i've had my Stillen Ypipe installed for only a few days and i've noticed measurable increase in gas mileage according to the Z's on board gas mileage display. i've had my 03 Z 6m/t since 3/03, currently just over 16k miles, i've never seen the gas mileage display gone over 31 miles per gallon cruising at 65 miles an hour highway. At 90 MPH, the gas mileage would drop to 21 MPG. Today, the display reads 35.4MPG cruising at 65MPH......i am wondering....Is this for real?
BTW...i'm still using the stock muffler.The only other mod is the underdrive UR pulley.

 

so does all exhaust upgrades save gas?
like headers and test pipes?

 

I would think that anything you do to make the intake/exhaust less restricted would improve gas mileage somewhat.

 

at 80mph i averaged between 28.5 and 31 mpg. the only "mod" i have is a k&n drop in........

 

i was quite skeptical at first before trying any exhaust modifications....now that it made a believer out of me. i might just swap my oem muffler for an aftermarket which deletes the resonator and create a louder exhaust note. A stillen or a Nismo would work.... it should gain another 3 horses.i also have K&N direct insert.

 

is something wrong with my MPG display? it goes up and down slow as hell, it seems to be displaying the average MPG...

 

I'm thinking about just getting a y-pipe myself. were there any problems with install? how do you like it performance wise?

 

dont forget aout the cooler weather.


you guys get some good mpg! i avg 22-24 at 75mph

 

i got my stillen Ypipe from Stillen.com and it was delivered overnight express.
i've never done any exhaust work in my life and it only took me about an hour to do it...very straight forward. i would suggest you spray WD40 on the bolts the night before and unbolt them in the morning. Be careful with how you raise the Z with jack stands. The result was amazing...its hard to describe...i felt like i was driving a different car.
BTW...your loosing a lot of weight getting rid of the stock Ypipe which weights a ton.

 

Believe it or not

Not

 

any change in note or sound? how does it pull?

i'm kinda hesitant to do something like that on jack stands...maybe the muffler...but the y-pipe in right on there...i have a phobia of the car comming down on me..LOL

 

the change in sound is subtle at idle...but the improvement in acceleration is another story. At WOT the exhaust note sound more like a jet taking off. i let a buddy of mine (M3 owner) drove the damn thing yesterday and he was amazed at the added performance. He said it was equivalent to the M3 if not better. i raced my buddy's 911 TT the same day(drizzling) at the light after the installation....i was one car lenght ahead of him in 2nd gear but obviously his 911 took over when the turbo kicked in. As soon as i heard his turbo kicked in i pulled back before i hit the next light. As far as the install is concern, i used the two jack stands for the front as indicated in the owners manual and used my 3 ton floor jack to raise the rear axle. It was quite secure as far as i'm concern. If not .... used drive up ramps.

 

sweet.....looks like i'll go for that y-pipe..or maybe just for over the whole thing for a stillen single pipe exhaust...(the duals are a little too expensive for me)