1998 V70R: tire chirp? oversteer? unintentional drifts???

[atomicthumbs]

Yes, it sounds like a recipe for fun, but not if you're not expecting it.

I had a mechanic replace the transmission input seal on my '98 V70R (with ~185,000 miles), and while he was at it, install a set of poly subframe bushings and a pair of new front and rear AWD sway bars and HD end links from IPD.

Now, I know this car is a few hundred pounds heavier and a different layout from my 940 (also with IPD sways), but it seems much more... nervous. Taking tight curves at moderate speed leads to my tires complaining, and they squeal loudly if I take the at higher-than-moderate speeds.

The tires are Continental ExtremeContact DWS, installed by the previous owner; they have around 24,000 miles on them. My 940 (which I'm using solely as a handling comparison) has nearly-new Hankook Ventus s1 Noble2 tires, and shows no sign of squealing or losing lateral traction going through the same curves at higher speeds.

The AWD works correctly, and it's got fairly recent Bilstein TCs up front and Nivomats in the back. The spring seats and front and rear shock mounts were replaced ~22k miles ago, and the control arms were replaced ~27k miles ago.

This came to a head the other day, when I took a very sharp uphill curve on a rural road at ~5-10 mph higher than its signed speed, and the rear wheels entirely broke loose, leading to screaming tires, the rear end coming over the line, and me pointing a number of degrees further inside the curve than I meant to. I corrected, but this isn't the kind of behavior I'd like from my car. The 940 feels like it's on rails going through the same curves that the V70R threatens to throw me out of.

Can I chalk this up to any of the following:

• Worn tires - seems a bit severe for just this
• Alignment issue
• Natural behavior of a V70R with sway bars
• Improper sway bar installation - I have noticed a clanking noise from the front left side going over bumps
• Other worn suspension components?

Thanks!

[tryingbe]

What size are the new sway bars? Do you still have the old bars?

[Ozark Lee]

Much of it is just the nature of the beast. The weight distribution on a Volvo P80 is pretty awful but the AWD kinda masks that. I don't drive my AWD enough by myself (where I tend to push it) to really have a fix on its limits like I do on the 850s. The AWD is different than the FWD and my old RWD cars for sure.

The 850s and FWD 70 series cars have some real idiosyncrasies in the handling department and you get get in bad shape real quick if you go for the brakes at the apex of a corner. The passive rear steering unloads and it will instantly snap loose on you if you mash the brakes. On the FWD cars I tend to roll the apex and then nail it from the apex out. On my RWD 740s I could be much more aggressive through the center of the corner and get away with it.

All of that said, even with worn tires I don't really get a bunch of squeal when I'm pushing it. What are you running for tire pressure? At only five or ten over the corner speed "suggestion" sign it should handle that with no problem. I've only lost it once when I was doing double the flashing yellow light "suggestion". That corner was a weird bridge corner on a section of road I had never been on before that goes from 65 to 35 and I think I was doing about 70.

...Lee

[j-dawg]

So you're saying you've made your V70 into anything besides an understeering pig?

Hold on while I get my notebook and tape recorder, and I'll be listening very closely to find out how you did this. Which I will definitely not try to replicate. Safety issue. Mm hmm.

[tryingbe]

So you're saying you've made your V70 into anything besides an understeering pig?

Your FWD V70 is not the same as his AWD V70R.

Make a car to oversteer is easy, make the rear suspension stiffer than the front, either via swaybar, bushings, springs, strut/shocks, etc.

[kahl]

For some reason I am thinking about my 122S with studded snow tires in the rear about 40 years ago in the summer. Wow that was an eye opener.

[j-dawg]

Your FWD V70 is not the same as his AWD V70R.

True, but I thought AWD P80s don't send any torque to the rears unless the fronts are slipping. I imagine the oversteer/understeer balance would be pretty similar (all else being equal, which it's not - those sway bars probably make up a bunch of the difference).

[atomicthumbs]

What size are the new sway bars? Do you still have the old bars?

They're these; 25mm front and 22mm rear. I still have the old ones, but I don't have the equipment to drop the subframe myself.

All of that said, even with worn tires I don't really get a bunch of squeal when I'm pushing it. What are you running for tire pressure? At only five or ten over the corner speed "suggestion" sign it should handle that with no problem. I've only lost it once when I was doing double the flashing yellow light "suggestion". That corner was a weird bridge corner on a section of road I had never been on before that goes from 65 to 35 and I think I was doing about 70.

...Lee

I believe I pumped my tires up to whichever was the higher tire pressure listed on the label on the fuel filler door. I'm not sure that's the correct pressure to keep them at, though. And yes, my 940 lets me stay on the throttle all the way through a tight curve; I'll miss that about it (though I won't miss the gas mileage, or the various plastic bits that have been breaking off, and so on).

So you're saying you've made your V70 into anything besides an understeering pig?

Hold on while I get my notebook and tape recorder, and I'll be listening very closely to find out how you did this. Which I will definitely not try to replicate. Safety issue. Mm hmm.

• Step 1: remove front sway bar
• Step 2: let 10 psi out of rear tires
• Step 3: adjust rear camber like so
  

voila: car is now Unsafe at Any Speed

Your FWD V70 is not the same as his AWD V70R.

True, but I thought AWD P80s don't send any torque to the rears unless the fronts are slipping. I imagine the oversteer/understeer balance would be pretty similar (all else being equal, which it's not - those sway bars probably make up a bunch of the difference).

I believe it's 95% to the front without slip. (I have wondered at times whether a computer-controlled magnetic clutch to replace the viscous coupling would be possible, though certainly not affordable.)

[tryingbe]

Take out the new rear sway bar and put the old one back in and see if you like that setup better.

[mecheng]

I wish I had some oversteer. My s70 is an under steering pig, and it has newer Bilsteins in the front.
My 850 is all original and handles better.

I'm guessing the 850s had stiffer springs because the ride is firmer and less comfortable???