil springs

- From "Chassis Engineering" by Herb Adams

Welcome to the cult of JVL drink the koolaid or be banned.

Please Login or Register to post a reply

john vanlandingham
John Vanlandingham
Godlike Moderator
Location: Ford Asylum, Sleezattle, WA
Join Date: 12/20/2005
Age: Fossilized
Posts: 14,152

Rally Car:
Saab 96 V4

john vanlandingham

Re: Post your spring rates
August 24, 2007 10:40AM

Registered: 12/20/2005
Posts: 14,152

Tim, I don't.
Funny I know cause I suggest that people put figures and per cents to everything.

But with springs we can use "praxis" or previous practice if we have some records and know if it worked well.
See we have some things which are fixed and we cant change them:
weight on the corner
leverage ratio on the spring
strut or shock travel
available space

Those factors lock us in to a larger degree, and then we see what worked before.
Remember, often better to copy success than to think about ideals---when we don't have the space, or whatever to do the ideal thing.

When it comes to choosing in the past, I look in any of Ford's books from the rwd Escort to the 4wd World Rally Car in '97, and extrapolate.
Works good so far.

And worked really fantastic on Adam Crane's AE86 when I was co-driver.
A couple of times we were both (separately) all scrunched up expect a BIG FAWKIN WHAM, and the car just (dah dump) did NOTHING--and we'd burst out in giggles.

Dazed_Driver Wrote:
-------------------------------------------------------
> JVL might have used this formula
>
> Spring Rate = Gd^4/8ND^3
>
> G= Torsional Module for steel, 11,250,000
> d= wire diameter in inches
> N= number of active coils (all but the very ends)
> D= Mean Diameter in inches
> 8= Constant for coil springs
>
> - From "Chassis Engineering" by Herb Adams
>
> Fiesty Peacock? No no no... I'm Timm

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.