Oil changes

[R.O.R-2.0]

I was so impressed with their Diesel Purge I splurged on the oil and went with some of this

http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_1360.html?Opendocument&land=DE&voilalang=e&voiladb=web.nsf

I had bought a 3 pack of Mann filters when I first got the car so I put a fresh one of those in. 5000 miles on Rotella. No issues. I only have a couple hundred miles on it but Ill see if there is a difference in fuel economy.

Oh wait, I also just put on some fresh 185/70's and got a much needed alignment, so that test is null. 

Rides so much nicer! Has me totally rethinking lowering it! Lower RPM's, and they really soak up the bumps.

13 or 14" wheel? those tires are gonna suck your mileage down atleast 3-4 mpg if on a 14"

[DieselBalz]

There on my snowflakes. 14's. Its runnin 400 rpm less at 65 mph. Why would I get less mpg? Its the same aspect ratio as the previous set. Added weight is the only thing I could think of that may effect it but sureley not enough to offset the less fuel bein used to run 400 rpm less at desired speed.

Interested in your response.

[8v-of-fury]

Well not to mention the 14" snowflakes are an alloy, and therefore probably weigh less than a 13" steel.. so its not like rotating mass is any different. I have 185/60/14's on my snowflakes and I didn't notice any mileage difference between 14" alloy and steel, or 13" alloy or steel.

[theman53]

Width. More wider is more badder for mileage.

[8v-of-fury]

If your comparing 245's to the 185's i'd say so, but 185 and 175? Then you factor in the offset of the lower rpm's, and your probably not any worse off.

[theman53]

The difference from 175 to 155 is huge. I don't know about the 185 to 175 the only thing I have done with that is my snow tires and I did see a jump in mileage but only had them for 1 week and it was time to take them off.

[clbanman]

From the book "How to Select a Motor Oil for Your Car or Truck":

Sooner or later, wear from abrasive particles and deposits from carbon and oxide insolubles will interfere with efficient combustion in an engine. Valve train wear (cams, valve guides, etc.) can impact timing and valve movement. Wear of rings, pistons and cylinder walls influences volumetric compression efficiency and combustion blow-by resulting in power loss. Particle-induced wear is greatest when the particle sizes are in the same range as the oil film thickness.

For diesel and gasoline engines, there is a surprising number of laboratory and field studies that report the need to control particles below 10 microns. One such study by General Motors concluded that, "controlling particles in the 3 micron to 10 micron range had the greatest impact on wear rates and that engine wear rates correlated directly to the dust concentration levels in the sump."

[R.O.R-2.0]

I was so impressed with their Diesel Purge I splurged on the oil and went with some of this

http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_1360.html?Opendocument&land=DE&voilalang=e&voiladb=web.nsf

I had bought a 3 pack of Mann filters when I first got the car so I put a fresh one of those in. 5000 miles on Rotella. No issues. I only have a couple hundred miles on it but Ill see if there is a difference in fuel economy.

Oh wait, I also just put on some fresh 185/70's and got a much needed alignment, so that test is null. 

Rides so much nicer! Has me totally rethinking lowering it! Lower RPM's, and they really soak up the bumps.

13 or 14" wheel? those tires are gonna suck your mileage down atleast 3-4 mpg if on a 14"

our cars call for 175/70/13's...

my car has 185/70/14's on it, they are about 3" taller than stock size. and about 2 inches wider..

increased height, and width are badder for mileage.. pizza cutters are where you get the mileage.

my speedo reads 55mph when im doing 63mph.. so your speedo will be off DieselBalz.. WAY OFF..

my GTI got 34 mpg on the freeway with 165/80/13's..

with the 185's, all the better it would do is 30..

my wheels are LIGHT too.. old skool enkei 92s..

i didnt post up something just to waste my breath.. your car is going to get worse mileage, i dont care if its a diesel or not..

185/70/14 is the stock tire size on audi 5k cars.. FWIW.. not even close to the stock mk2 tire size..

[DieselBalz]

I went from 185/60's to 185/70's. I'm on my first tank after the changes. Ill letcha know.

[R.O.R-2.0]

just so you guys know, the first number, is tire width..

the second number is how tall the sidewall is, the second number is basically an aspect ratio..

185/70/14 would be read as, 185mm wide, sidewall is 70% of 185mm, and it fits on a 14" wheel..

check your speedo dude, you will see that its WAY OFF now.. actual 55 mph is just right below the 50 mph mark on the speedo..

if your going 55 on your speedo, you are really doing 63 mph..

[DieselBalz]

If that's the case than I am doing less rpms than I originally thought. Like I said though ill kee an eye on it and report back.

[8v-of-fury]

our cars call for 175/70/13's...

my car has 185/70/14's on it, they are about 3" taller than stock size. and about 2 inches wider..

No way.

175/70/13-

-sidewall 4.8"
-radius 11.3"
-diameter 22.6"
-circum 71.1"
-revs/mile 891

185/70/14

-sidewall 5.1"
-radius 12.1
-diam 24.2"
-circum 76"
revs/mile 834

Your tire is only 1.8" taller, and half inch wider.. where'd you get 2"?? that'd be the difference between a 175 and a 225  . Also when your speedo reads 60, your actually doing 64.1. %6.8 too slow.

DieselBalz, Keep it under a 225 tire.. and I think you'll alright.. There is negligible difference between a 155 and 185 even.. Don't sweat it. If your really worried about the tires being your biggest drawback, get some of those hyper-mileage tires

[theman53]

I am telling you the wider the tire the more you will lose in mileage. It is very noticeable with my car, and all the other ones I have owned. Best mileage and WORST ride were the 155/80r13 tires.

[ORCoaster]

Rolling resistance is equal to width on the road is it not?  That is why the skinny tires, 155s do roll so well.  The wide fat boys 225s just don't roll like their little brothers.  Any idea on how siping affects tires for heat and mileage?  Strange that cutting a tire up like that will reduce friction and increase traction.  Anyone running such tires?  Or are we all to cheap to do that?  I am looking for new tires by the end of the summer and with all the rain driving I do I may buy into it.

Opps sorry thread hijack.

Off topic my bad

[blackbird82]

So you are saying that my 205/45/ZR17's are hurting? haha
Maybe, but i'll take it cause the handling is out of this world
i still pulled 876k on the last tank, so can't be all that bad