Negative Camber Topic is solved

[Tonyx]

I didn't research but my strut bolts on XC70 was not TTY. Spec calls for 170 ft-lb and no added rotation. Never had slipped camber issue.

[mrbrian200]

I didn't research but my strut bolts on XC70 was not TTY. Spec calls for 170 ft-lb and no added rotation. Never had slipped camber issue.

Yes pretty sure that's what I'm looking at (high tensile). 982870 is also listed for the '01 V70/XC. Some retail sites show a picture of the old original style TTY fastener that is a narrower gauge in the non threaded area (966364) but are selling the updated PN. I'm 99% certain the new PN, which is straight cylindrical through the middle, is high tensile. I can't say absolutely 100%, but I'm highly confident. Various Volvo parts suppliers all sell this new bolt, but none of them say anything with regard to a different torque spec (It could be that 74ft/lb + 60 degrees is approximately 174lb). But as the bolt is physically different than the TTY bolts that came off my S60, but are listed for your '01 XC that doesn't use TTY I would say that's enough evidence for me. Thx for the bit of info regarding your XC.

[mrbrian200]

Very impressive fuel economy numbers. I've seen as high as 430 miles to empty before but not over 600 miles.
I can only agree with your logic of reducing rolling resistance by setting the suspension for least dynamic deviation from straight(vertical/polar/horizontal directions). But it takes a bit of genius to align that to fuel econ metric. Well done.

I can see that this can be done for the front suspension, but the rear suspension is much more finicky to set. The cam to adjust rear toe is just too hard to set then tighten without messing up the toe. Many trial and error is needed.

625 was coming off a highway drive. In mixed driving around the north end of Colorado springs this week (what I would call "suburban" not downtown, more go than stop) at fill up range says 525, and bounces up and down 30-40 miles with each stoplight/straight run. AVG as reported by the DIM sits around 29.5-30, which from what I can tell is pretty accurate. Seems AVG isn't accurate on strict highway runs when suspension is tweaked + LRR tires. I calculated 36.5, DIM never went over 31.

Also determined this week that overinflating tires does not make any difference in fuel econ. I tried 35/37 merely resulted in a harsh ride. Last couple days running slightly underinflated (28/30 instead of 30/32) seems to be the best balance of ride quality/econ. Smooth ride about like my friends MKX but with much better control/steering response. Less 2PSI does seem not to affect econ noticeably but makes a noticeable improvement over large cracks/gaps in the pavement. (P7 Centurato AS+ XL variant). Getting the front end camber set at a shop this afternoon. I don't expect any further improvement in econ. This should address some moderate uneven torque steer/instability on uneven pavement that I am seeing. Frankly 36.5 on that long run between Chicago to Colorado is awesome for this type/style of car.

[mrbrian200]

All good now. Both sides sitting perfectly at zero camber. Guy at the alignment shop test drove before handing back kept repeating "That thing drives nice". 15 miles back mixed interstate/local and a bumpy road, I concur. Pretty sure this shop sees P2s here and there. I got the impression this was the first one he's seen in awhile where everything came together to result at or near (maybe better?) than showroom new ride quality/handling.
If you're chasing highway econ with a reasonable balance of ride comfort the formula that worked for me after quite a bit of trial and error:
Pirelli P7 Centurato AS+ (XL variant), pressure 28psi rear 30 front. If you're going to load up with people and luggage add +2
Set front end Camber at zero. Stiff wall/LRR performance tires don't need negative camber for a daily driver. In fact, I think negative camber introduces drivability problems with these tires. Be ready (or offer the shop extra) to tweak toe with a few short highway runs while monitoring econ and bump steer. Rear end likes both wheels toe at zero/straight ahead. Ignore minor camber error back there. Stacking weird toe settings in an attempt to counter minor camber error that isn't adjustable doesn't solve anything. It just stacks another problem (makes it worse).
OE Volvo upper spring seats ONLY. No aftermarket: some of them (including the ones I tried) don't mate into the mount/bearing quite right and introduce instability over potholes/manhole covers etc. Close isn't good enough here. The suspension design is very unforgiving of anything 'not quite right'.

BTW: Jacks Alignment Shop in Colorado Springs...Thumbs up! Good friendly people. Knew what they were doing. Trustworthy mom runs the office sort of operation. Parts counter guy at the Colorado Springs Volvo dealer thumbs up there too. Friendly helpful pleasant experience (new SEMS nuts for the flange bolts).

[Tonyx]

Can you post the final alignment readings including caster?

BTW, are you sure you are running 30/28psi Front/Rear respectively? I recall it being 32/36 F/R on the factory label on mine.

[mrbrian200]

Factory label on mine says 30R/32F. That would vary depending on which tires were installed new at delivery. They had a computerized rig in one of the service bays but didn't use it with this car (no printout). They did this car more 'old school', digital gauges and worked from underneath the car in a pit spanned with steel ramps with what I think looked steel pads on ball bearings that would indicate the toe setting as they rolled the car back and fourth about a foot. They set the front toe to straight ahead (have yet to re-tweak that, in my experience it likes to be a little toe in, but for best high speed/highway econ I think it's a little more than OE spec (+.10"). The factory spec is likely a compromise/middle ground between slow rolling and high speed where theres more torque loading. When I get back through Chicago in a few weeks I'll have the shop there drive it onto their computer rig and retrieve the numbers.

[Tonyx]

Volvo tire placard.jpg (73.49 KiB) Viewed 1573 times

Here is my tire label. It reads 35/38 F/R cold. I always wondered why F/R were different that's the reason for asking question earlier.

[mrbrian200]

That is interesting (higher pressure in the rear). Whereas mine ('06) calls for higher pressure in the front, which seems more intuitive considering the weight of the engine/trans up there.
I did begin to tweak the front end toe setting. Shorter drives just for coffee but a few miles of it is at highway speed/relatively flat. Econ on flat open looks crazy high to me. However I'm at 6000 feet/low RH. Known drag coefficient for the '06 base S60 (with the lower splash shield installed, which I do) is .28 but that number would presumably be referenced to sea level. At 6000 feet there would be an 'adjusted' drag number that would apply. Calculators I can find via google are designed for avionics (lift) which doesn't seem directly applicable to a rolling vehicle. Closest thing I can find is for cycling but plugging some numbers it appears that the effects of decreased wind loading at high altitude vs sea level may be more substantial than many people realize. It's around a 20% reduction in air mass per given volume. If the correlation to drag coefficient were linear (I don't think it is) that would make the effective DC of the S60 at 6000 feet .22 --quite a big deal.

[abscate]

The drag coefficient won't change but the drag force will go down roughly linearly with pressure in that range, so you would expect less drag at altitude.

[mrbrian200]

Plugged some numbers into ecomodder power and mpg calculator. Yes when I adjust the air density for this location/elevation MPG figures jump around +5 at highway speeds. The car should be capable of low-mid 40s at conservative highway speeds under 70mph at altitude which is in the neighborhood I am observing. Nearer sea level the range drops back to what I was seeing back in Indiana (mid-high 30s). Econ that looked absolutely crazy to me at lower speeds (under 50mph) seems to be predicted by their calc. But there's a disconnect between their calculator and my observations at very low speeds under 30mph (I do not observe anything near 80mpg at 30mph...more like 50-55 rolling along. But very low speeds also go in hand with with stop and go traffic so you would never actually get that...