Greetings and Salutations

[brok3n]

Hello everyone. Just figured I would post an intro to hopefully get an idea on if what I'm planning on doing to my car will be worth the investment. I have an 07 Honda Accord Sedan 4cyl autotragic, a 95 Subaru Legacy L 2.2l, and an 03 Kawasaki ZX6R

Long story short, I do a lot of out of state driving with my Accord for backpacking trips and really want to maximize my expressway fuel economy. For the most part, depending on speed I already get pretty great MPG's (30-36.7) but I want to step it up even further.

Will the following make substantial gains at 70mph (cruising expressway speeds);
Coilovers
Disc Hubcaps
Full undertray
Partial block off (fog lights, maybe grill)

I'm hoping to get 45+mpg? Is that unrealistic?

[larrybuck]

As you have mentioned: auto-tragic! If you had a 5 speed, I think you would have a chance.

Have you been brave enough to bump up the tire PSI. by 5-7???

That's about the limit so one wouldn't prematurely wear out the tires.

Don't get discouraged. Have you considered the lawn edging type air dam for the front?

There are lots of little things to do.

Are you really using the back seat, or passenger seat much?

[UltArc]

Originally Posted by larrybuck

As you have mentioned: auto-tragic! If you had a 5 speed, I think you would have a chance.

Have you been brave enough to bump up the tire PSI. by 5-7???

That's about the limit so one wouldn't prematurely wear out the tires.

Don't get discouraged. Have you considered the lawn edging type air dam for the front?

There are lots of little things to do.

Are you really using the back seat, or passenger seat much?

I love this site. Some people are able to live what I can only dream of!

Flatroad cruising in 6 I get 40-45, at 65 mph. The belly pan will give crazy results for yourmission. Also checkout body kits, or make a home made air dam. Even if it is just for high way, as in removable, it will get great results. Are your wind screen wipers catching air? Some card board just tied to the grill to block air will help. No roisk to over heat, and easily removed. Check the 65+ list, you can easily get that average on highway in cruise with a few mods.

[MetroMPG]

Originally Posted by brok3n

already get pretty great MPG's (30-36.7)

Coilovers
Disc Hubcaps
Full undertray
Partial block off (fog lights, maybe grill)

I'm hoping to get 45+mpg? Is that unrealistic?

It's a bit unrealistic if you're not also willing to slow down some. (That's where the single biggest saving is to be found).

Based on 30-36.7 starting point, you're looking for 8-15 mpg, or ~10-50% better fuel economy.

The mods you suggest might be good for a ~5-7% improvement (guesstimate).

Why only "maybe" a partial grille block? Grille openings are sized for a worst-case, high load cooling scenario: full load, towing, with the A/C on. How often do you do that? Progressively block, starting with the upper opening, and monitor coolant temperature.

[mcrews]

you do need to slow down.
And you need a gauge of some kind (scangauge available here)
once you can instantly track......you will realize the addvantages. Tanks to tanke is a very passive appraoch to improving mpg.

bump up the air in tires is a must(read other threads)
Once you have 'instant abulity'
, do a 10 mile run up & back at 60, 06, 70, 75.
Also, if you can do any coasting/engine on, this will help. (I do not coast to below 50mph) Usually only going down a hill.
The you will have you own proof that slowing down is woth it.

[scivicblu83]

what rpm's is your engine turning at 70 mph?

[brok3n]

Originally Posted by MetroMPG

It's a bit unrealistic if you're not also willing to slow down some. (That's where the single biggest saving is to be found).

Based on 30-36.7 starting point, you're looking for 8-15 mpg, or ~10-50% better fuel economy.

The mods you suggest might be good for a ~5-7% improvement (guesstimate).

Why only "maybe" a partial grille block? Grille openings are sized for a worst-case, high load cooling scenario: full load, towing, with the A/C on. How often do you do that? Progressively block, starting with the upper opening, and monitor coolant temperature.

I guess I'll have to evaluate what my car needs exactly for cooling.

Originally Posted by mcrews

you do need to slow down.
And you need a gauge of some kind (scangauge available here)
once you can instantly track......you will realize the addvantages. Tanks to tanke is a very passive appraoch to improving mpg.

bump up the air in tires is a must(read other threads)
Once you have 'instant abulity'
, do a 10 mile run up & back at 60, 06, 70, 75.
Also, if you can do any coasting/engine on, this will help. (I do not coast to below 50mph) Usually only going down a hill.
The you will have you own proof that slowing down is woth it.

The kicker is that with backpacking trips, reaching the trail head at a certain time is usually imperative. Obviously I could leave earlier but on very long trips it increases the gap substantially. Our next trip planned is 451 miles away, the gap in 10mph (60mph vs 70mph) is an hour of drive time. Quite frankly, I hate driving to begin with... 65 mph would probably be doable as it makes the gap 1/2 an hour and might negate a fuel stop which would eat half of that.

Originally Posted by scivicblu83

what rpm's is your engine turning at 70 mph?

I think around 2200-2400 rpm's, but definitely not over 2500.

[mcrews]

good luck

[MetroMPG]

Dropping from 70 to 65 mph will result in a noticeable difference in MPG. Missing a fuel stop is gravy.

EG. see http://ecomodder.com/forum/showthrea...you-15182.html

I also agree with mcrews about instrumentation: it's worth it to get a MPG display. A ScanGauge or equivalent is also useful since it reports coolant temperature (and saves your "max" value) - perfect for developing a partial grille block.

[brok3n]

Originally Posted by mcrews

good luck

Based on some of your other posts... not sure if being serious or being a dick. Either way, Shorter trips I can definitely reduce the speed because it's not as time sensitive..

Originally Posted by MetroMPG

Dropping from 70 to 65 mph will result in a noticeable difference in MPG. Missing a fuel stop is gravy.

I also agree with mcrews about instrumentation: it's worth it to get a MPG display. A ScanGauge or equivalent is also useful since it reports coolant temperature (and saves your "max" value) - perfect for developing a partial grille block.

I'll have to look into that. Thanks to both of you guys (and for all the other information on this site).