Saving gas [Merged 3-8]

[EHeye]

Alright, our gas prices here locally have sky rocketed like there is no tommorrow. So I have a question, I dont make much money so I wanna save as much gas as possible.

Say im going up a hill about 7% upgrade and im doing about 80km/h (50mph?), in 5th gear to keep it constant im running at 2500rpm and 4-5psi boost, in 4th gear im at 3000rpm and 13inHg in Vaccum. Which one of these will give me better gas mileage, lower rpm in small boost or little bit higher rpm in vaccum.

 

[nutshot]

Originally posted by candela
eat a dick...

:laugh:

 

[KRAZYKOREAN]

Why not fu*k this thread cuz its going no where... and its never going to be solved.. just drive and quit worrying about wasting a pint of gas..

 

[dsmstunna]

I'm new but comon sence tells me its 4th! the way the turbo works and spools is cause of a load and if your not boost in 4th but in 5th your putting more of a load on your engine and put more fuel in it and its makeing the air hoter and making the boost go up! with little load it won't boost. and 5th gear at only 50mph up a 7% hill has to be working the engine hard

 

[nutshot]

Hey, dsmstunna, does that name stand for DSM's Tuna? If so, that's an awesome name.

 

[KRAZYKOREAN]

Originally posted by nutshot
Hey, dsmstunna, does that name stand for DSM's Tuna? If so, that's an awesome name.

:laugh:

 

[dsmstunna]

dsm-stuner or dsm's tuna either way works

 

[nutshot]

Sorry, this was written buy my co-worker, I will hit her for it.

 

[dsmstunna]

 

[Bohrn]

hey, he's just trying to find out some useful info, if you don't want to actually help, why not just go and do what Candela said and go eat a dick? Maybe chocolate covered?

Or, god forbid, we could help out the community, and save some money.

But, Travis, we already discussed this Its a vacuum guage thing. More vac = better mileage. Generally.

And its not that long a hill really. Just take it at 65(km/h) in 4th. Id say that would do it best.

 

[eclipse13]

Originally posted by candela
you cant calculate it you dummy...give it a fuggin rest!!

did you just say dummy?

 

[dialogue]

A higher revving engine does not always equal less gas mileage. By driving in a higher gear, (lower RPM) will cause your engine to "lug", this condition will burn more gas. If lower engine speed always got better gas mileage, we would not need additional gears. One gear would work.
Try driving around in one gear higher than you would normally and watch your gas mileage drop. In city driving, leaving the overdrive off will give you better gas mileage.

Driving on a level ground at highway speeds, overdrive will normally get better mileage. Going up a long hill in overdrive will get less gas mileage.

In the first Gen, turbo, the factory rateing (not modified) according to a Car & Driver article on the 90 Eagle AWD, listed 203 foot lbs @ 3000 rpm other years, makes, transmissions, modifications will be different. To obtain maximum efficiency, i.e. gas mileage, it would be best to drive on a level road at maximum torque (3000 Rpm), acceleration, hills. wind, road conditons are all aditional variables that will make a difference.

On the other hand going down hill, with the wind blowing at your back, on a smooth highway a lower rprm, (overdrive) will give better mileage.

A turbo induction will generally give better efficiency than a non-turbo at the same load/rpm. The turbo will generally mix the air-fuel mixture better than a non-turbo.

If you did run your test, all conditions would have to be the same, engine same temperature, outside temp the same, wind the same, humidity, day or night, electrical load, and the same acceleration, just to name a few, then try the 4th gear verses 5th gear. For the most part it will not make any difference.

In cross country driving most people think a cruise control set at x mph will give them the best gas mileage. This is true if they are not a well informed or experience driver.

Driving with the cruise control off, allows you to slow down going up hills, speed up going down hills, slow down in a head wind, speed up with a tail wind. On a stright road, no hills, no traffic, no wind, maintaining your max torque@rpm will give the best mileage.

Other factors come into play, example, driving during the day with no headlights on (even more important with pop-up headlights), big watt stereo off, wipers off, AC off, windows rolled up, sunroof closed.

On several cross country trips I have made 43 miles per gallon during several stretchs. Driving from Salt Lake City to Kansas City with the wind blowing from the west and this is with a 91 Talon AWD (turbo) Automatic transmission. If I had a manual I could have done better.
Remember also that in the mountain states the octane is many times 2 points lower than the flatlanders. Lower octane will cause the computer to retard the ignition, giving lower gas mileage.

