Best mods for enhanced fuel economy?

[Alex37211]

I'm not talking about hydrogen conversion or anything.
Do the cai's work?
High flow exhaust?

Anything out there below $300 that works?

[drdisque]

if you want better fuel economy the most important thing is to modify yourself. In the 70's a lot of people got vacuum gauges to keep an eye on how much load they were putting on their engine and thus how much fuel they were burning.

[Alex37211]

So how about the high-flow intakes and cats? Do they effect fuel economy? It's dyno tested that they add horsepower, so doesn't that mean they'd get better mpg at the same speeds?

[beef_bourito]

if you make your engine work more efficiently you'll get more mpg. free flowing intake and exhaust work well. the problem with these mods is that you have to modify your driving style when you upgrade because you'll have more power so you need to learn to use less throttle at the same time.

but i agree, the best thing to do will be to change your driving habbits to use less gas. the upgrades will help but you'll be spending money on them and i doubt you'lll make it back with the fuel you save.

I don't think a cat back will do much without modifying the rest of the exhaust. headers will help, high flow cat will help, after those, a cat might help. intake will help but i dont think a bigger throttle body will, it'll let more air past. increased compression, better ignitioni might help. anything that isn't rinnung right will hurt performance and mileage. using a synthetic oil will help, i've seen some people get alot more and others get about the same mileage. and taking out any weight from your car will allow you to use less gas.

[PlayStation3]

i heard on ngk website that there plugs suppsuple help save gas.

[cody_e]

Well how old of a car are you driving? I mean if it's older you could probably replace the O2 sensors and get a little better gas mileage. I think O2 sensors go for about $70 a piece. Then you can buy a K&N filter which should increase your mileage by 1 or 2 mpg. I think they go for about $40. The sparks plugs will help. The more effeciently you burn fuel the better gas mileage you're going to get. I heard synthetics will help. I tried synthetic oil and really didn't see any increase. I heard synthetic tranny fluid also helps.

The main thing is to take it easy and not gas on it everywhere. Slower acceleration always helps. If anything carpool with some friends. It doesn't save gas on the car but it saves gas overall and that's a few less people driving.

[kcg795]

I plan on ditching my belt driven clutch fan and going with electric. My clutch fan usually doesn't engage unless it's over 85 degrees outside. But when it does, it sucks a lot of power. I imagine it kills the mileage too. It would be a lot easier for the engine to drive the alternator to power a pair of 10" fans than it would to power one big belt driven fan. What amazes me is that a lot of older cars had a fan that didn't even have a thermostatic clutch. It was directly connected to the pulley. Man, what a waste.

[bluevp00]

Walking shoes and/or a bicycle both get good gas mileage.

But doing a basic tune up helps a lot. Like stated earlier, change the O2 sensors if they are old, new plugs, wires, and fuel filter helps a lot. Also, don't forget about the fluids in your engine: be sure the coolant, oil, and transmission fluid are all recently new, these help reduce friction (oil & trans) which lead to less stress on the engine. If your car isn't too old, then you might want to consider switching to synthetic or synthetic blend oil when you change your oil.

[kcg795]

Amen on the synthetic. My engine was rebuilt about 20,000 miles ago and I'm running Mobil 1. I'm also going to switch the rear end to synthetic. My transmission has 215,000 original miles and still going strong with a new torque converter installed when the engine was rebuilt. I may go with synthetic in that eventually. My power steering pump also uses transmission fluid. I just might switch to synthetic in that too. Anything to reduce friction. I also did a tune up a while back and made the mistake of using Bosch plugs. The AutoLite plug wires are pretty cheap too. So I'm gonna get the NGK plugs that are specified in my manual and get a set of NGK plug wires. I'll try the K&N filter thing to see what the fuss is about. Right now, I get around 23 MPG. My highest about a week ago was 27. I'd like to see 30 someday. I'm driving an 84 Toyota Van and it's amazing how good the mileage is for a cracker box on wheels.

[Alex37211]

In response to the earlier question... I'm driving a 95 Civic hatchback 1.5 with 145k mi.
And it's not like I get bad gas milage, I just want better. I DO drive efficiently. No quick take offs ect.. I get around 40 mpg. I'm using NGK spark plugs. They aren't anything special, they were $2 each at autozone. Are you guys talking about some fancy ones? Or are there just these kind?
And about the synthetics, I'd be spending more money on oil than I'd be saving in gas. And don't tell me I only have to change it every 10 or 15 thousand miles. That's just nonsense, I've done a lot of research through other forum strings about synthetics. Look them up before you try to dispute this.

[Alex37211]

Oh yeah and it's a 5-speed so advice about transmission fluid won't help much.

[kcg795]

Yeah, the 10,000-15,000 mile drain interval on synthetic is just bullshit. Some oils can guarantee protection up to that many miles. But that doesn't mean you can go that high all the time. I'd still change every 3,000 miles, but it wouldn't hurt if you're overdue a couple thousand miles because you haven't had the time or the money to change your oil.

The NGK sparkplugs my manual specifies to use are $6.99 each.

[cody_e]

No you can run synthetics longer than 3k. Changing at 3k is kind of a waste because of price. You have to watch the oil quality and make sure it doesn't get dirty. My car leaks a little oil so I found out synthetic isn't that great because it leaks way faster.

[bluevp00]

Originally Posted by Alex37211

Oh yeah and it's a 5-speed so advice about transmission fluid won't help much.

Manuals still use MTF, which does require changing over time. MTF lasts longer than automatic trans fluid though.

[Alex37211]

After how many miles should the fluid be changed on a manual tranny? And isn't it just gear oil? Could I use that lucas stuff? My civic has 145k mi. on it.