Hi all,

Just picked up a 5psd 92 DA for daily driving. The gas mileage is decent and I was wondering if anyone has ever had something like that ECU tuned for better fuel economy? What were the gains? What setup did you use? How much was the hardware? I average 30-32 on the freeway at 65-75mph, Trying to get it over 35 if possible....

I tried searching for it but I only found tuning threads about making power...

Thank You.

 

If you're doing it purely for fuel economy then you'll never recoup the costs. If you already have a setup for power then it makes sense to tune it for fuel economy since it wont interfere with your ability to make power.

Engines make power in the heavy load region of the calibration. Cruising on the freeway 2500-3800 is very low load. It only takes about 15hp for the car to maintain freeway speeds. You can lean out the fuel mixture on a Honda upwards of 16:1.

You'll need a wideband O2 sensor like the AEM and some kind of programmable engine management. I used an AEM EMS. On an OBD2 SOHC Civic engine I was able to lean the mixture out to about 18:1. The sensor will only read to 18:1. The hardest part is getting the ignition timing right to prevent misfiring. The engine isn't at risk because of the low load, so you don't have to worry.

The best way to go is to have it tuned on a load bearing dyno by someone who knows what they're doing and is willing to tune Hondas. Bisimoto is well known.

 

Unless you are ONLY driving freeway, I would not worry too much and be happy with your 30-32.

 

you can advance timing to at least 20*btdc safely on a stock b18a. that'll up your fuel efficiency and power slightly

 

I would do a stock tune up, [the right spark plugs properly gaped, fuel filter, valves adjusted, valve and ign. timing] use a good quality engine oil and tranny "fluid", have injectors cleaned, make sure you have the correct tires that have a proper wheel alignment and most important, proper tire inflation.

I agree with Scooooter7 30/32 MPG is pretty good, but with a good tune up you should see some improvement.

Try this, make sure tire pressure is correct, [as recommended] if it was not correct adjust it and see if it makes a noticeable diff. 94

 

Thank you everyone for your replies. I will do all everything listed for the tune-up and hopefully I see some gains, if not at least I will have caught up on the tune-up schedule for the car. Thanks again!