I have an 86 gxl with 150k miles, original suspension as far as i know, with the exception of rear toe eliminator bushings. I have 16x7 wheels, on 205 50's in front and 205 55's in back.

My problem is that my car has a REALLY bumpy ride, bounces all over on rough road, but more than being bouncy, the ride is HARSH! theres lots of noise from the suspension, especially in the rear. for example, the little bumps that mark lane divisions dont phase other cars i drive, but in my car they really hit hard, makes driving a bit of a pain.

My question is how much of this harshness do you think is from the worn 150k old shocks/springs, and how much could be worn out bushings? which of these factors affects ride more? I want my car to handle bumps and irregularities like a much newer car, where should i start?

thanks alot guys -Matt

 

Info on which bushings are the most important to replace and where to get them could be much appreciated also.

 

its possible that because your using 50's and 55's that the ride is harsh.

higher psi on those tires. imagime if you use 155/80/13's do you think it would still be a harsh ride?

probably not.

 

well, some fcs came with 16 inch wheels that had 55 or 60 profile tires, and i'm sure they rode MUCH better than this. And in dont think tire size can make ride THIS bad, i havea friend with a 91mr2, (a different car i know) but he has 17's in front, 18's in back, and his car rides REALLY nice, soaks up bumps and imperfections in the road REALLY well.

any more suggestions?

 

umm.. bouncy usually means your dampers are gone.. harsh on small bumps with supposedly stock suspension could mean bushings, but it could also be that the springs have sagged and you are riding on/near bumpstops most of the time.

Other things to consider include what tires you have and how much pressure you are running in them.

I would guess you might replace dampers first since that's probably an easier install than bushings, unless you have a press. If you were planning on taking it to a shop for it, if you had the money, might as well do both at the same time. I kinda think it a bit unlikely that the springs are really _that_ bad.. unless the car's been abused.. but if you've got the money, springs aren't that expensive..

I'd advise not to neglect the dampers, though..

sorry, I am not currently a bushing expert.

let's hope someone else chimes in on that.

 

as far as wheels /tires go, im running 16's all around with 50 profile in front, and 55 in the rear. I run them all at 36 psi, any more infoi guys?

 

This is a sports car... you want a cushy ride get a caddy.

I know thats not any help, but it has a lot of truth to it.

Try a set of adjustable shocks. AGX's can be had for less than $400 to your door. I know my car rides a lot better now that I have new shocks in it than before.

I also went with stiffer springs (ST) and I don't think it rides any worse over the rough stuff. I have a more warped perspective too so maybe we're seeing things differently. I love that my chasis hardly moves when cornering, and to make that happen I have to accept a little rougher ride. New bushings, unless stock rubber, will make your car even harsher. Aftermarket poly is inteded to remove even more compliance from the suspension. This will worsen what you seem to be complaining of.

Why did you do the DTSS eliminators? (not to get into the debate again here, I want to know what you wanted to get out of the mod)

 

Get a set of higher profile wheels and tires and try them on your car. 60 series all around would make a big difference. Your car is a sports car, it is sprung very hard. It is always going to ride hard, low profile tires will magnify the issue....

 

Wow - 36PSI is OK for 60-65 profile, but is way to hard for 50's.
I use 28PSI in front, 26 in back. This gives both better ride and better grip (more footprint)

 

I must agree...36 psi too high. It's like riding on wagon wheels. It'll probably build to 38/40 when extremely hot. Drop back to 28/30 max cold and give it a try. It'll make a big difference.

 

I also agree that 36 is VERY high (sry to sound like an echo), but I'd also replace the stock suspension too because it's pretty darn old.

 

Try these for bushings

http://www.eshocks.com/pro_ind.asp?M...ts&B_Color=Red

http://www.suspension.com/mazda.htm

 

Thanks alot guys for all the info.
OK, I know its a sports car, and road feel is something i cherish in cars, i cant stant plush luxo cars. And i've driven LOTS of differnt sports cars. Many with upgraded suspension, many heavily lowered (and properly lowered) cars, cars with 19 inch wheels, For some reason my car rides worse than any of these, even a friends car with JIC flt's on the hardest setting. With that setup the car still seems to handle bumpy road and bumps WAY better than mine does with stock stuff. I've also driven other FC's with the same/more agressive tire/wheel setup as i have, and mine rides far worse for some reason. I'm going to go lower the tire pressure to 28 cold, and see if that helps. I'll keep you posted, and let you know what it feels like, more input is always appreciated though. _thanks guys, -Matt

 

If you want a quick check on the effectiveness of your dampers/shocks, push down on the car above the shock, It should come up and basically stop, if it bounces up and down their nailed (something that was pointed out to me after I replaced my original shock with Koni's). I used to go over cateye's in the road and the backend of the car would jump around

 

I'd be willing to bet that the struts/shocks are shot. Look for wetness around the top of the body tube. Not necessarily shiny wet, but certainly not dry. If you replace them, see how much resistance they have to being pushed in. I've had them drop an inch or two just from gravity! and then firm up. The car feels mostly ok, but can also feel 'choppy', almost like there is a bunch of play somewhere, but it still feels ok when you push it (because the suspension has more load on it). I've also had shocks that fell completely into the tube.

