MPG Mods?

[JMG]

Any mods that improve fuel economy while not decreasing performance? Post em up here cause gas is gonna get epic.

[3 bar]

Find my links. Im going to change the 6th gear in mine to decrease my RPMS to about 1800 rpm @ 70 mph. A less restrictive exhaust and even a chip have been known to increase gas mileage.

[jcll2002]

^second that advice. That's all i know as of now other than taking the foot of the gas a little :)

[B6_Rakete]

Find my links. Im going to change the 6th gear in mine to decrease my RPMS to about 1800 rpm @ 70 mph.

How much will it cost to buy the new gear/remove the engine & transmission/crack the tranny case/install the new 6th gear/put it all back together again? Seems like a pricey endeavor!

[B6_Rakete]

^second that advice. That's all i know as of now other than taking the foot of the gas a little :)

I find that If I short shift, drive smoothly, and try to practice some hypermiling techniques on the way to and from work, I can average about 20mpg on a 22 mile commute (16 miles on the highway/4 miles in town/4 miles in the city). It seems all it takes is one good rip or two to redline in 2nd or 3rd to drop that average down to 16mpg or lower :)

[likewater]

You can see the mods I have in my sig and I routinely see 23 MPG or better on the highway. If I could just drive the speed limit, that would obviously go up. Also, 95% of the time, I shift from 2nd to 4th and I started doing this years ago. The 4.2 has plenty of TQ, so unless I'm in a real hurry to get somewhere, I rarely use 3rd gear which probably helps the MPG a little too.

[wwb4]

Also, 95% of the time, I shift from 2nd to 4th and I started doing this years ago. The 4.2 has plenty of TQ, so unless I'm in a real hurry to get somewhere, I rarely use 3rd gear which probably helps the MPG a little too.

Huh, that's interesting.

[drvolkl]

I don't know how you guys do it...I drive basically all city and I get 14.7 mpg. I believe I'm fairly easy on the car as well. (I'll often drive around in 5th gear at 45mph.)

I did get about 21 on a complete highway trip, but that was the best it ever did.

[ngng]

Find my links. Im going to change the 6th gear in mine to decrease my RPMS to about 1800 rpm @ 70 mph. A less restrictive exhaust and even a chip have been known to increase gas mileage.

if you have an aftermarket exhaust, 1800RPM is PRIME drone territory at crusing speeds.

forged wheels have helped with MPG too (or lighter, smaller wheels)

[Addicted2Bass]

You can see the mods I have in my sig and I routinely see 23 MPG or better on the highway. If I could just drive the speed limit, that would obviously go up. Also, 95% of the time, I shift from 2nd to 4th and I started doing this years ago. The 4.2 has plenty of TQ, so unless I'm in a real hurry to get somewhere, I rarely use 3rd gear which probably helps the MPG a little too.

+1 on skipping gears, I go from 1st to 3rd to 5th, if I'm not in rush to get anywhere and just driving normally from A to B.

[Monchichi8]

I've been thinking about this...even though its not listed, I believe they make a part to fit our cars.
http://www.fitchfuelcatalyst.com/pro...uto/index.html

[Eddie Man]

LOSE WEIGHT.
There are many cheap ways to do so right off the bat.
Then there are more costly ways, but go cheap first.

[ChronicTeutonic]

Doing regular maintenance goes a long way to improve MPGs. Taking out my old dirty air filter and putting in the K&N got me about 2 more MPG all around. Stay on top of your tire pressures too.

As far as shifts go, I have a Tip and notice that it keeps the tranny in 5th around town which is about 1800 rpm. Shifts happen at about 2000rpm in light cruising driving.

[Lugi20]

LOSE WEIGHT.
There are many cheap ways to do so right off the bat.
Then there are more costly ways, but go cheap first.

Could you throw out some examples of cheap mods?

[bsrpilot44]

Could you throw out some examples of cheap mods?

