Pontiac G8 2008-2010 - Mods for mileage??

First off, please try to keep the flaming to a minimum guys.

I was just thinking of all the guys who use their G8 GT as a DD. Have any of yous done mods that actually increase the mileage you get?? Or if anyone else has any ideas too.

Would LT headers push the mpg up due an increase in effeciency?? Or lowering the car a bit.

I know driving like a granny would save gas, but screw that, there's no fun in that.

Most of my mods increased mileage except for the gears. Do headers, intake, tune and that will be a good start to get 26-27MPG.

I am gonna be honest, Ive never seen an improvement in mpg with any mod in any car, minus maybe a tune.

I went from getting a best of say 16 city and 22-23 highway stock to 18 city (if I keep my foot out of it) and 26-27 highway with the mods in my sig. So yes they can help.
Tate

Intake, headers, exhaust and tune will help. I was averaging 20-26 when I had just bolt-ons. Now that I have a cam, converter and gears I average around 16.

No idea how you guys can get 26/27. If I am nice to my car for a full tank of gas, best I can still get is 22/23. That's 25% city, 75% freeway @ 70-75mph.

Anything but changing the rear end ratio!

Anything but changing the rear end ratio!

Even then it only drops about 1-1.5MPG which is so worth it.

Wow, thanks for the input guys. Are most you guys running an A6 with the AFM and VVT still active?

I thought headers and intake could potentially make a difference. It makes a difference how you drive too, but pure highway mileage is what Im looking for mostly So if 26 is attainable, thats pretty close to me and the wifes current DD's, so thats pretty good.

I ditched the AFM.. been a few failures that have wiped cams. Plus you need to remove it to run a decent sized cam. Really AFM is only good for about 1MPG, not worth the hassle and the terrible noise it makes when active.

Hmmm, thanks for the info, thats interesting about the 1mpg. I dont know about a cam swap in this thing cuz I wanna keep the mileage as good as I cant and still be able to have some fun.

If you want the best of both worlds, get a tune from an email vendor like Livernois.

That way, if you want milage, you can run that tune with AFM. If you're just gonna go cruising around or to the track, you can use a tune thats more aggressive with AFM tuned out.

I have to disagree on the AFM only giving you 1 mpg gain... After some AFM tweaking with hptuners(no other mods) i was getting around 26 mpg on the highway. Switching over to manual (AFM off) got me about 23 mpg.

I have since installed Doug Thorley long tubes and did a retune. Now i get right at 24.5 on the highway without AFM and about 29 with it.

All fo my testing was done on the same stretch of road at the same speed within about 3 weeks (sorry engineer by profession:bang:) so i feel fairly confident in increases I saw with my mods. Not too bad for a 4000 lb car with close to 400 horsies that was only rated for 24 mpg highway from the factory!

Even if AFM made a 10MPG difference its a crappy system that has failed lifters, wiped cams, and sounds like crap when its activated. Just not something I want on my vehicle.

Even if AFM made a 10MPG difference its a crappy system that has failed lifters, wiped cams, and sounds like crap when its activated. Just not something I want on my vehicle.

+1 on this comment. My car started getting some lifter noise so I ditched the DOD before it caused a catastrophic failure. Yes the cam will slightly impact mpg but the extra fun and reliability is well worth the price.

You could do the V6 mod :|

First off, please try to keep the flaming to a minimum guys.

Well that didnt take long ;)

In all honesty though... any mod that gets you more air in or more air out and is tuned to account for that will be more efficient and therefore better mpgs.

Thanks for the info. 29mpg sounds pretty good. Some would say pretty hard to get. Anyone got their car lowered?? Did that make a difference??