TalkSick

ive noticed lately, mostly when turning left at decent speed, be it long curves or 90 degree corners, that the car enters corners nicely, but mid corner if i hit a bump or move the wheel to tighten my radius the car immediatly darts hard to the left. its almost like it wants to throw itself into a slide. the closest thing i can compare it to is that its as though the tire is in a rut and pulling the car into oversteer.

any thoughts on what might be causing this?

legokcen

iTrader: (8)

Have you recently lowered it? Almost sounds like the Ackerman Angle is off and when the weight transfer goes to the outside tires they turn in more. Does it happen going right much?

snivley whiplash

iTrader: (4)

check the ball joints for wear

rwatson5651

iTrader: (5)

Idler arm bushings.

81WideMariah

iTrader: (8)

I had the same issue, but going right.

I had installed the bolts that attach the strut to the steering knuckle incorrectly, (there is a long and a short bolt) and one of the bolts worked it's way out. Long story short I was very fortunate that the strut fell out while backing out of a parking space and not driving down the road.

Do yourself a favor and put the car in the air and check everything VERY well.

DivinDriver

iTrader: (15)

Could be one of several issues with front geometry control; tie rods, ball joints, idler arm bushings or ball, etc. Any of which can let the direction of the front wheels become dis-coordinated on turns.

Could be excess toe, too, though that would probably be more symmetrical in behavior.

Time to go over your running gear in fine detail, and have the alignment checked out.

j9fd3s

iTrader: (3)

need more infoz. if the car is lowered at all, and you have good rubber, you're probably hitting the bumpstops in the front.

but it is a good idea to check everything for wear/looseness too

sevens4me

iTrader: (1)

Nobody else thinks this sounds alot like the "snap oversteer" that happens from the watts linkage causing a bind? That's how my car is while making either left or right turns...Everything's fine, you make a small adjustment or hit a bump, and then BAM! INSTANTLY, the rear of the car makes a break for the outside of the turn. My plans are to get new suspension goodies to reduce body roll and try to elimate or reduce this "snap oversteer" as I call it.

Kentetsu

The main suspect for darting in mid-corner is worn ball joints.

There is a slight chance that it could be other front end parts, but only ball joints usually only dart in one direction.




.

Kentetsu

That's a good plan. You might consider removing the rear swaybar until then, if you haven't already done so. I used to have terrible snap oversteer with my car when it had stock springs, and even with Racing Beat springs. Switching to the Respeed coilovers and front swaybar cured it. I can even run a competition rear swaybar now without any issues.

TalkSick

i appreciate all the responses. very helpful. i didnt post the specs previously cuz i didnt wanna taint the survey.

car is lowered on RB springs and kyb struts, idler arm replaced with heavy duty moog one. tie rod ends replaced. new bushings on front sway bar, rear sway bar disconnected and removed. rubber is less then 6 months old, wheels were balanced when they were installed, car was aligned after all the above was performed.

known issues are wheel bearings, possibly all 4 corners t this point
passenger side ball joint had/has some play when i had it aligned (i realise this means a proper alignment cannot be performed but necessity is a bitch)

i suppose since its the most obvious ill have to get the ball joint replaced an get off my *** an do the bearings.

also since its somewhat related, has anyone heard of driveline vibration caused by using lowered RB springs as well as oversized tires (15" 215 in this instance) ive read that it misalignes the tail shaft/driveshaft/input shaft and causes drive line noise however ive spoken to many others who say they have never heard of this.

thanks again for the responses

DivinDriver

iTrader: (15)

Tire diameter has nothing to do with rear axle alignment, as I understand things - provided the same size wheel and tire on all four corners, and nothing's rubbing.

Axle alignment is referenced to the chassis, not the ground. Strut changes likewise do not change axle alignment, if they are the right size.

RB springs only drop the car about 1" IIRC; I know that was the spec on mine when I bought them ages ago. That should not be enough of a lowering to cause troublesome misalignment of the control arms; RB's been doing said work for decades. They're even legal for Spec-7 racing.

That said, tire tread width does play into cornering geometry, as does wheel centerline. Wider & larger tires have a wider and longer contact patch, which changes the relative angular change rate between inner and outer treads.

Essentially, by increasing the wheel and tire diameter and tread width, you've changed the shape of the rectangular patches of rubber that touch the pavement, and (due to larger diameter) you've moved the position of those patches relative to the frame of the car, since the strut is not vertical with respect to ground due to caster and camber angle. Larger diameter tire moves the patch forward and outward given the same C/C angle settings, because you're increasing the distance over which the angles act.

In trig terms, you've lengthened the hypotenuse of a pair of triangles; even if the angles are the same, the lengths of the other sides change proportionately. If the wheel offset has moved the centerline of the tire, that too repositions the contact patches and could change the angular relationship between them while cornering. Which is directly related to the resulting effects of the "Ackerman Angle" mentioned by legokcen above.

Whether or not that 's enough of a change to cause symptoms, that I don't know.

Kentetsu

I run a hell of a lot lower than RB springs will get you, and haven't had any vibration issues. Based on that (admittedly) small sampling, I doubt that is your issue.

Much more likely:

Transmission mount
U-Joints
Wheel Bearings (already noted by you)
Bent wheel (move fronts to back and see if vibration changes)

TalkSick

https://www.rx7club.com/showthread.p...ighlight=noise

this is the sort of thing i was reading about regarding lowering the car.

front wheel bearings helped, cars a bit more stable.. control arms next i guess

also got a sound clip of the noise, however have no idea how to go about posting it

Kentetsu

I was thinking about this, and I think I was a bit quick to rule this out. I'll have to look into this and see if there are any issues...

Glad to hear there's been some improvement for you.

TalkSick

update sorta

ive had a thought, tell me what you think

i believe the noise im hearing is as a result of the rear bearings being so toasted that the axle is moving in an out of the diff an being held in by the brakes.

first of all is this possible?

second of all, as i search for replacements.. the car is very much a hybrid, most of it is an 84. 4 wheel discs, LSD rear, big bearing front

ive ordered rear bearings and am now worried i may have ordered GSL SE ones.
is there any difference between the bearings on the rear of an SE and GSL? i ask because i noticed the respeed moser axles are different for GSL and GSL SE, at least as far as length goes, not sure about bearings. i know the bolt pattern is going to be different between the two, no idea what other differences exist. as far as i can tell 84-85 all had same bearings from what i can see on the mazdatrix site.

j9fd3s

iTrader: (3)

ALL of the 84-85 cars used the same bearings. i hope you got the collar thing too, its the piece that actually holds the bearing on the axle, you cannot reuse the old one

TalkSick

yes made sure to get the collar, spacers an new seals as well

how likely is it that the axle may have been damaged? this problem has been going on a fairly long time and as its my daily driver i cant afford to take it apart from what is now a poor but working state and find out i need parts i havent yet purchased to put it back together.