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Thread: Sunny N14 - Suspension development

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Posts: 1-10 of 21
2014-10-29 14:19:28
#1
Sunny N14 - Suspension development
Hi,

As you may have noticed... I trackday my Nissan Sunny N14. The Sunny is the same plattform as the NX2000 or Pulsar.
During this season we improved my suspension setup a fair bit. And I want to share a few 'unconventional' things we did!

First of all I tried to align the car with the basic stuff and a set of coilovers and top hats installed.
I got a really decent setup with arround 3 deg of camber in front and 1.5 in the rear. But I knew there was more, the car felt good, but there was more...

I asked Mike K. over facebook to give me a few ideas on the setup he used on his cars. And I realized really fast, that the car needed more caster!


You have way to little caster. I would run a minimum of 4 degrees. I would prefer around 5. I would run a higher rate rear spring, about 500-600 in/lb. I would run a bigger tire like a 225/45-15 and run more negative camber and, as much as 4 degrees and slightly lower air pressure.


My caster at this time was around 1.5 degress! I have eccentric bolts in the knuckle, So i can dial in or out some camber over the bolts there!
So we started with new sturt tops. They are 45 degress rotatet, with these I can dial in some more camber and castor together!


Further I wanted more camber to get it in a range above 3 degrees - which was not possible with my old setup, and would not be better with the new top hats.
I did research on the interweb and orderd a few different parts from Nissan - we realized that the Nissan N15 lower arms are the same as the N14 ones, but each is around 15mm longer!
Now things got really fancy! We got the N15 lower arms, replaced the bushings and fitted a Whiteline caster special one in it. The good thing about this modification is that I have now more camber, but what makes it even better is, that I can dial out some scrub on the front axle. The car should feel more stable and calm in the steering wheel!



As I knew the car was tooooooo low at the moment, and I calculated the front and rear roll center, I knew I had to fix this issue now! The front roll center was well under the ground, and the rear was ok. Surprisingly the rear roll center was in a really good position.
I had an idea, and i checked the internet and the local dealer again. The S14 ball joints had the same tapper! So I orderd a set of moonface S14 roll center adjusters - with this modification my rollcenter would rise a fair bit, as they offset the lowerarm by 15mm!



Here I installed them to the knuckle - to check if everything would work out! And it did... ... not. The housing has a diameter of 42mm whereas the lowerarms size is noticibly smaller! No problems for us, we just milled it down a little to make it fit and flush! Now it fits perfectly!
Here the comparison. old vs new



To finalize my setup I needed something to correct my bumpsteer issue. I orderd a set of Joe 2J-Racing bump steer correction parts...



--

For reasons unknown the 2J parts do not work with my front setup at the moment. I do not blame anyone, but I think this will need some time to work it out. The inner tie rods and the outer tie rods together are just to long....
I hope Joe and I will wind a solution for this issue!

Nevertheless - last sunnday I went testing the new setup with a new alignment on track. The car feels great, is very responsive, and very predictable. Right now I am really happy with it.
As we have engineering habits - it is a great progress with the new parts we made. But in my mind there is already more...
2014-10-29 19:49:02
#2
You should be upwards of at least 3-4 degrees of positive caster to help out the suspension a whole lot.

The 2J parts have a fun story with two parts. A. They hate SR20. B. The front of the B15 is not quite as similar to the B13/B14/N14 therefore, they do not support much of the chassis stuff particular to your car. I am not saying they can not help you, but that is certainly food for thought.

Good ol OG Mike K is a nice asset to speak with. I talk to him every few weeks and he is a good guy. A shame the forum ran him off like a lot of good folks were.
Last edited by Kyle on 2014-10-29 at 19-53-33.
2014-10-29 19:56:12
#3
@Kyle:
I run now +- 4.5 degress of caster with my modified strut tops and the Whiteline bushings. This and the raised roll center helped the car a lot! The car is much more responsive!

The 2J guys seem to be 'special' folkes. I think there is a story untold story about this. (If someone knows more -> PN me).

Fact is, Joe told me that the parts will fit the B13/N14 knuckle. And they do, but the tapper is far away from perfectly flush, and the parts
2014-10-29 21:28:22
#4
nice write up...where did you get your top hats from?
2014-10-30 06:03:44
#5
I run a custom 'Ksport Type Race' Setup - YES I know taiwan crap and so on.... But life is full of design constraints and this package was the best deal as I have good connections to customize them and support is really good.

The lower part of the top hat is still Ksport, but the adjustable part is custom made. I 'designed' it - and a friend milled it. Would probably fit Tein, Cusco etc. as well.
2014-11-02 18:33:57
#6
Now - I have a question, or i need input .

My car tends to lift the inner rear wheel while cornering. In some eyes this is a 'good' thing. In my eyes it is just the fact, that we tuned the suspension to handle well - based on the given options. But I am sure, with a more planted rear end the front end will gain mid corner traction. The reason for in-wheel lift is obviously a inbalance in front and rear roll couple.
Can someone point me in the right direction..? (I don't want just a parts list - I want reasons and ideas)
2014-11-11 01:09:05
#7
Hey Martin,

What's the N15 control arm part number?

I've got a rnn14 i would love to try this on.

We should have a little discussion regarding suspension setup. i've recently gone to this on my rnn14

Front
Ground Control Caster/Camber tophat
TDMimports bumpsteer kit
camber bolt
Double adjustable ground control advance design struts
600lb springs
0.1 toe out
5 degs caster
3 degrees camber
whiteline antilift kit
front control arm poly bush

rear

Shigspeed top hat
Double adjustable ground control advance design struts
700lb springs
camber bolt
0.05 toe out
1.5 degrees camber
whiteline rear adjustable bar
whiteline subframe align lock kit

I'll be testing it out this weekend at a local autocross event

as for lifting the inside rear i use this for rotation as i've got a 2way rear diff
but its also been on all my street touring prepped crx's and civics. i dont see it as a problem, you're creating a lot of roll resistance, placing grip and weight over on the front wheels and the outside rear wheel.
in order to get that wheel down, you need to be quite low, have a lot of droop travel, and use tender springs to push the strut down. i dont think its necessary, as long as you're keeping your two front drive wheels down with grip, if u don't have an lsd, this is the way to do it.
Last edited by nickr on 2014-11-11 at 01-13-40.
2014-11-12 23:43:50
#8
Will come back to this... Sorry hard week..
2014-12-28 07:07:14
#9
Originally Posted by MartinS
The housing has a diameter of 42mm whereas the lowerarms size is noticibly smaller! No problems for us, we just milled it down a little to make it fit and flush! Now it fits perfectly!
Here the comparison. old vs new




)


Can you please explain which part had to be machined down to make this work? I'd like to do the n15 lca conversion on my n14 too. Also, did you use any specific model n15 or are they identical between the years and engine variations?

Thanks
2014-12-28 07:09:46
#10
edit
Last edited by Doctor G on 2014-12-28 at 07-11-41.
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