92gransport Posted March 28, 2005 Report Share Posted March 28, 2005 With a combo of Highway/City driving this winter, I'm getting about 23.5 mpg average with my '92 Regal GS Coupe. I have taken a few all highway trips but haven't filled up until the tank was low so I don't know exactly what my highway mileage is but my guess is about 28 mpg which is what it was originally rated at for highway driving. Quote Link to comment Share on other sites More sharing options...
Grand Moff Joseph Posted March 28, 2005 Report Share Posted March 28, 2005 I get just shy of 20 in the city, and between 24-27 on the highway, depending on conditions. Last summer I drove my Lumina (packed down to the max) all the way to texas, and only had to stop for gas twice. Quote Link to comment Share on other sites More sharing options...
3pt1lumina Posted March 28, 2005 Report Share Posted March 28, 2005 My 01 Malibu gets 22-25mpg in the city and 29-33mpg on the highway. If you take the RPM's much past 3k gas mileage drops off terribly. On my 90 Lumina, I get about 18-22mpg in the city and maybe 25-27mpg on the highway. I can't really tell you for sure because I can't put a full tank of gas in because my sending unit leaks so this is just a guess. :oops: Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 28, 2005 Report Share Posted March 28, 2005 the sedan gets about 16 MPG around town, and about 30 MPG on the highway Quote Link to comment Share on other sites More sharing options...
HokemBokem Posted March 28, 2005 Report Share Posted March 28, 2005 My car gets SHITTY mileage. I dont know the exact numbers but it has to be terrible. I put 5 bucks in, go to school, go home, go to work, go home, and its like almost empty :x You surely CAN'T be serious. 5 bucks is like 2, 2.5 gallons. How far do you think that will get you around town? Your car probably gets better fuel economy than mine. And I think mine's pretty good considering little cars (saturns for one) can barely squeeze past 32mpg Hwy, and I'm just about there myself. I seriously dont think I get 32mpg on the highway. Brand new my car got 17mpg I think but now its in dying need of a tuneup. Quote Link to comment Share on other sites More sharing options...
Kalgorn Posted March 28, 2005 Report Share Posted March 28, 2005 I definately pull an average of about 16mpg. That's with city and highway driving so I'm not sure what it would be strictly city or highway. Probably not much of a fluctuation. Quote Link to comment Share on other sites More sharing options...
Black90Euro Posted March 29, 2005 Report Share Posted March 29, 2005 My 1990 Lumina 3.1L V6 Euro gets 17MPG in the city and 30-31MPG on the highway :D...your mileage seems quite low, but it all depends on driving habits as well. I could probably get 20-21MPG in the city if I drove like an old lady lol.. - Jeff L. That's about it for me too, my old '82 chevy truck V8 5.0-4brl. get's the same in the city :? Quote Link to comment Share on other sites More sharing options...
AWeb80 Posted March 29, 2005 Report Share Posted March 29, 2005 At 80 Mph and all highway, i will get about 370-390......At 75 mph i've pulled 410 before. but usually about 340 and that is intown... It doesn't matter how hard i drive, i've never got below 20 MPG.....and i check every tank. Quote Link to comment Share on other sites More sharing options...
Black90Euro Posted March 29, 2005 Report Share Posted March 29, 2005 At 80 Mph and all highway, i will get about 370-390......At 75 mph i've pulled 410 before. but usually about 340 and that is intown... It doesn't matter how hard i drive, i've never got below 20 MPG.....and i check every tank. Dang that's a sweet Ride ..... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 29, 2005 Report Share Posted March 29, 2005 its rare i get over 280 mi/ tank Quote Link to comment Share on other sites More sharing options...
bartonmd Posted March 29, 2005 Report Share Posted March 29, 2005 According to my wife, the 3400 in the Impala gets 26 MPG in the city (we haven't taken it on a road trip yet to figure out highway MPG, but I would assume it would be upper 20's-low 30's.) Disco, My dad puts a TON of miles from Indy to Detroit and Indy to Fort Knox on 3400 Impala company and rental cars for work... He gets about 34 highway with them pretty consistantly, along with 34 highway out of his '93 3.1 lumina on vacation a couple years ago... that was loaded with 4 people and their stuff for a week, PLUS the driving around they did when they were down there for a week... I'll find out at the end of this week what his '04 Impala 3800 got on the Indy-Alabama-Indy trip + driving around... I will usually get about 29-31 highway with my '92 euro 3.1, but my commute, which is mostly highway, I usually get something on the order of 26-27mpg because of the high speeds with stop and go in the middle... Mike Quote Link to comment Share on other sites More sharing options...
