Suggestions for suspension tuning

SON240sx Automotive
1

Well, today I adjusted my dampening levels, and wanted to get some feedback.

My setup is as follows:
-KYB AGX Shocks, s-tech springs
-Whiteline bushings all around
-Subframe spacers
-moog inner/outer tie rods.
-Good year Eagle F1 GS-D3 tires. 205/50/zr16
-New swaybar endlinks

I ran them for some time now at 3 front and 3 rear. In corners, it would be a bitch with understeer, naturally since the front was stiffer. I hated the understeer, but I loved the firmness of the ride. If I was going 180km/hr-200km/hr the car was still very planted, very stable, very firm, not bouncy, extremely confident and calm feel in car.

Last night I set the rear to 4, it was better… I drove it around, it certainly felt better but there was still mad understeer if pushed to the limit… so… I set the front to 2.

Now the car feels much better, more responsive, easier in corners, no squealing, no gay understeer maybe a tiny tiny bit if pushed to the limit but I’m not sure if I’d call it quite understeer… but the rear end gets more loose (naturally since rear is now stiffer).

The steering wheel feels more responsive, but more dangerous too (less confident/firm than what it was), more loose, it’s slightly more bouncy up front too… The car can slide now… but I can control it… however I’m wondering what kind of things can be done to further improve the ride… the handling, response, firmness, etc… One of my next upgrades once I have the money are good swaybars… to make the car more flat, but for the car as things are… how else can I tune the suspension…

I am wondering perhaps to eliminate some of that looseness (danger feel in steering wheel), I could get wider tires up front (and rear…)?

I am inexperienced with any sort of suspension tuning but now I’m feeling the need to make some changes to make the car handle better… I can’t believe for this whole time i was running on a shitty setup of 3/4 front and 3/8 rear… I was wasting the front tires with understeer like crazy as well…

What kind of things can make my car less slide, but not understeer, have more traction in corners… be better at grip handling, be faster in corners, but not lose the rear end, respond faster when I turn a wheel, yet still be firm and not dangerous.

2

swaybar endlinks?

maby a thicker rear sway bar? so you can set the fronts higher but eliminate more of the understeer

3

if ur still wondering

things for suspension upgrade are

get coilovers but u just got new struts

sway bars…hicas swap bar is 24mm vs 15mm stock…also get a front sway bar…mines now 28mm thanks to theo… suspension techniques

end links are also important as ur old ones are probably worn out

other stuff can include better tires

multilink

alignment could be important so u have the tires planted

struts bars are cheap and simple

4

im honestly shocked that you’re understeering with those tires, they’re just about the best all around tire you can buy at the moment (won best tire of the year for 2005 in just about every top 5 list I’ve seen)

I have garbage hankooks on my car and it was impossible to understeer, under extremely hard/fast cornering on a level surface I would oversteer before I would understeer, and thats WITH staggered tires, 255 wide on rear 235 wide on front.

I suspect that you’re camber or toe is stupidly out of spec and thats whats causing this. With a KA, these cars just don’t understeer unless something is wrong.

For all of the silly people out there, when you hear people saying “s13’s tend to understeer stock” that’s because they do when they’ve got an sr20 under the hood which is quite a bit lighter. :smiley: So I’m just retorting that argument before someone posts it.

I had camber plates on the front and admittedly when they were at “zero” and when I first lowered the car on the coilovers and didnt adjust any camber the car did understeer, I manually added 1 degree to both sides and it made the biggest difference in handling i’ve ever made to my car… more than the coilovers themselves made.

Coles: get an alignment if you havent already.

5

Well I did get an alignment… so I guess it wasn’t done to spec… the rear camber couldn’t be adjusted due to the fact i dont have aftermarket RUCAs, and just the stock ones with whiteline bushings. All my arms, rods, etc… are stock except that I have whiteline poly bushings. Front-wise I heard that aftermarket rods are needed to adjust the caster and whatever else to spec once the car is lowered, that might be my issue?

