Performance upgrades that don't lower fuel efficiency

Hi. Good gas mileage is important to me, but I'd like know if there are some ways to boost the performance of a car without harming the fuel efficiency. Does anybody have some suggestions?

Anything that gets more power, or better handling, without significantly decreasing gas mileage.

Thanks.

2 words.

Weight reduction.

Faster acceleration and braking, better handling, and better gas mileage.

2 words.

Weight reduction.

Faster acceleration and braking, better handling, and better gas mileage.

That sounds great. What are some of the best ways to reduce weight? What would you suggest for say, a 1994 Honda Civic?

Take out things you don't need. Spare tire, jack, rear seats, carpet, AC, radio, speakers, lighter rims, etc.

Yep. Rip apart your interior and look for any sound deadening material. Get rid of it.

also in terms of the engine, there's intake, echaust, all their components so, cold air intke, heads (or port and polish your current ones), valves, headers, nigh flow cat (or no cat but i think the environment's screwed up enough as it is), cat back system, port and polish exhaust side of heads. all this will get you beter fuel efficiency if you don't floor it and drive with gas mileage in mind, in other words, accelerate slow, shift early, don't speed. shifting early is just a rule of thumb, there's a specific spot where you'll get the best efficiency but you need some graphs of some sort from the manufacturer, then you need to understand them, but for a rule of thumb, the lower your rpms the better your mileage.

i assume you dont mean handling by "performance" but if I wanted to make a car like a civic more fun to drive without hurting gass mileage i would install:

lighter/stronger clutch

lighter flywheel

16 or 15 inch wheels but kinda wide maybe 7 or 8 inches and make usre they are light (starting to see a patter?)

suspension parts, all of them, bushings, sways, springs, shocks, anything to stiffen the ride while maintaining good geometry

take off everything you dont need, seats, carpet, plastic, lighter exhaust

in case you were wondering,the pattern is LIGHTWEIGHT

The best way to drive for fuel effeciency is to accelerate at 80% throttle, staying in the highest gear possible, and when you get up to speed, mantain it. When do you have to slow down, engine brake with the lower gears.

Yeah, anything related to opening up your intake and exhaust (letting your engine breathe better) will result in more hp, and better gas mileage if you don't race it around .

As far as weight reduction, yes it's free to rip stuff out, but it also reduces ride quality if your car is a daily driver. My suggestion is to replace some parts with lightweight aftermarket parts. For instance, a carbon fiber hood can weigh 30-50lbs lighter than a stock steel hood.

Also, if you want to get more power and shave weight, focus on rotational mass. Anything that the engine must spin, that you can lighten up, will reduce rotational mass, causing you to both lose weight AND free up lost hp used to spin the extra weight. For instance, a carbon fiber or aluminum driveshaft, lightweight rims, lightweight flywheel. All of these can help in both departments.

a turbocharger will decrease gas mileage but if you don't use it it won't be by much. that's the great thing about turbos they only work when you want them to. the decrease in gas mileage is from the backpressure from the turbine.

i thought turbos had better mileage in that they make up for the lost back pressure in the way they compress the intake air. the main thing for mileage is to be the most efficient engine possible. a lot of energy from the fuel burning is lost through heat and friction. too bad we havent come up with a way to use heat as propulsion lol.

also, i would do the early shifting thing although dont drop the rpms too low or you will mess up the engine because it is harder on an engine to be revving low and pushing hard than it is to be revving higher and not having to push as hard.

its the same concept as on a bicycle, you dont go riding around in as low a gear as possible or youll mess up your knees and it is a lot harder to keep your speed up. a higher rate of pedaling is easier on your knees, and it is exactly the same concept with cars.

also, i heard that using the lowest octane you can without pinging is the best fuel for mileage purposes...

that is true, although it's not significant. turbochargers make more power but they reduce fuel economy because it only really makes boost when you floor it, so if you're driving for fuel economy, the turbo on't be making much power if any. there's a thread in the fuel economy section of the light trucks forum that talks about acetone helping fuel economy, check it out.

so would a supercharger be better for mileage purposes since it is belt driven and wont rely on high exhaust flow?

so would a supercharger be better for mileage purposes since it is belt driven and wont rely on high exhaust flow?

Nope. Same deal. The belt driven charger puts a load on the engine to turn the impellers. This is lost energy. No free lunches. :smile:

Jim
SR Racing Inc.

simple, never offer a ride, rip out all seats bar the drivers one less people-weight less fuel consumption

The best way to drive for fuel effeciency is to accelerate at 80% throttle, staying in the highest gear possible...I know this isn't completely true all the time. I can always ride with my car in 5th gear... but it's not a good idea. I think it's typical to keep things inbetween 2000-4500rpm.

How much the throttle's open also really doesn't seem to matter much of anything with my car either, but I have 17" low pro rims on a Corolla. It's pretty crazy that no matter how much I drive in city vs hwy and how fast on the interstate I drive 70 to 95mph... I consistently get 26mpg with these rims.

The only way I can get better than 26mpg ever is if I know where I'm going, haul ass and cut the car off way before I see a stop sign or a light that I'm familiar with it's timing or a long 2-lane road with a 90deg turn. Once I've gotten to the line or rounded the turn, I pop it in third and drop the clutch in to place so no damage is done to my starter. By doing this I've gotten ~31mpg, my only variation from the number 26.

and when you get up to speed, mantain it. When do you have to slow down, engine brake with the lower gears.This was the meat of my digging up this ancient thread: How is engine braking good for fuel economy, I don't get it? I just use my brakes, and (as previously mentioned) I turn my engine off when I'm slowing down because it's fuel injected and doesn't benefit from even idling in my experience, much less more strain. Is there really more strain on engine by engine braking, tho? I dunno... I guess more gas being sucked out, no, but more strain on the engine, yes.

No... when an EFI engine is braking (when your foot is off the gas but still above idle) it injects zero fuel. When your foot is off the gas, the computer will inject enough fuel to maintain idle... which, if the engine is being spun faster, means it needs to inject no fuel.

If you push in the clutch or put it in neutral, it returns to idle where it begins injecting fuel again.