'Summer weight oil'

[heyjay]

quote:

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Originally posted by zoomzoom:
heyjay If I'm not wrong M1 0W-30 is acctualy thicker then M1 10W-30 at 100 C!

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I'm not refering to Kinematic at 100 C, but to HTHS. The numbers change quite a bit:

Mobil 1 0W-30: 2.99 mPa s @ 150 C
Mobil 1 10W-30: 3.17 mPa s @ 150 C
Mobil Delvac 1: 3.99 mPa s @ 150 C
Mobil 1 15W-50: 5.11 mPa s @ 150 C

This test is under high shearing conditions of one million shears per second.

The difference in HTHS viscosity is JUST enough to eliminate most of my valvetrain noise. For a modern motor with hydraulic valve lifters, I'm not used to hearing this:

ticktickticktickticktickticktick.

If my local Mobil distributor doesn't have Mobil 1 Truck & SUV 5W-40 by April, I'll just use Mobil 1 15W-50 again.

I tried Mobil 1 15W-50 in summer of 2001 while doing heavy towing: the motor was SILENT, and after almost 12,000km of heavy use, the oil was still at FULL on the stick. Mobil 1 10W-30 will be down to ADD under the same towing and distance.

Jerry

 

[moribundman]

heyjay wrote:

quote:

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Moribundman: Actually, if your tire is half-flat at -35 C, driving around will usually make the bead unseat from the rim.

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I've had a couple tires disintegrate at high speeds, one in the rear at over 200 km/h. Luckily, the bead never came off.

At -35 degr C, you won't find me on the road, or out of my chair, for that matter.

The nitrogen fill was popular in Germany back in the '80s. I don't know if it still is.

 

[Thomas Pyrek]

Remember though that the environment we live in is 80% nitrogen. Putting nitrogen in your tires is kinda silly anyway. Even after 1 year of just being outside a tire has gone through so many heat cycles that the compound has hardened and become less grippy. I'd rather replace a tire more often than stretch out the life of a tire. Fresh tire compounds are quite nice to me.

 

[moribundman]

The main reason for the gas fill (I assume it was nitrogen, but it maybe have been another gas) was that you didn't lose any pressure over time, because the gas molecules were rather big. I had little valve gauges that would show pressure loss, but those were way too inaccurate. I got the gas fill only once.

 

[Thomas Pyrek]

It is nitrogen. I just keep one of those minicompressors with me all the time (in my car the spare is stored flat...) and a really spiff tire gauge.

 

[brad_d]

Some of you guys are talking like using nitrogen instead of air will reduce/eliminate pressure fluctuations with ambient temperature.

I don't see how that could be. PV=nRT applies to both pretty much the same way (pressure and temperature are still basically proportional). Am I misunderstanding?

 

[Hankrr]

Air is already 78 percent nitrogen so I seriously doubt if anyone would really see much if any difference in going to 100 percent.........

Oxygen which makes up another 21 percent is also a heavy molecule so your only looking at about 1 percent of the gas being lighter , ie: mostly hydrogen and helium with some carbon dioxide making up the bulk of that last 1 percent.

[ February 26, 2004, 09:29 AM: Message edited by: Hankrr ]

 

[Forkman]

Ah yes, tire pressure. Something I'm even more anally retentive about than the oil.

In summer I check it at least once every 3 weeks and before any long distance trip.

In the very cold time of the winter season I check about every 3 weeks. However, when it gets like it has been lately with wild temp swings during the week (45deg on day 15degF the next) I check them at the begining of each week.

I look at what the current temp is and what the expected variations are over the week and set the tire accordingly. For example, if the temp today was 35deg and the expected highs for the week were 45 and lows of 20 I'd set the tires at about 30.5psi. For every 10degF there is approximately 1psi change in tire pressure. So when the temps dip to 20 the tires would be about 1 psi under inflated and at 45degF the tires would be about 1.5psi over inflated.

 

[Eddie]

The main scientific reason for going to a 100 percent Nitrogen fill is because 100% N. is processed DRY meaning there is no water vapor to degrade and dissociate. Ed hayes

 

[jason07-1zzfe]

Mfr tire pressure sure as heck are set for 'soft'. Ever try an auto-cross at mfr spec? You will not be competetive, even if you are the best driver.

Or in the case of previous gen explorer...set to even more greatly reduce traction over normal so it does not flip.

