n8kaywa

I just purchased a 1980 Rx-7 and I am concerned about my gas mileage and range. I was hoping for a range of 300 miles per tank because I'm looking to drive this baby from Alaska to Seattle without running out of gas. Any feedback or tips for increasing range? Thanks from a newbie

t_g_farrell

iTrader: (1)

I'd be more concerned about reliability of the car as whole. Have you replaced all
the hoses and fluids and reconditioned or rebuilt the brakes? Tuned it up etc etc.

Do you have a lot of spares for fixing things on the road? Is that all paved yet? Is
some of it still rock road? Do you have tires that can handle this?

I don't think running out of gas is your biggest risk here.

jdi_knght

The only "gas saving tip" that I can think of beyond the stuff that applies to all cars (tires properly inflated, alignment in spec, etc), would be to try to keep out of the secondaries which can usually be accomplished by refraining from mashing the pedal to the floor, accelerating reasonably/gradually, and refraining from really high speeds.

If you're looking for any sort of modding beforehand, I suppose you could step up to slightly taller tires. If I'm remembering right the stock size is 185/70R13 - you could bump up to 185/80 although it doesn't take much extra weight at that point to make the tires rub over bumps, and really I think the circumference difference was only 4 or 6% so *maybe* a 15 mile gain on a 300 mile tank if I'm remembering right, minus any losses from the added rotating weight.

Jetting leaner's another possibility (can prob find a little more info on jet sizes etc on Sterling's site), but for the time involved... better be a good reason for wanting that extra bit! :p

Not sure exactly what the reason is that you're adverse to a gas stop during the trip, but if it's something like you're travelling remote roads/etc in the middle of the night and are worried about gas stations not being open, you could always consider bringing a jerry can of gas with you.

BigIslandSevens

iTrader: (4)

I bought a 81 FB for 500 bucks. Hardly ran to get home. I had the carb rebuilt and put it back on. At this point I was only getting about 17 MPG. I then replaced the spark plugs( which had not been changed in who knows how long because they were all crossthreaded into the engine) I performed the second gen coil mod, replaced the wires and the fuel filter.

Now, I get about 25-26 MPG. This is on a highway run to and from work.200 miles a day. I actually brought a can with me and delibratly ran the car out of gas on the interstate to see exactly how far I could go. I ended up with 420-35 miles( can't remember the exact #) Point is, these cars are just as fuel effiecient as most new cars built for economy. I would only get into the secondaries maybe 2- 3 times to merge into traffic on the interstate or whatnot. hardly ever hit them if you want economy.

This is what I did and my results. The car had 135,xxx miles on it when I got it. I have changed the oil and the above things to achieve good milage out of a 28 year old car.. I love it.

Dave

j9fd3s

iTrader: (3)

my last 1st gen was (well it still is!) a stone stock 79. when the points were new, and the tune was right, it would get 25 mpg on the freeway. the idle mixture had a big impact on mileage.

with the points in more average condition, it needed more fuel, and mpg was more like 22-23

we also noticed that mpg stays about the same (or gets slightly better) up to about 4000rpms, so this gives you about 75-80mph

'87 turbo II

iTrader: (1)

The best example everyone points to is Stu's hypermiling thread, but it's worth a look. Try to adapt as many of his techniques as you can live with comfortably to achieve the best mileage you can. I personally have a rich running Dellorto 48mm carburetor so I get 13MPG lol, but this thread is the one to read for mileage.

https://www.rx7club.com/showthread.p...ight=hypermile

'80 GS OO

I did a lot of highway driving back in the 80's when my car was still new. I did a road trip across Canada to the west coast, and another trip down the east coast all the way to the Florida Keys. I would consistently get 30 - 33 MPG - mind you that is a Canadian Gallon - so mid high 20's per US Gallon is very possible.

600 KM or 450 miles per tank is very doable.

When you factor in the extra cost needed for premium gasoline in some of today's modern day sports cars - the older RX-7's were actually pretty good on gas especially for a nice long highway run.

After a week of commuting back and forth to work, I would pull the spark plugs and inspect them and then adjust the carb for lean or rich. You want the spark plugs to be a light brownish color - not white (lean) or sooty black (rich).

Make sure your tires are properly inflated.
Get an alignment (that can make a significant difference).
Watch how much extra "stuff" you're carrying in your car.
Keep the speed under 70 MPH.
Drive with the windows up - sunroof open if the weather is nice.

