Nissan 370Z Forum  

Spring rate help?

Lincoln is too far from SD when there's no jacket at stake.

Go Back   Nissan 370Z Forum > Nissan 370Z Tech Area > Track / Autocross / Drifting / Dragstrip


Like Tree63Likes

Reply
 
LinkBack Thread Tools Display Modes
Old 08-13-2014, 03:13 PM   #46 (permalink)
Base Member
 
Join Date: Jul 2014
Location: San Diego
Posts: 154
Drives: 1967 Camaro Z28
Rep Power: 11
j-rho is on a distinguished road
Default

Lincoln is too far from SD when there's no jacket at stake.
j-rho is offline   Reply With Quote
Old 08-13-2014, 03:22 PM   #47 (permalink)
Track Member
 
03threefiftyz's Avatar
 
Join Date: Apr 2010
Location: MD
Posts: 536
Drives: 03 350z 6mt
Rep Power: 16
03threefiftyz is on a distinguished road
Default

Troof.
03threefiftyz is offline   Reply With Quote
Old 08-13-2014, 03:24 PM   #48 (permalink)
Track Member
 
GSS138's Avatar
 
Join Date: Mar 2013
Location: Mission Viejo, CA
Posts: 769
Drives: '12 370Z 6M Sport
Rep Power: 13
GSS138 is a jewel in the roughGSS138 is a jewel in the roughGSS138 is a jewel in the rough
Default

Quote:
Originally Posted by j-rho View Post
Sure every car is different, but increasing front spring rate with no other changes (increasing the ratio you mention) will make the front tires do relatively more work in a corner, which as a primary effect, shifts balance towards understeer. Your generalization is backwards of the general truth. If you want to make a case the general truth does not apply for some reason to the Z, you need to be able to explain why. You also need to be able to separate a discussion around bump handling (where shocks come heavily into play) vs. handling balance at steady-state limit cornering.

I encourage you (and anyone following along while scratching their head) to get a basic education in vehicle handling dynamics - Herb Adams, Fred Puhn, Paul Van Valkenburgh all have fairly accessible texts on the subject. A few $ for a book and a few evenings of reading, and you'll be much better equipped not only to understand what's happening with your own car, but to help others in their pursuits.
fair enough and I agree with you, but feel my point is being missed a bit, as I am not addressing over all vehicle handling dynamics, weight transfer, tires, or anything else. All I am saying is this:

There is a ratio between front and rear ride frq that will tell you if the car has a tendency to oversteer or understeer.

If you want to change that tendency-change that ratio.

To redo my example, let's go back to our OEM rates:
I am using 392 front springs, and 440 Springs (listed OEM rates I could find)
They produce a ratio of:
1.6334/1.8563 = .89

Do you not find it interesting, that using completely different spring rates, this same .89 number is produced by just about every post market spring kit within a few decimal points?

Swift Spec-R's claim 10K and 10.5K so approximately 560F 600R
they produce a ride frequency on the same car of:
2.0115/2.2427 = .89

Much stiffer springs, totally change the way the car handles, so why is that .89 ratio still popping up?

All I am saying is that .89 is not a coincidence and was put there by your car manufacturer, and by Swift, and Eibach, and by every other lowering spring I can find rates on.
__________________
Current Mods: Vorpal Weapon +5.
GSS138 is offline   Reply With Quote
Old 08-13-2014, 03:34 PM   #49 (permalink)
Track Member
 
03threefiftyz's Avatar
 
Join Date: Apr 2010
Location: MD
Posts: 536
Drives: 03 350z 6mt
Rep Power: 16
03threefiftyz is on a distinguished road
Default

I should have given up when I said "I give up"...
03threefiftyz is offline   Reply With Quote
Old 08-13-2014, 04:04 PM   #50 (permalink)
Base Member
 
Join Date: Jul 2014
Location: San Diego
Posts: 154
Drives: 1967 Camaro Z28
Rep Power: 11
j-rho is on a distinguished road
Default

Quote:
Originally Posted by GSS138 View Post
fair enough and I agree with you, but feel my point is being missed a bit, as I am not addressing over all vehicle handling dynamics, weight transfer, tires, or anything else. All I am saying is this:

There is a ratio between front and rear ride frq that will tell you if the car has a tendency to oversteer or understeer.

...
By itself, it can't begin to tell you that.

