3S gearing, I'm shocked!

[foreveralone]

Hey all,
While I have enjoyed an '88 Conquest TSi 5-speed, a '95 Probe GT 5-speed, and an '85 300ZX 5-speed, I'm mostly a Camaro / Firebird guy, except for a few Mustangs.
I did a carbureted 5.7L '78 Camaro that managed 25.1 MPG at 65 MPH with the ignition advance being way late. I used a 700R-4 automatic, and was geared for 1800 RPM. A year later, I drove a second-gen Eclipse 4-cylinder, which, to my extreme amazement, would also cruise along at 65 MPG doing just 1800 RPM! Great!
Just now, unable to sleep, I looked up all the gearing options ever used on any / every version of these cars. Very sad. The best possibility is the 6-speed, which is 1940 at 65! Can any of these cars even see 25 MPG? And my automatic, ( which is geared identically to '90s Cummins-powered Rams ), is 2300 at 65! Even then, it doesn't have enough first gear, even with the 3.958:1 final. We get a 10.1:1 first, when I know from experience that an 11.4:1 is great for a similar-weight, same-tire-diameter '88 IROC-Z 5.7L with a shorter-runner intake manifold.
I can see I'll need to do a 6-speed swap to like this car. Yet having done the whole Fiero thing, I'm thinking of the F40-MT2, ( not Ferrari ) which would require custom axles, flipping the engine around 180*( or outright swapping a GM V6, in my case ) and would give a cruise RPM of 1870. Plus the trans itself can be had new for under $1,000 delivered, and has proven strong enough for 500 HP V8 swaps. Ratios are 3.7692 / 2.0400 / 1.3208 / 0.9538 / 0.7547 / 0.6208 with a 3.5455:1 final.

[Alan92RTTT]

I get 27 on the highway with my TT and my SL while running 80 with no issue.

[deathsled]

My VR4 gets 25mpg easily on the highway.

[2fnloud]

I figged about 26MPG average driving. And that is just doing the math with one tank of gas, no average.

[EvanH]

I've gotten 25 on my TT. And a record of 32 with a tail wind going cross country. That's with 370hp at the wheels.

[niterydr]

My 700+hp 3/s build (last one) averaged over 30mpg on the highway, of course under load it was gallons per mile...but every highway trip was consistantly 30+mpg.

My E-85 stealth so far is getting 17mpg city/flogging on it. Ill see how the mileage actually is when I am done tuning. Anticipating 17 city/24 highway on E-85.

[Alan92RTTT]

Is 17/24 good for mileage on E85?

[niterydr]

Is 17/24 good for mileage on E85?

I would anticipate so as E-85 has less energy than pump fuel. Most vehicles average 5-30% less fuel economy on E-85 than pump. If I can achieve 17 city/24 highway it is cost effective for me as the price per gallon is 15-25% cheaper. Only problem is the car is currently on an E-70 blend and E-85 will be less fuel efficient due to the higher ethanol content.

Oh well, it is still cheap "race gas". Being able to run "all boost" on the 9b's is nice.

[Keyan]

I get 21.5MPG, but I have 2 dying cylinders, so that probably explains my perdicament.

[DocWalt]

28mpg through the hills of PA all day long. 17mpg around town haha.