I have an 08 C6 3LT Z51 A6 with the factory NPP option.

Several months ago; I removed and sold my factory bimodal mufflers and replaced them with the B&B Fusion bimodal's.

I am curious to hear what mod's can be performed to my LS3 platform that will not have a negative impact on city and highway fuel economy.

And more importantly; what specific modifications can be made that will have a real world impact on rwhp, torque and perhaps boost city and highway fuel economy on my current LS3 platform?

 

1) Maximum Tire inflation
2) Good Tune. Most of these cars run rich from the factory.
3) Good Alignment

 

I was thinking of a good CAI (perhaps the Callaway Honker) and a good set of LT catted headers ( perhaps the LG Pro's or American Racing) and the Chuck CoW tune for the A6.

I was curious as to what kind of performance impact these mods would have and how would they affect fuel economy.

I would imagine in the engine is breathing better with regard to the intake and headers; that would help fuel economy.

I'm not that knowledgeable about what goes into a tune; but would want the C6 tuned to take advantage of the "power adders" to serve two purposes; increase rwhp/torque and increase city and highway fuel economy.

Also; what about a change to the factory ignition with regard to a better quality spark plugs, wires and coil packs if available yet for the LS3 and if so; what specific manufacturer and what can I expect from this mod?

 

A cold air intake and headers both should increase mpg. Replacing coilpacks on a near stock lsx is throwing your money away, the stockers are more then adequate for your power level. Wires couldn't hurt though.

 

Take an egg, place it under your right foot when driving. Your mileage will increase drastically! (of course, you can just drive like you have an egg under your foot!)

 

and use the cruise control; it comes free with the car...

 

Given you still drive the car the same......

I picked up about 1.5 to 2.1 MPG with our headers, and a tune on my own personal '06 MN6 Z51.

The cold air, FAST, and cat back did not seem to change anything.


The inflation and alignment I would take as a given.

 

I think you would get more out of installing new headers than just a CAI.

 

I think ur in the wrong car...

 

Thanks for your valued input Seinfeld!

 

 

Remove weight
Impove engine breathing (intake / exhaust)
Tune it leaner
Increase compresion.

OR!

You could reduce the number of cylinders, make it front wheel drive, doing away with weight and some additional drivetrain loss, put skinnier tires on it and use a much less agressive camshaft.

You would have a honda civic, or a dodge neon, or a cadavalier.. Or any of the other turds that prowl the streets and take up the left lane. Once you realize how much that sucks you will be happy to pay for the small premium in gas associated with driving one of the most powerful cars money can buy

 

SOME PEOPLE HERE HAVE NOTHING BETTER TO DO THAN WRITE SOMETHING THAT HAS NOTHING TO DO WITH THE POST
anyways, here is what i did.....
vararam intake, tb spacer, x-pipe, magnaflow, tuning. my mpg went from 27 to 29-30 on highway.
than i added Kooks long tube headers, Kooks racing Cats with 3" pipes. fast intake, more tuning......now its almost 33mpg on highway.
not only that i have way more rwhp.
i am sure and people here will agree, anything that will let the engine breate IN AND OUT the air better, will increase mpg.

 

Better breathing with regard to either a Lingenfelter or Callaway CAI and a set of LG Pro Series LT headers are in the certainly in the cards as well as a good aftermarket tune which I will probably have done by Chuck at CoW.

But what I was referring to and hoping to get some intelligent feedback on was what type of rwhp and torque power adders would be the most effective on an LS3 A6 platform that would have the least effect on combined city and highway fuel economy with a 2.73 factory gear set-up.

That opens the door to forced induction with either a maggie or procharger as well as the possibility of turbocharging.

The other option is a forged LS3 stroker short block or perhaps an LS7 427 forged short block from SDPC. I was curious to here if anyone had gone any of those routes with an existing LS3 and what kind of increase in performance was noticed as well as any significant changes in fuel economy with an A6 platform with stock 2.73 gears.

But, even though no intelligent answeres surfaced, I still found the humor as well as a good laugh from some of these knuckleheads that stray from the topic.

 

Just remember, if you create more cubic inches, you have to feed those cubic inches.
That may take more fuel to do so.

Using the stock cubic inch engine, I think the best way to increase mileage would be to tune for an increase in low to mid range torque in the rpm range where you drive the car most.

This could be done by a better AF ratio and increased timing in those ranges.

I think that is why Anthony from LG had success with his header setup on his car.
It increased available torque in the rpm range that he was monitoring for mileage.

 

Practical to spend performance mod $$ to increase gas mileage?

Headers installed = $2,000
CAI installed = $500
Tune & dyno = $500

$3,000 total to increase the gas mileage by 3MPG? (27 to 30)highway

Average miles per year; 12,000 miles @ 27MPG = 444 gal per year

Average miles per year; 12,000 miles @ 30MPG = 400 gal per year

44 gallons saved @ $4.50 per gal = $198 saved per year

I won't even try to figure the high $$ guys with heads, cam, Forced Induction, etc. Forget appearance mods, there is NO $$ return there.

I don't know how to factor in the loss of Warranty due to the tune and headers, hard to even estimate the $$ lost so I ignored that part.

Spend $3,000 to save $198 a year in gas costs? Aprx. 15 years or aprx. 180,000 miles to recover your performance mod costs with increased gas mileage?

AIN'T STATISTICS GREAT!?!?!?

Lots of assumptions on costs of mods and on mileage increases. Who drives only highway? Who actually gets 30MPG? Who really gets a 3 MPG increase with mods? Mods are for performance, not gas mileage.
Total up your own mod costs and your MPG increase (if any)

Personal experience; I drove a lot harder with mods and got worse gas mileage.

The C6 is NOT ABOUT ECONOMY! Performance and Luxury costs or we'd all be driving a $10,000 4 cylinder, stick, 4 dr sedan with roll up windows and no A/C.

 

That's because it wasn't a particularly intelligent question. Supercharging as a means of increasing fuel economy? How does your reasoning go on that one: I will put this big 60% (in the case of the roots type magnacharger blower) compressor on top of my engine, drive it from the belt, consuming 50+ horsepower, retard ignition timing and add fuel to prevent detonation, and then magically my fuel economy will improve?
Or, increasing engine displacement as a means of improving fuel economy? You might not know anything whatsoever about engines, but I would imagine you may have looked at the window sticker of a Z06 at least once, right? Has the fact that it gets LESS gas mileage evaded you when you asked about putting an LS7 on your car to improve fuel economy?

IMO you got all your the "intelligent" answers you needed from the people (myself included) who pointed out that you can get some small increases in fuel economy by removing intake and exhaust restrictions and tuning the ECU more agressively. What you are asking about now is just a waste of time.

 

There are great deals right now on Prius and Yaris models...
I hear they get great MPG;s...Head on over!
Sorry Just tired of hearing about Gas...Hope ur undies are tangled too much...

 

Exactly. I have a really hard time understanding how someone spends 40000 dollars buying a V8 sportscar and then whines about paying 4dollars a gallon for fuel... That's like eating like a pig and then complaining you are fat...

 

A v8 sports car which gets better fuel economy than many sporty/sports cars out there on the market, so chances are fuel economy is something which attracted some buyers to the Corvette. I really don't find it surprising at all that people actually care about increasing mileage while modding. Sure the money saved may not offset the cost of the mods, but what's not to like about increasing power and efficiency and being able to drive your toy while still getting better highway mileage than some econoboxes out there.