[Bob in St. Louis]

I do have a 9-3 Viggen.  It's a fun car.  And useful to boot.  (I chose my moniker not because I'm a car guy -- I'm not -- but because no one has this name anywhere.)

Gotcha, just curious.

Bob - General Motors Guy!! aa

[lazydays]

1** once the engine has circulated the oil for three or four minutes (most of the manufacturers are specing 5w-30) the oil is right where it should be. If you happen to be using synthetics; there is no real difference between cold oil and hot oil.

Yes, the engine oil, which still leaves the transmission fluid, the differential oil, and the grease in the various bearings.

2**that would be true in an older car built in the seventies or sixties. But all the newer ones sense the ambiant temp, as well as engine temp, and adjust from there. You can't change it as it's in the computor that runs the engine and fuel delivery system.

Still true today.  Try flooring the gas before the engine warms up to see how sluggish it is.  When the engine is in warmup mode, power and efficiency go down the crapper, this is what it's supposed to do, as directed by the ECU for emmissions control reasons.

3**virtually all fuel injection systems have a gas return line back to the tank or fuel delivery line. You will never use anymore gas than needed because the CPU will not allow it. Still if you happen to have a bad sensor the fuel injection system will automaticly go into a full fuel delivery. Might want to have a scan run on the sensors.

I think we have a mis-understanding here.  The engine is essentially an air pump, it takes X units of air to make Y units of power.  When it's cold the air is denser, thus X units of air will fit into a smaller volume, so to make the same amount of power, for say cruising on the highway, a smaller volume of air is needed.  To do that, the throttle valve is choked back, which results in more engine vacuum and pumping losses since you're now sucking air in through a smaller tube.

4**torque convertors are set to lock up at speed above forty mph, unless the speed sensor is out of wack. It's pretty much a mechanical thing after that.

In theory, and it also depends on the design of the darn thing.  Some, like the one in my car don't lock up until the fluid is warm enough.  Others have fuzzy logic which juggle speed, temperature, and a bunch of other parameters.  Still others are strictly speed based.

I worked for the company that invented the lockup convertor as well as the variable pitch convertor. We were doing solenoid controlled gear boxes back in the very early eighties (albeit somewhat crude by todays standards). We were the people that built the first four or five generations of CPU controlled automatic transmissions, and the latest generation of E-Prom controlled ones. Have seen them all at one time or another, and with the exception of valve body technology; very little has changed in the last forty years. It takes a lot more horsepower to drive an automatic transmission than most folks realize. All transmissions can be divided into two basic designs, and neither one is all that much better than the other except in high load conditions. There is a third design looming that will make all these obsolite. It's projected to only use about 25% of the power, and it's the future (sorry Mercedes). It maynot use a torque convertor, but of course it can if needed. Cannot go much further into it, but it's on the test stands right now. There's also a type of automatic transmission that has a built in electric motor (think G.M. & Chrysler  here) that make it's debut this coming fall in SUV's.
It's big and somewhat heavy, but still better than what they are using now. The Fed is really pushing the last one.
gary

[Bob in St. Louis]

Gary, if you're responsible for some of the engineering ideas out there, I've got some technicians that want to have a chat with you (in a dark alley)

HA HA, sorry, just kidding Gary.

Bob

[Berndt]

O.K. guys, I've got a few questions on cars that someone might be able to help me with.
1. Why does my car get poorer gas mileage in the winter?

Fuels ability to atomize is directly porportionate to its ability to combust or convert to heat.
High efficiency designs run at a higher operating temperature allowing the maximum amount of fuel to vaporize before reaching the combustion process.
When intake tract and the ambient air temperature is low it takes more fuel to achieve this level of vaporized fuel, hence a richer mixture and poorer fuel economy. Direct injection is the closest thing we have for mitigating the cold weather scenario, but it also take fuel to heat the motor to a desired temp, this comes right out of the fuel mixture. Ideally your motor wants to be tempX and it takes fuel to creat that heat.

MTBE was used in winter fuel formulations to assist in having fuel vaporize.
Alcohol doesn't do the job MTBE did.
I could get more specific but had an ot shift last night and my brain feels like mush, maybe I'll invite some fuel guru friends to participate in this thread if y'all would be so inclined. I used to blend racing fuel and hang out with some very gifted fuel guys who brought me out of the dark ages on this topic.
I hope I didn't thoroughly step on my dick here, 3 hrs of sleep messes with my fuel functions.

Bill

[Dan Banquer]

"I hope I didn't thoroughly step on my dick here, 3 hrs of sleep messes with my fuel functions."

If you can step on that then you are wasting your time in this forum!

Bring on the fuel guys; I have much to learn.
           d.b.

[sts9fan]

MTBE was used A) to prevent knocking and B) it is an oxygenate in other words it increases the oxtane of the fuel.  This helps create a cleaner burn.  Ethanol will not do these things.  It will reduce the energy conatined in the fuel thus decreasing you mileage.  Ethanol will remove water from your fuel becaue of its nonpolar structure.  This is one of its HUGE downsides as a fuel because it cannot be shipped via pipeline.  2-Butanol is a much better fuel because A) it has one more bond so more energy B) it is less polar so it will not pick up water. 

