First find out what's wrong. 13mpg is really low. Try fuel injectors, air filters, or other repair items suggsted. What's the point of saving gas at the expense of horsepower? Might as well buy a Civic.

Here's something a bit more reasonable:
Lower throttle is actually less efficient than high throttle, since the engine is fighting itself. High gas consumption from high throttle actually comes from higher top speed and increased braking. Avoid these and you can still have your fun. I get 18mpg city/22mpg freeway (80mph) and I hot foot it all the time.

Check your tire pressure.

Shift before 4000rpm because that's about when the 5th&6th ports open. You should still exceed 4000rpm every once in a while to keep your engine clean, though, and because your horsepower is rated at 6500rpm (see Civic argument above).

Synthetic oil will save you about 0.5mpg. A lower viscosity oil will help too. But higher viscosity will reduce oil consumption and provide better protection on more worn out engines (like yours may be).

Don't forget your differential oil. It was the last fluid I changed and mine was pretty dirty.

Reduce engine deposits with detergents from good quality oil and gas (Chevron, 76 or Shell). You can also get additives of varying quality in case you haven't been using good gas. I hear Chevron's is pretty good. Nearly all oil additives don't work, though.

Almost forgot the bigge: A bad O2 sensor can hurt your mileage by 2mpg or more. About $40 to replace.

 

uhh ok.... wish i knew if wired open gave the better gas mileage....

 

You get worse mileage when your 5th and 6th ports open. They normally open when you exceed ~4000rpm. They open to provide a boost in horsepower.

Oh, and here's a list of things that might give someone 13mpg:
bad compression
really bad O2 sensor
30mph speed limit and/or tons of stops (lots of idling)
engine sludge from cheap oil or gas (takes time to go away once addressed)
dirty fuel injectors

These are just common problems. You might find something totally different. Most important is knowing that 13mpg isn't normal, because now you'll want to go get your car fixed.

 

yes im aware it gives less but i thought he was implying it gave him 1 more mpg... i think 21mpg with 5/6 open is unbelievable in stop and go traffic

 

Either run some fuel injector cleaner stuff through the gas tank or send your injectors to witch hunter, 13.5mpg is VERY low.

Accelerate slowly, never punch the throttle and shift when the light tells you to (or below 3K).

 

is running the fuel injector cleaner through the tank going to harm the motor at all or does the good outweigh the bad in this case?

 

As long as your OMP works it should be fine. Just follow the directions (all 1 or 2 of them) and don't use more than recommended (ie don't use a bottle meant to treat 20-30 gallons, or rather too much).

I'd recommend using either Chevron brand concentrated cleaner or MMO.

 

do gas stations carry it or would you have to go somewhere like napa or lordco to find it?

 

Gas stations usually carry some kind of it, MMO (Marvel Mystery Oil) should be carried in any autoparts store as well as walmart/target/etc. I'm pretty positive MMO can be used as a fuel system cleaner, I recall reading that and then using it in my gas tank (and my friends gas tank). I think half of a bottle should cover a full tank, just double check the directions.

 

I set my trip meter every fill-up and every time I get 250k city...350-400...hwy

 

wow i drive an 87 n/a and i get about 12 mpg after full tune up. never rev above 3k, never have a/c on.

 

i meant to say i got only 1mpg better when i wired 5/6th port closed. 21mpg open/22 mpg closed, roughly.

measured using the trip odometer and gallons used at fillup. this is with a recently tuned up S4 n/a, no ac, redline gear oil in the tranny and diff, mixed traffic, driving like a granny.

If you are getting 13 mpg, something is wrong. Check your timing, that makes a big difference in mileage too

 

I have my secondary port actuators completely removed, no A/C, no emissions, with an RB header and stock cat/catback and I get an avg of 18-19MPG. All city driving - a lot of stop and go. While delivering pizza (a LOT of idle time) I consistently got 18.

My motor is a fresh rebuild, now it has about 6k miles on it, and I have a lot of fun with it - the buzzer talks to me at least 3 times a day. I've considered getting a S-AFC to lean it out some, but now I drive a lot less (I quit delivering). From what I hear, it'll get you a few extra MPGs and you'll feel a good bit of difference (seat of the pants), AND they can be had for ~$150 now.

 

the manual says the shift light is "for fuel economy" but i dunno how reliable it is

i never knew that engine braking cuts fuel

 

Canadian Tire in Kelowna should have Marvel Myster Oil.

 

my car gets over 20 on the freeway...

and it has less than 20 HC on both 15mph and 25 mph emission testing.

get your car to run right first before anything!

 

Engine braking is why you get lower efficiency at partial throttle - the engine is fighting itself. You get better mileage in the short run, but at a serious loss of horsepower. "Burn and coast" is more efficient, i.e. normal acceleration plus coasting in neutral.

Hybrid engines get the biggest boost in mileage from having a small engine, not from regenerative braking. The reason is because the engine stays closer to full throttle yet without outputting too much horsepower. A hybrid might have an 80HP gas engine plus a 40HP electric engine, giving a 120HP hybrid a little better city mileage than and similar freeway mileage to an 80HP non-hybrid.

If you mean "engine braking" instead of using your brake pads then that's bad for your clutch, tranny and motor. And it's definately less efficient than coasting because you don't coast as far.

 

Can those various fuel injector/fuel system treatment products be used in a Rotory? (ie: the stuff you pour into your gas tank). ?

 

I'd assume so. I mean, I don't see why not. I've heard of it being done, anyway, and done it myself.

Make sure you get a good one though. There could be some snake oil out there. I've heard good stuff about the Chevron stuff.

 

Well I actually noticed a difference in pedal response by using the Chevron Techron concentrate as well as the MMO.

 

Is anyone else getting 350-400 miles from a tank?

 

Come to think of it, it's definately rotary compatible because the same stuff is already in your gasoline. Good brands of gasoline have more, and those bottles you pour in (the good ones anyway), simply have much more.

I'd be skeptical about something with a name like MMO, but it sounds like people are getting good results. Looks like you can never tell except by experience and tests.

I can get up to 27mpg freeway going slow, so I suppose I could get 350-400 if I went to empty. Thing is I don't like to go that slow unless I have to.

 

MMO (Marvel Mystery Oil) is one of the few additives I've noticed here on the boards that has a far and wide good reputation of actually being useful and not a snake oil.

 

I've always wondered how much I can get out of a tank. The problem is I'm not sure my gas guage is working properly below 1\4rth. It seems to dip much slower than the rest of the tank.

I bought a 2 gallon container and filled it up with gas. I'm keeping it held down by the cargo straps in the hatch.

I plan to find out how many miles I can get out of a tank before the engine goes cough

 

cold air intakes can give u better gas mileage and echaust systems and if u take blinker covers or lights out it will bring more cold air to motor and cold air intake so maybe try that...