Increasing Gas Mileage

ghosstt · Post by **ghosstt** » Mon Jan 19, 2009 10:46 am

Ya, I know it should be an easy install. Just need the money.

Can anyone give me more information on vacuum gauges? I get that when you accelerate, less vacuum pressure is formed, and the gauge goes down, and when you coast it goes up? I'm not really sure how the gauge helps you drive better, so if someone could explain it, that would be great.

Rekarp · Post by **Rekarp** » Mon Jan 19, 2009 11:00 am

Bibin wrote:Why did my '88 Pontiac 6000 SE and our current Volvo 940 both get about 25-30 MPG, while these newer cars tote around 15-20 as being good MPG? When did the standards become total crap?

Because I bet your Volvo weighs allot more then the Pontiac. You know all those safety features add up.

vskid · Post by **vskid** » Mon Jan 19, 2009 11:13 am

I think a MPGuino (kit here) would be better than a vacuum gauge. Doesn't cost too much more than a vacuum gauge, and with a bit of calibration, can show you your realtime MPG, trip MPG, etc. A Scangauge is a more plug and play alternative, but it costs 4x more. Its easier to increase mileage if you can instantly see what works instead of waiting til the next fill up.

ghosstt · Post by **ghosstt** » Mon Jan 19, 2009 11:33 am

I think I'd rather just stick with a simple gauge. From what im seeing, It just helps you find spots in your RPMs and MPH that have the lowest fuel consumption? Is that right? After some research I found that it just shows how much fuel is going into the engine by showing how much vacuum is left, so 0 = full fuel intake, and a higher number = not much.

So when driving you just look at the gauge and try and find a nice spot that keeps the gauge in the high numbers?

Rekarp · Post by **Rekarp** » Mon Jan 19, 2009 12:22 pm

ghosstt wrote:I think I'd rather just stick with a simple gauge. From what im seeing, It just helps you find spots in your RPMs and MPH that have the lowest fuel consumption? Is that right? After some research I found that it just shows how much fuel is going into the engine by showing how much vacuum is left, so 0 = full fuel intake, and a higher number = not much. So when driving you just look at the gauge and try and find a nice spot that keeps the gauge in the high numbers?

Basically Yes.

ghosstt · Post by **ghosstt** » Mon Jan 19, 2009 12:23 pm

What's the not so basic version?

Post by **Triton** » Mon Jan 19, 2009 12:26 pm

Because I bet your Volvo weighs allot more then the Pontiac. You know all those safety features add up.

you would be supprised! depending on options a volvo 740 (sedan or wagon) weighs between 2800 and 3000 pounds wich is a scant 200-400lbs more than a honda civic. marshals mitsubishi 3000gt weighs about the same amount or a little more than my volvo wagon and after i do some work on it my volvo will be nearly as fast!

Also, what is sea foam? I have heard about it but never seen it.

it is magic in a can! i swear by it, its the best stuff you can put in your car for any number of problems.

On the trip to MGC last year (~800 miles round trip) my 1994 volvo 740 turbo wagon got an average of 21MPG and this was with NO O2 SENSOR CONNECTED! with the o2 sensor hooked up i would have gotten 26-30mpg

Rekarp · Post by **Rekarp** » Mon Jan 19, 2009 12:45 pm

1988 Pontiac 6000 SE

-2.8L V6
-3210 lb

Volvo 940

-Engine depends but the options are
--2.3L I4
--2.3L I4 Turbo
--2.9L I6
-3205 lb

From the weight and powerplant alone the Volvo 940 should get slightly better mileage (This is a extremely crude but somewhat effective measurement)

Oh and why modern cars get less mileage?

Strictly weight and Power. No one in America buys puny 4-bangers anymore. Heres a good article explaining it all. http://www.dailyfueleconomytip.com/misc ... provement/

If I removed all the 4x4 crap from my jeep I would probably achieve 20-22mpg. Replaced the 4.0L I6 with a smaller 4 banger I could probably hit 26mpg or more. Aerodynamics have a much smaller effect on gasoline usage when compared to weight and powerplant.

Kurt_ · Post by **Kurt_** » Mon Jan 19, 2009 1:04 pm

bicostp wrote:
Kurt_ wrote:I own a focus wagon
Is the interior really that spacious? I've ridden in a Focus hatchback a few times and it's like riding in a freakin' go-kart. It had nice seats, though. (No I'm not used to Excursion-size vehicles; my car's about the same size, and it doesn't have plastic parts bulging out everywhere.)

It's not ridiculously spacious. It's a rather narrow car (useful for tight squeezes and parking, though). What I meant is that tall people can fit in it. I agree there's not much arm room.

One time when I ran into some friends and drove them to the local bar, I had to fit seven people into my wagon. One rode in the trunk, and two of the people in the backseat are rather hefty. I'm talking 230+ pounds. They couldn't get the door shut with three people in the rear seats. It was latched, but without help from outside, they couldn't close it all the way.

It's a nice car. I like it. But if you aren't a family of twigs like me, I don't suggest going for it.

Post by **bicostp** » Mon Jan 19, 2009 1:40 pm

Rekarp wrote:Oh and why modern cars get less mileage?

