Author Topic: Shocks, springs and things  (Read 3906 times)

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Offline basher13

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Shocks, springs and things
« on: September 03, 2010, 07:02:25 PM »
Stiff suspension is the way to go correct? I've been told to run 850 or 900lb springs in the front, other than experience how do you get this number?
The Stude has stock springs that have been cut to get the front end down. I can't afford springs before WOS but I do have a set of Q1A adjustables. Will running a stiffer shock help if I have spongy springs?
It's been brought up before but I can't seem to find the recommended books for chassis/suspension.
Thanks in advance
 :cheers:
Dan
118.780mph in a stock(ish) Studebaker

Offline bvillercr

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Re: Shocks, springs and things
« Reply #1 on: September 03, 2010, 08:44:32 PM »
Is it front wheel drive?  If not what were you told to run in the back?

Offline Rex Schimmer

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Re: Shocks, springs and things
« Reply #2 on: September 03, 2010, 09:07:15 PM »
Pretty difficult to just say you need 800 lbs springs without knowing what the wheel rate is on your car and this is related the dimensions of your front suspension. On a strut car like the 222 (Troy, as I remember you do run struts, right?) the wheel rate and the spring rate are very close to the same where as on a car like your Stude with double A arms the wheel rate could be less than 1/2 of the spring rate. I assume that the rear is a live axle set up and this should be fairly softly sprung to keep the tires on the ground. Bvillercr (Troy) and his dad have done lots of work on suspension on their Camero and run on both the salt and dirt and their recommendations for wheel rates are a real good place to start, but first you need to calculate the wheel rate.

Rex
Rex

Not much matters and the rest doesn't matter at all.

Offline basher13

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Re: Shocks, springs and things
« Reply #3 on: September 03, 2010, 10:00:55 PM »
I wasn't told about the rear, 09 SW I went around talking with other Stude owners about the front end and if it would be worth keeping. More than one guy said that they have run stock front ends close to and just over 200. I'm a long way off from that, warmed over 289 with cad intake and a 4bbl.. The figure of 850 to 900lbs was what I got from these talks.
The car is the Stude in my avatar, pretty much stock with the exception of the monkey bars inside and some other safety stuff.
I'll start with finding out what wheel rate is, and how it relates to spring rate.
I don't mind reading and searching, how bout a shove in the right direction?
Troy, Ill say it again, that camaro is the baddest fawking door car on the salt, thanks for the entertainment this year.
 :cheers:
Dan
118.780mph in a stock(ish) Studebaker

Offline jl222

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Re: Shocks, springs and things
« Reply #4 on: September 04, 2010, 01:05:17 AM »
Pretty difficult to just say you need 800 lbs springs without knowing what the wheel rate is on your car and this is related the dimensions of your front suspension. On a strut car like the 222 (Troy, as I remember you do run struts, right?) the wheel rate and the spring rate are very close to the same where as on a car like your Stude with double A arms the wheel rate could be less than 1/2 of the spring rate. I assume that the rear is a live axle set up and this should be fairly softly sprung to keep the tires on the ground. Bvillercr (Troy) and his dad have done lots of work on suspension on their Camero and run on both the salt and dirt and their recommendations for wheel rates are a real good place to start, but first you need to calculate the wheel rate.

Rex

  Rex.... Stock Car Products  double A arms, hubs and steering arms on front with fairly stiff springs around 500 lbs we originaly had an anti- roll bar on the front which I liked but had to remove it when we went to a 3 inch blower pulley.

  Basher... one way to figure your wheel rate [ the amount your chassis moves at the center of wheel] is to add weight untill
the chassis moves 1 in. for instance 400 lbs and it moves 1 in means 200 lb wheel rate [NOT spring rate] 400 divided by 2 springs, 1/2 in would be double. You have to figure the motion ratio to figure spring rates thats how far the spring compresses
compared to how far the wheel tralvels. If those 900 lb springs are to much it will show up just pushing to start line and can be changed later but better to stiff on front than to soft. You don't want to much chassis roll if you get out of shape.
 Stock car racers have rubber inserts they insert between the springs to change rates during a race [forget what they call them]
 I like all of Carroll Smiths books starting with Tune To Win also Hp books has several chassis books.

             JL222
  
                            

Offline basher13

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Re: Shocks, springs and things
« Reply #5 on: September 04, 2010, 11:30:11 AM »
 Headed out to work on the car today, I'm going to try and get the motion ratio and do some figuring on the front end, printed out a couple things to help remind me. :roll: I'm not sure if these QA1s will work or not, but from what I've been reading a stiffer shock will help even a stock spring.
Thanks for the book info as well,
 :cheers:
Dan
118.780mph in a stock(ish) Studebaker

Offline Interested Observer

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Re: Shocks, springs and things
« Reply #6 on: September 04, 2010, 07:15:22 PM »
To translate from wheel rate to spring rate (or vice versa) one must multiply by the appropriate displacement ratio SQUARED.

For instance:  wheel travel/spring travel = 2 and wheel rate is 200 lb/in, then the spring rate would be 4 times 200 lb/in, or 800 lb/in.

Offline interested bystander

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Re: Shocks, springs and things
« Reply #7 on: October 03, 2010, 07:39:17 PM »
Just stumbled on this topic after calming down from the NASCAR race excitement(?) this PM.

DOORSLAMMERS is a book by Dave Morgan that should be a tool for any suspended Landracing car.

It's Drag Race geared but it explains, other than IRS, suspension physics, the phenomenon in pretty readable (small math stuff). context.

PS

 Any time Interested OBSERVER posts, it ain't me (trig dropout) - tho I DO read a lot and have a decent library and a little fab and racing experience and try not to give bad advice, but IO has the no BS engineering to back it up. LISTEN, or rather, READ!

This goes for Blue, too!
5 mph in pit area (clothed)