Gas Mileage: 454

[WitheringWalter]

Sent: 5/23/2004

I have an '87 Winnebago Chieftain 22' with a 454 engine. I was getting 10 mpg. It started dropping down to 5 mpg. I have given it a complete tune up, changed the fuel filter and adjusted the carburetor. I'm still running between 5 and 7.9 mpg. Is this normal for this rig? My driving is mixed highway and city with a normal load, water and two people. Tires are also inflated properly and can find no fuel leaks.
Would appreciate any advice on this.

Jim

[denisondc]

Sent: 5/23/2004

If thats a carburetored engine, you might check if the vacuum advance is still working. When they get a leak in the vacuum bladder the thing will drive just the same, but the mileage will suffer. Also check that your handbrake isnt dragging. If it has a mechanical centrifugal advance inside the distributor, make sure that mechanism isnt stuck and failing to operature - mileage and power would suffer. It would have an EGR valve, and unless you have replaced it in the last 10,000 miles or 2 or 3 years, I would suspect it of being stuck slightly open. If the engine has TBI, then try getting an extra computer, and swap it out to see if its a failure of one of the computers modes. I have an 87 chevy van with the 350, and I carry extras of all the engine electronics with me on long trips, as spares. I got most of them from ebay, and have swapped them with what was on the motor to make sure they work. If it has an O2 sensor, how long ago was that replaced?
My 1972 winny with the 413 gives me 8 mpg or slightly less.

[kevsws6]

Sent: 7/27/2004

I did a 680 mile round trip from San Diego to Paso Robles this weekend. Went to Eberle winery for dads 60th B-day. Went up the 5 over the grape vine and across the 46 to get there. Then down the 101 home. Lots of steep grades. On the 5 is the grapevine and the 101 has a couple also. She did 60 to 65 mph on all grades and 60 mph on the flats. I push the hills hard just to see what she will do. Never got above 215 degrees on the climbs and pulled down 8.12 MPG.

This engine is in tip top shape with an excellent tune. I don't baby the gas at any point. I push hard on the hills. I come off the line hard to get to speed when entering the highways. I always floor it when passing on the highway. This was the first trip without towing a trailer and I didn't do any better in MPG. Oh well.....

[discoverer]

Sent: 8/1/2004

WW ....... how about a restricted air filter ??... IN a non dusty enviorment - TRY removing the filter completely THEN take a mpg read. I think that you will be surprised.

[HeavyHaulTrucker]

Sent: 8/4/2004

Un-ohh!  Bad move, Discoverer.  Even a small particle of grit or dirt can do immense damage to the engine.  Besides, a replacement air filter only costs about $5.00 -- cheap enough to just change out even if not really needed.

John

[denisondc]

Sent: 8/14/2004

Ive run without air filters for a long ways, 2000 miles once, when I forgot about the filter being out. All on highways. Worst problem was when I had to tweezer an insect out of the venturi inlet. Carburetors get dirty even with the air filter on anyway, just more slowly.

[tiinytina]

Sent: 6/26/2007

Yea! mileage up! 7.13 over a 200 mile haul, avg speed 55-60 to the pond and back. Ok it's not Excalibur's astronomical numbers but hey it beats 5.4.  I know my tires are about 10lb low all the way around.... Both places I stopped at  the guages didn't go over 80lb nor did they have the attachment that can do the double back tires. Yes I now have a good guage on board as of today.
And no I wasn't hauling a van, water,  or running the genny. As TJ said, Gone is just a heavy old RV....  Still have yet to stop at a scale because I'm either in a rush to get someplace or in a rush to get home to get her cleaned up...oiy.

Tina

[ClydesdaleKevin]

Sent: 6/27/2007

Yay Tina!!!

7.13 mpg is GREAT mileage...I think Excalibur is a fluke...lol!  On that note, do you have a vacumm guage on the dashboard?  I pay close attention to the vacumm guage when I'm driving, adjusting my driving style and speed to maximize the amount of vacumm the guage is reading.

The higher the guage reads, the more efficiently the engine is running, and thus the better gas mileage you will get.  It seems to work!

[tiinytina]

Sent: 6/27/2007

No vac guage on the dash.... I have yet to fully check out the vac system... we disconnected a bunch tubes off the old carburator housing when we dropped in a K and N filter thing... Stoppered up a few and the others my mechanic didn't think were significant... but who knows... 
thanks!
Tina

[tiinytina]

Sent: 8/19/2007

Never gotten her weighed yet..... but we don't haul full water or tanks etc. Everything is empty 98% of the time. We take on maybe 15gal of water because we usually stop on the side of the PA turnpike for dinner etc....  hmmm. lets see basic poundage calculation... for bodies... 535lb .  All dinner ware is plastic. pots and pans can't be more than 15lb.

