Improving my gas Mileage

[NickF]

When I first started driving my car in November, my gas mileage was absolutely ****. I drive almost entirely in city miles, so take this into consideration. I drive a '93 Buick riviera with 68,000 on its GM 3800 L27 engine (3.8L V6).
Averaging around ~11MPG on 87 octane fuel, I felt like i was driving a ****ing truck. it was time for a tune, I put in a K&N air filter, Castrol Syntec oil 10W30, and an ACDelco filter (yeah that generic one **** :P), new fuel filter (napa im pretty sure), and used SeaFoam fuel injector cleaner (its a solvent that breaks down carbon build up) and finally rotated my tires.
After my tune-up i got myself up to ~19MPG, I was pretty happy and forgot about it for a while.
After putting ~4,000 miles it was time to change my oil and do a tune again, not to mention the further climbing of gas prices ($4.15 for regular in CT). This time I put Mobil 1 Extended Performance (they say its good for 15,000 miles, but I'll chnage it after about 5,000) and added a quart of Lucas Full Synthetic Oil stabilizer and a Purolator PureOne filter. You may also want to look into the more expensive Mobil 1 filter, costing 2 or 3 times as mucg as the PureOne, but filtering on par with it while being slightly less restrictive. This change brought my oil pressure up 2 notches on my digital on-dash oil pressure monitor. Next I decided to fill my tank up with 93 octane fuel, Lucas Fuel Treatment, and Lucas Octane booster (yes, the Octane booster was overkill, and yes I've began to love this company, here's a reivew. I'm going to use there oil for my next change ) I've been doing this for 3 weeks now, averaging around ~24MPG! This is not to mention a noticeable difference in res response.

Soon I will be redoing my exhaust, putting on a Flowmaster 80-series muffler (yeah, my muffler is crossflow), I don't have room for dual exaust from the headers down under my car, but i do expect the less restrictive muffler and dual tailpipes to bring up my fuel economy another notch, I'll post some results.

Products mentioned:
Lucas Octane Booster 15 oz.
Lucas Synthetic Heavy Duty Oil Stabilizer 1 Qt.
Lucas Upper Cylinder Lubricant and Fuel Injector Cleaner (1 Quart)
Lucas 10W30 Synthetic Racing Oil
Mobil 1 Extended Performance Motor Oil
Purolator - Pure Oil Now. Pure Oil Later.

[Jakor]

ditch the cat if you can (high flow/straight pipe). It's too bad you replaced your filter with the $50 k&n one already, the cone filter woulda helped better, then you could try it in different places trying to get the best mileage for the power air (cold air is more dense and will cause more fuel to be required) also don't forget your o2 sensors. Better spark plugs (cap/rotor if you have them) lighter smaller tires for around town. lighter bigger tires for highway(just make sure to compensate when you look at your speedometer smaller means you can speed a tiny bit, bigger means you must slow down some) either way make sure the rim is lighter. Better flowing exhaust manifold / header wrap (keeping the heat in the header or down the pipe keeps air flow speed higher thus less restriction. also when changing your fluids don't for get your differential. If you don't use a/c remove the v-belt (or bypass with a serpentine belt) same with smog pump (if you can ditch your cat) for non big trucks, ditch the power steering (trust me in 2 weeks *exact with my wife and her 280* you will have built the muscles to not notice it being gone) or other un needed belts. Switch from a clutch fan to an e-fan if you don't already have one.
also
lightened flywheel/flexplate
you could get a carbon fiber or even aluminum driveshaft
lighter hood (aluminum / carbon fiber)



lucas products are the best! Also change your fuel filter again soon. The FI cleaner will knock all the grime into it and plug your new one up since you didn't run it through a tank or two first then change the filter.

[John]

You should also buy a new fuel regulator chip. That should give you a few extra miles to the gallon.

[NickF]

Originally Posted by Jakor

ditch the cat if you can (high flow/straight pipe). It's too bad you replaced your filter with the $50 k&n one already, the cone filter woulda helped better, then you could try it in different places trying to get the best mileage for the power air (cold air is more dense and will cause more fuel to be required) also don't forget your o2 sensors. Better spark plugs (cap/rotor if you have them) lighter smaller tires for around town. lighter bigger tires for highway(just make sure to compensate when you look at your speedometer smaller means you can speed a tiny bit, bigger means you must slow down some) either way make sure the rim is lighter. Better flowing exhaust manifold / header wrap (keeping the heat in the header or down the pipe keeps air flow speed higher thus less restriction. also when changing your fluids don't for get your differential. If you don't use a/c remove the v-belt (or bypass with a serpentine belt) same with smog pump (if you can ditch your cat) for non big trucks, ditch the power steering (trust me in 2 weeks *exact with my wife and her 280* you will have built the muscles to not notice it being gone) or other un needed belts. Switch from a clutch fan to an e-fan if you don't already have one.
also
lightened flywheel/flexplate
you could get a carbon fiber or even aluminum driveshaft
lighter hood (aluminum / carbon fiber)



lucas products are the best! Also change your fuel filter again soon. The FI cleaner will knock all the grime into it and plug your new one up since you didn't run it through a tank or two first then change the filter.

I know a cone filter would have probably been better, but if I was to go to the trouble of ripping out the old intake system, I would have just installed a CAI. I've yet to look for one, but I would like to get a few ponies more out of my baby eventually. I did actually do my plugs, i put these in it, just forgot to list it. I didn't touch my o2 sensors but my father might have, I'll have to ask him. What would I have to swap in if I haven't? As per your exhaust recommendation, i might just wait and save up to do the whole system, rather than just replace the muffler. I'll have to see what goes on with money. I'm not disconnecting my A/C or power steering, lol. I'm also changing my ATF fluid and filter when i get around to it, probably using Lucas fluid

EDIT: wiould this fit on my car:
Chevrolet Camaro Cold Air Intake - AutoPartsWarehouse.com

[Jakor]

I havn't looked at your car specifically I just wrote the things that were on the top of my head for gas mileage. For the exhaust, you have to keep enough backpressure to close your exhaust valves. (unless turbo or rotary or performance exhaust valve springs) So you will want to match the diameter of the exhaust pipe to the power you are making ect. If you go too big there will be not enough backpressure. If you go too small there will be too much restriction and you will be fighting the engine and make less mileage and power. You can even go through the trouble of getting the right length for the exhaust. But most likely, keeping the stock size/length is probably enough when you make it straight through. You can punch the cat or replace it with the same length pipe the size of the rest of your exhaust. Headers are meant to flow better and keep equal lengths on all the cylinders exhausts (this is kind of important so your exhaust isn't fighting itself.

The downside of doing the exhaust work is you will make more noise, but as long as the pipe is the stock size/length and doesn't have anything blocking/restricting it, you will make a bit more power and mileage.

Theoretical world:
Say you have an engine rated at 100 hp running at 100% efficiency (this will never happen but just watch). You now spend 10hp looking for air to pump through (the intake). You spend another 10hp looking where to vent the air after it's been pumped (the exhaust). You also spend another 30hp turning every accessory run by a belt. You spend 20hp moving the weight of the vehicle. And lastly you spend 30hp turning the output shaft. Now lets say you make it easier to find air through a cone filter. You free up 5 hp that way. Again with the exhaust another 5. 5 again with an underdrive pulley. 10hp through weight reduction. All we did was make less work for the engine and it functions better (25hp more). Although the numbers are theoretical the idea is the same.