i own a 90 s5 na and now im going to be commuting to/from college and thats gonna be about 120 miles round trip. i really don't want to sell my fc, it has sentimental value to me, lots of memories.. anyways, i have some money laying around that I would of spent on mods like 17" wheels and suspension but i want to invest in something that will give me better gas mileage, a lot better. i am willing to sacrifice power but not really reliability. please let me know what you guys think. this is mostly highway miles so i don't need power really.

 

30MPG? I think you need to pray..

 

You might get close with all highway miles, but just get all the standard tune-up stuff, new O2 sensor, maybe even a S-AFC to lean it out a bit if you can afford to lose some fuel without sacrificing reliability. You might want to just consider a different car if gas milage is of that much importance to you.

 

Never go beyond 2.5K or so... drive gingerly, maybe redline once a day or so to keep the motor "stretched."

FULL tune up, new O2 sensor, etc etc, get an AFC and "tune it" so it doesn't run pig rich all the time as it does stock. This would be the same thing you would do to make power, but all the way down the RPM range so you don't use as much fuel...

You're still not going to get to 30MPG... maybe close on highway at optimum speed/rpm.

Make sure your tires are inflated to the propper pressure at all times.

 

get another car

**Edit: PS, y did you get a sports car if your looking for gas milage??**

 

Buy a geo and drive it for your regular driving and drive the 7 when you feel like going fast and the special times out

will save you soem ware and tare on your 7 too

 

i was reading about how some people with modified tIIs and standalones are getting around 25mpg. so if i have a stock na it wouldn't be unreasonable to get around 30mpg?? i am not overly worried about gas its just i would spend money for any mod that helps mpg because it will end up paying for itself because of how far i drive. and all the miles are freeway, not stop and go or sitting in traffic. i know this car isn't great for mpg but i have a bond with it. i know that might sound cheesy but i want to drive this car because im attached a honda civic doesn't do it for me.

 

standalone, wideband O2, and a stomach strong enough to cruise at 15:1 air fuel.

 

Put a B16 in a civic, its probably faster than an NA and gets better mileage.. j/k..

 

I doubt a few extra MPG will pay for a standalone over an amount of time that would make it worth it.

 

Im in Cali 87 gas here is 2.18. Figure in that i drive 120 miles each weekday to school (im not going to include use other than going to school)and gas savings are worth it.

 

how much more mpg will i save if it get a used microtech. my friend has one for sale for $700 and he will install it for me. but i can get a used Apex safc off his fc for just $100.

 

You wont see a savings for a long time since you'll have to purchase it and dyno tune it or buy a wideband. $700 for a used Microtech isn't a very good deal coming from a friend..

 

Cheesy but true..
i think i'd rather take the bus over the winter then drive anything bu a 7...

ok never mind the winter is too long and i want to get a cavalier so i can modify the front end with a phone pole at the end of the winter and distribute pics at a weekly J-body club gathering right by my house

Frank

 

well he would install it and he has the harness which hell include for free. so should i get a safc and have it wideband tested?

 

You dont need a Microtech and SAFC, one or the other..

 

yea.. an S-AFC is used as a piggy bad fuel computer to modify the stock ECU's signal controling the injector duty, a Microtech is an after market ECU which the user can tune or have tuned.. goes much more into detail letting you control A/F and Ignition timing

Frank

 

I get 27 with my 86 N/A. I am only running an alternator and an A/C compressor. No power steering, no air pump. I did a complete tune up like others said. I have lightened the car some and have a new engine, rebuilt tranny and all new wheel bearings. Also run your tires with slightly more air pressure on the highway. Mods also include K&N air filter, hollowed pre-cats and a cat back. Operational Pinapple 6 port sleeves and all emmisions removed.

Skip at KD suggested and electric cooling fan for another MPG or two. I have not done this.

MOST importantly.... KEEP YOUR FOOT LIGHT.. Shift when the idiot shift indicator tells you to. AND USE THE CRUISE CONTROL.

You might be able to get 28-29....

 

Hey MichaelFregoe, I saw you've got removed emissions and are running cruise control. Where did you run the vac line fron the cruise control unit?
Patrick

 

take all that money you have and buy a hf hnda crx they get like 45 mpg and are kinda fun to drive cause they are small but they are still slow. good commuter car if you don't want 4 seats. i would never buy a geo or festiva i think they are unreliable

 

Bah, just get a TII cruise control module - fully electric.

Run with the windows & sunroof closed - I normally get 22mpg with everything wide open, I was getting 25-27 with everything closed.

Also, apparently getting fuel injectors cleaned can help a lot. They're on my list of things to do, when I find a good place to take my car apart.

Replace the gearbox & diff lube, since drivetrain losses translate directly into lower fuel economy.

E-fan - arguments abound about how much power it really saves, but if you are doing mostly highway driving, put the fan on a thermo switch (or a manual switch and a good aftermarket water temp gauge) and shut it off on the highway.

-=Russ=-

 

get like a hiflow cat and catback. more horses and also better gas mileage

 

Actually, that's a good point. Freer flowing intake/exhaust will increase efficiency by reducing pumping losses. A cold air intake (or ram air intake) may help as well.

-=Russ=-

 

I put the vacuum hose fro the cruise directly to a nipple on the upper intake manifold. I have an S4

 

It probably doesn't make sense to spend big bucks so here's my advice:
1. I noticed ~10% improvement in highway fuel economy with a cone filter. They pay for themselves pretty quickly.
2. Learn to drive for fuel economy. There is a substantial improvement driving a little slower on the highway and ensuring the car is in closed loop.
3. Inflate your tires above OEM recommendations. I don't know what size/type of tires you're running, but I'd say aim for the high 30s psi and you won't lose performance but you will see an fuel economy imporovement.
4. Draft trucks. Expect ~5-10% fuel economy improvement doing this. Trucks also drive slower so you'll receive savings from #2.