As some posters said, stay off boost. This is generally correct, but not all the time. Driving up a long mountain pass on boost will sometimes get better gas mileage than driveing off-boost in a lower gear.
As in any case YMMV.

 

[Race94]

Let's see if you can help me, well i have a 95 GST, my regular driving routine includes some traffic jam, about 15 minutes total all together and one hill about a block long to my house, my gas mileage is very bad, the guy who sold it to me said it had a bigger fuel pump but the only mod is an air filter and a 14b, nothing else. Now to the questions: could it be the fuel pump??
Where do i shut off the overdrive since i almost never do highway mostly city?
If i turn the boost all the way down will it help my gas mileage?

I also shift at around 2,500 RPM and i am usually on 4th at 40-45 MPH

Thanks!!

 

[dialogue]

Originally posted by Race94
Let's see if you can help me, well i have a 95 GST, my regular driving routine includes some traffic jam, about 15 minutes total all together and one hill about a block long to my house, my gas mileage is very bad, the guy who sold it to me said it had a bigger fuel pump but the only mod is an air filter and a 14b, nothing else. Now to the questions: could it be the fuel pump??
Where do i shut off the overdrive since i almost never do highway mostly city?
If i turn the boost all the way down will it help my gas mileage?

I also shift at around 2,500 RPM and i am usually on 4th at 40-45 MPH

Thanks!!

One small hill will not make any measurable difference. Overdrive on the manual transmission is the 5th gear. You do not give enough information for me to help much. Your fuel pump used on a stock engine, without an adjustable fuel pressure regulator could be causing you to run rich. Rich running normally means lower gas mileage. If by air filter you mean a K & N then that is OK. No need to turn your boost down, for the most part you can control the boost with your gas pedal. Make sure you have a good tune-up, correct timing, new spark plugs, good spark plug wires, O2 sensor. There are many, many reasons for low gas mileage. How many miles is on the engine?, have you done a compression check? What is the octane of the gas you use? Is the gas oxygenated like winter gas up north? Make sure your tires are aired up correctly. Do you have a 195 degree thermostat? After you have done all the maintenance work you can, then take it to a shop that does computer tuning, anything and everything will help as the price of gas keeps rising. Oh, get rid of your spare tire, extra tools and junk as they add weight. Put the spare tire in if you travel and great distances.

 

[Blitzed95Eclips]

I have noticed my car runs at the same richness (is that a word) whether im running in full boost or if im in no boost and just cruising. Whenever i hit the gas pedal my fuel (richness) goes to the same thing. Your best bet is to just not floor it, drive like a granny.

 

[Bohrn]

4th is also overdrive on our cars.

Also a question. Max torque@rpm is measured with WOT, with full boost. Now we are no where near WOT when driving at a set speed on a relatively flat area. Does this still appy??

 

[babell2]

I'm sorry this has gone round and around but I think that not one of us has the knoledge to answer you'r question. The only people that I think could is TMO. They have logged the fuel usage maps in the ECUs and know how the ECUs think. Except it looks like TMO has fallen off the face of the earth at this point and no one is left to suply insite to the mistery. Sorry!!

 

[dialogue]

Originally posted by Bohrn
4th is also overdrive on our cars.

Also a question. Max torque@rpm is measured with WOT, with full boost. Now we are no where near WOT when driving at a set speed on a relatively flat area. Does this still appy??

I am sorry, but I do not understand your statement. What source do you use when you say "is measured at WOT", and full boost? Hp and torque are an SAE measurement. Non-turbo engines at max torque@rpm are not measured differently than turbo engines.

How does an engine rated at torque@rpm at WOT is different than one at a steady throttle setting? When an engine is on a dyno, do they take one measurement at (in this case) 3000 rpm at a steady state, mark down the torque, and then redo the 3000 rpm run at WOT? Wow, I've been doing this wrong for many years.

Help me out here, I'd really like to know the difference.

 

[Bohrn]

ok, I guess that on this board, if you ask a question that questions the data in a post it is implied that you are disrespecting the poster,and are really not asking a question, but, in fact, telling the poster that they are wrong. Publicly.

