Ways to improve MPG?

[K2e2vin]

Alright, so I'm picking up a 92 LX coupe this Wednesday. I really wanted a Civic VX, but the seller changed his mind. My last CB7(90 LX coupe) was getting around 26-28mpg average(mostly highway) but was far from being driven conservatively(I sped a lot in that car).

Just wondering, what's everybody doing to improve MPG? I really don't want to do anything that would make the car more uncomfortable(like remove A/C); I have a 88 Civic for that(stripped down, etc. but still got a best of about 57mpg highway; now it's closer to around 40-43mpg, and even lower with the bike rack on there).

Some ideas I had, but are not sure of; fiberglass or cf hood, replacing the front seats with other OEM Honda or Acura seats(does anyone know the weights of other seats?), power antenna delete/shaved and use a interior antenna, slightly lowering it, FULL tune-up, high flow catalytic converter, 7lb flywheel, reground cam+tuning, maybe even swap to a smaller motor(F20B?). Possibly even using a very small turbo to help with part-throttle efficiency(although would probably choke the engine to hell at WOT).

Any other suggestions? I know it'll get nowhere near what a Civic gets, but really just aiming for +25city/32hwy.

[bcjammerx]

I ran a over 30mpg straight highway (as in straight road no hills and all highway) going over 80mph

currently I hit 27-28 mpg driving 60-70mph on hilly curvey blacktops, then city traffic for 5-7 miles.

Best way to improve gas mileage is have all your sensor reading correctly, lay off the throttle, and air up your tires.


you could add up to 1-2 mpg by filling only half a tank, and taking 100 pounds out the interior...not or...AND...

[JesterMasque]

If you really want a crazy (10mpg+) increase, install a full MSD ignition and Blaster Coil on your car. My friend's CB9 went from averaging about 23 mpg to 35+ after the install. Plus your car runs WAY better and burns the fuel cleaner for the environment. He said it was some of the best $300 he ever spent.

I'm doing mine after I buy my bike. Currently saving up for a down payment...

[604_SE]

alot of it depends on how you drive...

[carlosamador16]

Keep your tires at the recommended pressure. Knowing that you like to speed, it would be best to avoid a high speed blow-out because of over inflating.

Besides that it sounds like you have a pretty good plan laid out. Make sure your engine is breathing freely, have a strong spark, and keep it as light as possible.

[K2e2vin]

I've actually had a MSD coil and cap on my old Accord, and start-ups were noticebly faster. The mileage was similar when I put the stock cap/rotor on but soon that deteriorated.

I drive much slower now than when I had my old Accord and with fuel economy in mind. For comparison, with my brother's car I can get ~37-40mpg with it while he only gets ~32mpg; this is a 93 Civic CX with stock DX engine.

The 96 Concorde I have gets about 27mpg hwy and I pretty much want to shatter that with the Accord.

[nighthawk]

lower it, put a big lip on it.

if it needs new tires go a little more narrow than stock.

alloy wheels if it doesn't have em.

[bcjammerx]

If you really want a crazy (10mpg+) increase, install a full MSD ignition and Blaster Coil on your car. My friend's CB9 went from averaging about 23 mpg to 35+ after the install. Plus your car runs WAY better and burns the fuel cleaner for the environment. He said it was some of the best $300 he ever spent.

I'm doing mine after I buy my bike. Currently saving up for a down payment...

I don't see how this would do anything. On a stock engine?

lower it, put a big lip on it.

if it needs new tires go a little more narrow than stock.

alloy wheels if it doesn't have em.

the stock tires are damn narrow as it is. This WOULD help but not worth the loss of traction.

[JesterMasque]

I don't see how this would do anything. On a stock engine?

The motor overall runs more efficiently which makes it burn less fuel and also gives you increased performance with less depression of the gas, which burns less fuel. What would make this possible is how the MSD sparks three times for every stroke, as opposed to the stock, weak single spark.

This, of course, is my understanding on "how" it would produce such results. But it was definitely the ignition that made this possible... unless is was his oil change he did the same day =P

Another great way to watch your MPG is to make sure your fuel filter is clean. When I changed mine after I bought the car it looked like burnt, sludgy coffee coming out of that filter. Immediately I ran a fuel system cleaner through my motor on a full tank of V-Power and my MPG went from 17 back up to the normal 27-30 (highway).

Forgot to mention, yeah, stock motor for my friend.

[d112crzy]

If you saw that much improvement with an MSD setup is because your stock setup was on it's way out or just in bad conidition.

The most gas mileage will come from tuning. Most h22's I tune all get over 400 to a tank in the city.

[JesterMasque]

It probably was... It had about 200k on it.

Then he put an H22 in and called it a day though.

[K2e2vin]

Just a FYI the MSD system and similar capacitive systems have multiple sparks at lower RPM's because they can not hold a longer spark duration.

[skilzz]

custom 5th gear. done and done

[K2e2vin]

A taller 5th does not always mean better MPG. If I'm sitting at a lower RPM but have to give it more gas to maintain cruise speed; chances are my MPG is going to lower. I live around a lot of hills so it seems more beneficial to just keep my 5th gear stock.

BTW, the 57mpg I got in my Civic was revving around 3700-4000RPM(about 65-70mph, DOHC ZC transmission with 4.25 Si final drive).

Right now I'm just doing a typical tune-up(plugs, wires, cap/rotor, fuel filter, valve lash, clean TB, new MTF fluid and oil/filter/air filter; pcv and belts were already changed). I have some TL1000R/GSXR750 injectors laying around that I may throw in there and see if they'll help. They're 4-hole Denso injectors that flow about 225cc@3bar.

[wed3k]

that sounds about right, 28mpg. i warm the car up int he morning and commute to work via streets.

i run slightly wider tires, 205 but i try and keep my tire psi maintained. run 87 octane