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Jazz86

New Spring option for the s30 240z

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Like many people with the tokico lowering springs have the issue of the front binding. The first photo is the red tokico 5020F that has less than one inch of bump travel. It rode worse than solid Pogo stick. So I looked far and wide for a fix. The rear end of the car is fine, tons of travel.
I got the dimensions and the tokico springs and the spring rates. I found out a few springs that fit and found that MOOG 80099 fit. But they need to be cut to match the 140lbs/in rate of the tokicos.

I cut the first dead coil and 2 active coils. And if my math is right the rate is close. I will update it when it settles after a nice long drive.

(11,250,000*Wire diameter^4)/(8*numberofcoils*meancoildiameter^3)=spring rate

first photo: old wornout tokico 5020F
second photo: side by side moog spring and tockico
third photo: cut moog spring

fourth photo: on the car

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Am I missing something? The rate does not change if you shorten the springs, unless they are progressive which they don't seem to be based off the picture. 

 

The spring rate increases if you cut the spring. See the equation in the original post.

 

I'm a little confused about what this is fixing though.  The lack of suspension travel is due to the stock strut design being at a lower ride height.  Are you just saying that the Tokico spring is too low and your replacement raises the ride height to alleviate the problem?

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The original coil binds from being fully compressed. Think of a slinky that's sitting on a table vs extended. Fully compressed it might as well be a steel tube instead of a spring.

 

How much were those Moog springs/where did you get them?

Yes, I know what coil bind is.

 

So you are saying that the Tokico spring binds _before_ the strut bottoms out?  

Most lowering springs with stock struts put these cars very close to riding on the bump stops anyway - I'm finding it hard to believe that as long as those springs have been around that a coil bind issue wouldn't have been flagged and remedied long ago.  You sure the car wasn't just hitting the bump stops?  Did it _have_ bump stops?

Edited by TimZ

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Is that an S30 or S130?  Nothing wrong with exploring new possibilities.  Here's a similar option using the Moog spring number for a Chevette.  That option gets kicked around often for the S30's.

 

http://forums.hybridz.org/topic/110278-need-stronger-front-coil-springs-for-240z/

 

Seems like people often leave spring preload out of their overall calculations.  That determines the weight that the spring will hold up (depending on spring rate of course) before compressing.  You can set ride height somewhat independently of rate using preload.  Nissan uses a somewhat soft spring, but preloaded when installed.  The tires are compressing along with the spring, when the suspension is in use.  Lots to consider if you want to end up with a good ride after making your car look right.

Edited by NewZed

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Yes, I know what coil bind is.

 

So you are saying that the Tokico spring binds _before_ the strut bottoms out?  

Most lowering springs with stock struts put these cars very close to riding on the bump stops anyway - I'm finding it hard to believe that as long as those springs have been around that a coil bind issue wouldn't have been flagged and remedied long ago.  You sure the car wasn't just hitting the bump stops?  Did it _have_ bump stops?

If I'm not mistaken, we actually have an entire thread here about the Tokico coil bind issue.

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theczechone Just to expand on your question. Think about this. If you have a spring with 8 turns it will take 269lb of force to compress 1in. Now if you remove a half turn IE if you cut the spring. You are now asking those 7.5 coils to move the same distance. They are not going to like that since each turn is now being asked to move even farther. They can't share the workload anymore. And for Math sake:

 

11,250,000 x (.610 x .610 x .610 x .610) / 8 x 8  x (4.485 x 4.485 x 4.485) = 269 Lbs.

 

Now if we cut say 1/2 turn off this spring the active turns become 7.5.

 

11,250,000 x (.610 x .610 x .610 x .610) / 8 x 7.5 x (4.485 x 4.485 x 4.485) = 287 Lbs.

 

Hope that helps. 

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Hey, everyone I finally got to finalizing my spring cutting. I had to cut an additional half coil to get my ride height back to what it was with the tockico lowering springs. It sits exactly the same as it did before switching to Moog springs. If any of you want I can post my calculations. 

post-50676-0-38326400-1483071103_thumb.jpg

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The original coil binds from being fully compressed. Think of a slinky that's sitting on a table vs extended. Fully compressed it might as well be a steel tube instead of a spring.

 

How much were those Moog springs/where did you get them?

That was my problem when I was running the old tokico lowering springs. I like the height but the springs would have less than an inch before coil binding, meaning my spring rate when to infinity. I bought them for about 50 dollars on amazon.

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Is that an S30 or S130?  Nothing wrong with exploring new possibilities.  Here's a similar option using the Moog spring number for a Chevette.  That option gets kicked around often for the S30's.

 

http://forums.hybridz.org/topic/110278-need-stronger-front-coil-springs-for-240z/

 

Seems like people often leave spring preload out of their overall calculations.  That determines the weight that the spring will hold up (depending on spring rate of course) before compressing.  You can set ride height somewhat independently of rate using preload.  Nissan uses a somewhat soft spring, but preloaded when installed.  The tires are compressing along with the spring, when the suspension is in use.  Lots to consider if you want to end up with a good ride after making your car look right.

I did have that in my calculations but I never thought to post it since my messy chicken scratch is almost unreadable  :D. My car is a s30 with 240z strut tubes and 240z hubs. 

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Yes, I know what coil bind is.

 

So you are saying that the Tokico spring binds _before_ the strut bottoms out?  

Most lowering springs with stock struts put these cars very close to riding on the bump stops anyway - I'm finding it hard to believe that as long as those springs have been around that a coil bind issue wouldn't have been flagged and remedied long ago.  You sure the car wasn't just hitting the bump stops?  Did it _have_ bump stops?

My tokico springs would bind before I would hit my bump stop. I seem to have gotten the batch that had the issues with coil bind. See my first attached photo, there is very little room and I marked the travel distance. The car had less than an inch of bump travel, since the coils would lock up. Yes, I have bump stops installed they are super small and tucked at the top.

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Hey, everyone I finally got to finalizing my spring cutting. I had to cut an additional half coil to get my ride height back to what it was with the tockico lowering springs. It sits exactly the same as it did before switching to Moog springs. If any of you want I can post my calculations. 

SO, more of an update I drove the car around and it is 100X better than before. The car is a lot more comfortable. Back then the coils would bind and I would loose grip and the car would simply under-steer. Also my braking feel seems to have improved since there is actually suspension travel on the front. If anyone has problems with their tokico springs (very few) please give this a try. I just used my tiny little dremel to slowly grind away without heating up the metal too much. I will continue to drive this set up on multiple road surfaces and report back.

Recalculating my spring rates I seem to have made the front end stiffer 

tokico Spring rate : 140lbs/inch

Moog 80099 CUT: 160lbs/inch

 

This does put a bit of fear in me since I am running equal rates front and rear but I will continue road testing and track testing this setup.

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Edited by Jazz86

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