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

I'm looking at making changes that result in better fuel economy for my 04 Mustang, i went from 14mpg to 18 mpg by changing my Plugs and wires, as well as trying to adjust the nut behind the steering wheel a little.

Welcome!

I recently sold an '01 Mustang V6 auto Vert. It was a bit of a pig as far as economy, but on a good day I'd get 21-22mpg hwy. I never had any luck getting more out of it, but I didn't try too hard either.

Start a fuel log, it will help you track what works and what doesn't.

Welcome to the site.

I have currently increased the tire PSI on it from 35 to 45 PSI, and blocked off the lower grille/bumper openings, the results are the ability to get 30 MPG but the reality is that i have re-entered the stage of the Throttle being an ON/OFF switch more often than before, that is because I just had the ECU tuned and it is just so much fun.

Well then hopefully soon the reality of it being a V6 mustang (the "old" v6 at that) that is slower to 60 mph than a typical family car of today will set in and you will go back to shooting for mpg lol.

I can't wait for my scangauge E to get here tomorrow. Then it should make it more interesting.

Welcome.

Read up on forum member Ultarc's activities, his Mustang is a generation newer than yours but I can't help but think that you could pick up some useful stuff from him. His Mustang has plenty of go-fast bits, all the power you need (and most of the power you want) and still delivers Civic-like fuel economy when he keeps his foot out of the go pedal.

Clearly. :)

I hade the same thought.:)

My car has a combined of 20, and I live in the city. Not to mention when I got it there where 85k miles on it (november) and the plugs and wires hadn't been changed, ford recommends every 100k.

The tune put more air with the fuel and gave me better low end torque which is good for the city, and even the higher flow CAI gave be better mpg. Changing the plugs and wires (3 weeks ago) has resulted in better mpg without change my driving style. No:turtle:

I just got my scangauge 3 days ago and just filled up, and it was my best tank 20.2 mpg. Having that display keeps my foot out of the throttle too hard when it's not necessary to maintain or gain slight speed.

And it being an automatic that torque converter, especially of that generation couoled with 1 less gear than the manual brother, does make quite a difference, but hey I've already seen results and that's with still giving the pony a little love when that light turns green on occasion.

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.

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.

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. :D

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.
http://i.imgur.com/0Eiq27K.jpg

http://i.imgur.com/9qn0JgG.jpg

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

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.

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...

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

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...:p

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 :thumbup:

Filled this morning. 32.2 MPG. The new tires seem to be breaking-in well. 4 consecutive fill-ups over 32 since I installed the underdrive crank pulley.
I've had occasional 32 MPG fill-ups in the past, but those were just "one-in-a-row.;)

What where your previous consecutive fill ups? 4 consecutive at 32+ is really awesome

Last Summer I got 6 consecutive fill-ups over 31 MPG. My count is currently at 7 consecutive fill-ups over 31 MPG for this Summer.
I'm currently at 30 consecutive fill-ups over 30 MPG. My last fill-up under 30 MPG was January, 2014. Ideal driving conditions make for great fuel economy numbers.
If I could drive 40 MPH around the Indianapolis Motor Speedway for a full tank, I believe I could break 40 MPG.

On edit, I see that your last fill-up was significantly better than the previous fill-up. :thumbup:

Update: I'm currently at 10 consecutive fill-ups over 31 MPG, 7 consecutive fill-ups over 32 MPG, and 33 consecutive fill-ups over 30 MPG. :thumbup:

Wow that is really impressive, Congrats :thumbup: The best I have hit is 21 mpg on a tank, that is with having a bit of fun one day, If only it was manual, then I could do a lot better.

Thanks.
The city is going to be adding another stoplight to my morning commute, bringing the stoplight count to 21 over a distance of about 8 miles.:p One more opportunity to be the first one through the intersection when the light turns green.;)
Now that the weather is cooling off and fuel is switching over to winter blend, my economy will be dropping a bit. The switch to Mobil 1 0W-30 in the crankcase got me through last winter without dropping below 30 MPG. Maybe the under drive crankshaft pulley will keep me over 31 this winter. That would be :cool:.

I looked at your log. You're doing really, really well, pushing an '04 to a lifetime average over 30. That's fantastic.

Thanks!
It took me almost 8 years to get my lifetime average over 30. It's NOT impossible to get over 30 MPG with a Mustang. I've done it for over 90 fill-ups. My lifetime average would likely be better if I had found ecomodder.com before I bought my Mustang.:)
Mine is actually an '07, and the displacement is 2.5% larger than an '04 3.9 Liter. I have overhead cams, while the '04 (if I'm not mistaken) is a push-rod engine. My "EPA combined" estimate is 20 MPG (same as for "04). My daily driving conditions are (mostly) ideal for fuel economy (with a few exceptions:p).

<headslap>

'07. Sorry.

Depending on the build date, Dipped's pony might be the 3.8. According to Wikipedia - which means the information is absolutely reliable - FoMoCo didn't start dropping in the 3.9 until October 7 '03. The ratings were the same, however.

Also according to the Wikipedia Oracle of Irrefutable Facts, the Essex 3.8 owes a tip o' the cap to the Buick V6, since the Blue Oval needed a new middlin' large V6 and didn't have one in the stable, and reverse-engineered the Buick.

My Pony is a 3.9.

The 3.8 and 3.9 are both Pushrod engines.

My commute isn't ideal, only because I have to go through 7 constant stop signs, up a significant hill to get out of the city, but once i'm on the highway, it is better.

No need to apologize.:)
It's on the internet; it must be true!;) I once saw a t-shirt that said, "Wikipedia - you get what you pay for.":)

I just replaced my rear tires with LRR Michelins that are slightly taller. I'm replacing my fronts within the next week or so.

I hope the tires make a difference for you. The taller LRR Yokohama tires I bought for my Mustang in July haven't made a noticeable difference in fuel economy - yet. They may, after a few more thousands of miles. They seem to be as grippy as the Pirellis they replaced - at a much lower price. No complaints in the performance department.
Winter fuel seems to be here for the next few months. I'm hoping to make it through this Winter without dropping below 31.
Best of luck.

So far they are nice, and see like they have plenty of grip, just like the High Performance Continentals that I had before.