JoeyMazda

I eliminated the vaccuum system from my car & have a mechanical secondary. I took a trip from PA to Mass. and only spent a little more than a 1/2 tank. I even made a stop in NYC & drove around for a while. I was left with a little more than a 1/4 tank of gas when I got to Mass. I didn't have to gas up until I was on my way back to PA.

Sterling

With practice, you can get very respectable fuel mileage from a Nikki with stock jetting and mechanical secondaries.
I find that most people that are actually serious about getting decent mileage have a bit more decipline with the throttle. The rest that do too much complaining have those devilish horns that come out of their heads too often.
-The Rx-7 is too much fun for those who suddenly become concerned about fuel conservation after their wallet starts to ache. It's a hard habit to break, but it can be done.
I (personally) like tooling around conservatively, all the while knowing I have plenty of power on tap.

OneRotor

iTrader: (3)

I've started keeping track of my mileage recently. I drive 50/50 highway to city, and shifting between 2500 and 3000 I get ~18mpg. I have achieved 28mpg@78mph on the trip north from Ann Arbor to St. Ignace, MI.

Rx-7Doctor

iTrader: (13)

Since we get mileage thread requests on a regular basis. :-)

https://www.rx7club.com/1st-generation-specific-1979-1985-18/fuel-economy-report-since-recent-mods-se-656700/

n8kaywa

Very encouraging tips. I just ran the car dry and managed to get 20 mpg without having done any work. An extra 5-7 mpg is looking good. Once I get home I don't care so much but driving 5000 miles every mpg is definitely gonna help my wallet.

Rotarx7

iTrader: (3)

10mpg on a stock 6port and a 48 IDAweber! does that seem right?? i thinnk it sucksss

7aull

iTrader: (2)

n8-
Here's the BIG secret of gas mileage going down the ALCAN - know where to buy gas!!
1) Top up at last station before Beaver Creek/ Border, cause once into Yukon: ka-CHING $$!
2) That fill up should get you to Whitehorse, cheapest gas in Yukon.
3) judge your tank, using a Map (get the latest Alaska Hwy Guide - $15 at Walmart, well spent),
get yourself to MAJOR population centers. Prices highest thru N. BC.
4) drive INTO TOWN, don't fill up at outside Hwy gas stops. usually in-town stations used by the locals are a bit cheaper.
TAKE SPARE OIL!! at least a couple of quarts. Check your oil DAILY with those kind of miles driven, you will go thru it quicker than you think.

Enjoy! have driven my RX twice up the Alaska Hwy with no problems - best driving experience I've had!

Stu Aull
80GS
Alaska

DivinDriver

iTrader: (15)

I've been averaging 17mpg since my last carb rebuild, but that's based on 60/40 city, and not being conservative at all... and I'm still running a little richer than I like just now, too.

My -7's a hobby car these days, driven almost exclusively for fun or to meets. Mileage is not a concern, so I tend to drive/shift in the "fun" band.

Back in my poverty-stricken days when I used this car for my DD and drove mostly highway miles, I recall routinely being in the mid 20's. This was prior to ethanol oxygenation in fuel, however. Ethanol admixture cuts a couple percent off your mileage, A/F mixes being equal.

LongDuck

For the record, 'oxygenated' fuels are statistically insignificant for improving or reducing fuel mileage on our cars (test bed for me was my 84SE at 195k original miles, stock intake, RB exhaust).

Test conditions were 3.5% ethanol content (EPA regulation), 'regular' unleaded pump gas (Mobil brand), and statistical testing via one-way Analysis of Variance (ANOVA) to test for center - Standard Deviation. Test result was P-value of 0.845 - insignificant impact of oxygenated fuel vs. standard unleaded. Also tested for spread (Test for Equal Variances) with P-value of 0.770, also insignificant impact of oxygenated fuel vs. standard unleaded.

My point is; oxygenated fuel has NO EFFECT on fuel mileage as measured in our cars across a mix of city/highway driving, summer/winter/spring/fall, or differing levels of performance.

Hey, I'm a geek. What can I say?

My fill-up this morning yielded 18.8mpg at 204k original miles, and I'm pretty proud of that for mixed driving.

DivinDriver

iTrader: (15)

Oxygenate in California is mandated at 5.7% statewide, and 10% in urban smog zones (like where I live). And they are discussing raising it to 20%.

'Nuff said?