From Cheaper ----> More Expensive:
-Lightweight battery
-Lightweight Forged Rims
-BBK
-CF Hood/Trunk....CF just plain rocks when it comes to weight reduction

[cit1991]

Has anyone contacted a European tuner about re-flashing the ECU's to the European tune including/enabling true FSI (stratified mode)?

[JMG]

Has anyone contacted a European tuner about re-flashing the ECU's to the European tune including/enabling true FSI (stratified mode)?

I didn't even know you could do that... Why don't they just do it here, unless it's an emissions issue?

[ChronicTeutonic]

I'm assuming this is only on the FSI engines since the MPI does not have the same intake design or the injectors directly in the combustion chamber.

[B6_Rakete]

Has anyone contacted a European tuner about re-flashing the ECU's to the European tune including/enabling true FSI (stratified mode)?

There are a bunch of reasons why this would likely not work:

http://en.wikipedia.org/wiki/Gasoline_Direct_Injection

[S4Sumi]

Trade the s4 in for an a4.. Think about it.. is spending all the money to mod your car to save money in gas going to be worth it when in the end you end up getting around 2mpg more? Gotta pay to play!

[Lugi20]

Trade the s4 in for an a4.. Think about it.. is spending all the money to mod your car to save money in gas going to be worth it when in the end you end up getting around 2mpg more? Gotta pay to play!

Common sense FTW!

[cit1991]

I didn't even know you could do that... Why don't they just do it here, unless it's an emissions issue?

My understanding is that the RS4 engine itself is the same US/EU.

The reason we don't have FSI mode enabled is related to emissions, but only indirectly.

When running in FSI mode (stratified, or lean burn), there is excess O2 in the exhaust. In this mode, a normal 3-way catalytic convertor will take care of the CO and unburnt HC, but will not reduce NOx. In the EU they have a NOx trap that adsorbs NOx in lean mode, then periodically the ECU switches to homogeneous mode (stiochiometirc mode) to regen the trap, and release the NOx as N2.

The problem is that in the US, the gasoline sulfur level is higher, and the trap would be poisoned by sulfur. So, they disable FSI mode, and just always run the engine in homogeneous mode with a stoichiometric mixture.

I think the VW 504 oil spec also has lower metals limits to avoid poisoning the trap and that's why we can use the older 502 spec.

So, we don't get to use the FSI mode, and it's economy improvement. That's why RS4's in EU are/were rated 29-30 MPG highway. You can still look up the RS4 cabs on the Audi UK website to see the different mileage rating.

In the US, we don't have the NOx trap in the exhaust, so in FSI mode, we'd fail NOx emissions, but get much better mileage during warm, part throttle operation (highway driving). At idle, and high-power, they all run in homogeneous mode.

There are few tuners out there in Europe, and I was just thinking of asking them if I could get their tune package put into US ECU's, with the FSI mode intact/enabled.

As a side note, this trap technology is used in the newer clean diesels (diesels always run lean), and it's why 2007 and later diesels have to burn the new diesel fuel with no more than 15 ppm sulfur.

If it could work with our hardware (exhaust sensors, etc.) enabling true FSI would be good for 29+ MPG highway with no other changes.

[b00st]

You can see the mods I have in my sig and I routinely see 23 MPG or better on the highway. If I could just drive the speed limit, that would obviously go up. Also, 95% of the time, I shift from 2nd to 4th and I started doing this years ago. The 4.2 has plenty of TQ, so unless I'm in a real hurry to get somewhere, I rarely use 3rd gear which probably helps the MPG a little too.

i see 22 to 23 on the highway...and i have no mods...this is me driving 75-80mph all the way through on my daily commute to work.

my brother who has milltek CB and REVO doesn't see any better than i do and i'm stock. and honestly i'm not sure he's even seen 22 lately. so this was another myth i was looking in too...does these mods increase MPGs or not.

i too drive, 1st, 2nd to 4th, 6th. right now i don't know if these mods actually increase the gas mileage. right now...i gotta say i don't see it being any better than stock.

[RAudi Driver]

Could you throw out some examples of cheap mods?

Dump the spare tire!

