Hey all, I took my 97 Z to FL for spring break at the end of March, and the best gas mileage I got was around 25.3 somethin, mostly near 21.5 or 22. I'm rather certain the car is stock (bought it used from dealer so I don't know for sure) less exhaust. I was doing around 80 to 90 most of the time around 2-2200 RPM...the reason I had the question was my 92 305 M5 RS got its best (wanna say 26-ish around 24-2500 revs)doing around 90 to MN, and I figured with lower revs and lower gear, the Z would have done much better. Oh, it also only has/had 34k so it's not tired by any means. Any info would be great, and TIA.

-Jeremy

 

Sounds fine to me...that number would go up if you were around 60-70 mph I believe

Bill

 

I got close to 28 MPG when my old 6 speed was stock, so your number is fine.

 

Another "sounds 'bout right to me" here. My (stock) 95 M6 TransAm gets around 19/20 in mixed driving and about 24-25 highway.

My M6 98 LS1 Camaro was worth about 28 mpg highway.

BTW... were LT1s tuned to run somewhat rich from the factory? I.e. is there anything to be gained from a flash tune (assuming plugs, wires etc are all in good shape) to lean it out just a tad in places (while keeping it within safe parameters)?

 

My '94 pulled 27-28 on a highway trip at around 65-70mph. Be glad you dont have a stalled auto.

 

You might could have squeezed a few more mpg out of it under better circumstances. Your guess as good as mine as to what those could be... a little slower average speed, straighter highways, etc. I assume you aren't running some kind of wacko oil like 20W50 or something else unusual. I got about 29 out of my previous '95 M6 on a flat four lane trip once. I was only driving 70 or so. The car had about 50k on it, 5W30 Havoline, bone stock with max psi in the tires.

 

That's pretty close to what I get... ~25 mpg on the highway in 6th gear with 3.73s...

Although around the city it's closer to 10-15 depending on how hard I'm driving the car.

 

Using cruise at 65 mph around 1700rpms I get just shy of 30 mpg on the open road with 130,000 on the clock!