I have a 95 non vtec automatic 4cyl accord. 32 mpg. I used to get 450-500 miles per tank and the best was 35.46 mpg 540 miles using only 14.1 gallons going through the mountains from Utah through Montana. This was with stock wheels and tires.

Now have 18" 2010 accord wheels 5 lug swap. Header, k&n filter in oe box. I do have a exhaust leak that I need to fix that isn't that bad but 3 out of the 4 bottom manifold/header bolts broke inside the head. That I need to try and drill out and replace. Car seems to be running the same and no check engine lights.

But now all of the sudden Im lucky to get 25 mpg 350 miles to 14 gallons. Would/can and exhaust leak between the head and header make this much of a difference?

Is there a better engine to swap in to get better mpg. f22b1 vtec or f20b.
I don't want to get rid of my accord. Just want my good mpg back.

 

If you have a exhaust leak before your o2 sensor I would think it messes with a/f and it would run lean or rich.
Also bigger heavier wheels, heavier suspension and bolt ons is not working in your favor.

 

So main problem, get exhaust leak fixed then see how it goes after that?

 

thats how i would start. the bigger and heavier wheels will also reduce mileage from weight and worse gearing.


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When you switched to 5-lugs, I am guessing that you changed some suspension parts, like maybe the front knuckles and such. Did you have it aligned afterwards? Did you put on wider tires? All that could have an effect. But I gotta say that mileage in the 30's is a lot better than I ever did with my '94 VTEC.

 

From my perspective, the wheels and tires, the header, the K&N; all of it, they all can lead to a reduction in fuel economy.

 

A drop in K&N panel filter wouldn't bother it all that much. I agree that the larger wheels and tires + exhaust leak would be your suspects. Exhaust being the prime!

Also the usual basic maintenance stuff,
Plugs
Wires
Cap
Rotor
Coil
Air filter (done) and
fuel filter

As far as an engine swap goes;
The F22B1 is a slight gain in the MPG but IMO not worth the time and effort to swap. The F22B2 is a pretty good engine for fuel economy. Keep up the basic maintenance and keep your foot off the floor and you would be able to see 32-34 MPG HWY consistently. I was getting 30-33MPG mixed driving with 255cc injectors, ported intake and throttle body, a CAI, header and chipped OBD1 ECU (tuned myself) on my 96 F22B2.

 

Cap, plugs, wires only 4k miles on them, Fuel filter 15k miles. K & N panel filter in.
Yes I align my car myself. With camber front and rear set at 0.0 degrees front and rear for best tire wear and least rolling resistence. 215/40/18 tires.

 

Lest rolling resistance vs stock specs.

Camber
Front = 0°
Rear = 30°

Caster = 3°

 

I still would get 30-31 mpg with my heavy rims and 225/40/18s

Get the exhaust fixed and judging mileage by how many miles you got on a tank is wrong and worthless. You need to figure out ACTUAL mpg.

 

this

 

You could get actual MPG if you divide your gallons per tank into the total miles/tank that you get. Or you can fill up your tank, drive 100miles and fill your tank back up. Divide the amount of fuel required to fill the tank back up into 100 and that would be your MPG. Same thing really.

I used to get 750 km/tank and fill up with 55 liters consistently. That's 13.6Km/L or 32MPG.

 

Not really, different pumps click off at different points, in fact, even the same pump can click off at a different point if the pressures fluctuate a bit (as most do). Filling, and then driving only 100 miles and then filling again can lead to a HUGE calculation variance. A full tank is better, and several tanks averaged together is even better.

 

I am going off of filling the tank. I fill the tank every time I go to the gas station. Right now I am almost to the empty line, but it goes past that before the low fuel light comes on. I am only at 320 miles on this tank. At this point it used to be at around 430 miles.
I will get the 3 exhaust/head bolts replaced.

Has anyone had any good luck on drilling them out and replacing without damaging the head?

Should I loose the header and go back to a stock manifold. I always thought a header would help mpg? NO?

 

Bigger wheels( i'm assuming they are bigger than stock) causes less miles driven than actually driven since the speedometer is calibrated for smaller wheels. This causes your odometer to show less miles than actually driven and your trip meter is less. This will show like your getting less miles per gallon.

 

Typically a header in-and-of-itself cannot improve fuel economy. Why? Because the job of a header is to aid in cylinder scavenging at high RPM engine operations; not exactly the type of operations one typically employs in day-to-day driving when fuel economy is important. So, at best, headers can only achieve the same fuel economy as the factory manifold.

And at worst?

At worst, depending upon the valve timing of the engine in question, there is typically a certain duration when both the intake and exhaust valves are open at the same time (called "valve overlap"), and when the pressure and flow characteristics in the exhaust system is changed from what the engine designers specified for said engine, fresh/unburned air and fuel can flow through beyond the exhaust valve. When this happens, instant lower fuel economy.

 

Thank you, I will get the exhaust leak fixed and run a couple of tanks to see if it gets any better. If not I will find another stock, oe manifold.

 

Faulty emission o2 sensor.
Clogged throttle body.
Clogged cat.
Clogged FITV.
Faulty fuel injector.
Lack of fuel to fuel rail
Lack of spark [spark plugs/wires/distributor cap]

Those could all contribute to lower then usual gas mileage.
Check all those, they are all pretty easy to identify if they are having problems.

 

Also vaccumm leaks can be another reason why MPG drops.