fivepointseven

iTrader: (19)

Is this even possible? I swear in my case it is

KrazyDan

id say with the better air flow its possible. But in my case it is not possible because i like to listen to the roar too much .

LS1Adam

my gas mileage went waaaay downhill after the header/dual install. its definitely worth it tho just to hear that car rev up and fly. maybe after a tune it'll get better. You are one lucky guy to have better gas mileage now after the install

SmokingWS6

iTrader: (1)

Mine went up. Scans showed it was running lean, after I tuned it milage stayed the same as before the swap.

Cody Brooks

iTrader: (2)

shouldn't change much if any.

Lithium

iTrader: (47)

it should go up a little with a good tune. But mine has definitely gone down, I just cant seem to keep my foot from going to the floor.

Coy

iTrader: (4)

mine was down pretty bad till I deleted the air, then it improved slightly. (better than stock)

BlueSix

In theory is should go up. The engine is working more eficiently than it was before....that should increase mileage. I know that Nine Ball said his ols SS vert got better mileage after the heads/cam since everything was working more efficiently....Colonel said the same about his H/C Z28.

SLPCAMAROSS

its possible.. not common

rush7

iTrader: (2)

mine went in reverse...dropped from about 20mpg to about 15. My PCM was dumping a lot of fuel when I scanned it. The weird thing was I put on an underdrive pulley and got my 5mpg back. It's been hovering around 20 ever since and my PCM dumps less fuel (I still need to have it tuned though)

blkZ28spt

If you have it tuned, or the air/fuel ratio just happens to be good and you drive it the same you should see slightly increased gas mileage. Maybe not anything you notice, but it should get better.

Mine didn't.

badSol

For some reason, I get a good extra 2 mpg or so after my header/dual install, but some of that is likely attributed to the new plugs.

Frosty

iTrader: (17)

I'll tell you next weekend

2000slpss

iTrader: (27)

when i put my headers and true duals on my mileage improved by 2 mpg on average. thats without a tune

DWillTA

iTrader: (3)

I have headers and true duals. My mileage, the best I have seen, is 22 mpg. That is with a mix of in town and interstate running. I think if anything I have stayed the same. If I run the car hard I can still get 17 mpg. My Ltrims are in the +5% range. Strims are around 3% to 6%. So I am alittle lean but not to bad for no tune.

DONAIMIAN

iTrader: (18)

You reducing backpreasure so it should go up, but with most it dosent becuase we romp on it a lot more because of the new found sound. Also heads will improve gasmilage because of better efficency in the burn of the A/F mixture.