[JMG]

Trade the s4 in for an a4.. Think about it.. is spending all the money to mod your car to save money in gas going to be worth it when in the end you end up getting around 2mpg more? Gotta pay to play!

I was thinking more along the lines of cheap mods like the air filter etc.. Besides you would have to mod the A4 significantly to get the power of an S4. Either way you pay to play.

[b00st]

drop in K&N panel filter is the only mod i have...if you can call it one. funny thing was the day i dropped it in...that next day to work...i was hitting 24.5 MPG. i haven't seen 24 since then...but i was being nice then too. i merge onto the highway...and i get up to 80 pretty quick if you know what i mean so i typically see between 22.4-22.6mpgs on my daily commute. it might peak out at 23.4 or 5 but thats it.

and i don't have a spare either...got a nail in the tire...the spare is on now.

properly inflated tires help yield better MPGs and clean air filter and plugs.

[likewater]

Dump the spare tire!

Ha....I tried that and ended up stranded on the side of the highway. Those freakin cans of fix-a-flat don't work worth a shit either. Don't do it!!

[Race Shooter]

my brother who has milltek CB and REVO doesn't see any better than i do and i'm stock. and honestly i'm not sure he's even seen 22 lately. so this was another myth i was looking in too...does these mods increase MPGs or not.

I put on an exhaust and MPG went down. I do a lot of hwy driving and when lucky with the cruise set at about 70 will only see 21. Most of the time I'm in the 20s on a long hwy cruise and if there is any non hwy use I'm lucky to see 19. That is also with short shifting and skipping gears.

[Jrunr]

My understanding is that the RS4 engine itself is the same US/EU.

The reason we don't have FSI mode enabled is related to emissions, but only indirectly.

When running in FSI mode (stratified, or lean burn), there is excess O2 in the exhaust. In this mode, a normal 3-way catalytic convertor will take care of the CO and unburnt HC, but will not reduce NOx. In the EU they have a NOx trap that adsorbs NOx in lean mode, then periodically the ECU switches to homogeneous mode (stiochiometirc mode) to regen the trap, and release the NOx as N2.

The problem is that in the US, the gasoline sulfur level is higher, and the trap would be poisoned by sulfur. So, they disable FSI mode, and just always run the engine in homogeneous mode with a stoichiometric mixture.

I think the VW 504 oil spec also has lower metals limits to avoid poisoning the trap and that's why we can use the older 502 spec.

So, we don't get to use the FSI mode, and it's economy improvement. That's why RS4's in EU are/were rated 29-30 MPG highway. You can still look up the RS4 cabs on the Audi UK website to see the different mileage rating.

In the US, we don't have the NOx trap in the exhaust, so in FSI mode, we'd fail NOx emissions, but get much better mileage during warm, part throttle operation (highway driving). At idle, and high-power, they all run in homogeneous mode.

There are few tuners out there in Europe, and I was just thinking of asking them if I could get their tune package put into US ECU's, with the FSI mode intact/enabled.

As a side note, this trap technology is used in the newer clean diesels (diesels always run lean), and it's why 2007 and later diesels have to burn the new diesel fuel with no more than 15 ppm sulfur.

If it could work with our hardware (exhaust sensors, etc.) enabling true FSI would be good for 29+ MPG highway with no other changes.

WHAT???!!!???

[b00st]

I put on an exhaust and MPG went down. I do a lot of hwy driving and when lucky with the cruise set at about 70 will only see 21. Most of the time I'm in the 20s on a long hwy cruise and if there is any non hwy use I'm lucky to see 19. That is also with short shifting and skipping gears.

exactly my point. and my brother tried to baby his car to get better mpgs. i don't. i merged on the highway this morning...did a full 2nd gear pull and 3rd and then let off. i went from 20.3 to 18.0....took a while for it get back up. but when i pulled in to work i was at 21.3MPG. i'd say because of my little romp session merging on...my average highway was about 19.5ish.

i don't believe these mods to increase fuel economy. i'm not sure if my brothers has gone down but....but i know he's not doing better than me.

and my point about these 2 mods gaining HP. i can't say i see them doing that either. i know dps will yield you higher than both flash and cat back.

