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Improve economy/performance - Intake, exhaust, coil?

4997 Views 47 Replies 15 Participants Last post by  Dragonis
I want to improve the performance and ecomony of my 01 Elatra. I was wondering how well does a aftermarket cold air intake work on the Elantra? I noticed some cars get worse economy with that mod and some get better. I'm also thinking of a cat back/pully, coil. Just wondering what mods you have and how did the ecomony/performance change.
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My CAI delivered better economy, but because I liked the way it sounded I had my foot to the floor constantly.
I took it off and replaced it with just the airbox, I didn't put the resonator back in.
I suggest you take that off first, it's only 2 bolts and some tubes but it's buried in the front fender. I even have the stock triangle shaped tube going to the hole in the fenderwell next to the battery, so (hopefully) it's still pulling in cooler air. It sound's different, too.
If you're looking for economy with this car, the pulley will make a little difference, but I'd go with a lightened flywheel.
The stock exhaust is great for economy because it has a valve in the muffler that directs the flow through a chamber under 4k rpms for backpressure, and lets it go in a straighter path over 4k rpms.
Taking out the resonator is free, and would also free up about 15 pounds.
I can't see a lighened flywheel doing anything. I'm more interested in mods that will pay off in a long run.
But yes it will.. Think about this, the less weight an engine has to turn, the easier and less work it has to do. This automatically adds to horsepower, and fuel economy. Just like getting pulleys. ;):

Its why people buy light weight wheels, they are easier to turn.
One problem, the extra rpm needed to launch the car for daily driving. RPMs hurt mileage. Also if he lives in a hilly area it will take more to go up them with the light flywheel. Maybe on flat highway. I saw nice highway gains from my UDP, but its underdriving everything.

[body]The stock exhaust is great for economy because it has a valve in the muffler that directs the flow through a chamber under 4k rpms for backpressure, and lets it go in a straighter path over 4k rpms.[/body]
Im going to strongly disagree with this one. Yes it has a valve but its not doing all that great a job of producing torque. Maybe it was the huge resonator I pulled but my exhaust or the fact I went with a "turbo" muffler instead of a fat can but it netted a nice gain in city mileage with a Very noticeable increase in low end punch. Either way when I got rid of that stock muffler and resonator my in city mileage went up 2-3mpg with my driving style. Nothing noticeable on the highway.

I noticed no gains with the CAI in mileage.. nothing noticeable anyway.

Best mods to do IMO for mileage. Exhaust (like mine), UDP, check tire pressure weekly, change plugs before they are "suppose" to be bad, get a lifetime alignment deal/get it checked out alot, change all filters when they need it, and run fuel injector cleaner from time to time (or run top teir fuel alot... close to the same thing. Point to keep the injectors clean) Then if you really want good mileage drive better. :ermm:

I try to stick to that and went from an avg. of 24-25city/31 highway to..

27ish city/33-34 highway. Of course that changes because of weather, my right foot, etc…

Two ways Ive seen that work. Drive like there is an egg under your foot or...

something i read about recently

Drove at near WOT but short shift (no big rpms or this doesn't work). This reduces pumping losses and makes the motor more efficient. The problem with that is if your an auto or if you live in a big city. Kinda hard to do that. The toyota prius's motor does that for you btw. Also I have to wonder about transmission heat issues with the WOT lugging thing.. that seems like it would/could produce some extra heat in stop and go. :ermm:
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Originally posted by zorro19s
I can't see a lighened flywheel doing anything. I'm more interested in mods that will pay off in a long run.
i know from experience that a lightweight flywheel helps mileage tremendously. i went from getting about 26mpg highway in my beta accent to 31mpg after installing my fidanza flywheel... although i also threw out a fried clutch and installed an underdrive pulley at the same time.
i can say from personal experiance after installing a fidenza flysheel and racing cluctch it did take some time to get use to, but now i can launch just like when the car was stock, in traffic 1600-1800rmp no prob, no bogging. and the car does drive a million times better with it. before doing anything big to my car i was getting around 550-75km per tank of gas (full to empty 48L) after both i'm now getting 620-650km per tank even with very very spirited driving and same week autocross!:)