P.S. My mileage drops around 10% in the winter but that is because of the winter treated D2. My TDI still gets 45mpg so I am not complaining.

[Bob in St. Louis]

Sorry guys if I'm a bit sceptical on using fuel blends as the reason for Dans decrease in economy. Working in the repair industry for the past couple decades, I'd be seeing hoards of people banging down my door if they noticed a 10mpg drop in efficiency. And that number is from a pretty fuel efficient vehicle, if it was the fuels fault, what would the Suburban, Excursion, Hummer owners be claiming for their mpg rating?
Besides, I believe the EPA would intervene if this happened to too many people.

By the way, I am the owner of a full size GM truck (5.3l) who's economy doesn't change by season.

Bob

[sts9fan]

most people barely know where to put the gas never mind what mpg they are getting...

[Bob in St. Louis]

Very true. Or they judge the mpg based on the useless trip computer

Bob

[alana106]

Very true. Or they judge the mpg based on the useless trip computer

Bob

  I agree...Sorta.  I had a Lincoln Towncar, and A Cadillac Deville.  I checked actual MPG compared the trip computer, and the computer almost always indicated better fuel economy, than reality.

  I've had an Acura for 8 months, and the few times I did the compare, it seemed to be right on.

Alan

[Bob in St. Louis]

Correct Alan, from what I've seen, they are either right, or indicate 'better' than actual economy. Hard to get some customers to realise that. Some aren't smart enough to use a calculator to check it for themselves.

So DAN, how's the Saturn coming along? Enquiring minds need to know!
Bob

[Dan Banquer]

Well Bob;
  The first thing I'm gonna do this weekend is check the air pressure in the tires. I'm waiting for the weekend  because it is supposed to be warm enough so that I won't freeze my old fingers off doing it! The Saturn is doing fine so far, I am letting it warm up less, and when I start to drive I start off slowly so as not to strain it much. You can do that at 6:30 in the morning cause there ain't much traffic. The mileage appears to be improving. I also added about a half a tank of 89 Octane to the regular 87 Octane and this appears to help a bit, or I just could be fooling myself.
So Bob; am I fooling myself? or does this help a bit in the cold weather?
               d.b.

[aerius]

Sorry guys if I'm a bit sceptical on using fuel blends as the reason for Dans decrease in economy. Working in the repair industry for the past couple decades, I'd be seeing hoards of people banging down my door if they noticed a 10mpg drop in efficiency. And that number is from a pretty fuel efficient vehicle, if it was the fuels fault, what would the Suburban, Excursion, Hummer owners be claiming for their mpg rating?

Actually a fuel efficient vehicle would see a much higher MPG drop than a gas guzzler.  Let's use a vehicle switching from regular gas to E85 as a worst case scenario, E85 having roughly 70-75% the energy content of gasoline per gallon.  Car 1 is say, a Honda Civic getting about 50mpg, it'll take a 25% mileage hit on E85 dropping the fuel mileage to ~37mpg, a 13mpg hit.  Car 2's a Hummer, about 10mpg on regular unleaded, on E85 it'll drop to about 7.5mph, that's only 2.5mpg lower.

In short, fuel efficient vehicles will see a much larger fluctuation in mpg numbers than gas guzzlers, but percentage-wise I'd bet it's pretty close.  Which is why many countries use litres/100km instead of miles/gallon to measure fuel consumption.

[Bob in St. Louis]

I also added about a half a tank of 89 Octane to the regular 87 Octane and this appears to help a bit, or I just could be fooling myself.
So Bob; am I fooling myself? or does this help a bit in the cold weather?

Dan -I wouldn't think it would make enough of a difference in your car to "save money". Your fuel delivery system is adaptive, so it would run a little more efficiently (better combustion process). But to justify the price per gallon, your not really gaining much.
Just out of curiosity, when was the last time the injectors/valve train cleaned of carbon deposists?
Keep us posted Dan!

aerius - I agree with what you just said. However, I wasn't refering to such a drastic change in blends. I was mainly talking about what changes the petrolium companies make from brand to brand, season to season, additive packages ect...
E85 is a marketing financial joke in my opinion. (I'll get blasted by someone for that one.)

Bob

[lazydays]

Gary, if you're responsible for some of the engineering ideas out there, I've got some technicians that want to have a chat with you (in a dark alley)

HA HA, sorry, just kidding Gary.