You probably are right about the alignment issue here… but I had it aligned that’s the thing… I had my dad take the car to some guy down speers (he had Lotuses and porsches in there, he had one of those scoop lifts… as apparently none of the places could get it aligned and it’s only a 1.5" drop…). I wasn’t there to oversee it…

I am currently running 2/4 front and 5/8 rear on my agx. It’s alot more lose which is nice since I can control it but a few times I manage to still somehow understeer (wtf?).

Sometimes when the tires are cold I just start the car… it slides easier… and sometimes when I turn in fast and its cold it understeers like a bitch. I’ve experienced this in the last few weeks driving at middle of night 1am-4am. I’d start the car and from the get go drive it a bit fast. If I did fast turn ins at slow speeds it would slide quick but if I did it at slightly higher speeds it would just understeer like a bitch… One evening I was taking one turn at the light corner at about 50-60km/hr… i was hoping to slide it and push it through at an angle but instead all i got was a thump thump thump thump of the front tires and understeer, it’s like the front tires didn’t have the right amount of tire contact… or as if they were not turned properly… i dont know… help :frowning:

I’d like to go to an alignment place that I can discuss the issues and that know 240sx cars…

I mean when I ran the 3/4 and 3/8 it understeered majorly, this one corner i was taking at 40km/hr it was understeering, then when i set it to 2/4 and 4/8 i was taking it at about 60-70km/hr, then i bumped it up to 5/8 to slide a lil more.

My next major suspension upgrade in mind are swaybars, my car is hicas (well i got hicas stopper) so I do have the hicas rear swaybar already.

6

ohh you just made a really good point actually.

Something I noticed when I first put my tires on, now that you mention it, was that they were extremely slipperly… And I kept blaming the tires but it was right after the snow was gone and it was still extremely cold.

You would be surprised how much of a difference the temperature of the road makes and this may be a part of the issue here.

By the way, when are you going to stop being an outcast and start hanging out with the rest of the oakville 240 guys? most of us have become really good friends, hanging out multiple times weekly some weeks. Where the hell are you during this? huh? Whats your excuse, bitch? :smiley:

7

im getting married LOL, no seriously :stuck_out_tongue: That’s my excuse :shock:

lol ill try to drop by, well i came to 3 sauga meets (derry 10th line timmies).

I used to come by trafalgar timmies and would chill with random buddies of mine including Jake (I made him come to one meet he has a black 240) but lately i’m really busy… and yeah im getting married. Bings isn’t the only one, but the car stays :twisted:

I have to buy a second beater… there is no way I want to drive this car winter :frowning: I have much plans for it…, when I save the money, out the interior and engine goes… and my ultimate plan of doom beings muahaha 8)

8

Which track was this at?

9

Which track was this at?[/quote]

Oh I hit you on that track so you forgot 8) Go civic :oops:

10

Were the tires brand new? If that is the case, won’t they need some mileage to break em in? I cannot remember where I read this exactly, but I will try to get the source. Essentially, each tire has this finishing coat - when they are new - which reduces the tire’s ability to grip.

Like I said, I read this somewhere. Anyone who knows better - help me out here.

11

Which track was this at?[/quote]

Oh I hit you on that track so you forgot 8) Go civic :oops:[/quote]
You know, that’s really odd, I don’t recall having any car crash into me at any point that I’ve had my S13. Maybe you could clarify.

12

Were the tires brand new? If that is the case, won’t they need some mileage to break em in? I cannot remember where I read this exactly, but I will try to get the source. Essentially, each tire has this finishing coat - when they are new - which reduces the tire’s ability to grip.

Like I said, I read this somewhere. Anyone who knows better - help me out here.[/quote]

No you are absolutely correct that tires need to be broken in. It’s called scrubbing and it was done extensively on these tires before I made these judgements… :smiley:

13

Were the tires brand new? If that is the case, won’t they need some mileage to break em in? I cannot remember where I read this exactly, but I will try to get the source. Essentially, each tire has this finishing coat - when they are new - which reduces the tire’s ability to grip.

