Gas mileage
Thread Starter
Instructor
Joined: Jul 2002
Posts: 245
Likes: 0
From: Raleigh NC
Gas mileage
I was wondering what some of you guys are getting for gas mileage. I've got a stock 1981 engine, runs VERY clean (hardly anything shows up on an emissions test), and runs very smoothly. But I'm getting about 10 miles to the gallon. On a related issue, I don't think my torque converter is locking up. Actually I'm pretty sure it isn't. What things should I start looking at to diagnose why that's not happening?
Race Director
Joined: Apr 1999
Posts: 15,136
Likes: 477
From: NM
Re: Gas mileage (Enkil)
Have two 73's. One conv with L82/auto and the other 454 4-speed. On major highway trips the L82 got 12.9 mpg while the 454 got 13.0. Highway speeds with A/C. L82 has 3.36 gear and 454 has 3.08 gear. Have no idea around town, have never check it. (By the way, my 90 coupe, L98/auto, gets about 27 mpg on the highway.)
tom...
tom...
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: Gas mileage (Enkil)
Sharks without over drive and or DPFI get typically 10-12 mpg, and anything over that is a blessing not to be messed with....adding DPFI will nearly double that....closed loop...alone....keeping stock duals, like I did on my '72 here...
now adding overdrive should kick it up 3-4 mpg also...butnot in city driving...
an 80 did not have lockup converter, 81 did....unless it was a late 80 intro.???
82 had overdrive, but the trannies are crappy, early models...and don't improve untill late '87 apparentyl....and well even then aitn' for much....
GENE
now adding overdrive should kick it up 3-4 mpg also...butnot in city driving...
an 80 did not have lockup converter, 81 did....unless it was a late 80 intro.???
82 had overdrive, but the trannies are crappy, early models...and don't improve untill late '87 apparentyl....and well even then aitn' for much....
GENE
Race Director
Joined: Jun 2000
Posts: 10,040
Likes: 672
From: FL
Re: Gas mileage (mrvette)
Around town probably 12 mpg, on the highway in OD and staying out of the secondaries, I get an honest 20 mpg.
Performance engines can get pretty good mileage if you stay out of the throttle, especially if you build an effecient engine. It is all in the airflow in and out.
My prior set (L-48 with Performer, headers, duals, Crane 272 cam (milder than the current cam) and 4 speed) got an honest 18-19 mpg at 70 mph turning 3000 rpm.
You can have your cake and eat it too if you do your research.
Performance engines can get pretty good mileage if you stay out of the throttle, especially if you build an effecient engine. It is all in the airflow in and out.
My prior set (L-48 with Performer, headers, duals, Crane 272 cam (milder than the current cam) and 4 speed) got an honest 18-19 mpg at 70 mph turning 3000 rpm.
You can have your cake and eat it too if you do your research.
Melting Slicks
Joined: Apr 2000
Posts: 3,286
Likes: 8
From: San Jose California
Re: Gas mileage (Enkil)
Speaking of highway steady 70-75mph cruise only:
69 350/350hp 4 speed, 3.36 gears 22-24mpg
69 427/550hp, 6 speed, 2.53 overdrive gears, 15mpg
79 L82 automatic, 3.55 gears 17mpg
85 manual, ~2.0 overdrive gears, 25 mpg
02 346/405hp, 6 speed, 1.91 overdrive gears, 29mpg
Chuck
69 350/350hp 4 speed, 3.36 gears 22-24mpg
69 427/550hp, 6 speed, 2.53 overdrive gears, 15mpg
79 L82 automatic, 3.55 gears 17mpg
85 manual, ~2.0 overdrive gears, 25 mpg
02 346/405hp, 6 speed, 1.91 overdrive gears, 29mpg
Chuck
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Le Mans Master
Joined: Feb 1999
Posts: 6,807
Likes: 0
From: Hoosier
Cruise-In III Veteran
Re: Gas mileage (SteveG75)
Performance engines can get pretty good mileage if you stay out of the throttle, especially if you build an effecient engine. It is all in the airflow in and out.