And struts/shocks don't have to fail in rebound and compression. They can be bad in one direction only.

 

Oh, if you are going to be replacing springs and shocks with lowering ones.... You don't need a spring compressor to assemble the new ones. Take a grinder or torch to the springs while still assembled and cut them. (no launched parts that way) Then take the perches off and put the new ones together.

Granted this is ghetto and if you can get a compressor by all means do it, but this will work if you need to save some cash.

 

I am a tire n00b so gotta ask what I am assuming from what I have been reading. Lower profile tires = lower psi? I got 205/40 all around and they are all at 35psi. My car is not insured and not being driven yet since I put the rims/tires on (today actually) and I have not felt they way it drives yet. Should I depresurize them a bit down to like 30psi or 27psi area? Thanks.

 

oh, also another question (hehe sorry but gotta ask cause I am boggled). My suspension is still totally stock. My front end is rock solid though, solid as in it does not move much more then 1inch when you push down on it. I would even go as far as saying not even 1/2 inch but I am not toally sure how far it goes. Anyways, would this be caused from sagging springs so riding on bottomed out suspension or from malfunctioning struts? And, how dire is it that this is fixed? My car can stay off the road as long as I want but planned on driving again soon, but should I replace entire front end suspension first or could it wait? Reason I ask is funds come in sorta slowly and I have other stuff to spend as well, but if this is really dire and should be fixed ASAP I will prioritize this over some other stuff. Thanks.

 

What people are saying is that with low profile tires the ride can be pretty harsh if you inflate it to the max pressure.

I'm curious if any of you claiming better grip at lower psi have run a skid pad with varied pressures for proof that traction increases with lower psi. I would be willing to bet that the increase in pressure over the surface of the tire footprint achieved with sidewall labled pressures will provide better numbers, and faster lap times.

Lower tire pressure causes the sidewall to flex more causing more heat to build up in the tire carcass, and subsequently reduces tire life. A tire rated for 44psi ran at 28psi will have sidewall failure long before the treadlife has been consumed. Granted max tire pressures are provided so that the natural heating of the carcass doesn't cause the tire to blow under designed useage parameters, runing significantly below that rating will have an adverse effect on tire life and gas mileage, as well as throwing your speedometer off.

Lower pressures also don't increase the footprint all that much... When off roaders speak of lowering pressures for a greater footprint they're talking about takeing a tire that has a 6" or greater sidewall and dropping it down to 6-15psi. Thats not enough pressure to hold a bead on a road course. It's also not going to give you better traction.

 

Actually I usually cut better 60 foots with lower tire pressure when at the drag strip. So it does increase traction IMHO. We will see how it goes when the motor goes into my 7 and I get a set of drag radials on it.

 

Drag times are a little different. You wouldn't take a turn at the end of the strip doing 110 would you? I'm speaking of cornering traction here. (which is really what's important on the street)

 

Well, i just got home from work, and driving over lots of rough road is my daily grind right now. It seems that they're doing construction on the entire town of olympia at once, lots of really shitty surfaces.

on the above advice of lowering my tire pressure, i drove TO work with the tire pressure i originally had, which i thought was 36psi (which turned out to be 40, FORTY psi when hot!) and then i lowered it to 30psi hot, and it made a HUGE difference. the ride is much softer, although i've lost some initial steering response. I think i'll raise it to 32psi hot, and see how that feels.

My dilemma is that it STILL feels like **** over really rough broken pavement, and i mean in a way that feels/SOUNDS like the suspension is worn out. The SOUND is another big worry of mine, over rough road, the rear suspension especially sounds really clunky, very loud, and makes me worry a bit. However, i didnt know that a damper's bound/rebound could wear at different rates, so I'm thinking my dampers BOUND/compression could be TOTALLY shot, and the REBOUND is still working much better. here's why- now, stay with me and PLEASE correct my thinking if its wrong (likely), wouldnt this cause the wheel to move upwards too easily, and then when the REbound orrurs, the wheel travels down with what seems like way too much force? maybe making the car feel like it's punching the road as it goes over unevn surfaces?

what do you guys think about that?

 

Oh, and any mroe input on which suspension bushings to replace first would be very helpful- maybe if some wear out faster consistently, or if some are more detrimental when worn out than others - any input?

 

I will take that bet.
Yes - if you go too low. But, a resonable pressure drop will give a huge grip improvement with 50 series tires.
What's off-road got to do with RX-7's.
My object is to stay on-road.

 

bump?