last week i took the pig out for a back-road run on the way to the border, met the minute men and took a couple of spins that scared the crap out of me.

the spins happened during wot acceleration at around 70, under moderate g.'s--light curves, third gear. the back end broke lose and spun the car, i don't know how many times leaving me still on the two lane highway. this happened twice under the same circumstances.

automatic tranny.
running a new set of kumho ecsta's on aftermarket 16 inch rims.
kyb shocks installed with tires.
steering wheel is offset suggesting the need for a front wheel align.
hood is unlatched--need to put on new cable.
no frame mods--car stock--top on with no rattle.
i have general vibration exhibited on freeway starting at 65.
tire pressure 35 all the way around.
stock bushings.
front air dam damaged.


any ideas? i have a couple, but what do some handling pros think.

thanks.

 

If everything is in good working order, too much rear swaybar will cause oversteer.

 

Not to be a smart a$$, but the 1st time didn't teach you anything??
Also, bad shocks and tires not inflated properly are other causes.

 

well, you are being a smart ***, but i'm dying anyway and don't get out much. i just don't want to wreck the car. now you can tell me your personal problems, and don't say you don't have any.

 

wot in third gear in the curves and she swapped ends? what's not normal?

 

the curve was light to moderate, but if this is normal, then i'm glad to hear it.

 

A car that suffers from understeer will be a bit safer in a bad situation than a car with oversteer. Most car manufacturers (if not all) will build in understeer from the factory. At least the car will still be facing foward if it looses traction. Inspect everything carefully. Safety first.

 

Was the asphault cold?

 

sounds like you just discovered what ""throttle induced oversteer'' is...gotta roll into the loud pedal gently and countersteer when the tail hangs out....some types of tire give very little warning when you ''reach the limit''...welcome to the suspension mods club

 

no, it was about 82 degrees.

 

At WOT a speck of dirt or sand will spin you out in a heartbeat..

Although once I was messing around with a buddy of mine, and I was folling him in my '85 Z51 automatic going from 70-110 in a long but sharp left turn, my '85 held up fine and had mroe to go I knew it, but his '92 was starting to slide and you saw smoke coming from his rear tires.

Although we were NOT at WOT, only about 1/2 throttle..

I'd say it's normal to throw the rear out at WOT going into almost any turn at high speed.

 

that's just what i was thinking. the kumho's have a wear rating of around 240: i read a post from a seemingly knowledgable person saying you need something around 140 and now i think i know why--i don't get any feed-back from the car at all prior to break-away. that's the problem. i'm no novice high stress driver, just a novice high stress vette driver.

will dead suspension rubber cause a lack of feedback?

 

it has got me thinking that stickier street tires and a rear wing could solve the problem. the spin happened right at the speed the wing is supposed to be needed and become effective. i guess now i can say something i've never been able to before: my *** end gets light at 70 and goes into a spin.

i was wondering whether frame flex may be a contributing factor.

 

Are you saying that you currently have the hood unlatched while driving or did I read that wrong? If so the hood is a structural piece of the car on a C4, that could be part of your shakeing issue, but I doubt it had anything to do with the spinouts. You just need to learn the feel of the car...get out to some auto-x events and hang it out, you'll learn quickly!

 

yeah, the hood is unlatched while driving. i knew it was structural, and am glad to hear it shouldn't have caused the spin, and that it maybe causing the shake.

thanks for the replies everyone.

 

I have KYB's on the 89 and its pretty stiff. It makes you feel like you can stick to the road better than you can. When hitting a bump on a curve, the suspension wants to skip (which can throw you into a spin real quick!) rather than absorb. Ive had the crap scared out of me on "moderate" freeway interchanges because the car reacts 100x faster than I can. Careful out there.

 

you nailed it on the road conditions: it was bumpy. is the problem with the kyb's that they aren't very adaptable? i think i may have just answered my own question. i guess for thirty bucks that's probably that.

 

the 85 should not have enough power to break loose in a corner at 70mph.

A few thoughts:

1) The rear bushings might be binding. At this age, the rubber has gotten hard and dry... and snapping out of alignment during corner loading. Same goes with the front suspension...

2) The hood... as Zix indicated, it is structural. As such, it's what keeps the front and rear ends connected in a corner. I say all bets are off with the hood up. Get that fixed before you drive it again. The 1985 did not recieve the strutural improvements that the 1986 got... the firewall is prone to fracturing, and you don't want to hurt that. It can also lead to premature windscreen failure.

3) Check the c-beam. If the bolts are loose strange things can happen.

That's all I can suggest at this time... keep us posted.

 

KYbs have one settin: stiff Most cars you can "feel" if its going to go away under some G's and gives you time to compensate, most vettes IMO dont, when they go they are long gone as you found out.
I think of it as a fail safe, because if I were to try abd overcompensate Id have been thrown into many a wall, the car seems to straighten itself out befor I can react. I learned to respect these things regardless of power level.

 

that's what i thought. i finally put in a new cable with my red-neck buddy a couple of weeks ago, adjusted the cable and closed the hood. he hadn't adjusted his side properly, and because i felt like crap, i didn't check his side. well, the hood wouldn't release on his side, and i broke the plastic pull thingy under the dash. i haven't had the money to buy a new one, so i hope to god i haven't cracked any body components. the good news is i have hardly felt well enough to drive it hard. i was having a good day when i had the spins. usually i get them outside the car on a bad day.

has any body ever had a buddy like this guy? now i use the term buddy loosely. this guy is a total meathead, but he's a good grunt. he can sure bust a knuckle, and frequently does, but anything that takes a little finesse tosses him overboard. he's the same guy that shorted out his electrical while messing with his le mans' headers, and started an electrical fire that melted the lead connector off the battery. now i know why they make them out of lead.

i've been thinking of trying to make a sheet metal insert to screw into the hood release to stop the breakage. i can tell it is common, cause' every high dollar vette shop has all the parts for it. if i feel well enough this weekend, i'll put the dremel and tin snips to work.