Gas mileage V6 Vs. V8??

Okay so im gunna get a beater car when i get back to Florida from Korea, and i've been looking on eBay and autotrader in the local area for a cheap third gen so i don't have to rack up miles on my '02 Z28, plus i've had a serious love affair with thirdgens. Its been a few years...like 5 since i've had one though (had 3- 83 4cyl. 4 speed firebird, 91 5speed firebid what a baby awesome car and a prestine 89 IROC-z L98 car) I seem to find ALOT of of 305 cars on ebay. What i want is a 3.1L or 2.8L auto car. Do any of guy guys notice a big difference in gas mileage between the V6 and V8??? I mean the reason why i want a V6 auto is for the gas mileage aspect for daily driving to and from base. Well any help is very much appreciated guys!!

My 5-speed 91 RS would get 24 city and 32 highway with 3.73 gears. That was with the 3.1 V6.

My 92 Z28 with the L98 would get 18-19 city and 27-28 highway. That was when it was stock.

How do you get that kind of mileage. I've got a 305 TPI 700r4 with 3.23 Posi and get 13 city maybe and 17 hiway. How do you do it.

How do you get that kind of mileage. I've got a 305 TPI 700r4 with 3.23 Posi and get 13 city maybe and 17 hiway. How do you do it.
tune up? fresh fluids? tire condition/psi? driving habits?


I was getting ~28mpg freeway, 23 city in my old car, 89 305 TBI, 3.73 gears

On the highways, you shouldn't see much of a difference, it's around town that the V6 will get better mileage. BTW, I'd steer clear of the 2.8. Been in the automotive industry in one form or the other for many years and I have never heard anyone say too many nice things about the 2.8's. I never owned one, so I can't say first hand experience, just what I've heard from mechanincs and such. Just my .02! :cool:
Mike

On the highways, you shouldn't see much of a difference, it's around town that the V6 will get better mileage. BTW, I'd steer clear of the 2.8. Been in the automotive industry in one form or the other for many years and I have never heard anyone say too many nice things about the 2.8's. I never owned one, so I can't say first hand experience, just what I've heard from mechanincs and such. Just my .02! :cool:
Mike


Hey man thats cool i appreciate honest criticizim (sp??) REally, i never owned a 2.8/auto car i had a 3.1 5 speed car but any helpful hints are VERY useful to me!!

when my motor had low miles I used to get bettween close to 20mpg city and as much as 30mpg all freeway speed,
3.08 5 speed

but I could make it terrible if I want, burned a tank of gas in less then a hour once

I've always found it odd that the 305 5 speed cars get the same or worse gas mileage than the 350 autos.

I've always found it odd that the 305 5 speed cars get the same or worse gas mileage than the 350 autos.


350 has more torque,
less gas same power

my 305 was wicked,

20 and 30mpg were just my average, thats decent throttle and acceleration all the time, I could get better if I wanted to

but the older it gets the worse the millage gets,
also i started tuning and I dump fuel into the thing now

the 2.8 auto trans is a sad story... best leave it at that.

now i dropped in a V8 5.0 TBI & 5 speed , hauls ass and gets better gas mileage than the V6.

the answer is simple, get a 5.0 TBI, VERY RELIABLE and the performance is ok especially on the manual 5spd equipped vehicles.

With my 88 iroc 350 i get about 12 in the city mabye 18 at the most on the highway i usually average 15-16 when i do the math on a fill up

With the 92 v6 3.1 i get on average about 25mpg

I don't know how you guys could get 30 MPG with 305 TBIs, but anyway...

My old A4 2.8 RS was kept in mint condition, and averaged 18 city, 25 highway at best in the 4 years I had it. My 305 TBI RS M5 averages pretty much the same...getting 26 on my most recent trip. Considering the EPA ratings were 17/26 for it, with 110k on it I'm happy!

2.8s aren't that great on gas...don't even bother with one.

I don't know how you guys could get 30 MPG with 305 TBIs, but anyway...

My old A4 2.8 RS was kept in mint condition, and averaged 18 city, 25 highway at best in the 4 years I had it. My 305 TBI RS M5 averages pretty much the same...getting 26 on my most recent trip. Considering the EPA ratings were 17/26 for it, with 110k on it I'm happy!

2.8s aren't that great on gas...don't even bother with one.

i get 30MPG no problem on highways with my 5.0 TBI, it has a lt1 camshaft. The diff. is 3.42. At around 60MPH i have 2600RPM.

when u buy 1 all u have to do is a basic tune-up, oil filters etc, change the ignition wires , spark plugs, cap rotor and O2 sensor, and u will have very good gas mileage. Obviously the engine has to be ok with normal compression.

Best recorded mileage in my old 305 tbi was 24 mpg, a decent mix of city and highway driving...

I had a 2.8 liter auto... not a powerful powerplant by any means, but I got plenty of miles out of it, despite the previous owner taking piss-poor care of it, myself not taking very good care of it (pizza delivery)

A buddy had a 3.1 that was almost indestructable...

I had a V6 Camry that got less MPG than some of you are getting with a 305 and 350. It's a puzzelment.

I regularly got 30 MPG on the highway with the 305 TBI, 5 speed, w/ 3.08 gears Formula I used to drive. I could cruise at 80 MPH and pull about 1800 RPM.

I think I got around 17 in town, but I don't remember.

I think the TBI cars make great daily driver/commuter cars. Good gas mileage and pleanty of passing power when you need it.

And yet, my 305 TBI 3.08 geared RS pulls around 2,500 RPMs at 75? That seems odd...

And before anyone asks, the only mods on my car when I bought it were a K&N drop in and a Magnaflow cat back, so I highly doubt it has gears...

My carb'd 305 got 30mpg highway. But on a side note, why buy a muscle car without the muscle? Thats like finding a hot girl without a body :think: But anyways get a v8 and call it a day.

Yeah, if you want mileage, buy a Prius. :D

I get 13 mpg city and 16 highway, so maybe I'm not a good person to listen to.

Yeah, if you want mileage, buy a Prius. :D

I get 13 mpg city and 16 highway, so maybe I'm not a good person to listen to.


The most honest post in this thread.

Honestly, I'm thrilled to get 25 on the highway with a 15 year old 305! I just tuned it up, and she purrs...

25 is nothing to sniff at, IMO...

Lol. I get about the same gas mileage now as I did when I had the 305/auto and 360 less horsepower. 26 mpg :)

My 86 LG4 5-speed with 3.23 gears and 4-wheel disc brakes gets between 20 and 22 MPG of mixed local / highway driving.

I owe the posters on this thread an apology. I just couldn't the mileage you were getting with these V8s. I was getting 12-14 MPG with my 305 TPI and 2.72 Posi. To be fair I did almost all my driving either in the city or rush hour traffic on Freeway.

Last night however I made a 250 mile round trip drive to Palm Springs and got 21 Mpg one-way and 24 Mpg back. I guess as long as you can keep the tranny in OD that's what happens. Needless to say I was pleasantly surprised.