Hi, New to the forum: 04 V6 Mustang Convertible Automatic

[Mustang Dave]

My Mustang also has a combined EPA estimate of 20 MPG. At about 68K miles, it still has the factory spark plugs and wires. Its fuel economy just seems to keep getting better as I make subtle adjustments to the "nut behind the steering wheel". My next fill-up's fuel economy will be down a bit, since I bought new tires 139 miles after my last fill-up.
My normal commute to work (6:30 AM) is 16.7 miles with 3 stop signs and 20 stoplights. In-town traffic at that time of day is not bad.
My normal commute home from work is 20.3 miles (15 miles of Interstate @ 65 MPH) with 5 stop signs. In-town traffic at 3:30 PM is a bit detrimental to FE.
On grocery day, my commute home is 18.7 miles (9 miles of Interstate) with 3 stop signs and 9 stoplights.

[bhazard]

Originally Posted by darcane

Clearly.

The 04's were still based on the same Fox chassis as the 79. Sure the body and interior and mechanicals were updated over the years but underneath its still pretty much the same.

[Mustang Dave]

Instrumentation such as a ScanGauge or UltraGauge is the most helpful mod. It helps you "adjust the nut behind the steering wheel". I bought a ScanGauge about 11 months before I found ecomodder.com. Enjoy your ScanGauge. It makes fuel economy a fun game.

Synthetic lubricants can also help. If your engine calls for 5W-30 try switching to a 0W-30 synthetic. I switched to Mobil 1 0W-30 synthetic in my 4.0 last oil change. I had been using Motorcraft 5W-30. I gained about a half mile per gallon - not a dramatic difference, but noticeable. It will also save me money on oil changes, since I can safely extend my oil change interval to 12 months (about 8500 miles).

One mod I did in May was installing an underdrive crankshaft pulley. It frees-up some power (and economy) by driving the accessories (particularly the water pump) 25% slower. It also reduced rotating mass by 25.5 ounces. It's an expensive mod ($300+) and I gained about 1 MPG with it, so it'll pay for itself in fuel savings in about 80,000 miles.

When you're due for new tires, you may want to consider Low Rolling Resistance tires. I found the Yokohama YK580, which is the unlikely combination of high performance, low rolling resistance, and fairly high treadwear rating of 580. They're rated for 130 MPH. I bought them on July 8, so they're still breaking-in. I also went one step up in diameter (235-60R17 vs 235-55R17) to reduce my cruise RPM. This required re-calibrating my speedometer, which I accomplished with my Hypertech power programmer.

Power programmers are a bit expensive, but they give a boost in power without affecting fuel economy (in my experience). They can also be used to reprogram shift points and shift firmness in auto transmissions. As mentioned, they can also re-calibrate the speedometer for changes in tire diameter and/or gear ratio.

If you're able to limit your freeway speed to 65 MPH, it can make a big difference in economy.

[Thatdippedstang]

Originally Posted by Mustang Dave

Instrumentation such as a ScanGauge or UltraGauge is the most helpful mod. It helps you "adjust the nut behind the steering wheel". I bought a ScanGauge about 11 months before I found ecomodder.com. Enjoy your ScanGauge. It makes fuel economy a fun game.

Synthetic lubricants can also help. If your engine calls for 5W-30 try switching to a 0W-30 synthetic. I switched to Mobil 1 0W-30 synthetic in my 4.0 last oil change. I had been using Motorcraft 5W-30. I gained about a half mile per gallon - not a dramatic difference, but noticeable. It will also save me money on oil changes, since I can safely extend my oil change interval to 12 months (about 8500 miles).

One mod I did in May was installing an underdrive crankshaft pulley. It frees-up some power (and economy) by driving the accessories (particularly the water pump) 25% slower. It also reduced rotating mass by 25.5 ounces. It's an expensive mod ($300+) and I gained about 1 MPG with it, so it'll pay for itself in fuel savings in about 80,000 miles.

When you're due for new tires, you may want to consider Low Rolling Resistance tires. I found the Yokohama YK580, which is the unlikely combination of high performance, low rolling resistance, and fairly high treadwear rating of 580. They're rated for 130 MPH. I bought them on July 8, so they're still breaking-in. I also went one step up in diameter (235-60R17 vs 235-55R17) to reduce my cruise RPM. This required re-calibrating my speedometer, which I accomplished with my Hypertech power programmer.