Traction control systems and the way they build transmissions eat a big chunk out of it because they don't let the car coast.

My dad's V6 Grand Am has no ABS and no TCS, and when you let go of the throttle you coast. Works great downhill on the highway. (It's broken 32 MPG a few times.) The Honda Accord, on the other hand, has both ABS and TCS and if you let go of the gas the car slows down. (This is why you test drive.)

That's one advantage to a manual transmission; you control the clutch, so you're not wasting gas trying to have the engine keep up with the car's momentum.

Overdrive helps, too, but only if it's done right. Our V6 Ranger only drops about 200 RPM in overdrive when you're doing 70 on the highway. Why did they bother installing one in the first place?

Also, why haven't vehicles gotten more economical over the years? We have a 1974 D200 (Ram pickup) with a 225 cubic inch slant-6 engine. It's rated for 3/4 ton payload and got 13 MPG city or highway, full or empty. It has no overdrive, 4 speed transmission. and a really low first gear. The new V6 Ram gets 12 MPG with an automatic, and is rated for half a ton. The slant-6 engine was designed in the late 1950s, and this particular truck has a 1 barrel carb, single exhaust, and it's tuned rich. (Putting more gas into the engine than normal.) What the crap?!

Post by **marshallh** » Mon Jan 19, 2009 1:42 pm

Triton wrote:
Because I bet your Volvo weighs allot more then the Pontiac. You know all those safety features add up.
you would be supprised! depending on options a volvo 740 (sedan or wagon) weighs between 2800 and 3000 pounds wich is a scant 200-400lbs more than a honda civic. marshals mitsubishi 3000gt weighs about the same amount or a little more than my volvo wagon and after i do some work on it my volvo will be nearly as fast!
Also, what is sea foam? I have heard about it but never seen it.
it is magic in a can! i swear by it, its the best stuff you can put in your car for any number of problems.

On the trip to MGC last year (~800 miles round trip) my 1994 volvo 740 turbo wagon got an average of 21MPG and this was with NO O2 SENSOR CONNECTED! with the o2 sensor hooked up i would have gotten 26-30mpg

Yeah, on that trip we had about 700 pounds of people and crap, bringing the total weight to 3700-3800 pounds (stock VR-4 weight lol) and yet it still pulled decently. The O2 sensor would've helped too. Oh, and for a lot of the trip, we were doing 80mph in THIRD GEAR because the transmission wouldn't shift into overdrive, lol.

Seafoam is pretty good for cleaning out carbon crap in your engine - put half a can in your gas tank, then put the rest in your intake (I unhook my brake booster hose and use that.) Creates a nice smoke show. John used it on his friend's Geo Metro and the engine magically started working

My 3000GT is 3300lbs, 225HP DOHC V6 and yet I still can get 30MPG on the highway

(But, in town due to my driving habits I get around 15-20

)

Rekarp · Post by **Rekarp** » Mon Jan 19, 2009 1:55 pm

With seafoam I do.

1/3 Can in the oil and idle 15 minutes before oil change
1/3 Can in the gas tank
1/3 Can in the injector

Remembver ONLY put it in your oil if you are going to change it. Don't let it run longer then 20 minutes.

vskid · Post by **vskid** » Mon Jan 19, 2009 1:57 pm

bicostp wrote:That's one advantage to a manual transmission; you control the clutch, so you're not wasting gas trying to have the engine keep up with the car's momentum.

I think most newer cars (started mid-90s or so) will turn off the injectors when you let off the gas in gear and keep the clutch engaged, even some autos will do it. So instead of idling to the stop or down a hill, you can use just the energy of the car to move the engine, giving you infinite gas mileage for that time. The injectors will kick in at 1-1.5k RPMs, depending on the car.
A way to test if your car does this is to get up to 20MPH, let go of the gas, coast a little in gear, then turn off the key. If the injectors were already turned off, then theres no difference between key on or off. If they weren't turned off, then the deceleration would increase, since the engine was still getting gas until you turned it off. Of course, only do this in an open area, since power brakes and steering go bye-bye when the engine's off.

Post by **Triton** » Mon Jan 19, 2009 4:37 pm

Overdrive helps, too, but only if it's done right. Our V6 Ranger only drops about 200 RPM in overdrive when you're doing 70 on the highway. Why did they bother installing one in the first place?

like marshall said here

Yeah, on that trip we had about 700 pounds of people and crap, bringing the total weight to 3700-3800 pounds (stock VR-4 weight lol) and yet it still pulled decently. The O2 sensor would've helped too. Oh, and for a lot of the trip, we were doing 80mph in THIRD GEAR because the transmission wouldn't shift into overdrive, lol.

overdrive on my volvo makes a HUGE difference as overdrive is basically 4th gear in the auto transmission. the overdrive solenoid was messed up so it wouldnt shift up most of the time so 80mph in 3rd = 3200RPM whereas 80mph in 4th was like 2500!

700lbs of people and stuff and i STILL could hit 112mph bone stock!

Rekarp · Post by **Rekarp** » Mon Jan 19, 2009 4:47 pm

Lucky bastards and your overdrives. I only have a 3 speed auto...NO overdrive :/