However, I say what I say,no games. If I ask you a question, it is just that. If I call you a dumb weasel, that is how I feel at that moment. By the same token, if I pay you or your ride a compliment, I mean it, and am not blowing sunshine, or currying favour.

So I asked you how a max torque setting, that would have to be gleaned on a WOT setting, could be the same as a small throttle opening, with regards to fuel economy.

OF course this assumes 2 things. One, that max torque@rpm is a WOT figure. I assumed here that maximum torque HAD to be at WOT. Turbocharged or not. This of course could be wrong, hence the assumption part.

Secondly, I assumed that by efficiency, in this context, we are referring to fuel economy,not general engine efficiency. 2 different things, of course.

So, I still want to know how a max torque figure could be related to a maximum fuel economy figure? Do they happen at the same rpm, even with greatly differing throttle settings?

And I reiterate, I am honestly asking a question here, no disrespect for any previously posted data, no rolled eyes etc. I am open to learn, and as always, welcome the opportunity.

 

[Race94]

Well my car has 102,000 miles on it, i got it last week, i will be changing oil and filter tommorow, i will try to change spark plugs/wires too, and also do a compression check and such, i will also talk to the owner to see what he did to the pump to see if i need pressure regulator.

Thanks

 

[dialogue]

Originally posted by Bohrn
ok, I guess that on this board, if you ask a question that questions the data in a post it is implied that you are disrespecting the poster,and are really not asking a question, but, in fact, telling the poster that they are wrong. Publicly.

I am not dissing you, nor have I ever dissed anyone on any board, please run a search on dialogue and you will find this to be true. I am only here to help, or in some cases ask for info/assistance.

However, I say what I say,no games. If I ask you a question, it is just that. If I call you a dumb weasel, that is how I feel at that moment. By the same token, if I pay you or your ride a compliment, I mean it, and am not blowing sunshine, or currying favour.

So I asked you how a max torque setting, that would have to be gleaned on a WOT setting, could be the same as a small throttle opening, with regards to fuel economy.

OF course this assumes 2 things. One, that max torque@rpm is a WOT figure. I assumed here that maximum torque HAD to be at WOT. Turbocharged or not. This of course could be wrong, hence the assumption part.

Which would have been OK, if it was stated as an assumption instead of a fact.

You are taking my comments wrong as, I did not understand what you were saying and was asking for a clairification.

Secondly, I assumed that by efficiency, in this context, we are referring to fuel economy,not general engine efficiency. 2 different things, of course.

Actually, you are right, in that the 3000 rpm figure for that engine was efficiency. It has been proven many times that the best fuel efficiency is obtained at very low engine/road speeds, example= I have never seen a test of a DSM being driven for maximum miles per gallon, as a wild guess, I would say, keeping the road speed under 40 miles per hour, due to the loss of efficency (gas mileage) from wind resistance and drag.
Also using fat tires means less mpg, skinny more, bias ply tires less, radial tires more, low tire pressure vs high pressure and so on.

So, I still want to know how a max torque figure could be related to a maximum fuel economy figure? Do they happen at the same rpm, even with greatly differing throttle settings?

They should happen at the same rpm, a steady throttle would maintain max efficiency/gas mileage for as long as you maintained 3000 rpm, if you are WOT of quickly moving through 3000, it will be the same, just for a much shorter period of time.

And I reiterate, I am honestly asking a question here, no disrespect for any previously posted data, no rolled eyes etc. I am open to learn, and as always, welcome the opportunity.

Again, I am somewhat clumsy with words, and ment no disrespect. If it came across that way, I am sorry. I guess I have been working around people with really thick skins.

Fuel efficiency and engine efficiency are difficult to understand and for me even more difficult to explain, because there are so many variables involved.

I hope this helps, if not, I'll keep trying until you feel comfortable with my explanation, or hopefully someone else will help both of us to understand.

 

[Bohrn]

apology gladly accepted, and I apologise for getting annoyed.

Thing is, alot of people here do that tho. They won't ask a question to ask a question, but, like I said, to disrespect the other person. It's not just here, but lately it seems that the only humour people find is in making someone else to be less than them in some way. Just getting rather tired of it thats all.

anyways, back on topic. I still can't see how a WOT setting can be compared to a part throttle setting, even at the same rpm. But if you have been doing this for a long time, and you say it is so, great. I have learned something. I would like to understand this better tho, it seems like a unique concept.