So... we filled up at the Heartsgrove BP coming in, that mileage was 5.9 running full genny with 15 gallons of water, all refuse tanks empty. We ran to Sandusky with maybe 5 gallons fresh water, and 30+gallons black and grey water since we didn't pump out.  We didn't run the genny to Sandusky but we did do some serious hills taking a back road by some Ski place.... We tanked up on the way back somewhere on the PA pike last stop before Breezewood.  We ran the genny from the OH PA border home.  Avg mph 55-60 given it was pouring horses, cows, pigs, puppies etc... and calculated 6.6mpg!!!  yipee!! haven't tanked again but probably will this week if I see gas prices going up by even a cent. 

I did notice a bit more energy on the gas. I want to redo the snorkel intake next chance I get... Going to see if I can fit something solid vs the crushed flex thats there even if I have to do a go around so its not in the 1+ inch on the side of the engine by the doghouse.

Question though. Can I put in a Y so some gets in through the rain diverter in front but some gets sucked off the side bottom? Thinkin' to mount a side scoop or something to catch air  up by the engine to the right etc....... any suggestions?

Tina

[jazzin112]

Sent: 9/5/2007

I've watched this thread with earnest since it was started.  My mileage has been in the 9-11 range since I've owned it.  It drops to the 6-7 range if driving over the mountain passes.  The previous owner did many mods to the 454...headers, dual 3" exhaust with Flowmaster 40 mufflers, and a K&N Air Filter.  Still running the stock intake snorkel.  I always drive in the 60-65mph range, as I find that the most comfortable speed for this rig.

I just had the oil changed and found the K&N to be almost plugged!  Just plain filthy.  I went ahead and put a stock paper element in its place as I am using it this weekend, and on the drive home it seemed to have a little more spunk.  I'll watch the mileage and the vacuum guage this weekend...it's about a 500 mile round trip...maybe we'll see some improvement.  I'll clean the K&N later when I have the time.  I cannot believe how dirty it was after only this spring/summer's use, around 1500 miles!

John - Jazzin112
'84 Winnebago ElanDan 31RT 454 "Ol Snort"

[tiinytina]

Sent: 9/7/2007

I took off the KN assembly I had bought  mid 2006 and we put back on the original snorkel and all its vacuum tubes (some of which were open to air connecting to inerior engine parts...) with a clean paper filter.  I need to redo the flex tube that runs from a ram intake rain blocker thing as it is crushed and twisted etc. There is little to no clearance between the doghouse and the engine for it so looking into ways to go around/under with a solid or multiple solid tubes.

Filling up before we headed out last weekend mileage was 6.2 running genny  on the PA turnpike then through Breezewood over the appalachians and back home.  Our mileage out was 7.1 over the same roads running full genny.

I put on a new set of plug wires ("best" set not cheap), pulled a couple of plugs.

Our rig has 2" dual exhaust original with original mufflers. Temp runs in the normal range. Had the transmission flushed 3K ago along with the radiator. Oil changed in the spring. Gone just flipped 70K.

Next project is snorkel feeder ram air system.... Need to see what clearance we actually have and what I can fit in.... 

tina

[ClydesdaleKevin]

Sent: 9/20/2007

Well, highway speed certainly does effect the gas mileage we are getting in Excalibur!  On the way from Wisconsin to Texas, I averaged about 65 mph, since we were in a hurry...and when I calculated the mileage, we were only getting around 8 mpg!  So, from Salado, TX to Plantersville, TX, about 150 miles, we drove at exactly 55 mph...and mileage was right back up to around 11 mpg.  Lesson learned:  Keep it at 55!

Kev

[tiinytina]

Sent: 10/8/2007

Just a Gone to the Dawgs update... Took Gone out to Trap Pond for our family fall get together. 100 miles each way and had to run the genny for AC on the way there as temps were nasty especially with 4 dogs panting in unison.....

Gassed up and weighed up on the way back. With a probably 3/4 load of fuel (55 gal or so) all dogs and probably 1/3 food load, empty black and grey tanks... Gone weighed in at 13,185lb. Rear axle was about 8500 and front 4800 or so. She took on 38 gal of fuel for 298 miles of driving. I kept to the 50-55 limit as I have driven her for all of those miles (included in were our trip to "Aqualand on labor day weekend). And..... 7.8 MPG!!! yipee! Figure 8 average due to genny.

