stav2201 Posted January 14, 2016 Share Posted January 14, 2016 (edited) I just recently took a 900 mile trip to southern California, bay area to san Diego. I wanted to share my car and engine specs in accordance to my mpgs from my trip. In a distance of roughly 900 miles I maintained about 22mpg average at an average speed of 75 miles per hour. Engine and car specs. -Engine timing set to 8 degrees tdc -4 speed transmission -enkei 92 rims (16x7) with correct tire size for stock setup -all smog equipment removed except for charcoal canister -tire pressure at 35 psi,tire tread at 80% -r180 differential with a 3.54 gear ratio, New fluid as well -10/40 full synthetic with a quart of Lucas oil stabilizer, fresh oil change -using a 280zx turbo fly wheel and clutch combination. -minimal weight loss on car, no ac or spare tire. -rebuilt l28 engine with an N42 head and stock cam (all cam lash within correct stock spec), stock exhaust manifold with a custom exhaust system which includes a resonator and magna flow muffler. -champion 3 core aluminum radiator, maintained perfect temp entire trip. -cleaned and polished throttle body -completely new set of after market injectors with new enjector plugs. -New spark plugs, plug wires, rotor and rotor cap. -repacked wheel bearings -kyb struts with coilover suspension, set 2 inches lower than stock height. -brand new engine mounts, diff mount, transmission mount, and every single bushing replaced, even the spindle pin bushings. Overall an excellent trip, there wasn't a massive mpg loss once I hit the grapevine suprisngly, I only lost about 1 mpg with such a huge incline from the mountain which I believe is about 12 miles full distance. Most of the trip is basically flat land on highway 5, I'm pretty sure I could of gotten 23 or 24 mph if people weren't so bad at driving and weren't constantly causing me to break my momentum. I also experienced issues with heat soak every time I stopped to refuel since I have a non egr intake manifold with no heat shield. Edited January 14, 2016 by stav2201 Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 21, 2016 Share Posted January 21, 2016 Sounds just like the Fairlady L28 with stock efi. Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted January 21, 2016 Share Posted January 21, 2016 (edited) I had slightly better mpg in my 280zx when it was "stock". About 25mpg. That was from Los Angeles to Daytona Beach, FL. I had a slightly larger wheel diameter and a 5 speed that I'm sure helped. Stock meaning, it was stripped, had a shaved non egr intake (with charcoal canister) and headers with a 2.5" exhaust system. Edited January 21, 2016 by BluDestiny Quote Link to comment Share on other sites More sharing options...
Chickenman Posted January 22, 2016 Share Posted January 22, 2016 (edited) After a long haul on the Freeway, I always pop the hood on all of my Cars ( Audi, Camaro, Datsun 280Z ) when I refuel. Lets all the stinkin' hot air out of the engine bay. After I refuel, I check the oil level, PS level etc etc, Then I'm on my way. Haven't had any Vapor Lock issues with any car since I adopted this procedure. Nice to give the engine a quick look over to make sure nothing is amiss. Edited January 22, 2016 by Chickenman Quote Link to comment Share on other sites More sharing options...
stav2201 Posted February 10, 2016 Author Share Posted February 10, 2016 After a long haul on the Freeway, I always pop the hood on all of my Cars ( Audi, Camaro, Datsun 280Z ) when I refuel. Lets all the stinkin' hot air out of the engine bay. After I refuel, I check the oil level, PS level etc etc, Then I'm on my way. Haven't had any Vapor Lock issues with any car since I adopted this procedure. Nice to give the engine a quick look over to make sure nothing is amiss. Yes, i adopt this method now, venting the air out of your engine bay reduces the duration of vapor lock quite dramatically. Quote Link to comment Share on other sites More sharing options...
Phantom Posted February 12, 2016 Share Posted February 12, 2016 I've kept mpg records on my 1977 280Z for 24 years now. The first 11 years was with the stock L28 with between 100 & 200,000 miles on it - that's how far I drove it in 11 years. After that it was with the LS1. The L28 originally had the 4-spd with the 3.54: R200 and then later an '83 280ZX 5-spd and 3.90 R200. With both set-ups i saw as high as 24 MPG on the highway but pretty much averaged 19-20 in combined city/hwy driving. Interestingly the LS1 with a T-56 and a 3.70:1 R200 does about the same - unless I'm in full aggressive mode and then it drops to the 10-13 MPG area. Quote Link to comment Share on other sites More sharing options...
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