how to increase miliage when towing

[bruceb58]

Re: how to increase miliage when towing

If you put a K&N filter on a fuel injected engine, it will not give you better gas mileage.

If one thinks they are getting 10% or 5% better mileage likely due to placebo effect.

K&N is a holdover from carburetor days. Modern fuel injection meters the fuel based on the air density being consumed by the engine after the air filter. Even a completely clogged paper filter isn't going to affect your MPG. It will affect your top end power and acceleration but not your MPG.

This article explains why you don't get better MPG:
http://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf
If you don't want to read about all the tests in the paper, skip to page 25 for the conclusions.

 

[kenmyfam]

Re: how to increase miliage when towing

Very interesting thread with some varied comments and widespread points of view.
Here's my opinion and findings for what it's worth.

Trailblazer alone @ 60mph = 20mpg
Trailblazer alone @ 70mph = 17mpg
Trailblazer with 2,000lb boat @ 60mph = 17mpg
Trailblazer with 2,000lb boat @ 65mph = 16mpg
Trailblazer with 2,000lb boat @ 70mph = 14mpg
Trailblazer with 5,000lb Travel Trailer @55mph = 13mpg
Trailblazer with 5,000lb Travel Trailer @60mph = 12mpg
Trailblazer with 5,000lb Travel Trailer @65mph = 8 mpg

Wind resistance and weight combine to increase mpg. Pulling the extra 5mph with the Travel Trailer costs an extra third in fuel.
Therefore I tow at 60mph for the best bang for my buck with the Travel Trailer and 65mph with the boat on the back.
Easiest and cheapest way to increase fuel efficiency without adding any "miracle modifications" is to simply slow down some.
Trailblazer is a 4.2 litre in line 6 cylinder with a 3.73 ratio. Only modifications are an additional tranny cooler and an electronic brake controller.
Slow down, Save money.......simple as that.
Just my thoughts on the subject.

 

[bigdee]

Re: how to increase miliage when towing

If you put a K&N filter on a fuel injected engine, it will not give you better gas mileage.

If one thinks they are getting 10% or 5% better mileage likely due to placebo effect.

K&N is a holdover from carburetor days. Modern fuel injection meters the fuel based on the air density being consumed by the engine after the air filter. Even a completely clogged paper filter isn't going to affect your MPG. It will affect your top end power and acceleration but not your MPG.

This article explains why you don't get better MPG:
http://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf
If you don't want to read about all the tests in the paper, skip to page 25 for the conclusions.

A+ I agree...Bruce is absolutely correct. Trust your vehicle's computer it knows best!

 

[bigdee]

Re: how to increase miliage when towing

Very interesting thread with some varied comments and widespread points of view.
Here's my opinion and findings for what it's worth.

Trailblazer alone @ 60mph = 20mpg
Trailblazer alone @ 70mph = 17mpg
Trailblazer with 2,000lb boat @ 60mph = 17mpg
Trailblazer with 2,000lb boat @ 65mph = 16mpg
Trailblazer with 2,000lb boat @ 70mph = 14mpg
Trailblazer with 5,000lb Travel Trailer @55mph = 13mpg
Trailblazer with 5,000lb Travel Trailer @60mph = 12mpg
Trailblazer with 5,000lb Travel Trailer @65mph = 8 mpg

Wind resistance and weight combine to increase mpg. Pulling the extra 5mph with the Travel Trailer costs an extra third in fuel.
Therefore I tow at 60mph for the best bang for my buck with the Travel Trailer and 65mph with the boat on the back.
Easiest and cheapest way to increase fuel efficiency without adding any "miracle modifications" is to simply slow down some.
Trailblazer is a 4.2 litre in line 6 cylinder with a 3.73 ratio. Only modifications are an additional tranny cooler and an electronic brake controller.
Slow down, Save money.......simple as that.
Just my thoughts on the subject.

Good data. It is interesting to point out that I get about the same MPG as you do at 60mph with a similar load with my 4cylinder S-10 and 4.3 Blazer.....which makes sense as they are all doing the same amount of work.

 

[oldjeep]

Re: how to increase miliage when towing

If you put a K&N filter on a fuel injected engine, it will not give you better gas mileage.

But you do get the benefit of letting a lot of extra dirt into the engine.

 

[bruceb58]

Re: how to increase miliage when towing

But you do get the benefit of letting a lot of extra dirt into the engine.

Yes! I used to use them until I decided I wanted my engines to last longer.

 

[QC]

Re: how to increase miliage when towing

Great data there Bruce. :facepalm: the closed loop explanation is so simple.

joe, yes upshifting is obvious. I was mostly reacting to the rear end ratio change out discussion. Vaccum will go up, fuel efficiency will go down. I have always struggled with ambiguity, there was even a kind of contradiction in the first Pop Mech link above:

The important thing is: drive in a manner that keeps the manifold vacuum as high as practical and still allows you to keep up with traffic. Paying attention to the readings will give you an appreciation for how hard your engine is working at any moment in time. If you have a manual transmission or an automatic you can shift manually, you can check out the difference in fuel consumption while accelerating away from a stop in different ways. Experiment. Shift short, at a low rpm, and see how you do. Then hold the trans in that gear for a longer time. You'll gain an understanding for the skills and thought required to save fuel.