 

[Dr. T]

Don't think manuf. specs autox'ing on all season tires either....but for all-around use ie. street driving.

In other words yes if you plan on auto-rx you increase the tire pressures and mud-slinging would require a decrease in tire pressures.

 

[jason07-1zzfe]

But the traction increase is still there whether you are driving street or running an auto-x. Possibly even moreso with the all-season tires because they have softer sidewall, which will exaggerate the difference, especially when cornering. Yes I do run slightly lower pressures on the street than when auto-xing, but that's because it is extremely harsh driving on the street like that. It's a compromise.

 

[dustyjoe1]

Call me old fashioned, but as a teenager working as a pump jockey I noticed that if you ran anything less than 32lbs, your tires would wear on the edges. Later came radials and the same rule held true. My 98 expedition calls for tire pressures of 30 lbs. on 400 dollar tires. I think that qualifies as a soft setting in my book. btw, i run mine at 33psi.

 

[zoomzoom]

I wonder what is the rule if you get bigger tires. OEM for stock 205/55-16 is 32PSI.
What would it be if you put 225/50-16 on the same rims/car?

 

[Dr. T]

tirerack will tell you the psi's will stay the same regardless of tire size/wheel combo because it is calculated based on vehicle weight

 

[buster]

According to Dr.T and John Browning, you should run a 100w-250 wt oil in the summer months.

 

[moribundman]

quote:

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However, moribundman, the manuf. tire pressures aren't set for 'soft'. They're based on OEM wheel/tire combos and vehicle weight. Increasing psi's will decrease your traction (especially wet/rough road) and noise. Fuel economy gains will be minimal (after OEM recom) unless you have a different tire/wheel combo...and all at the expense of ride quality (on anything but smooth roads). But, to each his/her own.... [Cheers!]

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Audi (other makers, too) themselves says, if you drive sporty, you should increase tire pressure. They also recommend increasing tire pressure before long distance high speed driving (Keeps the tire cooler). I've always run a few psi above recomendation. The footprint of the tire won't change enough to decrease traction noticeably. I mean, how much more traction could I need on a Quattro?

Anybody I know and who drives their car sporty increases tire pressure. The manufacturer's recommendation are based on a driver, a passenger, and a sack with groceries in the trunk. I got a nifty schematic under my gas flap. It shows how tire pressure should be adjusted depending on the number of occupants and cargo. I always run tire pressure that's close to the upper limit. Like someone else said, if I don't do that, the edges of my tires will be gone way too fast. Handling also improves with slightly increased tire pressure. And don't worry, I'm not anywhere near the 51 psi limit the tires have.

Audi recommends 32 psi for the OEM 205/55/16 tires. I run on 36-38 psi.

zoomzoom, I'm against putting wider tires on rims. I know places where that's illegal due to safety concerns. I've seen people force 225 tires on 205 rims, and the tire was deformed, its structural integrity most likely compromised. If anything, I'd at least suggest to not go more than 10 mm wider. For example don't go more than from 195 to 205. Tire pressure should change with size and type of tire, driving conditions, and driving habits.

Perfect tire pressure also depends on the tire itself. Some tires have stiffer sidewalls than others, and wear and handling can change dramatically depending on inflation. I had one Michelin tire that was so stiff, I could let the air out and drive around without noticing a thing. It wasn't even a run-flat tire! That tire should have mandated the use of a tire pressure monitoring system, but it didn't.

OEM maker will rather recommend lower tire pressure, but put crappy low resistance tires on the car. That Michelin Energy tire comes to mind. It's one of the worst tires I've experienced when braking hard.

[ February 26, 2004, 06:57 PM: Message edited by: moribundman ]

 

[moribundman]

quote:

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According to Dr.T and John Browning, you should run a 100w-250 wt oil in the summer months. [freaknout]

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10 pounds of clarified butter will work, too.

I'm afraid I'm one of the people favoring thicker oils, especially under hot conditions. I wouldn't go below an xW-40 oil, unless it's at least A3-rated and meets the car maker's specs. That's in MY case for MY car.

 

[Lubricious]

How about about filling the tires with methane?
This way you can sniff out any leaks.

 

[edhackett]

I fill my tires with Nitrogen 14 in the winter, then replace it with the heavier Nitrogen 15 for the summer months.

Ed