You can have your cake and eat it too if you do your research.
You can have your cake and eat it too if you do your research.
Melting Slicks
Joined: Oct 1999
Posts: 2,581
Likes: 14
From: Tolar Texas
Re: Gas mileage (mrvette)
...an 80 did not have lockup converter, 81 did....unless it was a late 80 intro.???...
Burning Brakes
Joined: Oct 2001
Posts: 1,185
Likes: 0
From: New Wilmington PA
Re: Gas mileage (SteveG75)
I too am getting around 20 mpg. Engine is a stock ZZ4 and I have a 3.08 rear with TH400 trans. I'm still in the break in period so I've been treating it fairly gently.... usually. My driving has been a total mix of highway, "city," and winding/hilly country road. My gas gauge doesn't work so I tend to refill every 100 miles and I seem to be putting in 5 gallons each time. :D That's better than my dad's 4 cylinder, 90 horse F*rd Ranger. :lol: Ranger's lighter too.
---EDIT---
Oh, did I mention my carb is running pretty rich? :p:
[Modified by Cookwithvette, 2:52 AM 8/12/2002]
---EDIT---
Oh, did I mention my carb is running pretty rich? :p:
[Modified by Cookwithvette, 2:52 AM 8/12/2002]
Advanced
Joined: Mar 2002
Posts: 51
Likes: 0
From: napanee ontario
Re: Gas mileage (Enkil)
I'll get 14 mpg in the city in my 1980 auto L48. It doesn't seem to vary much no matter how hard I'm driving it. A full tank of gas gives me about 450 km/ 270 miles. I have to keep track of my mileage since my fuel gauge doesn't work.
Le Mans Master
Joined: Aug 2000
Posts: 6,362
Likes: 7
From: Brazos TX
Cruise-In IV Veteran
Cruise-In V Veteran
Re: Gas mileage (Enkil)
With an L-82, 4 spd and 3.73's I get about 14 to 15 mpg on the highway. That is cruising at 80-90 mph, reving about 4000 rpm.
Instructor
Joined: Jun 2000
Posts: 167
Likes: 0
From: Madison AL
Re: Gas mileage (burners)
I have a near stock 81. It has a slightly larger cam that is still computer compatible, trans shift kit, and monolythic catalytic convertor. Still has all computer controls and sensors. I get 13.5 to 14 MPG in town. I don't do much highway cruising, so I'm not sure of the highway MPG.
It's easy to test the lock-up of the convertor. Take it up to cruise speed in final drive ratio and take note of the rpms as you hold it steady at this speed. Tap the brake pedal with your left foot and see it the RPMs jump up about 100 to 200 RPM. If they do, the lock is functioning, if no change, it's not. If not, it could just be the lock-up solenoid inside the trans pan.
[Modified by Widgett, 3:07 PM 8/13/2002]
It's easy to test the lock-up of the convertor. Take it up to cruise speed in final drive ratio and take note of the rpms as you hold it steady at this speed. Tap the brake pedal with your left foot and see it the RPMs jump up about 100 to 200 RPM. If they do, the lock is functioning, if no change, it's not. If not, it could just be the lock-up solenoid inside the trans pan.
[Modified by Widgett, 3:07 PM 8/13/2002]
Burning Brakes
Joined: Dec 2000
Posts: 795
Likes: 0
From: Madison MS
Re: Gas mileage (Widgett)
I have an L-48 with all stock internals. TH-400 transmission and 3.08 gears. Stock Q-jet intake with a 670 cfm TBI Holley Projection WITHOUT an oxygen sensor. (I know. It is a pain in the azz. I am always adjusting that thing.) I took a trip this past weekend and logged 1000 miles. My highway average was 17 mpg. My overall average was about 15 mpg. I drove about 95% of those miles on the highway. I typically get about 8-10 in the city. I just can't imagine a nicely tuned, computer controlled small block in an 81 getting worse mileage than my old 74.
dl
dl