What you might be able to say - if you had a neutral car, and then you increased front spring rate, or softened the rear spring rate (increased that ratio value), the car would probably tend to understeer. But that's the opposite of what you're saying.
j-rho is offline   Reply With Quote
Old 08-13-2014, 04:22 PM   #51 (permalink)
A True Z Fanatic
 
synolimit's Avatar
 
Join Date: May 2013
Location: Columbus, OH
Posts: 5,051
Drives: 2013 Silver 370z
Rep Power: 3389
synolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond repute
Default

Quote:
Originally Posted by GSS138 View Post
I Completely agree with this, but I am not counting grip, sway bars, or anything besides the motion ratios, corner weight, and spring rates. I am just talking about a natural frequency that the car exhibits when it goes over a bump. It's something that is there by the manufacturer on purpose in every car. And if you take those freq and divide them, I am completely speculating here, but I will say that 95% of the cars on the planet rolling of an assembly line are in the range of .80-.90.

If you calc the rates for every single post market spring kit or out of the box coil over solution, you will either get a number between .80 -.90 (Understeer)
or you will get something in the range of 1.13-1.25 (looser rear end).

(Assuming close to OEM un-sprung corner weights)

Swift Spec R= 2.0115/2.2145=.90

Tein S-tech= 1.682/1.87 =.89

Nismo T2 motorsports springs = 2.0821/2.4224 = .859


Now let's look at some popular performance coils

Tein Flex = 2.2035/1.9833= 1.11

Stance GR= 2.2035/1.9624 = 1.12

Megan Racing 2.0115/1.6650 = 1.21 (loose!)

Edit:

Synolimit's Setup 2.6880/2.0361 = 1.32 (have fun cowboy)

Our OEM(non nismo) 1.6334/1.8563 = .89


This isn't a coincidence!


Again, it doesn't make your car go fast, has nothing to do with grip, doesn't get you trophy girls. It's just a baseline calculation that you can use to have a reference point for what you can expect out of your spring, your motion ratios, and your corner weights to do. Of course putting the tires, driver, sways, fuel, etc on top of this number changes everything. But it's nice to have a solid starting point .


This PDF explains it better than I can: Freq of Ride rrates

https://m.youtube.com/watch?v=q5pESPQpXxE
GSS138 likes this.
__________________
13 370z-
synolimit is offline   Reply With Quote
Old 08-13-2014, 04:24 PM   #52 (permalink)
A True Z Fanatic
 
synolimit's Avatar
 
Join Date: May 2013
Location: Columbus, OH
Posts: 5,051
Drives: 2013 Silver 370z
Rep Power: 3389
synolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond reputesynolimit has a reputation beyond repute
Default

Quote:
Originally Posted by 03threefiftyz View Post
Oh...keep in mind syno is not running a spring in the bucket.
Correct. True type as of today. Well maybe not wtf??!!!

Sorry OP


https://m.youtube.com/watch?feature=...&v=l5i_kyW7_Y4
__________________
13 370z-
synolimit is offline   Reply With Quote
Old 08-13-2014, 05:50 PM   #53 (permalink)
A True Z Fanatic
 
Shamu's Avatar
 
Join Date: Jan 2011
Location: Nor Cal
Posts: 1,059
Drives: 370Z Racecar
Rep Power: 19
Shamu has a reputation beyond reputeShamu has a reputation beyond reputeShamu has a reputation beyond reputeShamu has a reputation beyond reputeShamu has a reputation beyond reputeShamu has a reputation beyond reputeShamu has a reputation beyond reputeShamu has a reputation beyond reputeShamu has a reputation beyond reputeShamu has a reputation beyond reputeShamu has a reputation beyond repute
Default

...And taking setup advice from DOT street tire AX guys on a track car is dangerous.
cossie1600 likes this.
__________________
Grant
Shamu is offline   Reply With Quote
Old 08-13-2014, 07:24 PM   #54 (permalink)
Track Member
 
GSS138's Avatar
 
Join Date: Mar 2013
Location: Mission Viejo, CA
Posts: 769
Drives: '12 370Z 6M Sport
Rep Power: 13
GSS138 is a jewel in the roughGSS138 is a jewel in the roughGSS138 is a jewel in the rough
Default

Quote:
Originally Posted by 03threefiftyz View Post
j-rho,

Mo CAM with this please....
I like this purple car.
__________________
Current Mods: Vorpal Weapon +5.
GSS138 is offline   Reply With Quote
Old 08-13-2014, 07:26 PM   #55 (permalink)
A True Z Fanatic
 
Masterbeatty's Avatar
 
Join Date: May 2012
Location: Whales Vagina
Posts: 4,586
Drives: the speed limit...
Rep Power: 122867
Masterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond repute
Default

Quote:
Originally Posted by GSS138 View Post
I like this purple car.