ursus Posted March 29, 2005 Report Share Posted March 29, 2005 1988 Regal 2.8l Long term average mileage since car was new 324,000km (201,000 miles) mpg figures are calculated for Standard (American) Gallons Total Combined Average since new 22.46 mpg (10.6 l/100km) Highway @ typical speeds of 55- 60 mph 25.5 mpg (9.3 l/100km) City typical 21 mpg (11.2 l/100km) New after breaking it in, 10,000 miles could get 28mpg 8.4l/100km on highway @ 50mph (not even 55) with A/C off driving like a granny no matting it to pass etc, which is close to what it was rated for from factory/epa when new 8.1l/100km or 29 mpg hwy, 20mpg city. Most ever on 1 tank of gas 385 miles, and took 15.9 gal of gas to refill tank after so still had 1/2 gal of gas in tank and might have made it to 400 miles on the fumes. Highway new since converting from MAF to MAP speed density 26 mpg about 1/2 mpg better than MAF (9.1 l/100km) only a couple trips tho so no long term data yet really. I read a lot here who say they get 29-30 mpg but only 325-350 miles to a tank and that does not compute, car has a 16.3 gal (62litres) tank so at 29 mpg leaving a gal or 2 in the tank should be = 425 + mile/tank. At 30mpg after 320 miles tank would still be 1/3 full. and 34mpg would take you 475 miles if you still had 2 gallons in the tank which is where the red light comes on Quote Link to comment Share on other sites More sharing options...
mousetom78 Posted March 29, 2005 Report Share Posted March 29, 2005 My girl's Luminia gets 22.2 ish mpg combined milage according to my spreadsheet. She gets 19-21 mpg on most refill. However, her car gets mighty good milage on road trips all highway. 27-29 mpg on those trips on a few tank of gas. Quote Link to comment Share on other sites More sharing options...
bartonmd Posted March 29, 2005 Report Share Posted March 29, 2005 At 30mpg after 320 miles tank would still be 1/3 full you don't ever want to run your fuel tank below 1/4 tank unless it's cold outside... The fuel in the tank is what cools the fuel pump... The hotter that fuel gets (like from recirculating from the engine, getting warmed up while in the fuel rail), the less life your fuel pump will have... My mom would consistantly run down to 1-2 gallong of fuel left in the '92 Astro my folks had... Dad put 2 pumps in it (meaning it had failed 3) before she finally started keeping it above 1/4 tank... the next (4th counting the original) fuel pump lasted twice as long as any previous fuel pump in that van and was still in there when my dad sold the thing... Van had far less than 200k on it... The fuel heating on the Astro was made worse, however, by the closed in engine compartment that didn't get a ton of airflow, even on the highway, and therefore heated the fuel more than a passenger car would have... It's an accelorated test, but a test none the less... Mike Quote Link to comment Share on other sites More sharing options...
bartonmd Posted March 29, 2005 Report Share Posted March 29, 2005 My girl's Luminia gets 22.2 ish mpg combined milage according to my spreadsheet. She gets 19-21 mpg on most refill. However, her car gets mighty good milage on road trips all highway. 27-29 mpg on those trips on a few tank of gas. WOW, I drive like a fuckin' idiot most of the time (used to the power of the bike, which I put 75% of my miles on) in the lumina and still get 25... The worse I've ever done is something like 19 driving like an idiot in the 'bonne... Of course, over 1/2 of my miles are highway... BUT... I'm switching between 60 and 80 a lot and there's the usual inner-city highway stop-and-go's... Mike Quote Link to comment Share on other sites More sharing options...
pitzel Posted March 29, 2005 Report Share Posted March 29, 2005 I get at least 30 on the highway doing 100-110km/hr (~65mph), and if I slow down to approx. 47mph, I get into the high 30's, low 40's. If you're not breaking 20mpg at least, time for a new oxygen sensor and maybe plugs. (all MPG's quoted in USA MPG's) Quote Link to comment Share on other sites More sharing options...