 

[dialogue]

Sorry, again, I did not understand how the reply worked. I did a long detailed answer to Bolrn previous response, by interspacing comments with his reply, looked good on my end, when I sent it, everything was'nt there. I'll Try again.

1st I did not mean to diss anyone. I never have. Do a search on all the DSM boards for dialouge and you will see I don't diss.

Back to your original question, in fact you are right. Using the 3000 rpm for the 91 Engine= max torque, then it is maximum efficiency which is also maximum fuel efficiency.

Max efficiency at a steady state 3000 will be for as long as you stay at 3000 rpm. If you are at WOT, then you normally would be at 3000 rpm for only a very short period of time. It is difficult for me to hold WOT at 3000 rpm for avery long period of time, I am old and slow, so that time is in miliseconds.

Max fuel economy or mpg is obtained using a multitude of factors. I have not seen any test of the maximum mpg with a DSM. I would think it would be obtained by driving not at 3000 rpm, but at the highest gear possible, without lugging the engine at a road speed of (my guess) 40 mph or less on a perfectly flat road. Wind resistance and drag would not be a factor, but other factors would be included, such as fat tire vs skinny tire, high air pressure verses low tire air pressure, power steering vs manual steering, and many other variable.

Of course for day to day driving, this would be nearly impossible and unsafe.

I think I'll start a new subject "Max gas mileage" and see where it goes. Maybe we can generate some more ideas. Again I am learning all the time and welcome discussion. Again I ment no disrespect. On the other hand if I did want to dis someone, I would be direct and blunt. Please except my apology. Also does this thing have a spell checker?

 

[WhipmastaFlex]

save gas = drive an N/A

 

[kylemoto]

Originally posted by EHeye
Alright, our gas prices here locally have sky rocketed like there is no tommorrow. So I have a question, I dont make much money so I wanna save as much gas as possible.

Say im going up a hill about 7% upgrade and im doing about 80km/h (50mph?), in 5th gear to keep it constant im running at 2500rpm and 4-5psi boost, in 4th gear im at 3000rpm and 13inHg in Vaccum. Which one of these will give me better gas mileage, lower rpm in small boost or little bit higher rpm in vaccum.

Ok, now that all of the smarta$$es have answered, now its my turn.

First off, I think I have a few qualifications. I took my Chrysler 300M (3600 pounds, V-6) for a drive, 70 miles long, on a freeway trip, including some traffic for about 6 miles. I got 37 mpg in that big tank of a car. Ok, another example. Same car, but this time loaded with four poeple and luggage, for a 200 mile trip. 32.4 mpg there. In the Talon Iv'e gotten more than 40, so I think I can stretch the milage a little. Its fun but hard work, kinda like you fav video game, you know?

So, how to do this? The main rule is revs cost money. Avoid them at all costs. If Im gunning for mileage in the Talon, I upshift at 1400 rpm. As long as the engine doesn't lug, you are ok. An engine at low revs/boost is still much better off than high revs/no boost. Charles Lindberg showed this in WW II with the P38 fighter. He got more than 400 miles additional range with that big plane. Big difference.

Another rule: when going uphill, never increase throttle settings! They will kill mileage like no tomorrow. Guessing what amount of throttle is needed to make the grade is part of the fun. Get it right and you cruise right over the top of the hill; mess up and you are forced to either increase throttle or downshift. Either way and you lose big time. This part is true guessing game!

Going downhill, its differnt. You now have gravity working in your favor, so if you need to pass, it doesnt hurt you anywhere as much.

On level ground, just keep the throttle at a constant setting. No big changes and you will do fine. If you feel the need to "cheat", draft a semi truck. You don't even have to get real close; I found a ten mpg increase if I stayed within fifty feet of a semi!! Thats two truck lengths!

They big key to mileage is using your eyes....being able to see grade changes, keep your foot steady and judge traffic are all what is needed to excell here. Trust me, its no piece of pie, but it can be rewarding! And you can save some bux at the same time.

Kyle

 

[Bohrn]

yea, the biggest thing kyle is saying is to pay attention!! Really! And not only will you get better mileage, you will be a safer, better driver,and you will get there faster as well.

Seeing whats ahead of you will do you and everyone else a world of good.