No haven't had time to even look at the snorkel ram air intake issue yet. This weekend was all about relaxing, food and friends.

Tina Pat and da pups

[lucidsodemite]

Sent: 5/12/2008

i have a 76 brave 22 footer with a 440 in it and i sometimes tow a two place atv trailer and i have never gotten less than 8 mpg. the motor is in fine tune so i think that is the big part. i never loose any power on hills, so far anyway. i do have headers and full duals, i think that makes a big difference. had to wrap the headers with header tape as they were heating the starter up. everything seems to work good though. i could use a good set of plug wires as these have seen better days. any suggestions where in ontario to get plug wires for a 76 440 dodge? in the good old days growing up on the prairies i would just go down to the napa but i ask for parts for a 440 and they look at me as if i am speaking a foreign language. sad.

[ClydesdaleKevin]

Sent: 6/9/2008

We got about 10.2 mpg coming up to Kentucky from Georgia up 75...towing the loaded Astro van, without the genny running...Maybe the mountains lowered the mileage a bit...lol!  There were some STEEP long grades on the way up here!  So steep even the 454 was laboring, pedal all the way down just to maintain 55 mph, and then coasting on the downhills...which were too curvy to really coast at full speed with without hitting the brakes and slowing down...which killed our momentum at the base of the next mountain...very pretty trip though!  Even though I kept hearing a SQEEEEELLLL SQEEEKK CHIRRRRRP that had me CONVINCED something was wrong with the rig!!!  It was just the cicadas!!!

Kev

[Cooneytoones]

Sent: 6/10/2008

I've noticed, and I might be just imaging it, that not only driving habits, weather conditions, geographic location will effect the MPG'S ...but a large factor could be the type (BRAND) of petro used. At times for me, it has differed 1 to 2 mpg. And 1 to 2 mpg's with our gas classic guzzlers, is a big....big factor.

Here around Louisville, KY during the spring and summer months the comapanies go to a re-formulated gas (KY law...to make some the Greenies happy)
No matter which vehicle I put the re-formulated crap in, fuel mileage goes down, the driving habbits, weather,  etc. stays the same. Now living just a crossed the boarder in Indiana we are not subject to the Kentucky re-formul;ated gas law, but unfortunatly, some stations may carry it from time to time due to the fact that the fuel comes from the same distributors, and I hate it when I get it in my tank....even the lawn mower uses more fuel to mow the same area.

On a trip once,  from NY to Florida, (in 24 hours) I notied that the no name fuels such as Sprint, Econo-gas Big-Foot etc. as opposed to Shell, Sunnoco, Mobile, EXON,  got 1 to 2 mpg better, the drive was all on I - 95 which is a pretty level interstate for most of the way. Except though parts of VA. One driver and the weather conditions did not change.

I was wondering if I was crazy for noticing this, or maybe it was an illusion. Has anyone else noticed a difference in fuel milage by Brand? If you did or do, post it here.

Timmy

[ZR91]

Sent: 6/13/2008

Timmy,
I believe you are right. My 02 SS Camaro convertible was finally ready for the dyno last week.

It has always had premium fuel, and only premium fuel from the the "biggest" name fuel supplier around.

When they tried it on the dyno, it made no power above 22 degrees of timing. After hours of tearing things apart, they sampled the fuel quality.

The specific gravity was 798 ( Damn near water ). We pumped out the very full fuel tank and put in 5 gallons of ethanol enriched fuel from the local discount el cheapo gas station, which measured 645 specific gravity.
Instantly, the camaro wanted 28-29 degrees of initial timing and we saw an additional 29 HP and 41 foot/pounds at the wheels.

Jay

[denisondc]

Sent: 6/13/2008

Dont forget that fuel for the 'pumps' is refined/blended in different ways, depending on the season of the year and the climate where it is sold (higher volatility in North Dakota in Feb. compared with Texas in August among other factors), and depending on the type of crude oil the refinery is intaking. That is to say, you get different gasoline, -a different mix of hydrocarbons- if the oil comes from different oil fields. (Arabian crude is about the best, Venezuelan crude seems to be the worst) Fuel is also blended differently depending on the requirements of the state it will be sold in, and sometimes different areas within a state.
And of course including ethanol affects the amount of energy a gallon has in it; the more percentage of ethanol, the less BTU's of energy a gallon will have.
But I suspect the variables due to a decades old carburetor and the equally old distributor centrifugal & vacuum advances has as much to do with the miles you get to a gallon.

[tiinytina]

Sent: 6/22/2008

Ok, new airlifts and new shocks all around... and... the result is... 9.8MPG! yipee! Last tank was 6.2.... go figure... 