Power programmers are a bit expensive, but they give a boost in power without affecting fuel economy (in my experience). They can also be used to reprogram shift points and shift firmness in auto transmissions. As mentioned, they can also re-calibrate the speedometer for changes in tire diameter and/or gear ratio.

If you're able to limit your freeway speed to 65 MPH, it can make a big difference in economy.

I will have to try the different oil and tires when those times come around.

The tuner that I have has given me better power and better gas mileage, as well as much better shift points and firmness, and it can also do the speedometer calibration .

I am working to improve the aerodynamics of my car right now. I'm looking at making a different spoiler that will give me the look I want but contribute to lower drag.

I also just built a partial main grille block using chloroplast.




Late this week I'm also replacing my fuel filter which is known to increase FE on my model of mustang.

[Thatdippedstang]

I tried out the Grille block on a shortish drive, but it had a mix of stop/go and highway driving,it was also 95F in Full Sun, during which the Water Temp peaked at 207F and then fell to 206F, My fan turns on to low speed at 210F, so I think I got the opening about the right size.

[darcane]

Originally Posted by bhazard

The 04's were still based on the same Fox chassis as the 79. Sure the body and interior and mechanicals were updated over the years but underneath its still pretty much the same.

Even underneath, there are a lot of differences. However, the SN95 (aka Fox-4) chassis is an evolution of the Fox chassis, and the claim could be made that the OPs New Edge Mustang is a Fox chassis even though there are more different parts than shared...

But he didn't call it a "Fox chassis". He called it a "Fox Body" which specifically refers to '79-'93 Mustangs and no others.

And now back to your regularly scheduled programming...

[darcane]

Originally Posted by Thatdippedstang

I am working to improve the aerodynamics of my car right now. I'm looking at making a different spoiler that will give me the look I want but contribute to lower drag.

I also just built a partial main grille block using chloroplast.




Late this week I'm also replacing my fuel filter which is known to increase FE on my model of mustang.

Most of the airflow into the radiator should come through the opening in the bumper cover. Unless there is a power steering cooler or something up top that you are trying to get air to, I would just block the entire upper.

Also, I tried to do a similar block behind the grill on my old Silverado. I believe the air pressure pushed on it and flowed around the block anyways. It was far more effective in front of the grill than behind.

[Thatdippedstang]

Originally Posted by darcane

Most of the airflow into the radiator should come through the opening in the bumper cover. Unless there is a power steering cooler or something up top that you are trying to get air to, I would just block the entire upper.

Also, I tried to do a similar block behind the grill on my old Silverado. I believe the air pressure pushed on it and flowed around the block anyways. It was far more effective in front of the grill than behind.

The upper grille is right over the radiator, the lower grille is fully blocked because it didn't give much to the radiator.

I don't plan on going to a front grille block if I don't need to, I like this look better

[Mustang Dave]

Originally Posted by Thatdippedstang

I will have to try the different oil and tires when those times come around.

Just adding more information - I switched my manual trans from Mercon to Royal Purple "Synchromax" Manual transmission fluid last July... It made no difference in fuel economy. Your rear axle probably already has 75W-140 synthetic gear lube in it, as mine does, so that's a non-issue. The 0W-30 motor oil made a significant difference. Hopefully, tomorrow's fill-up won't take TOO big a hit from the new tires...

Originally Posted by Thatdippedstang

The tuner that I have has given me better power and better gas mileage, as well as much better shift points and firmness, and it can also do the speedometer calibration .

Cool. So you can switch tire sizes without additional expense to re-calibrate the speedometer. And it's nice to get more power without sacrificing fuel economy.

[Thatdippedstang]

Originally Posted by Mustang Dave

Cool. So you can switch tire sizes without additional expense to re-calibrate the speedometer. And it's nice to get more power without sacrificing fuel economy.

The Key is "Additional Expense", it wasn't cheap, but it comes with free tunes and will reprogram my car in less than 3 minutes. There is one tune Faster than the one that I have in, but that is reserved for FAST back road driving, or if it ever gets a little time on a track.

Hopefully you don't take that big of a MPG hit