Like I said, I read this somewhere. Anyone who knows better - help me out here.[/quote]

No you are absolutely correct that tires need to be broken in. It’s called scrubbing and it was done extensively on these tires before I made these judgements… :D[/quote]

w00t! I feel Learn-ed :smiley:

So I should expect better grip come summer, in comparison to the girp - experienced in driving done - this month? (Bottom line - the S14 I just got is my first car up here. I have not really driven much since I came here. :oops: )

14

John is right, the cold is affecting all of us more now… my azenis are feeling like hockey pucks… and I took the Advans off cause of the frequent rains.

Those GoodYears made those lists with good treadwear also I bet, you are not going to have a really really good (read: sticky) tire that has good treadwear, and 205 is kinda skinny for performance style driving, like finding the limits of the car styles… as you are doing.

John has 235 front, that is like 1 1/4inch wider than what you are running, that is a pretty large difference even with it being a “lesser” of a tire.

Where you are at now, I would say tires (more grip and width) would make you really happy.

15

Well right now on my to do list I would believe would be probably SPL TC rods and RUCAs alongside largus swaybars and largus solid endlinks… that’s more like my wishlist right now haha, as I have to save some money… Actually not sure if I’ll get the SPL parts. When I get something I like to get the highest qual that I can get and do it right from the start as opposed to cheap out… so any suggestions on what the best quality parts are welcome. So far I know ebay, kazama, megan racing parts are the thing to stay away from.

rims-tire wise… I’m hoping to get something descent to run 235 front as well actually… The 205 really do look and feel thin… I got 205/50/zr16 all around… My goal with the car is a street car and circuit time attack car for personal use (with no rule restrictions in mind, I’m not interested in widespread competition, only personal challenge). I wish to just go all out on the S13 chassis… I am not sure about rims; 17"-18" rim with 9" to 11" width. 225-245 front and 255 rear I suppose would be about right. Something light preferably… Some fender cutting and arches bashing.

The F1 GS-D3 are great tires though, even in the rain, very predictable and sticky. I might next time consider something more pure dry oriented, but I’m not sure what would beat them. I’ve been in a few other 13s with different tires and mine seem to be the stickiest so far… They don’t seem to like the latest cold weather though… but once hot are very sticky icky.

Also do let me know a place that can do 240sx alignment properly… my car is 1.5" lower and has skirts and rear valances. A number of shops couldn’t lift it so only this one shop with a scoop could… but I wasn’t there when the alignment was done… would be nice to have a nice 240sx friendly shop…

16

hey john

sr’s are only 5bls lighter

17

^^ I highly doubt that is true being a similar sized motor and block and considering the KA is iron and the SR is aluminum. My logic tells me otherwise, but hey, what do I know?

ahmed, another thing is that I’ve heard one of the major disadvantages of gs-d3’s are squishy sidewalls. Being a fairly high sidewall profile, thin, etc. you are probably getting rediculous amounts of sidewall flex and ultimately ridding you of most of your contact patch.

I’ve been through this myself before. I did my suspension first. That brought out how shitty my tires were, so I got decent tires (just es100s though) which made a huge difference… then I realized how much the sidewalls were rolling due to the 205/60 profile, so I got bigger wheels (17s) and I couldnt be happier with them performance wise.

Also, for an s13 I think a 17 is the largest you should go. Even on an S14 18" is pushing it in most cases in my opinion (some people pull it off nicely).

If you want, take me for a spin in you’re car - I’ve felt my share of tirewall roll to be able to pick it our pretty easily. :smiley: You live right around the corner, no?

18

If you over drive a car, you can understeer anything.
Word of advice, take this sorta testing to the track.

Andrew.

19

I only read the first post but heres my advice as for the easiest way you can fix your understeer issue

set the front back to 3, right now you are underdamped thats why its bouncing.

Set the rear to 4 as you have it

get a stiffer rear bar leave the front sway bar stock. Should be niceeee

20

Jammy I have 50 profiles not 60 profiles.

None the less yeah sure, I hope so, I am just so busy lately :(… hopefuly I’ll come to one of the meets… and your msn sucks, stop using trillian lol…

later,

PS - I just had a shitty day at work :angry: