Trying to increase fuel mileage on our wagons........... (continued)

Ok as you all know I have been looking at many ways to make my 300-900 mile a week trips a little more cost effective. Some history. Was getting 16-18 with mostly highway (85%+). 3.08:1 rear gears, roller rockers, headers, stock cats, all else pretty much stock (after all it is NOT a hot rod).

• Put my foot on a weight loss diet. VERY tough mod to pull off!!!!! Got me 2-3 mpg.

• 2.5" exhaust has not hurt and might have helped about 1/2 mpg. Again tested my first mod by doing the second. This made it every tougher!!

• Looked at a T56 conversion - not cost effective, but a heck of a lot of fun!!

• I began reviewing my computer with the free trial of Data Master (with a little help from Joel). I found one bank was running a little rich. Switched O2 sensors (no change, and swapped out an tested and clean set of injectors I recently picked up (both Joel's idea's). This seems to have done the job of balancing the sides.

• Replaced fuel filter while I had her up in the air.

I will post the results for my next weeks ventures. I know I am going to Morgantown, WV and Pittsburgh and possibly DC as well, so it should be a 2-3 tank week. More to come!!

Thanks Joel for the help on this!!

I'm taking my Roady from Austin to Dallas for the weekend. Leaving tonight, back Sunday. Will try to see what it does. In the past it got as high as 24mpg going to Arkansas. Have not checked in a while.

What size tires are you presently running Tim?When I went from 225/75/15 28.2" tall to
235/50/17 26.3" tall I lost between 1 and 2 miles per gallon. It doesnt sound like a lot but
my rpms at 70 went up from1550 to about 1750,so I believe thats where my mileage went.
Just a thought but I am definitely interested in better gas mileage even though I only drive
maybe 50 to 75 miles a week.
Take Care
Jim Gordon
PS Damn corngas dont help my mileage either!

81X11 wrote:

I'm taking my Roady from Austin to Dallas for the weekend. Leaving tonight, back Sunday. Will try to see what it does. In the past it got as high as 24mpg going to Arkansas. Have not checked in a while.

What tire size are you running and which rear do you have? I am sure I will never get as good as you will in Texas. The hills and traffic I see do not help me.

Flasheroo wrote:

What size tires are you presently running Tim?When I went from 225/75/15 28.2" tall to
235/50/17 26.3" tall I lost between 1 and 2 miles per gallon. It doesnt sound like a lot but
my rpms at 70 went up from1550 to about 1750,so I believe thats where my mileage went.
Just a thought but I am definitely interested in better gas mileage even though I only drive
maybe 50 to 75 miles a week.
Take Care
Jim Gordon
PS Damn corngas dont help my mileage either!

Running 235/55-17 Michelin Hydroedge tires. Should be about 27.2" tall. Currently at 70 mph I am bettween 1900-2000 rpm's. I asked Jerry about his experience with both the 4L60E and T56 and he thought that a locked up 4L60E at 1900 rpm was about as good as you can get mileage wise.

Would love to see 24 with the new injectors. Next step is a new torque converter (not sue what stall) and rebuilt tranny (already in the garage).

With 225/70/15's, and 3:23 posi rear I got 24.8mpg on the highway @ 68mph (according to GPS). I wish I knew what RPM's I was running, but no tach. (Maybe if I ever get my new cluster...) City is about 15.5, can't really get that up anymore.

Not sure what's helped the most, but since my fuel sending unit, pump, and fuel filter as well as a new PCV valve i've seen a 2-4mpg increase. I check my tire pressure every friday also.

Hey Justin not to change the subject but have you heard anything about your cluster and if so
what has he told you?
Jim Gordon

Jim, sent you a PM so as not to derail the thread.

Cadet57 wrote:

With 225/70/15's, and 3:23 posi rear I got 24.8mpg on the highway @ 68mph (according to GPS). I wish I knew what RPM's I was running, but no tach. (Maybe if I ever get my new cluster...) City is about 15.5, can't really get that up anymore.

Not sure what's helped the most, but since my fuel sending unit, pump, and fuel filter as well as a new PCV valve i've seen a 2-4mpg increase. I check my tire pressure every friday also.

I thought about the pump as well. I may replace mine just so I sleep better at night. So afraid of failure on the road. What brand/size did you go with? Did you improve your harness? When did you get the sending unit? Thanks!!

BigBlackBeaSSt wrote:

Cadet57 wrote:

With 225/70/15's, and 3:23 posi rear I got 24.8mpg on the highway @ 68mph (according to GPS). I wish I knew what RPM's I was running, but no tach. (Maybe if I ever get my new cluster...) City is about 15.5, can't really get that up anymore.

Not sure what's helped the most, but since my fuel sending unit, pump, and fuel filter as well as a new PCV valve i've seen a 2-4mpg increase. I check my tire pressure every friday also.

I thought about the pump as well. I may replace mine just so I sleep better at night. So afraid of failure on the road. What brand/size did you go with? Did you improve your harness? When did you get the sending unit? Thanks!!

I bought all parts at Advance so PN's may vary at other stores. Everything is less than 2mo old now.

The sending unit is pn: FG127A it includes a new wiring harness. Also, the fuel gauge is much more accurate on the top end with this new unit, when the tank is full, the needle actually sits on "F". Thou the low end is still a bit off.

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Sender;-Includes-Fuel-Sender,-Float-and-Strainer-%28Fuel-Pump-Not-Included%29-Spectra-Premium_20370344-P_2159_R|GRPFUE2AMS_624623252____

For the fuel pump I used a Bosch fuel pump, pn is: 69224

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Electrical-Fuel-Pump-Kit-Bosch_20770240-P_52_R|GRPFUE2AMS_1710526994____

The sending unit is special order but arrives in about 2-4 days. Fuel pump is carried in some stores. For example, the Advance in town didn't carry it, but one about 5 miles away did.

Getting better gas mileage is all about two things:
1. Burning less fuel overall.
2. Burning the fuel you DO use as efficiently as possible.

You all can probably figure out most of it from there. Just take a look at every step of the air, fuel, combustion and mechanical processes and you should be able to determine a path of optimization. You would also do well to remember that GM had this same goal in mind but also had other goals as well. Once you ponder and understand what those other goals were and whether or not they matter as much to you as they did to GM (and to the EPA, for example), you can begin making changes that will affect gas mileage more significantly. I'm not saying you'll get 35mpg, but there's some mileage to be had...

run skinnier tires with more air in them,.with light aluminum rims,.(SS rims are notoriously heavy,.) put an aluminum driveshaft in it,.
don't use cruise control,.
let it slack off on the hills and let it run fast the other side,.
get a decent tune in the pcm,.so it has better shift points and locks up sooner,.
put the roof rack to the back to help break draft,.
for what its worth,. i have gotten better fuel mileage with 3:73's than i do with 2:56's,.
change the cam and heads,.
JM2C

Nick

i,ve done a little fuel mileage checking with the black wagon recently,.
observations,.
2:56 gears really suck a lot of fuel around town,.
running 44psi in the 255-50 17's increased mileage 3mpg over 36psi,.
a leaking exhaust right at the headpipe (gasket blew out) because the bracket off the tranny lost a bolt allowing the exhaust to swing, fuel mileage dropped 5mpg,.
dropped the pipe added a new gasket and it went back to normal,.
average fuel mileage for 2400 miles has been 22.6mpg (us gal) and i haven't been "trying" for economy,.
car gets better mileage at 85mph than it does at 65mph,.
wish i had had enough time to add the 3:73's,.
be interesting to see how the mileage will be in the mountains,.
nick

I'm the other way with speed. At 85, I get 18MPG and following Mike at 65MPH, I get 26....

with the 2:93 rears.

Thanks for the input Nick.

Tires not to wide running 235's. Running at 36 psi, rides WAY to rough at 44 psi. Working on changing the front sway bar to help this.

Most of my mileage includes some Pennsyltucky mountains (not the rockies but hills none the less).

I have been told that a torque converter can make a difference as well. When it makes sense I will swap to the rebuilt 4L60E into the wagon and go for a new converter. Not sure I can afford an aluminum driveshaft, although a great idea.

I am going to try the pressure increase to 44 lbs on my OCC.Currently running 35 lbs in
Conti's 235/50/17 on BBS alloys.Cant hurt !
Jim Gordon

you can lighten the car. will require less fuel to get it going. fiberglass hood, alum. heads, trans crossmember, hole saw to bumpers

I wonder if shifting down to drive and keeping the engine speed up using the lower gears via
the shifter will help with the gas mileage.If the engine is kept in its powerband and not allowed to lug ,this should theoretically aid mileage.
M2C
Jim Gordon

mtrhead79 wrote:

you can lighten the car. will require less fuel to get it going. fiberglass hood, alum. heads, trans crossmember, hole saw to bumpers

Are you my new sponsor!!! If so I am in!!!!

Krzdimond wrote:

I'm the other way with speed. At 85, I get 18MPG and following Mike at 65MPH, I get 26....

with the 2:93 rears.

I've got the same situation. At 75 I get 19 MPG and at about 62 I get 25 MPG

Jon.

I need to FORCE myself to stay at 62 and try. I have got down to 68, but it tough when a prius goes buy at 80.................

When I bought my 1A2 I avged 22.5 over 1400 miles from Erie, PA through Altoona, down to Front Royal, along Skyline drive, then down the west side to 77-26-95 to home.

