what is everyone else getting for gas milage from their 305 tbi's ? i know mine is horrible it is like 10 miles to the gallon

i am getting like 150 miles to a tank and the tanks are 15 gallons right ?

 

Am getting around 350 km per tank, converts to a little more than 200 miles, mainly city drivimg in MOntreal, Canada . On highway, more economical because of 70 mph @ 1600 rpm...good luck, mine's an autom = TH700r4 ??

'88 Camaro coupe 305 TBI
46 000 miles

 

10 mpg is horrible. If it is completely stock, you should be getting 20+ on the highway. Is your computer putting out any codes? they will drastically decrease milage depending on the code

 

i have no idea if it is putting out codes, the lady i bought it from said it had a chip in it, but she had no idea what kind or anything about it, where is it and i can look to find out what it is and maybe someone can help me from there, but i was hoping that it was maybe just me and not all firebirds/camaro's cuz that would be just horrible for all of them to have that bad of milage, atleast now i know i can have it looked at and figure out why it is getting such horrible milage

 

i have a LO3 with a 700r4 and 2.73's. i get 16-17 mpg city and 26 on the highway. when was the last time you did a tune up?

 

I just put about 355 miles on my last tank, so I'm thinkin that has me around 23-25 mpg. It's all stock except for the open element.
Scoty

 

I never got over about 16mpg when I had my LO3.

 

In the city I get between 16-18 mpg and on the highway I will usually get over 25 mpg, but I've never really driven a full tank on the highway so it's not 100% accurate.

 

i only get about 15-17 no matter what temp. my car is at

 

with my timing at 4* i get like 10 mpg in the city and like 20 on the highway

 

i haven't had a chanfce to get it tuned up yet, i just got the car

 

Lot of badly tuned TBI Camaros out there I guess, I have NEVER gotten less than 20MPG avg. from a tank, and can get 27-31MPG on the hwy. That's 400-450 hwy. miles on a tank folks!!!

 

Same as above here. 305TBI auto w/2.73's(other mods listed in sig) and I got a little over 650kms(140km/hr avg speed) on a highway trip up north this summer. I'll get at least 400kms in the city but not more than 450kms. 213,000kms on the motor. I d

 

I got 24MPG last tank with my 305 TBI. Mostly hwy driving with 4 quarter mile times just for fun.

 

~15 city and ~23-25 highway

Used to get more when it had 3.08s in there, way back in the day.

 

Before I modded it, all stock except for open element I knocked off a couple of 31mpg trips. Now it is much much worse

 

would the straight exhaust have anything to do with it, if i put a muffler on it would it help it at all, creating more back pressure ?

 

NO, Backpressure is bad in just about every way you look at it, including power and effeciency.

 

Check this thread for more information on backpressure. rx7speed has a great post in there regarding how the exhaust system works and why backpressure is bad.

Jared

 

With stock exhaust: 20 mpg everyday driving, 27-28 mpg highway

With headers and catback: 20 mpg and 28-30 mpg

Backpressure - BAD....... Free flowing exhaust - GOOD

 

with my setup i avarage around 25-26 mpg with mixed highway and city driving, assuming i dont beat on it. Liberal use of the go pedal results in the car emptying the tank in no time flat.

 

am i correct that there is a 15 gallon tank under there ?

 

If I remember correctly my owner's manual says 15.5 gallons, not to nitpick.

 

thank you i dont have a owners manual so i wasn't able to look it up, thanks a bunch

 

i get about 18-22 city driving, and about 32-34 on the hi-way.

lots of chip tuning ot get there running 6* timing, i have hi-way mode set to about 17.8:1AFR.

btw, that is with a 3.42 rear gearing, and a T5.

 

d@#n dewey you da man!

 

its just one more reason for people to get into chip tuning, driving for a year, the gas savings alone would pay for all of the equipment. heck for the guy getting 10mph, the 22mpg savings would ad up FAST.

 

it would add up fast. i wish i could get into chip burning, but i believe im far too computer illiterate to be any good at it. oh well, just have to have someone do it for me.

 

it really doesn't take any computer skills. it is all math. if your BLM's are off by 4%, you change the fuel by 4%, ect. nothing that takes a CS degree.

 

i got 24.8 mpg going to ga doing about 80-90!!! i am also burnin oil like a mad man!!! but i have 138,000 miles on the car i think i should have spent a little more time and chaged the valve seals when i did the cam. but this is a 305 lo3 when the engine goes i will be puttin in a 350!!

 

same with me. my car could choke out an insect at 100 yds when i start it after its sat more than 3hrs!

 

see what i mean, BLMs????

 

all the BLM, INT, PW, ect, will make sense to you. read the articles about tuning for newbies on the diy board, they go step by step on what to do, and explain what all of those mean.

 

cool

 

I need to read up on tuning too, dont know **** about it.

Anyway, i get about 17mpg (if im nice )15-16 if im not, but im getting an error 32 code right now. Does anyone think fixing the EGR valve would help my gas milage out? Ill be getting new plugs at the end of this season too, that should help also.

 

try soaking your egr in carb cleaner, worked for me. probably would help your mileage. but i wouldnt advise letting it get to the diaphram though. just the bottom half.

 

Some of you guys make me envious, I get like 13 city, 16 hwy, with an L03/700R4/2.73:1 gears. I keep it in tune...

 

Keep in mind all these #'s mean nothing. 90% of it is all in how you drive it. If you go around flooring it everywhere ofcource your gas mileage will suck. If you don't drive like an idiot most likely you will get pretty good mileage.

 

Well with no fuel gauge I actually had to keep note of my gas mileage. I usually filled up every 150 miles and it put about 9-qo gallons in the tank. Then I got my straight pipes put on and, well I kinda like the sound so I get anywhere from 9-15 mpg But over all I would get 20 highway, 15 city.
Lc

 

Are you saying you get 350km per tank on the highway? Thats horrible! I have the same drivetrain and I can 26-30mpg----farthest I have got is 592kms--and it only took 50 litres--tank is 58 I think.

Don't trust the gas guage---real, real, pesimistic

 

No, more economical on highway, over 400 km I guess. I live in Montreal so , mainly city driving. Changed fuel filter recently, noticeable difference overall, thus probably more economical now. Pretty well tuned up . Will keep count and reply soon... : ) Have to do O2 sensor soon...mine's pretty much stock but slowly improving it...BTW, you have a true 1LE? Excuse me for asking, please some pics : )
Thanks Hoser....from a Frenchie ! (he he)

 

I live in the city. I mainly speed everywhere i go and take as fast as well. I am the one that posted about the no thermostat. some guy,i think it was nick harmon, asked me how many MPG i get. well. i decided to give it a try..i put in 7.2 gallons....and i got 140 miles. It is atleast 20 miles per gallon.
I have no thermostat so thats a free flow, and my fan is installed straight into the ignition key. I think its pretty mpg for the way i have my car.

 

What temp does your engine run at when it's warmed up?

 

My engine runs between 160-220 during the severly hot days. if i Accelerate peeling out often then the temp will run up to 220...during the night crusing it says around 160....