Higher spring rate in front than rear?

[nusevad]

So I bought a set of coilovers from an enthusist and his spring rates are 225 front and 200 rear.  Anyone ever run this? I thought normally its always higher in the rear.  The previous owner bought the coilovers and springs were purchased from Top End Performance racetep.com if anyone is wondering. 

 

Should i swap the rears to the fronts? 

[santoph]

I think it's higher in the front usually. BC's I have come standard with 5k front / 4k rear.

 

Then I have Megan's on another car that have 7kg Front and 6kg Rear.

Edited April 29, 2015 by santoph

[nusevad]

interesting...from the threads i read everyone had higher spring rates in the rear.  

[NewZed]

The Nissan factory supplied higher in back.  

 

Probably depends on how you plan to drive the car.  Good stuff from the internet - http://www.zcar.com/forum/10-70-83-tech-discussion-forum/100085-spring-rates-sudden-enlightenment.html

[nusevad]

Thanks NewZed!

 

So for daily driving and AutoX, what do you guys recommendi I do? Keep it 225 f / 200 r or swap it? 

Edited April 29, 2015 by nusevad

[Miles]

Setting up suspension is not like choosing between corn or peas for dinner.  You are going to have to do some reading.

 

Search Google and HybridZ using terms like:  "spring rates handling"   "spring rates over steer"  "spring rates under steer" "spring rates racing"   "spring rates autocross" etc etc.

 

For example:  https://www.google.com/search?q=%22spring+rates+autocross%22+&ie=utf-8&oe=utf-8&client=ubuntu&channel=fs&gws_rd=ssl

 

Go to Autocross events and talk to the drivers.

Edited April 30, 2015 by Miles

[jt1]

You can't talk about spring rates without including the bar(s) you plan to run.  One affects the other and they both affect how the car handles.

 

jt

[johnc]

Search, this has been discussed a lot here.

The short version:

It depends on the power you're making.

For autocross you want the car to rotate well.  If your power numbers are around 200 or less put the higher spring rates in back. The more power you make the more you move spring rate and roll stiffness forward.

For street it doesn't matter because at most you drive at 8/10ths.

[260DET]

Never heard it put so concisely before John, like.

[nusevad]

ok, thanks everyone for the input, i will switch the 225 to the rear then as its just a stock L24

[Six_Shooter]

You could also try it both ways and see which way works better for you. You could also buy more springs at different rates and fine tune it for your driving style and use.

[socorob]

Thanks John! So for a Z with an LS swap, with plans for lots of autox and 1-3 track days a year, would it be better for me to move my heavier springs from the rear to the front?

Edited May 4, 2015 by socorob

[nusevad]

Thanks John! So for a Z with an LS swap, with plans for lots of autox and 1-3 track days a year, would it be better for me to move my heavier springs from the rear to the front?

 

From what i read from the links and searching, it could be better to do that as it will reduce oversteer and make the car more manageable especially if you are putting down big power coming out of corners.  For AutoX im not sure if it will be ahuge difference as its alot of slalom type movement, it might require more steering input?

 

 

Also quick question and i searched, for the 15/16 brake master cylinder, i have calipers all around, do i need to remove the spring thats attached to the check value too? or just remove the check value and leave the spring in?

[Miles]

Remove the check valve and the spring.

[socorob]

I just did my 1st autocross with the Z and with my konis set to full soft I had more understeer. That's with the heavier springs in the rear.

[NewZed]

Here's what seems like a good example of a successful autocross setup - http://forums.hybridz.org/topic/122227-fs-datsun-240z-f-prepared-fp-125k-obo-texas/?do=findComment&comment=1143065

[socorob]

I've been reading the suspension faq for a few days now. I have 300 and 250 pound springs and a st rear sway bar. Would putting the 300 in The front, the 250 in the rear and put on the rear sway bar be the best setup using the parts I have? This is what I seemed to walk away with from the suspension faq. Can any of the experts let me know if this would be the best route using what I have?

[tube80z]

It sounds reasonable.  If you weighed your parts then you could do some frequency calculations and know where you start for sure.  I'd probably start where you propose knowing it's a little soft but should give some scope for tuning.  While I wouldn't use them while driving on the street the use of droop limiters will help to control roll and pitch.  When setting up A S30 chassis roll is something you try very hard to avoid.  The limiters let you run softer rates for the amount of body roll that you'd normally see.

 

Cary

[socorob]

Thanks, just did my 1st track day 2 weeks ago, and want to try to make some improvements by the time the next one comes around in a few weeks.

[RebekahsZ]

I ain't no expert, but for me, the rear swaybar was just a pain in the ass. And I just don't think you need it. With the torque of the V8, anything you can do to keep the rear wheels hooked up is an advantage. Anything that costs you traction in back is a liability and will land you in the grass in a heartbeat. In my limited experience, one of the hardest things about driving these cars is exercising restraint exiting corners-you can spin them at will, so you have to make sure you pay lots more attention about getting slowed before turning and getting the car straight before you pile on the right foot. If you did a lot of autocross with the L6 when you could floor it with little fear, its a whole new ballgame now-ya gotta be careful. Of course it's easy to remove or disconnect the swaybar at the track. So you can play with it and do some laps with it attached and then some with it off. I bet you can't tell a difference. So it then becomes an issue when doing maintenance, and that was when I really felt like it was in my way all the time. When you run CV axles, it gets really crowded back there.

Edited May 15, 2015 by RebekahsZ