i love it and woulnt' give it up.
Dont have one and never had, so I guess I was wrong on that one (as far as in city, I could see the gains on the highway as I said in my last post). I do know that fixing a slipping clutch will help milage alot. Also I KNOW the UDP helps highway alot, esp when running the a/c. :ermm:
I don't know but on the highway the ligher flywheel will have absolutely no impact on economy. In stop and go traffic it might. But once engine is at constant RPM weight has no impact since it has no impact of parasitic drag. So a CAI has no affect, exhaust has no affect, I guess a pulley will be the only thing that might.
Get your underdrive pulley, get some good spark plugs, good plug wires, and always Get your regular oil change and Transmission fluid change

If you want to see a little extra improvement, toss in a CAI i dont know who would have told you that there is no improvement in gas mileage with a CAI, I made a 550mi trip in my Accent (On a bout 11 Gallons of gas) You do the math

If you keep up on your maintenance, your car will reward you this is the only advice i have
My car gets good milage but I want to see if theres anything else to be squeezed out of it. I get 780km per tank 85% hwy.
Cat delete=yes

I figured id spell it out for you.. they ALL will increase milage and performance. Mostly its in the driver. I pulled 35 mpg in my 10 year old car when i went to the car meet. I drag raced, burnedout, did donuts, and did servral 100+ mph stints. And still.. 35 mpg.
you seem pretty hard headed. we aren't making this stuff up. on the highway is where these mods make the MOST difference. not city.

how can you say that a lighter flywheel won't help but an underdrive pulley will? the purpose is almost the same (i konw the pulley turns stuff slower but the lightweight part) and the flywheel is about 9lbs lighter than the stock flywheel and the pulley is 3-4lbs lighter i think.

the constant RPM thing doesn't matter. its the fact that less of the engines power is wasted turning the heavy stock flywheel and pulley. just like if you went running 2 days in a row same constant speed but the second day you run with 50lbs on your back. your gonna be a helluva lot more tired on day 2.

[Edited by ryanolson on Jul 11, 2006 12:01 PM]
Getting a lightweight flywheel is like turning your ac off instead of on. get the picture?
An electric water pump is another possible option, as it cuts down the number of ancilliary devices that are run off the crank.
To accelerate a heavier flywheel will use more power but at constant RPM the flywheel hardly any power no matter the weight. I'm more interested in getting better highway miles as thats 85% of my driving so a ligher flywheel will not impact my economy. And regarding other mods its different from car to car, as my friend with a 240Z put a CAI and cat back and his economy dropped disgnificantly. I'm just trying to figure out how does hyundai react to mods.
It seems that it dosent matter what we say. So just go do your own thing then. Nobody can tell you different.


Can you read it now? Seriously guy.. most of us are experts here. You have to be purdy ****ing stpuid to not listen to them..
Like I said I I'm interested in Hwy Economy on a constant speed. A lighweight flywheel woun't do me any good in that situation when there is no engine acceleration, thats basic physics. A 50lbs flywheel will have the same parasitic drag as a 20lb flywheel period. The only place where it help is in stop and go traffic. A engine pulley change will help cause it will decrease parasitic drag so that will help both city and hwy economy.
dude... stop being so fvckin hardheaded.. a lightweight flywheel will give you better hwy mileage. your physics are wrong. we are telling you from fvckin experience.

how can you think an lightweight crank pulley will help but a lightweight flywheel wont?
OK, explain to me how a highter flywheel will increase highway economy you dumba$$.
First an aftermarket pully is smaller and decreses the rotation speed of all other units running on those belts. You loose some power steering input, AC etc since less energy is used to run them therefor freeing up power for kinetic use. 5 years of mechanical engineering biach!
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