Yeah my car is an A4.....and if i dont have my rear 02 sensors should that throw my mpg off???

 

straight city driving back and forth to work average about 220ish actually just got 246 on my last tank

drove to biloxi last summer and I averaged about 400-420 per tank on the highway cruise set about 70-75


car is M6 with full bot-ons except for pulley and heads, small cam all tuned about 395ish rwhp and still goes down the track once in awhile... stock bottom end about 94K miles

not to bad

 

Around town a full tank will get me about 200 miles. I have seen as high as 360 to a tank, that was basically a whole trip of 80 mph going up and down a few mountains while I visited a friend at the other end of the state. If you are getting 200 miles to a tank ALL highway, then something is wrong. But 200 miles aint bad for around town.

Mike

 

If thats the case for getting around 200 miles per tank, then why are other ls1's getting more than me an dthey have more mods than me

 

I should be getting more thna 200 if u estimate it....longtube headers intake lid w/filter,y-pipe w/dual cutouts

 

how much difference would spark plugs and fuel filter get me

 

I seafoamed my car back in Jnauary and havent changed the plugs can seafoam really harm them

 

Not sure why everyone is saying to get a tune. I have the exact same mods as you and I can pull 30 MPG on the highway going 60 - 65 with NO tune. I'm currently tuning it and the car runs LEANER with the long tubes then without them so I'm having to add fuel to the tune to get it correct. That and getting a dyno tune is going to change your WOT and not your VE tables that control your dialy driving routines. BTW your rear O2's are pointless they measure if the CATS are working correctly, they contribute to your AF ratio 0%. Only your front O2's have any say of how much fuel the car will see.

If it was me I'd go out and get some new front O2 sensors, change the plugs and check the wires to make sure they are good, buy some maf cleaner and clean up the intake (maf, IAT, and spray into the intake), and replace the fuel filter before going any further.

 

Checking mileage by the gas tank is not a valid comparison since some of our forth gens have different size tanks! Mine is the newer 16.8 gallon tank and I've got 30mpg hwy when kept around 55-60.Got 27 keeping around 70-75.
This is with headers,LS6 intake, catback, Maf and no tune....so maybe tune is not essential after a lot of bolt ons (or maybe I'm just lucky) but a good investment at some point.
Also,in order to check current condition of engine,I try to plan a 100-120 mile trip of just highway driving and check mileage(using math not the gas gauge) for a tip off of any problems.At least once a year.

 

I have an LT1 and I get 260 miles to the tank, regardless of city or hwy. I knoe it sounds crazy but I normally drive around 50-50 city-hwy. I took a road trip just under 280 miles and I averaged 19mpg. I used math and not the gauge. Fill up, reset trip meter, drive, fill up. Divide the miles driven by the amount of gallons I poured in. Under DD conditions I average around 17mpg. Is 2mpg improvement on all freeway driving at 70-80 about average?

I have hooker lt's, 3" straight back with a magnaflow exhaust and a K&N. Recent plugs, wires, fuel filter.

 

Hey 1987 Firechicken .....you say u have the same exact mods as me ...one question do you actually feel a power difference after all the mods???? my guess is my longtubes threw my air/fuel ratio off

 

how much is your tune running?????

 

I don't see why he needs a tune with just headers, I had a cam and all bolt ons in my 98 when I had it and got close to 270 miles a tank with a shitty tune. My 01 M6 car gets about 320 so something is up. Wonder why a tune fixes every problem? I'd check your
O2's, also could be driving habits.

 

when i first got my formula ** M6 Car** the only mods i had done at the time was complete SLP loudmouth LT exhaust and a K&N air filter..everything else was BONE STOCK...i went from allenhurst ga - to - homestead FL * right at 505 miles* on one tank of 93 octane...80 mph and cruise was on..

now with forged bottom end ported heads and my lunati cam..i dont know as of yet...ihave a street tune to break in the engine with..and here shortly i will go back to get a WOT tune..and will be able to judge better...

 

Mine varies. If I beat on it and stay off the interstate I have gotten as little as like 150 to a tank. When on the interstate, in 6th, if I keep it below 80 I have gotten about 300 or so to a tank. Cam, 4:10's and all the bolt ons.

 

im getting 290ish mostly hwy. A4 with 2.73's. mods are lid, drop in k&n, pacesetter no egr LT's, catless tsp x-pipe with dyno max's

 

H/C/I/longtubes here and no cats, 50/50 city/highway and a good tune, 250 miles per tank. I'm sure a long trip would yield better results.

 

I drive 200 miles per week and use near a tank so I'm getting similar mileage.

 

Get your maintenance checked first. Change the fuel fitler, spark plugs/wires, service your Air filter, clean your MAF sensor. I've got bolt ons/stalled auto, 3.42 rear and I get about 220-260 city driving, depends on the traffic and get straight 350ish miles a tank.


either those option or put in a TORNADO.

 

Hey John Shea what kind of mods do u have because apparently we are both doing something wrong getting 200 miles to the tank