Be very careful if you have a factory &/or extended warranty on your vehicles. Some of these mods will be OK, many will void any warranty - especially the chip. There are some mods that you can purchase through your manufacturers parts department also, like cat-back from DC.
With the new electronics & 'black-box' in newer vehicles - there are no secrets from a qualified technicians.
PICK, the trucking firm ENGLAND has been using propane injection for over 15 years. They probably have data, if your interested.
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I read somewhere - maybe on this forum? that if you use premium fuel it will save you money and increase gas mileage - that is because most modern engines are computer controlled and since premium fuel burns better and thus better mileage. I'm sceptical, but I do plan to try a few tanks and see what happens. I'm please with my 8.1 motor - 17mpg on hwy.......
I read somewhere - maybe on this forum? that if you use premium fuel it will save you money and increase gas mileage - that is because most modern engines are computer controlled and since premium fuel burns better and thus better mileage. I'm sceptical, but I do plan to try a few tanks and see what happens. I'm please with my 8.1 motor - 17mpg on hwy.......
Ken J
Ken -- It's an old wives tail that says premium fuel is better. The word premium refers to the price not quality. Premium fuel simply is designed with a flash point that is lower than regular. High compresion engines need this to prevent them from igniting the fuel in the cylinder from the heat of compression . In that case an engine designed for premium might have better performance,otherwise it's a waste of money. ---pieman
My understanding (again I am very skeptical) is that because of the lower flash point (or something) that the computer retards the spark advance which gives you the better mileage.
What you say is my understanding too - that premium is just a waste of money - however what the hey - I'll try a tank or two and see if it does make a difference.
What I do notice is a difference between summer gas and winter gas - not sure what they do, but I know I get better mileage in the summer than winter.
I also use synthetic oil and I think I'm getting about 1mpg difference with it.
Have you looked into bio diesel? I have done some research and can home brew from waste veg oil for about 1 dollar a gallon + the parts to build the still about 200 bucks.
I am thinking of trying it.
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Cat back systems: Can improve horsepower, usually at the cost of torque. For towing, this means no net gain is likely. Could even be a loss of mpg.
Premium fuel will improve mileage only if the engine is optimized to burn premium. It would be a very odd computer map that anticipates higher octane MAY be used and would then advance accordingly. Most, maybe all modern computers will retard ignition if pre-detonation is occuring.
On diesels, it is fairly simple - more air in and more exhaust out means better power. But be aware that some high flow air filters do not do as good a job at filtering, and a replacement Duramax engine will make you forget all about fuel prices.
Nothing you can buy, add, or adjust will give the kind of gains you can get from backing off from 70 mph to 60 mph while towing.
"More Milage" money back guarantees rely on the fact that most people who buy their gimicks start being more conscious of gas usage - no jackrabbit starts, coasting to a stop, obeying speed limits, etc. And, surprise! They suddenly get better milage!
What I do notice is a difference between summer gas and winter gas - not sure what they do, but I know I get better mileage in the summer than winter.
The EPA requires different additives in the fuel based on the overall Air Quality in your region. In the summer your Air quality is worse than winter so they add stuff to deal with the issue (MTBE?). In WI it was just the opposite, the additives were in the winter fuel, summer was normal, most years. All of the additives also add to the cost and make the distribution of fuel a nightmare as not all of the fuel from a single depot may have to have the additives depending on where it is going to be delivered. Here in FL they don't add anything as we have hurricanes to get rid of the nasties in the air
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Your Avalanche is a fairly new vehicle with gm's new electronics package and the larger tailpipe. I would question if you will get anything from the breathing packages except dirt in your engine from less restriction.
You should go on chevytalk.com, 99-current year vehicles and ask the same question. There are some real gear heads on there that have tried it all.
It is my understanding that what works on a diesel has very little application to gasoline engines.
I would look at Michelin tires when it comes time to change. They have done a lot of work on class 8 tractor trailer rigs to reduce rolling resistance with tire design. I don't know what they have done for pickups.
Last edited by wingfoot321; 09-07-2005 at 10:08 PM.