Tina

[89Elanden]

We have a 37 ft. Elanden with the 454 and have never gotten more than 6 mpg, 5 mpg is the standard, this is just a fact I have had to accept. After numerous trips, short, long, flat, mid summer, winter, regardless the mpg never varies much above 5 mpg. I once discovered a fuel leak at the fuel pump and just knew my mileage was going to double, no dice, apparently it only leaked while ideling, I guess at speed the fuel demand from the engine drew the fuel up the line so very little actually was lost. I have never weighed the rig, but we never carry fresh water, or full holding tanks, tire pressure is always monitored, clean air filter, oil changed regularly etc. It just is what it is 5 mpg, thankfully gas is not 4 bucks a gallon anymore.
Rick aka 89Elanden

[RayCameron]

We have not had our 1984 31' Elandan for that long so don't know what the MPG is yet. I noticed a MPG gauge in the upper left on the dash I wonder if this is just a glorified vacumm guage This is one of the largest vehicals I've driven " aside from a Sub " and it has VERY little spunk and sometimes gives me a back fire.

[tiinytina]

We average about 7.2 at this point if I'm driving as my foot isn't quite as heavy as  Pat's. We never haul with full water tanks, we may put 10-15 gallons in so that we can pull over on the PA turnpike and cook dinner and use the facilities etc but thats it.

I put a naked KN filter assembly on her in fall of 07 but we got 3.2 driving her in cold snowy wet air... so we reinstalled the old air filter assembly. I still have to get a KN for it so for now its just paper filter. I also need to redo the snorkle from the assembly as the one there leads to a ram air intake near the radiator but the hose is about beat to death.... The carburator leaked like a sieve when we bought her so  new edelbrock has helped but its still running a bit too rich as she will run on sometimes after cutting the engine off and will very occasionally backfire. I added racing level silicone plug wires and made sure all are in thier clips as we had 2 melt on us, talk about no pep! running on 6 cyl vs 8.... Dropped in new plugs as well.

I'd never driven anything as big either other than a big Ford dually tractor. I just take it easy I know I am a land boat.... She weighs in at 13,883 lb with 4 dogs, 1 human and basic supplies.

As I've said many times.. price of RV $$, price of customizing $$, price to fill her up $$ - having your own potty on the road and the joy of being able to escape reality when you need to ... Priceless!!!

Tina

[ClydesdaleKevin]

Hey Rick!

I would imagine that because your rig is almost 40 feet long its a LOT heavier than ours.  That said, I would still imagine your should be able to squeeze 8 mpg out of her with some modifications to the carb and intake, and of course the exhaust.  Perhaps ram air induction and the like as well. 

The one thing I've noticed over the last couple of years and I say this as gospel truth is that sticking to 55mph (coasting down a hill excluded of course) will maximize your gas mileage.

Also, getting a vacumm guage and then modifying your driving habits so that you are drawing as high a vacumm as possible in various conditions will also maximize your fuel economy.

These two elements are to me the most critical and crucial means of getting better gas mileage, and they are definately under your control...and they cost nothing to do.

Our gas mileage varies widely depending on terrain, wind direction, and even the road surface.  Provided I stick to the 55mph rule and keep an eye on my vacumm guage (driving habits now at this point), I get anywhere from 11mpg maximum, to as little as 6mpg.  I try to stick to highway driving for the long haul, stay in the slow lane at 55, and plan my trips so that I don't end up in rush hour traffic near any major city.  We've pulled over many times into rest areas if we were approaching a major city and it was near rush hours.

And wind direction does play a major factor.  On the same road going the same speed, I've gotten 11mpg with the wind at my back, and less than 9 into a headwind.

All of the above of course is dependent on keeping your engine in maximum tune with good plugs and wires, cap and rotor, a clean air filter, good current flow from the alternator and coil, a clean and well tuned carb, an exhaust that flows efficiently enough, timing set properly, clean oil to keep the lifters and everything else running smoothly, brakes adjusted properly so they don't drag, driveline greased to keep friction to a minimum, tires inflated to near maximum pressure, etc.

There are a lot of factors involved and even doing everything "right" your mileage will still vary...but at least you have control over most of the factors.  Dave Denison is quite correct though when he states that fuel quality and mixes play a major factor in your fuel efficiency and you can't really control this factor...but you can certainly maximize everything else.

Kev

[4winds]

When I drove my Midas from Dalton, Ga to Harrison Bay St. Park last Oct., I averaged 10 mpg.  Granted it was only 40 miles, but it still gave me an idea what to expect.  1oleman(Ed)