Help freshening up my S13's mushy suspension...

[slipnfall]

Hi there, I'm taking a break from drive-train work to freshen up my suspension a bit. This is a '92 240SX coupe BTW. I'm hoping to get some input, b/c I know there are some really sharp folks in here. I hope this isn't too much to ask in one post, but here goes...So far the only work done is:

NISMO T/C front bushingsOEM tie-rod ends.

Original shocks/springs/everything else... alignment spec's are unknown. This car is, and will continue to be, daily street driven.

The T/C rods solved a trembling at 50-60MPH, but there is still major wheel-hop in the rear(I hope this is the correct diagnosis). Basically if I hit a small crack or irregularity in the road when turning(at a light, 30MPH+, or coming off an off-ramp, 40MPH+), the rear end skips outward from the turn. My guess is it hops about 0.5-1" laterally. 205/60/R15 FYI.

I am ordering an S-Tech/AGX setup next week some time, along with upper adjustable mounts. What else, minimally(for budget reasons), should I replace in the rear at the same time(while I'v got shocks/struts off)? OEM upper rear mounts? My sub-frame bushings *seem* OK, there's no visable metal-to-metal. Obviously a good alignment will be done.

This may or may not be related, but there's a metal-to-metal rattling in the rear, passenger side. I pulled some oddball stuff out of the fender(fell in from the trunk), but I can't seem to isolate this rattling. Sounds like a heat shield, but it'd definately from the pass. side(so not the exhaust). Could this be suspension related?

Thanks for any suggestions you can make, feel free to pick me/my ride apart if it helps.

Cheers,-JamiePS-won't be able to reply untill Monday, so be patient pls!

[slipnfall]

Oh I forgot to add. I cam across these alignment spec's from a 'mod. Do you suggest this as a starting point?

Caster F: 7.0 degs. Camber F: - 2.5 deg. Toe F: 0.00 deg. Camber R: - 2.0 deg. Toe R: 0.00 deg.

In order of importance(is that a word? ), here's what I'm looking for:

Street handling overallLow suspension wearSafetyReasonable tire wear

[chmercer]

thoes alignment specs sound like a pretty good starting point for a grip setup. some will tell you that is too much camber and will wear the tires, but i think its good.

and your problem sounds like you have some kind of rear bumpsteer issue. im not really qualified to diagnose anything, but thats what it sounds like to me.

[skydragoness]

I would definitely replace all your upper strut mounts while you have all the stuff out, that way you don't have to worry about it later.

Inner/outer tie rods--definitely go with something that SPL or Tein has to offer. I have Tein's (inner and outers) on my S13, the steering input is great, feels tight but not as harsh as the other 'drift-spec' ones. And try out subframe collars, they're a cheap effective way to stiffen up the rear.

As far as something rattling in the rear, have you checked your trunk too? I have the factory 'toolbag' w/ the wheel chucks etc and they would rattle around until i shoved a towel in there. Is it a constant rattle? Or only when you hit bumps?

[superDorifto]

The T/C rods solved a trembling at 50-60MPH, but there is still major wheel-hop in the rear(I hope this is the correct diagnosis). Basically if I hit a small crack or irregularity in the road when turning(at a light, 30MPH+, or coming off an off-ramp, 40MPH+), the rear end skips outward from the turn. My guess is it hops about 0.5-1" laterally. 205/60/R15 FYI.

i have a similar problem with my 92, its an intense vibration from 50-55 mph, i noticed the bushings on th t/c rods were pretty junky, but i never put the two together. i think you might have just solved my problem for me!

[ytboy4ever]

2 degrees of negative camber in the rear may be a lil much. People have gotten 1+ handling g's with only -1.5 in the rear. The more negative camber you have the faster your tires will wear.

[slipnfall]

boy: thanks for the heads up, -1.5 sounds more reasonable.

super: the car didn't sit for any extended period of time did it? Mine did for about a year, and the tires *all* had flat spots on them. They weren't visable, but go get your tires ballanced, you can see it on the ballancer. After having my tires ballance(all flat-spotted), the vibrations from ~38-65MPH moved to 58-60MPH for me. The TC bushings did *not* solve the problem, only the symptoms. It's just less noticable now.

sky: would it be ok, or ill-advisable to mix a pillow ball upper mount with an OEM? I more-or-less *need* the front Tein upper mounts for adjustability, but I don't see spending $150+ on a solid rear upper mount... Would this affect handing, mixing the two types?

I didn't know the 240 came with wheel chocks! :lol: It's a rattle when I go over bumps.

[skydragoness]

$150? For solid rear strut mounts? I thought they were around $30-$40 a pop. I don't know for sure if they will affect your front mounts whether they are adjustable or not (i've never seen rear adjustable upper mounts actually). I'm just recommending on replacing them (the rears) if they are in bad shape, which they might not be in your case. So nevermind what i said then, just check them out when you take them out.

[superDorifto]

i dont know how long the car sat. i bought it for 400 bucks, and have yet to have the alignment or tires balanced. it just caught my attention that you were having vibration at the same speed as me. my vibration only happens at 50-55 mph, thats it. im gonna head down to my local shop and see if a balancing does the trick...

[slipnfall]

Huh... well if you can point me to a place that sells 'em for that cheap, please do so! The ones I was looking at were made by Tein.

I see a lot of people are using the escentric bolts to adjust their camber... definately a cheaper solution. I'm wondering if they hold up just as well? If so I'd sooner just buy the bolts and spend the rest on a 'matching' set of upper mounts(ie oem).

How much does worn shocks affect 'bump steer' and wheel-hop? I just hope that these replacements will be enough to eliminate the majority of it.

Cheers,-Jamie

[skydragoness]

Blown shocks definitely can induce wheel hop, so can out of round rims. I've had both occur on my ol' white coupe. Not a cool feeling. Bad bumpsteer can occur if the car is too low in the front, then the suspension isn't perfectly horizontal (the tie rods specifically), or if the car's toe settings are out of whack.

[slipnfall]

Yeah I don't know why I waited this long to do this, but I pushed and released each corner of my coupe:

Front: each side compressed, came back up, then settled immediatelyRear: each side compressed, up, back down, back up, then settled.

Certainly worn: I'm sure the front is worse, but the engine weight just makes it less noticable.

[turtl631]

0 toe in the rear isn't the best idea for a predictable daily driver. Try 1/8" toe in, and less rear camber as the other suggested. As a side note, camber doesn't really cause severe tire wear. Its the attendent change in toe when changing camber that kills tires. As long as you have very minimal toe, tire wear should be fine with those camber settings.

[weeble]

i had the exact problem with my 90 coupe. when i hit a small bump on the freeway my rear end would hop about a inch or two. i found out it was the shocks and springs. luckily i got a set of megan coilovers before i killed myself just driving to work, now i can kill myself drifting...LOL j/k