Bad, And I Mean Bad, MPG

[mcgsecrest]

Kevin510...... Generally speaking with modern engine tech, Plugs may last 100,000 miles, routinely. A missing plug would likely turn on the On Board Diagnostic "Check Engine" Light. In addition,

A Plug Wire, if used, may be replaced only if it tests bad... Not necessarily the whole set.

Use Premium Quality Plugs, Pay the Price ! Barrel Plugs will Haunt you.

[Jacran]

Hello All, I am a 2nd year member to FMCA but have done a lot of RVing in a short time. Our rig is a 2000 Rexhall 31 foot Aerbus no slides. Toad is a 86 Jeep XJ Cherokee 4 door. Gas milage is 8.4 -8.8 constant . Speed is 55-60 Never much more. 90% on cruze control. The Rexhall is slightly aerodynamic and a low profile for a A RV. we run pretty Light I est. under 17,000 Lb. The FORD V-10, 115,000 Plus miles. had 92,000 on it when I bought it I had some Oil burn a qt every 1500 miles. I added LUCAS Injector cleaner. Good god it was better then a tune up . Added it in the mourning some place in Texas going west on the I-10 , after about a hour the engine gave a surge changed tone it just went zoom . 2 years later and adding the LUCAS aproz every 3rd tank very little oil burn . If any at all I add LUCas top oil to Engine. Now running all synthetic oil. See you all in WY in June. Jack

[garyj]

Kevin,

It wouldn't hurt to pull one of the plugs and take a look to see if it is really sooted up. Black soot could mean that it is running too rich and a hotter plug might help. I am sure there is a tuner made for your 8.1. If you have a GPS you can check your speedo with it. Since our odometer is off (about 2 10th), I drive by the GPS for my speed.

Herman

I just happened to notice that you and I have the same coach and engine (400 ISL). I am wondering about MPG on this size of coach and engine. I pull a 3500 pound Saturn Vue and I live in California, meaning no matter where I go I am rarely on flat road except up and down the San Joaquin valley. Depending on the average terrain I get between 6 and 7.5 mpg. Does that sound about right to you? Also, is there a "tunner" of any kind for this engine that's worth its salt?

Gary (garyj@prodigy.net)

[bsinmich]

My Newmar is 37' 11" and weighs several hundred pounds more than yours empty. I suggest you take it to a scale and get a real weight. I would bet you are well over 25K#. Mine weighed more than the posted weight because of options.

[syckproducts]

I had the P30 Chassis (Chevy 454) and I installed Doug Thorley Headers and a free flow exhaust system with a larger and shorter pipe system which helped increase my pulling power (Torque) and did improve the gas mileage a bit, but I also had it tuned for pulling up grades. I now have the P53 Chassis (Ford V10) and I have been researching the Banks and now I am considering doing the same thing again, Doug Thorley Headers, Larger Exhaust (Cat Back) and a free flow exhaust system. I will look to see If they have a carb legal air intake that I can get, if not I will install a K&N filter to help it breath a little better.

Anyone ever do this to the V10's, it worked great on the 454 and now I wonder how it will be on the V10.

[wolfe10]

What year V10?

You will find more improvement if an early/275 HP. Doubt it would be worth the money if a late model/362 HP engine.

[wildebill308]

I installed a Banks Economind diesel tuner and IQ. One of the features on the IQ is you can calibrate your speed using GPS. I found I was running 5.7% faster than what my speedometer was showing. I also checked using the mile markers for 5 miles at 60 mph. The gps speed and mile markers are close enough. I checked my mileage and on one leg it went from 8.6364 to 9.1286 after correcting the mileage. I wonder how accurate the different speedometers out there and how the differences affect the reported mileage.

We have just arrived at Cherry Hill Park from Texas. Went 30 to 40 then 81 to 64 then 95 to DC. Not the best route to get great mileage but I did an average of 9.1137 mpg. I have been running 60 to 65 where I could. I was getting 8.2446. I don’t know how much the Banks setup helps but I have been running in level 2 and getting an average of .8691 improvements traveling the back bone of Tennessee. That doesn’t sound like much but it’s about $50.00 so far on this trip.

