beneharris

anybody know what the 89 irocs with the 350's got in the way of gas mileage

GuitarJunki17

iTrader: (1)

18 city / 22 highway.

This is assuming you drive without having fun, if you were driving it like you stole it, expect 15/19.

beneharris

alright thanks

'89 Iroc

I was getting about 15 or 16 on the highway. Maybe it will improve after the rebuild.

GuitarJunki17

iTrader: (1)

That's about what I am getting, and 13 in the city when I am having fun with it =( . But something isn't quite right. Those numbers up top that I posted are what the car SHOULD be getting in good stock condition. Some guys have even had claims of pulling off 25mpg strictly highway on a 305.

3.8TransAM

25 is easy on a 305 a factory one should be able to hit that easily.

I manage 23+ mpg in my GTA with a 350 on extended highway trips.

Persaonl best was just shy of 26mpg twice.

I avg 18-20 in town.

My Formula did similar when stock and even with the 383 now I was pushing 22 on the highway without using any tuning tricks, just a good tune worked form the stock bin.

later
Jeremy

GregWestphal

iTrader: (1)

I got 25 mpg over 600 miles on the highway driving from Indy to Baltimore. I was running the Highway Fuel mode with an 15.8:1 air/fuel ratio. This is with a 355 TPI, A4, and 3.42 gears. I average 18-20 mpg combined city/highway, less if there's more around-town driving.

1MeanZ

iTrader: (9)

2 weeks ago I got 28.5 mpg coming back from Dayton. Sunday I got 26mpg coming up to Detroit, we will see what I get going home today. I usually average 19-22 back and fourth to work and around town.

super89irocz

I can only get about 10 mpg city and highway combined, thats not even havinh lots of fun?....what could be wrong?

camarogirl91

I get about 15 around town and close to 30 mpg on the freeway, but I installed a performance chip, that might help you out some too!

crazyryceman

i only get around 11 in the city. im in need of a tune up

HorseflyDF

350 8 5 1 compression with 342 gears + 5 speed
4 barrel holley, idle 750 rpms..
12 city 17 highway..approx.. gas is now up to 3.22 for regular.
When I got the car gas was a dollar cheaper a gallon, time to
sell..or work more overtime. looking to sell or trade 200sx

qube

My desmogged but otherwise stock 305 gets about 340 miles to a tank if I'm doing a lot of freeway driving, down to as little as 220 city driving.

Work out the MPG from that.

M.

TPeye

i'm getting 18 city and about 30 highway

HorseflyDF

I have the consumer reports for the year 91 covers all the camaros from
82 -91
All of the 305s listed with either tbi or tpi are not rated at 20mpgs or better
on the highway...they are well below that..avg around 15-17 on the highway.

fire350tpi

im getting 13

Stephen

iTrader: (12)

'87 GTA, 700R4, 3.27 gears...

A shy under 15 mpg

And that's taking it pretty easy. I was getting about 16 mpg, before fixing the AC. So, the AC is costing me a bit.

Just figured my fill up from Sunday...Just under 14 mpg!

Sheez! The easier I drive, the worst it gets! I'm gonna go back to driving it like I stole it!

bigchief

stupid question....... but how exactly are you guys making these calculations?? usually waht i do is, fill up my tank (which usually doesnt take more than 10 gallons) and run it to the bottom, take the amount of miles i drove, divide it by 10 (or however many gallons of gas) this is obviously the most straight forward way, but is there a better way to do it??? my gas guage isnt the most accurate, and i dont like running my tank completely low..........

qube

They must have all been nailing it on that highway!

I know standard US pump gas is a much lower octane than in the UK but I get at least 25 to 30 MPG on the highway unless I'm pulling over a ton.

M.

Black85sport

89 IROC with 350 TPI, automatic, stock 2.77 gears, and lockup not working - I got 20.6 mpg on a trip that I took in April. I did 65-70 the entire trip.

Stephen

iTrader: (12)

Does octane level make difference in mileage? 87, 90, or 93 octane? And does the price difference in octane levels make the gas mileage difference worth running a higher level? In other words, you get better mileage, but pay more per gallon, equalling the same as a lower mileage average with lower octane?

qube

I get better milage using the higher octane fuel but it is more expensive to buy, in the UK we've got the choice of 95, 98 or 102 (RON) for unleaded (the latter costs $16.65/Gallon so not really for daily use!).

I would have thought that to get best results though you'd want to tune the engine specifically to the octane you're using. The higher the octane the higher the compression you can run without knocking, can't see how the ECU will 'know' to adjust itself.

Matthew

Wadebryant

"hurts my motor to go so slow" James Taylor

1MeanZ

iTrader: (9)

is that quote from two lane blacktop?

thaforce

with a 5.7 TPI Automatic I have been getting about 16.5mpg average, thats a little play and about half and half city and highway. If I have a few races I have seen it as low as 12mpg.

Wadebryant

JT Traffic Jam

bigchief

again, how are you guys calculating this number so accurately?

thaforce

I calculate my mileage after every fillup. Miles traveled divided by gallons used. I forgot to mention the mileage I listed above is with 93 octane fuel.

bigchief

thanks force....... but do you drive it down completely to an empty tank?? i think i might have to, b/c my guage doesnt work too good...... it never shows completely full :-/

jethawk

theres no need to drive it all the way to empty.... reset your trip meter and refill till full.....(i usually let it fill till the stop activates.... then fill it a little more until it activates again).... then drive around or whatever....... then the next time you fill up.... see how much you put in to fill it back up to full..... now you use that number to calculate your mileage on the miles travelled on your trip meter....

Hypothetical situation

you fill up and your full at 10 gallons...you reset your trip meter with this fill up

you go on a 200 mile trip and fill up again and put 5 gallons of gas to fill it back to full

so your mileage on the trip is 200/5 or 40 MPG.... thats pretty much the easiest way i do it.

then if you want to do the next trip.. just reset the trip meter again and away you go.

Les Holt

I feel good now, I was getting just a tic over 14 with my 355 tpi in a 87 3/4 ton 4x4 with 4.10 gears and no over drive going back and forth to work and half that trip is back roads. On the freeway I get about 13.5. That babys a winging on the freeway at 75 mph no to mention it has the areodynamics of a mobile home.

thaforce

I normally run the tank pretty low before refilling. But the way jethawk put it is definately the way to git-r-done.

Wow Les, not bad, I have a F-150 4WD 1/2 ton extended cab flareside with a 5.8L I get between 10 and 12mpg out of it.

The 16-18mpg I get out of my thirdgen was a nice upgrade hehe.

3.8TransAM

Best advice, throw the Consumer Report away and enter the real world.

That magazine has, is and always will be filled with liberal garbage.

They name a car "Car of the Year" for cupholders. Oh wait! My bad! Motor Trend does that too.


I own three thirdgens, all were stock when I bought them

2 are 91 TPI 350 cars and one is a 89 TTA.

They all got equal to or better than rated.

Its extremely easy to get 23-24 mpg out of a stock properly tuned 350 car.

18-20 around town is normal too.

Just having underinflated tire can cause a decent drop in fuel mileage as can a myriad of other problems.

Dont believe what u read unless you consider the source, printed or internet.

EDIT: For the record I have a friend who does his own customixed tuning. He has a 454 TBI/4L80E Utility truck.

He would get 10 and 13 mpg unloaded, and like 7 and 9 with car trailer, he now has it up to 17mpg unloaded and about 14-15 around town. Towing mileage is up by the same amount as well. No crazy stuff, no crazy tricks, just running open loop and lots of data logging.

later
Jeremy

bigchief

wow man, thats awesome, thanks for sharing all of that