Hey guys, pretty simple question i guess, i tried searching but couldnt really find anything to helpful.

Here is what i was wondering. I have 2.25" exhaust from ... kamikazi head + Dp back ** no cat ** and intake.

It seems, mainly that ever since the headers and test pipe, my gas milage has sucked ***! I mean, i've been trying to be very conservitive lately with the gas ** not flooring it or pressing the gas too hard ** and it hasnt been working, im lucky if i get 170 miles from E to F.

Im just wondering if there is something wrong with this picture or the price you pay for modding the car?

Thanks guys

 

Well, you removed the second cat when you put on the test pipe. This causes reduced backpressure and causes the car to run rich, using more fuel, but not burning it to produce power.

I think the first cat is attached to the headers...if so you're running totally open, meaning nasty smelling exhaust and low mileage.

Any car needs a certain amount of backpressure to operate cleanly and efficiently. Since you've already reduced mileage by putting on an intake (which forces the motor to work harder at low RPMs, hence the loss of low-down torque and HP) you've set yourself up for frequent trips to the gas station.

Now that Naperville gas is 1.90 a gallon for 89, that's gonna be a lot of cash, and if a Naperville cop gets pissy, you're gonna have a hell of a ticket for a free flowing exhaust. You might get a court order to have the car towed to a test facility and have readings taken. If you fail Illinois emmissions, you can't drive the car until it's fixed, and they'll keep on you about it, belive me.

EDIT: Oh yhea, I'm pushing 320 before a light even with my intake. You might really want to consider dumping the test pipe and putting the cat back on. Even automatic, you should still be knocking down 290 a tank.

 

ouch man, i get about 230-250 before my fuel light comes on....and im all stock....i've been driving really slow lately, maybe stomping on it at only 4 lights the whole time, about twice i've just mashed it to hear the sound(i pulled the front of the intake box out and stock the 2 metal clips down in there like one other person did...sounds bad ***, and this monday im buyin a muffler off my friend)...and im at 247 and the light isn't on....other times i mash it from MANY of stop lights and am always on it...and ill get aobut 225 before the light comes on..

at this point i ask myself...is saving myself $1.50 worth driving slow all the time? lmao...i figure i get a very low 23-24 mpg...mainly city driving, and many 3-6 mile trips to/from work.

 

ya, i may consider putting the cat back on, i mean... its too cold out right now, but once it gets warmer. Im getting a new muffler this week, one with a silencer, i doubt that will help, but atleast until the test pipe comes off it wont be as loud.

thanks for the help guys.

 

I get around 250-300 miles on a full tank. U can look in my profile to see my setup. I have no cats and mine isnt that bad. I have a turbo, header, intake, cat back exhaust, and test pipe. If you are only getting 170 miles on a full tank I would get your **** checked out. Ur only getting like 13 miles to the gallon. That sucks.

 

ya, i am not sure, next time i fill up im going to check everything and make sure my numbers are right. I am also re thinking everything and thinkign it could be due to letting the car warm up for 5 mins every morning with the heat on 3rd highest setting to get her nice and warm... could that also be why the gas is goin down so fast?

 

it could be bad gas too, during the winter they add something to the gas so it wont freeze or something.

 

well! that could also be it, haha ya because in the summer i had same set up ... minus test pipe and header, so not really, but my gas mileage wasnt nearly as bad! but then again i didnt warm up the car or use the heat / ac because i just drove with the windows down, LOVE THE SOUND OF THE EXHAUST!

** which is for sale if you visit
https://www.evolutionm.net/forums/sh...threadid=59348 it there **

Gracias Guys & Gals.

 

I just filled up today and got 330 miles on almost 12 gallons. My mileage has held steady around 25 mpg with my current mods (auto). The biggest drop I got was when I got my header installed; that was a drop from 27-28 down to the current 25.

 

Ghost... how is that TP?

 

I think i might be replacing my test pipe with a hi-flo cat in the next couple months, perhaps when summer comes along. I dunno, we will see if the gas mileage is still sucky *** by then.

But i watched the little meter drop a little from a 8 mile trip, rediculous!

 

also with most cars, the first 1/2 tank u get better gas mileage...so fill up at 1/2 tank a few times and see how well ur MPG is

 

its not actually better is because the sensor has a float area and the tank is going down but the sensor does not move right away... thats why after like half a tank it seems like it just sucks up the gas... if you go to the how stuff works site its on there.

 

First off, Intakes only help gas milage and so does a cat back. When you free up the intake system the car actually runs a little leaner and thats good in a normally aspirated car for power. So not only do you run the same amount of gas but your getting a little more power, so you don't have to hit the gas as much. On the other hand when you have an intake its just so addictive to hear, so your mileage goes out the window.

 

To answer your questions:

Yes, warming up the car burns gas.
Yes, using the heater burns gas.

I'd say between that and the unburned gas that is flying out your tailpipe, that's probably the cause of your issues.

I know my mileage went way down in my last car due to a burned out O2 sensor, but there were other signs of it.

PS - I complain if I get anything less than 30mpg, so thanks for putting my problems in perspective.