Never really took another ride in that car as I bought Dusty 3 weeks later. Full tune up including vac hoses and I could never get into the green on the Datamaster fuel matrix.
Car has always run rich and best mpg was 21.5 with 2.93s 5 adults no luggage....

ImpalaSSdude, has a 94 SS was getting 23ish on the hwy, got a Herter tune and mileage jumped overnight to 27-28 hwy. I'd say that's worth the price of entry....

BigBlackBeaSSt wrote:

mtrhead79 wrote:

you can lighten the car. will require less fuel to get it going. fiberglass hood, alum. heads, trans crossmember, hole saw to bumpers

Are you my new sponsor!!! If so I am in!!!!

come on tim you are sitting on a stock pile of alum heads {horder}

uh......well............ah...............

I must be doing something wrong then! The average I get on all of my B-bodies is aroiund 15mpg. Mixed city/highway. I think I got 20mpg on my 1A2 going to WF last year. I average between 220-260 miles out of a tank.

OUCH!!!

^What Tim said x2!^

so the rest of the story,.

thru the mountains, it got waay better mileage,. although i did hypermile quite abit,. every chance i got i used neutral,.
when i could see the road heading up i did use direct and let the trans lockup,. it would motor up the hills with much less throttle than in overdrive,.
almost 28mpg(us gal)
time for an oil change real soon,. over 5000kms since april 28th,.

nick

In order to put more pressure in the tires I needed to soften the front end. Removed the F Body sway bar and installed an Impala/9C1 bar with stock bushings. It really tool the harshness out of the front end. Will put the tires to 44 psi and watch the mileage........

95BRMW wrote:

I must be doing something wrong then! The average I get on all of my B-bodies is aroiund 15mpg. Mixed city/highway. I think I got 20mpg on my 1A2 going to WF last year. I average between 220-260 miles out of a tank.

Try getting hooked up to a PC with Datamaster and look at the fuel Matrix. My 94 Roadie has the same problem and it runs rich all the time, but I get about 320 out of a tank vs 420 when I was Highway in the 1A2. I know 2.93 to 2.56 isn't that big of a deal...

I you are coming to Wagon Fest I may have Data master by then. If you are OBD1 I can hook up the look at it. I AM BY NO MEANS AN EXPERT, but we can see if something is obviously out of wack.

Tim

44 PSI? Is that because you run the SS wheels? I know the door says 30 front 35 rear for the 15's, is that too low? My tires do look a little underinflated, but they're always kept at those numbers, because I run the stock size and that's what it says.

Would anyone recommend something different?

BigBlackBeaSSt wrote:

I you are coming to Wagon Fest I may have Data master by then. If you are OBD1 I can hook up the look at it. I AM BY NO MEANS AN EXPERT, but we can see if something is obviously out of wack.

Tim

Not sure which wagon is going this year, but regardless I'll take you up on your offer. Maybe its just my style of driving thats out of whack

On a good week, I might get 10 mpg with 450 horsepower. Need to get my ALDL hooked up again to capture and log the data stream.

Dave

Hell, at one point (pre-tune up) I was getting 10mpg with 200 horsepower.

I'll take your numbers, Dave.

lakeffect wrote:

On a good week, I might get 10 mpg with 450 horsepower. Need to get my ALDL hooked up again to capture and log the data stream.

Dave

If I had that much power at those numbers there would be ne complaining!

Amen to that.

Quote :

every chance i got i used neutral

Theoretically, using neutral should use more gas than coasting in D/OD. Neutral forces the engine to flow fuel through the injectors to keep the engine turning, while throttle off in-gear coasting does not.

jayoldschool wrote:

Theoretically, using neutral should use more gas than coasting in D/OD. Neutral forces the engine to flow fuel through the injectors to keep the engine turning, while throttle off in-gear coasting does not.

theoretical,. smechtical,. in the real world neo,. it works,.;
when you are coasting down hill in neutral, the engine is not slowing you down,. any decrease in speed costs fuel to return or maintain speed,.
an LT1 doesn't use much fuel at idle,.
Think of lbshr at X speed the longer you stretch the 'hour' the further you go,. capice??
when i,m climbing a hill i oft times let the car slow off 10mph holding my foot steady rather than increasing fuel,. and then down the other side the car gains quite abit,. P"s off the folks behind you somewhat tho,..

Nick

There is a subroutine in the program called DFCO, Deceleration Fuel Cut Off. When you lift your foot off quickly, it cuts out the gas entirely. It's not quite the same when you simply back off a bit. Our cars are still using fuel as the subroutine did not see the TPS go to it's zero point, or see sufficient change in position for DFCO to be engaged.

Going to bump this.

