BlizagaXx

Alright. I've posted this before, no one really gives me many ideas or help, so please help, say anything, please. lol

I guess this would be the appropriate place to put this, so here goes.

I drive a 1998 Tiburon Beta 1 2.0l 5 speed manual tib with 93k miles on it. Weather I drive it like I stole it, or drive like a grandma, I get roughly the same mileage. There is about a 25mile difference. Racecar driver = 225, Senior Driver =275. My mileage has not changed at all since I've put any of my mods on, nor has it changed through maintenance. Unnoticeably anyways...

I have these mods on the performance end.
- AEM CAI
- OBX 4-2-1 Headers
- 2.5" Full exhaust, high flow cat, OBX fart can, over axle.
- 1.8l intake cam
- 1.8l ECU (The best one to boot)
- ARK short Throw Shifter
- Factory Tuned Strut Bar
- 18lb 17" Enkei Evo 6 Rims with Cooper Zeon W rated 17x205x45 tires

Basic Maintenance Done and up to date
- Seafoamed my engine and my gas tank.
- Splitfire Triple Platinum plugs, less than 1k miles. I also have bosh platinum 2s in the garage
- Duralast Wires with about 2k miles on them
- PCV valve, 3k miles
- Fuel filter, 3k miles
- AEM dryflow filter, I am cleaning it this week
- Unleaded, midgrade, premium fuel, I never see a difference.
- Properly inflated tires
- Belts have 5k on them
- Brand new battery as of 2 weeks ago
- Mobil 1 5w30 synthetic oil, changed every 3k miles religiously


Basically all that is left is injectors, or fuel rail. I think maybe my O2 sensors are shittay as well, so I am going to replace those anyways. Can't hurt, right? I will be doing a compression test and changing my plugs to Denso iridium tomorrow. Other than that, I've gone above and beyond basic maintenance...

Why is my fuel economy so shitty?

Korean_Redneck

To be honest, I think it has to do with the driver's behavior from whoever had it first to do the break-in period. I heard that will determine the car's future mileage.

Hive

Well if I calculated correctly that would be 362 km (racecar) and 442 km (senior). Well when I was N/A I had quite a few mods plus shaved head and port and polished internals and I've got like 550 km (342 miles) with senior drive and roughly 430 km (267 miles) when pushing. Now with a turbo on I get 230 miles of boost and who knows how much less when in boost. Mind you, my car is at the moment of tune and I need to take it to lower gas injection as I am running reach and burning oil at the same time.

DTN

Plugs? Wires? All your performance parts make your car burn more gas. That's how we make power. The only way you can save gas from performance parts is to go Carbon Fiber everything. Lighter weight = less gas, engine performance parts = more gas.

radu_rd2

I think that mods that allow the engine to breathe easily (CAI, headers, exhaust) should increase your gas mileage when driving like a grandma. Of course at WOT you'll use more gas than before, since you have more power, but when you're cruising or taking it slow it def shouldn't use more gas than it did before..

supercow

275 seems about right for lots of stop and go traffic, even when granny driving. Really though the important thing is not how many miles you got but how much gas it took to fill it up after that many miles. If you stop right when it gets to e your might be putting in only 9 gallons. which is 30.5 mpg, which is pretty good!

after you fill up reset the trip. Then when you fill up write down gallons and mileage. Then divide miles/gallons. Turbo'd I get low 20's in town and the regular 29-31 highway.

edit: btw, n/a performance mods, when not used, increase fuel economy. After headers and intake n/a I gained a couple mpg highway.

fresh97

This is blizaga, im with fresh and this is just easier...


I do ALL stop and go, and i drive it like i stole it. I think the 02 sensors are effed up, but whatever. I fill up a full 12-13 gallons most of the time. Which means I'm getting like... 19ish. Shit.

tdonnell

Yeah, something is up,

I drive the exact same car as you with many more mods and I get 26.5 when I beat it. If I drive like a grandpa and shift at 3k all the time I could easily get over 30, probably 425-450 miles on 13 gallons.

If you are going to replace your o2 sensors, the front one is the one that controls your a/f, the one after the cat is only for emissions readings. But if you don't have a code for an o2 sensor problem, then they are probably operating fine, do you have a CEL?

Check and make sure your brakes are not dragging and all of your wheel bearings are in good shape. Has it always gotten this poor fuel mileage? Does it smoke at all?

funkypc

ya, I get way better fuel economy then you. The 1.8 ecu boosted my fuel milleage probably 3-5mpg. I get over 30 mpg. (thats all hwy miles though - city is usually less)
Check to make sure your wheels all turn nicely. Does the car pull funny to one side or the other? A wheel alignment could be in order as well - to much toe-in (or out for that matter) will affect your fuel milleage.

HyundaiKitCoupe

dtn's got it right. every try taking your trunk lifters off? yep, good luck trying not to get your fingers smashed. that hatch weighs half the car right there. if we had fiberglass/carbon fiber hatches our cars would act like GTO's.

as for safety, i'd rather have the half ton metal hatch.

far as your fuel economy goes, yeah i'd say spend some ca$h and get all those sensors and filters replaced.