Looks blue to me.
GSS138 likes this.
__________________
2011 MB 6MT
Masterbeatty journal
Masterbeatty is offline   Reply With Quote
Old 08-13-2014, 07:40 PM   #56 (permalink)
A True Z Fanatic
 
wstar's Avatar
 
Join Date: Mar 2009
Location: Houston, TX
Posts: 4,024
Drives: too slow
Rep Power: 3594
wstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond repute
Default

Ok so after all the other diversions, I still have a couple fundamentally-simple questions (one of which I already asked!):

1) Will I need to use shorter springs if I switch to a significantly stiffer spring and want to keep ride height and stroke about where it is today? Or should I basically plan on ordering the exact springs I have today, just in a different rate value? What would a normal person that knew what they were doing tend to do?

2) The rear sway: it's a given I at least need to cut back to the stock bar. What about just dumping the bar altogether? I know others have dumped the rear bar and been happy in 350Z's, but I suspect this was in combination with an upgrade to stiffer springs all around. What's the worst that could possibly go wrong* if I dump the rear bar and fail to do (insert some other unknown thing that needs to be done at the same time)? Would the car get unstable in some way that I'd really hate?

* - https://www.youtube.com/watch?v=20KJhBX9xtE
__________________
7AT Track Car!
Journal thread / Car setup details

Last edited by wstar; 08-13-2014 at 08:27 PM.
wstar is offline   Reply With Quote
Old 08-13-2014, 08:04 PM   #57 (permalink)
A True Z Fanatic
 
Masterbeatty's Avatar
 
Join Date: May 2012
Location: Whales Vagina
Posts: 4,586
Drives: the speed limit...
Rep Power: 122867
Masterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond reputeMasterbeatty has a reputation beyond repute
Default

Have you spoke with Z1 on what spring rates they use on kleemans car? I would just start with a popular track inspired setup then refine it from there.
__________________
2011 MB 6MT
Masterbeatty journal
Masterbeatty is offline   Reply With Quote
Old 08-13-2014, 08:27 PM   #58 (permalink)
A True Z Fanatic
 
wstar's Avatar
 
Join Date: Mar 2009
Location: Houston, TX
Posts: 4,024
Drives: too slow
Rep Power: 3594
wstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond repute
Default

Well I've got a good idea on ballpark spring rates at this point (and a little confirmational math to do before I pull the trigger, which will be after I've dealt with the rear sway). Keeping in mind that I don't want to have to swap springs constantly at this stage for different tires and don't want to be too unstable on wets or r-comps, I'll probably shoot a little lower than the track specs listed in this thread, but still considerably higher than where I'm at now. Something in say the ballpark of 900 and 700 - which would be approx the same ratio of raw spring rates as what I have now, with both ends boosted by about 30%. I know there's more math to be done than that, but it's a starting point guestimate at this stage. I'm gonna go measure the suspension later today or tomorrow so I can make some easy conversion factors for F/R spring rate -> F/R frequency.
__________________
7AT Track Car!
Journal thread / Car setup details
wstar is offline   Reply With Quote
Old 08-13-2014, 08:40 PM   #59 (permalink)
Ronin Samurai - Assassin
 
Rusty's Avatar
 
Join Date: Dec 2011
Location: Fayettenam,Pennsyltucky
Age: 68
Posts: 35,170
Drives: 2011 Nismo GM 6M
Rep Power: 2684437
Rusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond repute
Talking

Quote:
Originally Posted by synolimit View Post
Correct. True type as of today. Well maybe not wtf??!!!

Sorry OP


https://m.youtube.com/watch?feature=...&v=l5i_kyW7_Y4
Great sound effects!

Trying to learn from this thread, and my mind is going hu.............................
FL 4Motion likes this.
__________________

浪人 - 殺し屋
"The Difficult Anytime, The Impossible By Appointment Only"
http://www.the370z.com/members-370z-...o-journal.html

Last edited by Rusty; 08-13-2014 at 08:43 PM.
Rusty is offline   Reply With Quote
Old 08-13-2014, 09:13 PM   #60 (permalink)
Track Member
 
clintfocus's Avatar
 
Join Date: Jan 2011
Location: los angeles
Age: 38
Posts: 933
Drives: 370z, EK Civic, F150
Rep Power: 15
clintfocus will become famous soon enough
Default

good to see the Z track people putting enough 2 cents each to get a informative thread into page 4
clintfocus is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
JPY - USD Rate change diddy535 The Lounge (Off Topic) 7 05-11-2013 12:49 PM
Yes or no? Please rate xbigb4ller69z Wheels & Tires 26 03-11-2010 11:53 AM
Rate Your Exhaust jpit Intake/Exhaust 22 09-29-2009 09:18 PM
Selling Eibach spring and OEM spring spia Parts for sale (Private Classifieds) 8 06-13-2009 09:18 AM


All times are GMT -5. The time now is 02:07 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0 PL2