Drove about 120 miles to and from CT the other night with my buddies. With the a/c on about half the trip I only got about 19mpg on the way down and 17.6 ( ) on the way home. I did my normal highway speed of about 68-70 and we didn't get stuck in any traffic. Last year going to WF (its last big road trip) we got 22.5 and 24 mpg with the ac on. According to my records, last tune up was 3 years ago, but only about 15k mileage wise. Think its time for some new plugs/wires/EGR/MAP sensor?

Did you replace O2 sensors when you did your tune?

BigBlackBeaSSt wrote:

Did you replace O2 sensors when you did your tune?

Me? I haven't thrown any parts at it. Just want to see if folks thought I should do a tune up. O2 is 10 years old. Has 52k on it.

Cap/Rotor/Wires were done at 106k in 2006 (car now has 130k). No mention of plugs. So figure at least 24k on all of them.

Stingroo wrote:

44 PSI? Is that because you run the SS wheels? I know the door says 30 front 35 rear for the 15's, is that too low? My tires do look a little underinflated, but they're always kept at those numbers, because I run the stock size and that's what it says.

Would anyone recommend something different?

Sting, the 44 is because they're the larger 17" wheels. 30fr/35rr is correct for stock 15's.

+1 to getting new o2 sensors. just don't get bosch.

just FYI I got 1.5 mpg on my mustang when I went to a electric fan over mechanical. Not sure if LT1's come with an electric fan or not :/

Also when I got 4.10's in my mustang, my city MPG went up by 2, and my highway went down by 1.


A cheap mod would be to install a vacuum, or boost gauge, and try your hardest to keep the vacuum high.

when your onthe throttle the vacuum gauge will drop, the car eats more gas. keep out of the throttle, and the vacuum high, and your saving gas.

also some "fuel saver" tires might be worth the investment if you drive that much, that often, as im sure you go through tires much faster then the average person.


just a few tips off the top of my head.

Welcome to the group DethWgn187.What kind of wagon do you own/cherish?By the way my
vacuum gauge/mileage maker from J C Whitney arrived yesterday.Always used this kind of
gauge for everything related to tuning and diagnosing engines and liked this design,so I
ordered one and am impressed with its quality.Going to install it this weekend in the RMW
and if I like it I will get another for the OCC.Again welcome to the insanity!
Jim Gordon

Cadet57 wrote:

Going to bump this.

Drove about 120 miles to and from CT the other night with my buddies. With the a/c on about half the trip I only got about 19mpg on the way down and 17.6 ( ) on the way home. I did my normal highway speed of about 68-70 and we didn't get stuck in any traffic. Last year going to WF (its last big road trip) we got 22.5 and 24 mpg with the ac on. According to my records, last tune up was 3 years ago, but only about 15k mileage wise. Think its time for some new plugs/wires/EGR/MAP sensor?

I believe your gas mileage has alot to do with the corn factor in the gas. I noticed a 4+ mpg difference on my trip to WF last year.
Same number of gallons, same road types. different results

Sprocket wrote:

Cadet57 wrote:

Going to bump this.

Drove about 120 miles to and from CT the other night with my buddies. With the a/c on about half the trip I only got about 19mpg on the way down and 17.6 ( ) on the way home. I did my normal highway speed of about 68-70 and we didn't get stuck in any traffic. Last year going to WF (its last big road trip) we got 22.5 and 24 mpg with the ac on. According to my records, last tune up was 3 years ago, but only about 15k mileage wise. Think its time for some new plugs/wires/EGR/MAP sensor?

I believe your gas mileage has alot to do with the corn factor in the gas. I noticed a 4+ mpg difference on my trip to WF last year.
Same number of gallons, same road types. different results

That might have something to do with it, but before winter came, I got about 4-5mpg higher on average than I do now. But the winter fuel sucks in my car and it seem ever since winter I can't get any decent MPG's, except that one weekend I got 24.8 mpg combined from my house to Boston.

that was the weekend you got good gas I would think.......

Sprocket wrote:

that was the weekend you got good gas I would think.......

I did, we went out for Chinese food that night... OH you ment the CAR!

Flasheroo wrote:

Welcome to the group DethWgn187.What kind of wagon do you own/cherish?By the way my
vacuum gauge/mileage maker from J C Whitney arrived yesterday.Always used this kind of
gauge for everything related to tuning and diagnosing engines and liked this design,so I
ordered one and am impressed with its quality.Going to install it this weekend in the RMW
and if I like it I will get another for the OCC.Again welcome to the insanity!
Jim Gordon

thanks!

I just picked up a 1993 roadmaster wagon. It failed emissions and since I bought it at auction, the previous owner has to fix it, or give me my money back. now that i have learned a few things about these wagons, im kinda hoping I get my money back, so I can find a LT1 wagon.

I have been looking up vacuum gauges. My brother has one on his rig that he lives by, and has really helped. so i've been thinking about getting one myself