I did all the tricks I could think of on my last diesel...chip, synthetics, driving style, air pressure, exhaust, you name it. Did I save fuel? You betcha! Did I save money? Not a red cent! The math just doesn’t add up.
On my new diesel truck I kept it stock and just drive more sensibly. So far it's working and fuel is what it is and will be.
Cat back systems: Can improve horsepower, usually at the cost of torque. For towing, this means no net gain is likely. Could even be a loss of mpg.
Mark
Mark.....
I drive with a light foot already......towing and other driving. I drive the interstate speed limit 65mph......so should I slow down to 60 mph on interstate (semis will be passing me)? Mark, what you're saying is that I will not realize any appreciable improvement in mpg by adding a cat back exhaust system to my 8.1L Avalanche while towing......but may see an improvement while just driving around town/highway. I don't understand????
The muffler shop guarantees better gas mileage with the cat back system or my money back. Of course I would have to show them my average mpg on the onboard computer before he makes the change to prove what I was getting before the modification. I'm confused.......you're the first person who has poo-pooed this idea
OK, now I will weigh in as the lowest common denominator of vehicle owners.
Mine is a 2000 Chevy S-10. I know nothing about its workings other than how to jump someone else's dead engine. Don't even know how to turn the headlights on & off since they seem to be on at all times.
When I bought it in 2002, the dealer said it ran around 23 m.p.g.
I didn't believe him & found it to be around 18 combined.
Despite my disinterest in the maintenance, I live 2 blocks from a great autobody shop & frequently drop it off for the regular stuff. George at Hollywood Motors also is under orders to err on the side of fixing things because I do not want to break down on a Chicago interstate at 2 a.m. by myself.
I always got the medium gas out of ignorance & figured I was splitting the difference. The truck generally got 280-290 miles per tank that way.
Last week when I filled up, I went the cheap route because gas had just spiked 50 cents a gallon. And now the needle is exactly at the halfway point & the odometer is at exactly 100. Normally I should be at 140-150.
No changes in driving habits, unless you count driving less. Are you SURE the different grades of gas couldn't have accounted for this fairly significant change in mileage?
Oh, P.S.: If I got 323 miles per tank when I bought it & have had it in the shop regularly, does anyone know why that average would have dropped to 280-290 after a few months of owning it?
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Last edited by summerkid; 09-07-2005 at 10:54 PM.
Reason: add something
I just got rid of my 2000 S-10 Blazer...4.3L LS....I always ran it on regular gas and found that my mileage differed, depending on the gas station I went to....some brands got me better mileage, but on average I got about 19MPG. The only time that I got better mileage was when I first bought it, and Sherri, the kids and I went up to Wahpeton, ND for Sherri's grandmother's funeral. The Blazer got 31MPG at one point....average was 24MPG's. I just went to Arizona several months ago and took the Blazer and averaged 28MPG with regular gas.....weird truck. In retrospect, I'm glad I got rid of it.
check computer codes with a scanner available at auto parts store.
Typically a truck with over 100K miles will benefit from EGR valve and O2 sensor replacement. The latter will not set a code, it just goes lazy from age. The Exhaust Gas Recirculation valve is an emissions device designed to improve mileage, and it goes bad from age and gets carboned up.
I've always driven cars with around 100K miles on them and found out that replacing both of these items can bring up the MPG by as much as 3-4MPG.
What's really cool is a laptop which can give real-time readings. I want to get software and monitor all sensors to make sure they are within operating range.
Poor MPG means the vehicle is running rich. It's running rich if some sensors are malfunctioning.
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1986 Excella, 32' - FOR SALE ON EBAY, AUCTION # 160034864277
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Grace - When you get what you don't deserve
I hear that best MPG is where the HP and torque curves intersect. For my 7.5L engine and auto, it's 2200 rpms. Which usually means 47mph. I have gotten almost 12 mpg once like that. Usually it's 10 empty.
I would love to own a 5 speed due to reduced rpms. 3 speed automatic and big block does not lead to good mpg.
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1986 Excella, 32' - FOR SALE ON EBAY, AUCTION # 160034864277
Justice - When you get what you deserve. Mercy - When you don't get what you deserve
Grace - When you get what you don't deserve
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