Herman and Operation 30MPG

[ZionXIX]

Should we start a tire thread? I am not opposed to buying pricier tires if they last longer. Currently I have a set of pirellis I purchased like 5 years ago but car has not been driven much there is more cracking than tread wear.

[callahanoffroad]

Man, Who would have thought a little offhanded comment would have sparked so much debate!

I went up a size in tire. 195/65/15 instead of the 195/60/15. With all the bumps, open gutters and potholes around the St. Louis area I've found the slight lift gives a little more forgiveness from scraping the front bumper going up steep inclines. We have many steep inclines in my delivery area as it is a very very hilly area. Got some continentals on Herman now. Had Firestone Ecopias before.

What I was implying was not necessarily that 850's eat tires by nature, but they are very easy to knock out of alignment (at least in my experience) which causes the car to eat tires/tyres My last 850 came out of alignment about every 4 months or so (because we have such terrible roads around here). It would go through a set of tires every 12 months. Crazy, right?

I've been doing a little research over at ecomodder, and have begun to format an "MPG attack plan." Step one: Sell Herman, Step Two buy Honda Insight. Just Kidding. I don't think Herman is actually worth anything if I sold him! Hahaha

I remember from doing my bit of ricing back in the day that lowering unsprung mass is more effective than lowing sprung weight. I'm not really sure what I could lower in that department as I'm already running alloy wheels. I know the bigger tires are a little more heavy, but i'll just have to deal with that. I do agree with Matt that removing the spare tire is foolish. Although I do have a few spare cans of fix a flat....

Im currently thinking that if I could build a flexible but sturdy front lip to reduce the airflow under the car it may help a bit with MPG. Admittedly only on the highway. But I do know that lowering the side skirts and front bumper will help displaced air move around the car more smoothly. The big puzzler for me currently is the rear window/trunk(boot) aerodynamic dead area. Any air moving over that roof is going to tumble off the car and create all kinds of bad aerodynamics. I can actually see the dead area when i drive in the rain. Water just sits on the back window and first half of the trunk. So I'm thinking that I need to make some kind of Kammback spoiler, or aileron to help the air transition more smoothly.

Other easy/free options include blocking off the front grill, and the lower bumper grills where the fog light should be. There are also large voids on the right and left sides between the bumper and engine bay (for example where the Charcoal Canister and Vacuum reservoir are.)

So, those are the issues i'm looking for solutions to, and I invite as much conjecture as possible.

-Ryan

[Rattnalle]

The body itself should allow a low consumption in line with my figures, its what all my five cylinder Volvos have consumed as long as I've avoided excessive stop and go traffic. There's something else that's wrong, either that or petrol over here is supercharged or something.

How's your driving style? Always in highest possible gear and so on? Fourth at 50 kph and fifth at 70 kph. Not doing long slow accelerations but getting up to speed so you can shift up. Engine braking when coasting. Basic Eco driving in other words.

[callahanoffroad]

The body itself should allow a low consumption in line with my figures, its what all my five cylinder Volvos have consumed as long as I've avoided excessive stop and go traffic. There's something else that's wrong, either that or petrol over here is supercharged or something.

How's your driving style? Always in highest possible gear and so on? Fourth at 50 kph and fifth at 70 kph. Not doing long slow accelerations but getting up to speed so you can shift up. Engine braking when coasting. Basic Eco driving in other words.

Well that's what I thought as well, a 5cyl should have consumption between a 4 cyl and 6 cyl.

My driving style is not 100% eco focused but I'm rarely over 50% throttle.

Results are in for midgrade and mpg is almost identical to premium. 23.5 mpg. So that's some saved $$ there. Running a test tank of regular now. My goal with these tests is to document the differences bt all three grades and finally put the debate to rest. Hahaha

Like I've said before I really need to take a road trip and test the highway mpg. Get some solid results.

I'm doing this for the science! Right? Right?

[Rattnalle]

My figures posted earlier included going onto the motorway or a larger road in second or third and letting the engine road to the red but then quickly getting into fifth instead of doing a slow half throttle acceleration in fourth. Eco-driving doesn't have to be boring, a lot of it is about conserving momentum, not breaking if you don't need to and not riding in a low gear longer than needed.

[FLXC90]

Your aero stuff will be pretty much useless under about 45 mph. unless you can do a full belly pan! Look to reduce rolling resistance and friction losses. And of course weight. As for the rear window to trunk transition, look at the vortex generators and a Mitsubishi EVO.
Full synthetic fluids everywhere, look at modifiers like Z-max and such. Do it for science!!

[Rattnalle]

Do it for science!!

Just don't expect too much (or anything)

[abscate]

You can probably get Herman up into the high 20s in mixed driving but the reports of > 30 mpg in P80s stretch credulity, Hyper Miling or hilly country, notwithstanding.

My 1999 will still get high 20s on the highway at 55 if I stay off the boost, I wrote a thread on how it drops from 55-60-65 mph

My P2 NA with its sexy body and slippery lines and no guzzling turbo breaks 30 routinely.

[Rattnalle]

I can't really tell a difference between my two previous P80 or previous and current P2 when it comes to consumption apart from the two latter being autos and therefore terrible in the city. Long distance roughly the same at lower speeds <100kph. The higher gearing of the autos does make a large difference at high motorway speeds though.

[abscate]

Even when new my 99 would get 29 mpg at highway speeds of 55 mph, I've never broken 30 on that car

I'm not sure the 2005 has ever given under 30 mpg mixed driving