Lets make the best real world *MPG* THREAD EVER !!

[Killer6]

On the way down to Winchester VA to lodge for a Pentastars At the Point event(Summit Point circuit), the '88 ShelbyZ got 37.6mpg on the way down, 15mpg on the road course. That was July '98...

 

[RustyRatRod]

It's not that you cannot tune. Other people don't know how to measure mileage or just flat out lie for the sake of conversation or just to brag.

 

[toolmanmike]

It's not that you cannot tune. Other people don't know how to measure mileage or just flat out lie for the sake of conversation or just to brag.

Back in the day (I love to tell stories like that) when I worked at the dealership, we had a mileage tester. A glass jar that held 1/10th of a gallon that clamped to the outside of the driver's door glass. Crude at best but it did work to test mileage. Pre port injection. Carb and tbi only. We disproved a lot of poor mileage claims.

 

[66fs]

Man I took a hammering here from several guys on how I couldn’t tune worth a shot when I said I was getting 17 mpg’s on the Hwy.

I am sure you did what you could but I never found these engines in great shape to get the almighty reported 30+!

A lot is in the drive. Living in South Dakota and visiting , or going anywhere, was a long drive. When you can cruise literally for hours at steady speed with little to no traffic you can put up some big numbers. I learned to use a vacuum gauge from my brother's 67 Barracuda. I could even beat cruise control for gas mileage. To give some perspective, we put over 300,000 miles on that car with the same drive train, trying different combinations. Not as many with my 64 Barracuda, maybe 150,000 to 200,000 miles. 64 and 65 Barracudas have good aerodynamics as do 67-69 fastback Barracudas. Plus I was running a 4 speed. I guarantee you I am not exaggerating the mpg we used to pull, and I can also guarantee you my odometer was closer than any back in the day. I still get in our trip car and cruise 5 hours between stops. My cousin said one of the carbs I modified would get around 30 mpg in the 67 Barracuda 273, 904, 3.23 gears at around 55 to 60 mph. But not many could duplicate the carb, tune, and combination, let alone believe it. I can also tell you the monster 273 in the 64 Barracuda only got 10 mpg not cruising on the highway. The 170 was a blast for what it was, and would easily pull almost 30 mpg on a trip.

 

[Killer6]

Driving technique is easily over half the battle. The key to the TurboII above is never let the engine drag enough to generate 15"Hg or more vacuum downhill, toe-it & let it roll(unless You know/expect a speed-trap there), & try to keep it out of boost uphill if possible. Accelerate & shift quickly, & never lug it just to try to use OD, watch that vac/boost gauge & follow the rule.
By contrast, My '84 Laser XE TurboI managed only 34mpg on highway trip to Akron, the final drive was 3.54 vs 3.87 for the ShelbyZ.
My MP non-feedback "export" carbed '86 Horizon America, with 2" exh. & GLH rims w/205-50r15's managed 33mpg combined round-trip to Chryslers at Carlisle on one tankful.