Bob

actually I retired in December with the golden handshake (if you know what I mean). The folks I worked for know more about hybrid drives than all the rest of the automotive world put together (not bragging as this is a well known fact). We've been doing fuel cells for five years, as well as hybrid electric drives. We also get the task of undoing miss engineering from other divisions, and there's plenty to go around.
     Right now we can build you a mid sized Saturn that will get 80mpg with zero emissions (this is a fully loaded automatic transmission car), doubt any of here could afford one (about a million dollars a piece right now). That same car stripped down and with a manual transmission got 108 mpg, and was much faster than a gas engined car.
But the hold up right now is Eccotec and Baldwin Fluid Power's hydrogen fuel cells. Technology is really expensive these days, and moving so fast it's hard to keep up.
     Right now the Fed is really pushing us for mass transit development. If you keep your eyes open you'll see are units all over the place in the bigger cities (N.Y.C. and L.A. for example). Yet these are nothing more than a stop gap measure, but get almost triple the gas milage. From what I saw the next big push will come in Class A RV's and medium duty trucks (think school buses) in a hybrid electric drive units. This technology is just way too expensive for automobiles right now, but it's just around the corner.
We messed with everything from gas turbine powered semis to four wheel drive electric cars thru the years. Some of it's a bust, and some of it's on the road right now.
gary

[lazydays]

Sorry guys if I'm a bit sceptical on using fuel blends as the reason for Dans decrease in economy. Working in the repair industry for the past couple decades, I'd be seeing hoards of people banging down my door if they noticed a 10mpg drop in efficiency. And that number is from a pretty fuel efficient vehicle, if it was the fuels fault, what would the Suburban, Excursion, Hummer owners be claiming for their mpg rating?
Besides, I believe the EPA would intervene if this happened to too many people.

By the way, I am the owner of a full size GM truck (5.3l) who's economy doesn't change by season.

Bob

I get 19 mpg out of my 5.3 in 2 wheel drive or 4 wheel drive on the highway. The H2 is nothing but a 1 ton Tahoe chassis with a box put ontop of it. Doubt they get 16 mpg. The Excursions are even worse. There is a couple new deisels being developed that are getting in the mid twenties, and are maybe 18 months away. That plus a certain new six (or even seven speed) automatic will make a huge difference. But you wont see them in the H2 hummer anytime soon.
gary

[Bob in St. Louis]

Gary - you sound like you'd be a cool guy to sit down with a beverage and chat with.
Neat information there. As a service department employee, hybrids, electrics all that stuff scares the hell out of me. I'm glad I'm not the guy turning the wrench anymore. Anything "Non-Conventional" is just a pain in the ass to diagnose/service. Not enough training in the industry for the new radial stuff. And I mean radical stuff by "our" standards. Some of these guys in the shop have been working on cars since before cassette decks were standard. You think THEY are going to be able to adapt to a car driven by an electric motor, or hydrogen?

But the 'techie' in me, loves new technology. Like GM's new skateboard / Hy-Wire chassis. That things cool.  aa
Even the GM "Volt" is pretty cool (Hope it works!)

Bob

[Bob in St. Louis]

Opps, I was typing while you posted.
What 5.3 are you driving that your getting 19?!

(Modded H2, was I reading that right??)

Bob

[Dan Banquer]

I also added about a half a tank of 89 Octane to the regular 87 Octane and this appears to help a bit, or I just could be fooling myself.
So Bob; am I fooling myself? or does this help a bit in the cold weather?

Dan -I wouldn't think it would make enough of a difference in your car to "save money". Your fuel delivery system is adaptive, so it would run a little more efficiently (better combustion process). But to justify the price per gallon, your not really gaining much.
Just out of curiosity, when was the last time the injectors/valve train cleaned of carbon deposits?
Keep us posted Dan!



Bob

Hi Bob;
   I don't think I have ever had the injectors or valves pulled out and manually cleaned. I have used some fuel additives in the past that claimed that they would clean the carbon deposits but I am rather skeptical as it appeared that there was no increase in performance. My mechanic has told me flat out that these additives don't do diddly squat as there are plenty of additives in the fuel to take care of this.

What's your take on this?
             d.b.
P.S. I only use the 89 Octane when it's very cold, (single digit temps) seems to help a bit when starting the car, or is this my imagination? The car does seem to run a bit smoother in the cold with a touch higher Octane mix.

[Bob in St. Louis]

I don't think I have ever had the injectors or valves pulled out and manually cleaned.

No, not a physical removal of the parts, just a chemical cleaning.

I have used some fuel additives in the past that claimed that they would clean the carbon deposits but I am rather skeptical as it appeared that there was no increase in performance. My mechanic has told me flat out that these additives don't do diddly squat as there are plenty of additives in the fuel to take care of this.

Two products exist that I would put in MY fuel tank. One is only available only to industry, the other is "Chevron - Techron". A little expensive by "in the tank cleaners" standards, but it works.

I only use the 89 Octane when it's very cold, (single digit temps) seems to help a bit when starting the car, or is this my imagination? The car does seem to run a bit smoother in the cold with a touch higher Octane mix.

Definitely Plausible, sure. I'd buy that.
(We had a car in the shop this week with a very bad cold start problem. It would cough, sputter and die, repeatedly. It is 6 years old with 80K. Once it was up to operating temp it ran great. No warning lights seen, no codes in system.
We cleaned the injectors, now it fires up just like a new car.)
Just a point to ponder.........

Bob