Bill

[belsen]

I installed a Banks Economind diesel tuner and IQ. One of the features on the IQ is you can calibrate your speed using GPS. I found I was running 5.7% faster than what my speedometer was showing. I also checked using the mile markers for 5 miles at 60 mph. The gps speed and mile markers are close enough. I checked my mileage and on one leg it went from 8.6364 to 9.1286 after correcting the mileage. I wonder how accurate the different speedometers out there and how the differences affect the reported mileage.

We have just arrived at Cherry Hill Park from Texas. Went 30 to 40 then 81 to 64 then 95 to DC. Not the best route to get great mileage but I did an average of 9.1137 mpg. I have been running 60 to 65 where I could. I was getting 8.2446. I don’t know how much the Banks setup helps but I have been running in level 2 and getting an average of .8691 improvements traveling the back bone of Tennessee. That doesn’t sound like much but it’s about $50.00 so far on this trip.

Bill

Hey there Wild Bill, this is Duner Bill,

My experience is that the speedometer can be way off while the odometer could be accurate. Not sure if you checked the odometer against the mile markers? I would put a destination in the GPS and note the miles to get there. Then read your odometer before/after and compare those. I wish I could average 8 or 9 mpg, I'm around 7 to 7.5 mpg with a 39 ft Chieftain on Workhorse W22 and 8.1L engine pulling a 3600 lb Suzuki Grand Vitara.

Happy Trails,

Bill

[wildebill308]

Duner Bill,

I think my odometer is off about the same as the speedometer. I checked the "corrected mileage against Google and it was pretty close.

What speed are you traveling?

Bill

[belsen]

I go about 63-65 mph since it seems to keep the engine rpm's higher on the torque curve and she seems to pull the little grades better. If I drive 58-60 then she seems to lose speed faster and downshifts 5th to 4th more often. Unless there's a head wind, then I'm going the slower speeds.

Used to get 0.5 more mpg's before ethanol was added to gas. In '07 & 08 I made two loops around the country... LA, Seattle, Minn, Mich, PA, FL, Tx, Colorado, Az. at the time various states were making the Ethanol switch-over. I maintained an Excel spreadsheet accounting for every drop of gas. CA was one of the last states to quit mtbe and add ethanol and I could measure the drop in mpg.

[catskillchriss]

I had a gasser Ford 460 with a 3 speed auto on a Oshkosh chassis. It came with a gear venders overdrive system. Fully overloaded heading into the mid Atlantic states I would average about 9 to 9.5 MPG. When we headed up into the mountains of the northeast fully overloaded we got about 6 to 6.4. Has a lot to due with driving habits, type of fuel, wind conditions and total wt. I believe that without the gear venders overdrive that we would of had to figure GPM not MPG.

Recently we traded up our gasser to a 22,550 lb. diesel. I'm hoping the MPG figures improves a little with the diesel.

[five]

We are on the road, and yesterday I had a conversation with a neighbor that has the same 400HP ISL that we have. During the course of the conversation, I asked what they got for MPG. "6.2, with or without the toad." I said that seemed a bit low, and asked what they used for cruise speed...75!!

[jc21014]

We are on the road, and yesterday I had a conversation with a neighbor that has the same 400HP ISL that we have. During the course of the conversation, I asked what they got for MPG. "6.2, with or without the toad." I said that seemed a bit low, and asked what they used for cruise speed...75!!

People like that should be banned from driving a RV.

[jdmiller52]

I would not install a Banks system of any kind. You would be better off spending the money on fuel than the Banks system. If you have problems the first thing the mechanic will want to do is uninstall the Banks. As you can tell I have not had good luck with any Banks product. Also out of the box they tell you if you have any problems of any kind its not their fault.

[nomad]

Another thing that will help your mileage is to buy "ethanol free" gasoline when you can find it. It definitely makes a difference. There's an app for I-Phones called Pure Gas that shows ethanol free gas stations all over the country. Interestingly, some of these stations have no signage outside that shows they are ethanol free. Can't understand that. Many gas stations near lakes have the ethanol free gas for boats.

Mike