ursus Posted March 29, 2005 Report Share Posted March 29, 2005 At 30mpg after 320 miles tank would still be 1/3 full you don't ever want to run your fuel tank below 1/4 tank unless it's cold outside... The fuel in the tank is what cools the fuel pump... The hotter that fuel gets (like from recirculating from the engine, getting warmed up while in the fuel rail), the less life your fuel pump will have... My mom would consistantly run down to 1-2 gallong of fuel left in the '92 Astro my folks had... Dad put 2 pumps in it (meaning it had failed 3) before she finally started keeping it above 1/4 tank... the next (4th counting the original) fuel pump lasted twice as long as any previous fuel pump in that van and was still in there when my dad sold the thing... Van had far less than 200k on it... The fuel heating on the Astro was made worse, however, by the closed in engine compartment that didn't get a ton of airflow, even on the highway, and therefore heated the fuel more than a passenger car would have... It's an accelorated test, but a test none the less... Mike Basically the heat generated by the pump is transfered to the gas in the tank. The fuel in the tank is cooled by the gas running back and forth through the fuel line and its exposure to the ambient air by being in contact with the bottom of the gas tank. The amount of cooling is dependent on the surface area of the gas tank exposed to ambient air and the length of the fuel line. Of course the area in contact with the tank doubles when it is also in contact with the top of the tank but this only occurrs when the tank is completely full. So, the amount of fuel in the tank is irrelevant, it may take an extra few minutes to heat a full tank up 5 or 6 degrees above ambient but the final temp of the gas will be the same. The length of metal fuel line between the tank and the fuel rail ~16 feet (8 up and 8 back) length of fuel line in the heat under the manifold 1 foot, ok Ill give you 2 feet maybe, max hot air temp 292 F( else the temp sensor would set a code), So on a 100 degree day temp of fuel returning to tank assuming 30% heat transfer (thats prob way high an oil kewler with multiple lines and plates would typically be only 40% and this is just a straight tube) heat transfer to the 2 feet of hot fuel line = (100 deg +(292deg-100deg)*33%)*2feet/16feet = 108 deg or 8 deg above ambient (so only 80 on an 72 degree day) The fuel tube will give off heat at the same efficincy to the kewl ambient air on its trip to and from the tank under the vehicle as it picks up while running through the hot part of the engine. And this ignores that even with 1 gallon in the tank the gas will be spread out over the entire surface area of the bottom of the metal of the tank (except during high speed cornering but you said this was your mom ) , about 900 sq inches 30ish x 30ish, which is exposed to cool moving air, unless the car is parked. This will provide signifigant addition kewling, I doubt the gas in the tank would ever rise more than 5 degrees above ambient and even this would only be 1/8 of the time the car is operating, that time when the tank is between 1/4 and 1/8 full, 2 gallons being 1/8 of a 16 gallon tank. Quote Link to comment Share on other sites More sharing options...
bartonmd Posted March 29, 2005 Report Share Posted March 29, 2005 Astro (along with most trucks now days) had a plastic gas tank... at least that's what it looked like... It's been my experience that anything that either is, or looks like (is coated with) plastic doesn't conduct heat really well... The Astro also has a bunch of fuel line that doesn't get cool (also proven by the tranny that ran about 20 degrees hotter than it should... they all seem to do that)... and it also must be noted that not much cooling happens in town as most of the airflow directly below a vehicle is either from the engine or radiant heat from the hot road surface... Only when you're moving does it cool down the fuel in the lines... If I recall, there was only about 4-5' of fuel line that wasn't either above the tank or in the tunnel (next to the exhaust manifolds and pipes by the way) because the engine is fairly far back and the gas tank was to one side kindof under the sliding door and was positioned long-ways in the vehicle, not sideways like in a car... It's been like 6 years since they sold it, so if I'm wrong about anything, somebody who really knows (like somebody who works on them) can say so... Actually, the heat is part of the problem (like a transmission and most electronic pieces... every 10 degrees rise in temperature cuts their service live in half from what it was 10 degrees below... like you start out at 100% life at 80 degrees... If it jumps up to 90 degrees, you are now at 50% life, if it jumps up to 100 degrees, you're at 25% life, 110 degrees, you're at 13.5%, etc), but the other part of the problem is the occational running dry... running dry is HELL on a pump... This does actually happen some... like if the fuel pump's in the back of the tank and you're going pretty fast on the highway and you end up stopping all the way from 80 to 0... um... not gradually, the pump can start to run dry... also, ever have a low tank of gas and do a pannic stop going anything but up hill? Sometimes the engine will die... that's because all of your fuel sloshed out of the baffle in the tank. I also knew a couple people in HS who would go through a fuel pump every 6-8 months on fairly new cars... didn't make sense until I found out they would get $5 worth of gas every 3-4 days... fill up to 3/8 tank then run it almost dry and repeat... As for the cool calculations.. yes... I know... I'm an engineer too... Mike Quote Link to comment Share on other sites More sharing options...
sonyman87 Posted March 29, 2005 Report Share Posted March 29, 2005 Averages 20-23.5 mpg lately. mixture of highway(70+)/city(lead foot). Quote Link to comment Share on other sites More sharing options...
cutlass1991 Posted March 29, 2005 Author Report Share Posted March 29, 2005 If you're not breaking 20mpg at least, time for a new oxygen sensor and maybe plugs. my plugs are new, so do you think replacing the oxygen sensor will help my mileage? less than 200 miles per tank is sucking. Quote Link to comment Share on other sites More sharing options...
frank358fr Posted March 29, 2005 Report Share Posted March 29, 2005 540KM with a full tank of gaz(Super 91) or 460KM with full tank of gaz(Ordinaire 87) Quote Link to comment Share on other sites More sharing options...
