lr 150lb spring extended #

[brett4]

we went from a 80lb lr spring with 200lbs of extended load to a 150lb lr spring with 225lbs of extended load, trying to get a quicker jump out of the corner. It did that,but now the car won't turn in as well when the track slows down. I am thinking if I lower my extended number to 175lbs and take two turns out of rf I will keep my jump out of hole....am I thinking correctly??

[billetbirdcage]

we went from a 80lb lr spring with 200lbs of extended load to a 150lb lr spring with 225lbs of extended load, trying to get a quicker jump out of the corner. It did that,but now the car won't turn in as well when the track slows down. I am thinking if I lower my extended number to 175lbs and take two turns out of rf I will keep my jump out of hole....am I thinking correctly??

You're gonna have to clarify this a little. Assuming your talking a single spring (no stack stuff) since you didn't say anything about a stack, so:

Unless you really altered the ride height, the 80# spring should have way more extended load then the 150 spring. So not really sure if you have a typo or just added rounds to the 150 spring to get the extended load higher then the 80#'er.

If you changed nothing but stiffen the LR spring, to get more extended load the LR has to be a pretty fair mount higher at ride hieght.

[brett4]

i am calling extended load by installing 80lb with 2.5" of preload to get 200 number and 150lb spring with 1.5" of preload to get 225 number....single spring yes,doing this we got way more initial drive but lost some hike up and doesn't turn in as nice when the track slows down,thanks for your time

[RaceEngineer]

i am calling extended load by installing 80lb with 2.5" of preload to get 200 number and 150lb spring with 1.5" of preload to get 225 number....single spring yes,doing this we got way more initial drive but lost some hike up and doesn't turn in as nice when the track slows down,thanks for your time

What's that do to your ride height?

[brett4]

lowers the lr about 5/8" from standard with the 80lb spring and 1/4" with the 150lb

[Kromulous]

Lost some hike up, i am guessing thats where your tight-ish entry problem is coming from. The car just doesnt have enough rear steer to turn in well.

Its interesting the more droop load and stiffer spring lost hike thou, maybe Billet can help there. I have seen this with our own car thou. I some what believe that if your running some indexing on the LR cage, that this can interfere with hike up, due to the loading against the birdcage / shock mount. This high pre-load business seems to work best with parallel bars, and high compression valving in the shocks, but a lot of that is just my theory.

[brett4]

yes,hope Billet has more to offer

[billetbirdcage]

yes,hope Billet has more to offer

I haven't responded because your numbers don't add up at all, or I'm completely missing something.

The LR spring loads at ride height and 1" travels of extension (Pin to pin NOT the travel of LR like measuring the chain length). Gonna guess at around 700# for a ride hieght load number

80#: 0" = 700#
1" = 620#
2" = 540#
3" = 460#
4" = 380#
5" = 300#

150#: 0" = 700#
1" = 550#
2" = 400#
3" = 250#
4" = 100#
5" = 0#

I don't know how much pin to pin travel you have but it's likely between the 4 and 5" travels. I just don't see any way your getting those numbers without having the LR ride load way higher on the 150 spring, like something in the 1000# range which is gonna effect the other 3 corners pretty hard, including raising the COG, and effective J bar rake also. Basically if you old schooled it by scaling it, the 150 spring should have a ton more LR bite by the way I think you did it.

[billetbirdcage]

Again the 5" of total pin to pin travel may be a little far but if you actually have 225 extended load on the 150, then the loads would look like this: (about the 1000# mark at ride I thought)

150#: 0" = 975#
1" = 825#
2" = 675#
3" = 535#
4" = 375#
5" = 225#


Shrugs. . . .

[brett4]

I appreciate your time walking me thru this,Billet,but so far the way we have been taught:if we take an 80lb spring compress it 2.5" we will have 200lbs of extended load, 80x2.5=200,so the we tried a 150 compressed it 1.5",150x1.5=225,we would have 225lbs of wheel load...haven't done any smashing just that type of math with the car in the air...again thanks for your time

[billetbirdcage]

I appreciate your time walking me thru this,Billet,but so far the way we have been taught:if we take an 80lb spring compress it 2.5" we will have 200lbs of extended load, 80x2.5=200,so the we tried a 150 compressed it 1.5",150x1.5=225,we would have 225lbs of wheel load...haven't done any smashing just that type of math with the car in the air...again thanks for your time

Nothing wrong with doing it that way, math will get you close and least give you an idea of where your at. However you need to keep in mind the ride load which is your ride height. You just altered your ride height a ton and with that I have to assume the ride was way lower on the 80# spring (possibly way below it's supposed ride height listed my the car maker or what the RR is supposed to be). The car may have been lazy on starts and anytime the LR set down some. Without seeing the attitude of the car while racing, I'm guessing. But I think the 150 made the car better in some places due to the LR ride being higher but hurt it in other places due to the same thing.

[brett4]

correct on every thing and the car will not hike up as well with the 150 or turn in as well as the 80,the car is awesome on corner entry with the 80 but lazy off,the 150 is great off but sux on corner entry due to lost steer and the car not being on the rf as much....thanks for time dawg!

[billetbirdcage]

My suggestion would be to put the 80 back in and increase the ride height which obviously will increase the extended load or split the difference and use a 100 or 125 to get ride up and lower the extended load if the car gets too tight in the middle with the 80# and the high extended load.

Measure where your at on the ride height with the 150 by pin to pin or over rail to axle so you have an idea, then you can fudge that a little lower but least in the ball park you are with the 150#