[a2gtinut]

Statified mode - lean burn, casues higher combustion temp. Side effect of high combustion temp. - higher NOx levers.
Euro emission rules allow higher NOx levels than in US. In Europe the main focus is on CO2g/km which is proportional to fuel economy.

regading diesel high sulfur fuel damages particle filter and react with engine oil.
New diesels require additional post treatment to lower N0x - ex. Benz AdBlue

3 way catalist is in charge of :
Reduction of nitrogen oxides to nitrogen and oxygen
Oxidation of carbon monoxide to carbon dioxide
Oxidation of unburnt hydrocarbons to carbon dioxide and water.

Before posting nonsense, please read some SAE books.

[channad]

When puttering around town, shift from 1st, to 2nd, to 6th. That may help

[quattroanillos5]

When I bought this car gas milage was the last thing I was thinking about... Thats not to say I wouldn't like getting better gas milage, but I just have a lot of trouble driving slow in this car.... On my commute to work there are a few nice twisties that I enjoy way to much to baby the car... I have always had four cylinder cars until I bought my S... and none of them could come close to feel of torque in this car... the feel of it is just way to addicting! If gas gets to $10 a gallon like they are predicting I might rethink my current stance...

[JMG]

When I bought this car gas milage was the last thing I was thinking about... Thats not to say I wouldn't like getting better gas milage, but I just have a lot of trouble driving slow in this car.... On my commute to work there are a few nice twisties that I enjoy way to much to baby the car... I have always had four cylinder cars until I bought my S... and none of them could come close to feel of torque in this car... the feel of it is just way to addicting! If gas gets to $10 a gallon like they are predicting I might rethink my current stance...

$150 a tank is NOT going to cut it with me. That's insane. I might buy a hybrid for my 1hr commute and save the S4 for weekends.

[b00st]

Statified mode - lean burn, casues higher combustion temp. Side effect of high combustion temp. - higher NOx levers.
Euro emission rules allow higher NOx levels than in US. In Europe the main focus is on CO2g/km which is proportional to fuel economy.

regading diesel high sulfur fuel damages particle filter and react with engine oil.
New diesels require additional post treatment to lower N0x - ex. Benz AdBlue

3 way catalist is in charge of :
Reduction of nitrogen oxides to nitrogen and oxygen
Oxidation of carbon monoxide to carbon dioxide
Oxidation of unburnt hydrocarbons to carbon dioxide and water.

Before posting nonsense, please read some SAE books.

thanks for today's science lesson on the periodic table. what does this have to do with modding for higher mpgs? please post in english next time...you have to be a rocket surgeon to understand that.

but i understoodified it.

[cit1991]

Statified mode - lean burn, casues higher combustion temp. Side effect of high combustion temp. - higher NOx levers.
Euro emission rules allow higher NOx levels than in US.

If the mixture is rich, then leaning it raises combustion temps, but if you're starting from a perfect mix (stoichiometric), then leaning it out reduces temps due to the presence of dilution air (the extra air).

Lean burn engines make lower NOx from the engine itself, but the 3-way cat can't reduce them because of the extra oxygen. So, the exhaust after the cat is higher in NOx, hence the need for a trap (or in the case of diesels, a chemical reducing agent, like urea).

And yes, Europe has easier NOx regs, which is why they can sell diesels with oxidizer-only convertors, and we can't.

The point is, 29 MPG is only a few bytes away in RS4's. I just wanted to know if anyone has successfully made it happen.

[b00st]

i bought this car knowing gas mileage IS TEH SUCK.

[RAudi Driver]

Ha....I tried that and ended up stranded on the side of the highway. Those freakin cans of fix-a-flat don't work worth a shit either. Don't do it!!

My new car doesn't come with a spare tire at all.

[Silvercreek]

I drive a Camry hybrid around town. (34 mpg)

[b00st]

22.9 after 100 miles of driving.