ursus Posted March 30, 2005 Report Share Posted March 30, 2005 Astro (along with most trucks now days) had a plastic gas tank... The point is this though. The equalibrium temp of a plastic tank will be higher than a steel tank and so perhaps pumps don't last as long wih this design, but, the amount of gas in the tank doesn't have any effect becasue its a closed system. If I take a sealed can and put a light bulb in it, it will heat up inside the can to some equalibrium temperature. That temp will be dependant on several things, the power of the light bulb, the surface area of the can and the ambient temperature of the outside air. If the can is plastic vs metal yes it will reach a higher equalibrim temperature because the plastic will indeed have a higher thermal resistance. But,,, if you add 1 inch of water in the bottom of said can the equalibrium temperature will not change, and if you put 2 " of water in it it will be the same and if you fill it with water it will be the same. In our case the light bulb/heat source is the fuel rail and fuel lines maybe wrapped around the exhaust even , the can is the gas tank. The amount of fluid(gas) in the tank will not change the equilibrium temperature up or down at all. The amount of gas in the tank doesn't matter. So tell dad to quit blaming your poor mom for all those pump failures I recently changed the steel brake lines in my Regal and it took 120" for the front to rear lines with about 2 feet going up to the master cylinder, the gas line runs right along with these lines to the rear of the car thats where I came up with 8 feet but of course that will varry from vehicle to vehicle. Quote Link to comment Share on other sites More sharing options...
Brian P Posted March 30, 2005 Report Share Posted March 30, 2005 Astro (along with most trucks now days) had a plastic gas tank... The point is this though. The equalibrium temp of a plastic tank will be higher than a steel tank and so perhaps pumps don't last as long wih this design, but, the amount of gas in the tank doesn't have any effect becasue its a closed system. If I take a sealed can and put a light bulb in it, it will heat up inside the can to some equalibrium temperature. That temp will be dependant on several things, the power of the light bulb, the surface area of the can and the ambient temperature of the outside air. If the can is plastic vs metal yes it will reach a higher equalibrim temperature because the plastic will indeed have a higher thermal resistance. But,,, if you add 1 inch of water in the bottom of said can the equalibrium temperature will not change, and if you put 2 " of water in it it will be the same and if you fill it with water it will be the same. In our case the light bulb/heat source is the fuel rail and fuel lines maybe wrapped around the exhaust even , the can is the gas tank. The amount of fluid(gas) in the tank will not change the equilibrium temperature up or down at all. The amount of gas in the tank doesn't matter. So tell dad to quit blaming your poor mom for all those pump failures I recently changed the steel brake lines in my Regal and it took 120" for the front to rear lines with about 2 feet going up to the master cylinder, the gas line runs right along with these lines to the rear of the car thats where I came up with 8 feet but of course that will varry from vehicle to vehicle. So just for argument sake, the pump basically isn't cooled by the gas AROUND it? Just the gas flowing thru it?? Quote Link to comment Share on other sites More sharing options...
ursus Posted March 30, 2005 Report Share Posted March 30, 2005 So just for argument sake, the pump basically isn't cooled by the gas AROUND it? Just the gas flowing thru it?? The pump is cooled both by the gas around it and by what flows through it but the Temperature of that gas and the inside of the tank because it is a closed system is dependent only on the rate of and how much heat the tank and gas lines can disipate to ambient air not how much gas is in the tank. Whether or not much heat is disipate by the lines or picked up in the fuel rail would depend on proximity to heat sources Like the exhaust etc and I don't really know how much cooling the lines provide vs the tank but again it is irelevant to the central point, In a closed system the amount of gas in the system has no effect on the equalibrium temperature Quote Link to comment Share on other sites More sharing options...
bartonmd Posted March 30, 2005 Report Share Posted March 30, 2005 In a closed system the amount of gas in the system has no effect on the equalibrium temperature In theory, in a perfect world (or in all stop and go city driving, never getting up to speed), this is correct... BUT... very rarely are you at equalibrium, which is what I'm talking about... What more gas in the tank does, is, it stays cooler for longer when you apply a heat source... For instance... If you have a full tank of fuel vs. 1/8 tank of fuel and are traveling on the highway, it's cooled very well... maybe only, like you said before, 7-8 degrees above ambient for both of them... You hit some traffic and have to slow down/stop... The fuel tank with more fuel in it, sends a much lower %/minute of it up to the engine to get heated up, so it takes longer to heat up than the one with 1/8 tank... Usually what happens is, you are at speed for awhile, then are stopped/slow'd for awhile, and repeat that cycle... The fuel in the tank with more fuel in it will remain a more constant temperature than the one with very little fuel in it... Mike Quote Link to comment Share on other sites More sharing options...
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