For example, this combo is very confusing if you take it literally. Basically I would be discouraged to upshift based on vacuum. While upshifting early would result in lower vacuum, but better fuel efficiency. I know you get it, but explaining my comments. From experience, I know a lot of people that would drive around seeking higher vacuum, and get exactly the opposite of what they wanted, particularly if they shifted manually . . .

 

[QC]

Re: how to increase miliage when towing

K & N is great example of marketing and branding. Kudos to them even if they should be ground into the pavement

 

[joewithaboat]

Re: how to increase miliage when towing

K & N is great example of marketing and branding. Kudos to them even if they should be ground into the pavement

I agree that optimum filtering at different times during the filter use... from clean to dirty... looks to be questionable.
As long as K&N, and others, keep proving to make intake systems that increase HP on the Dyno they will have Zero problem selling product.

Ive Seen it over and over again in back to back pulls... They just flow more air.

The old carb setups often make more power than just an open carb. Filter and filter base cleans up the airflow into the carb, sometimes enough to necessitate a jet change.

 

[bruceb58]

Re: how to increase miliage when towing

Bottom line is that when talking about MPG, the throttle plate itself will have more restriction than the air filter is causing. We also aren't talking about carburetors here. We are talking about fuel injection.

If you want to increase top end power, then maybe a K&N might help you. Problem is that the amount of dirt they let in just isn't worth it to me. AC and Wix air filters for me.

 

[bruceb58]

Re: how to increase miliage when towing

Great data there Bruce. :facepalm: the closed loop explanation is so simple.

So simple yet obviously ignored by the sheeple.

 

[bigdee]

Re: how to increase miliage when towing

If you want to increase top end power, then maybe a K&N might help you. Problem is that the amount of dirt they let in just isn't worth it to me. AC and Wix air filters for me.

Yup, they have to give up something to breath better. Today's technology is making the after market guys more and more obsolete.
MPG is gained by CONSUMING less HP...NOT BY TRYING TO MAKE MORE! There is 49 HP/hr available in a gallon of gas but since engines are only 20-22% efficient there is is only about 15 HP/hour to play with after burning it through the engine. So the trick is to decrease load by whatever means. It is hard to believe but it only takes 13-15 HP to move a pickup 60 mph and maybe 23-27 hp when towing an equal weight

 

[yabuoy]

Re: how to increase miliage when towing

If one is towing a boat on a relatively flat road or on a long downhill road, is it ok to tow in OD? I hear this and that about how bad it is to tow in OD but I am curious about how most of you guys tow your boats. The main route I must take from home to the lake has many hills, but there are slower, flatter routes that I could use as an alternative. I would like to drive that route and tow in OD if it is practicable

 

[bruceb58]

Re: how to increase miliage when towing

Consult your owner's manual but as a general rule, if your transmission is not constantly shifting in and out of OD, you are probably fine.

 

[joewithaboat]

Re: how to increase miliage when towing

If one is towing a boat on a relatively flat road or on a long downhill road, is it ok to tow in OD? I hear this and that about how bad it is to tow in OD but I am curious about how most of you guys tow your boats. The main route I must take from home to the lake has many hills, but there are slower, flatter routes that I could use as an alternative. I would like to drive that route and tow in OD if it is practicable

Depends on the type of transmission really. Manual or auto, what make?

 

[joewithaboat]

Re: how to increase miliage when towing

Yup, they have to give up something to breath better. Today's technology is making the after market guys more and more obsolete.

Aftermarket guys are quite happy. The increase in technology has made parts cost more and they are selling more product at higher prices than ever before.

The aftermarket frequently improves the manufacturer's product and often the manufacturers improve there own by looking at what the aftermarket has done with it.

 

[joewithaboat]

Re: how to increase miliage when towing

MPG is gained by CONSUMING less HP...NOT BY TRYING TO MAKE MORE! There is 49 HP/hr available in a gallon of gas but since engines are only 20-22% efficient there is is only about 15 HP/hour to play with after burning it through the engine. So the trick is to decrease load by whatever means. It is hard to believe but it only takes 13-15 HP to move a pickup 60 mph and maybe 23-27 hp when towing an equal weight

So... your towing your boat around with a 25 hp engine to save on fuel?
No, my point being all you keep talking about is what it takes to keep a load moving on a flat road once you have it moving. In the real world we have to get it moving and keep it moving even when varying loads are presented.

 

[bigdee]

Re: how to increase miliage when towing

Has anyone had any experience with this? http://www.gtechpro.com/ss_fanatic.html This looks like the ticket for learning how to adjust your driving,using different brands of fuel,tires, air dams,etc. to reduce/optimize horseower.

 

[Scott Danforth]

Re: how to increase miliage when towing

call it placebo effect, call it advertizing, call it change in driving conditions, call it the ability to not have to mash the throttle to the floor all the time. either way, the durango went from 275 miles per tank to 310 miles per tank (23 gallon tank) pulling the same boat over the same route after putting in the FIPK.

 

[bruceb58]

Re: how to increase miliage when towing

I can pull my same boat over the same route every year and get that type of mileage variation and I have done nothing to it. Unless you know the exact speed you were going, the wind speed, temperature...not a very scientific comparison. Guess its just the engineer in me!