momointegra

Hey guys, so I did a Tune up on my (auto) 2000GS.
It shifts better but i feel like it runs more sluggish and I think im getting less MPG.. I get currently 300km/ tank.. Aprox $40. I went to MTL this weekend and moth trips only got me 400km/ tank on ALL HIGHWAY.. any comments?

momointegra

Someone told me cuz my rims are bigger LMAO! but honestly i got waaaaay more from my 3.0cl VTEC before it was totaled and i only spent about 10 more a tank..

Datenshi

iTrader: (3)

It is probably because your rims are big. It definitely ***** with your MPG considering your rims are 3" bigger then an Integra recommends. If your car is running mechanically fine.. and you said you just re-tuned it.. which I'm guessing means cleaned it out, checked whats going on in there and did some maintainence.. you should be getting closer to 400, atleast I was and my Teg was a 94 auto

XNXIXTXRXOX

My teg has 17's on it before and I didn't notice much fuel milage decrease... What do you mean by tune up? What did you do?

Neon_Dave

iTrader: (1)

It must be your rims. I remember I used to get maybe 400 or so if I was lucky with my 17's, but not all that much highway in that.

Now with my hammerheads and 205/50/15's I got 530 km last time I filled up and went for a highway trip.

MPR

The size of the rims doesn't have as much effect as the mass of the rims.

Super lightweight 17" rims may yield the same mpg as stock 15" rims. But heavy-*** 17" bling-bling rims will hurt mpg.

Datenshi

iTrader: (3)

You can generally say that every extra pound your rims are, it's like 10x the weight because of rolling resistance.. I don't know how it works out like that, nor am I a physist.. but that's just word of mouth and research lol.

P.S. Also, this is probably the reason your car feels sluggish as well. Try putting your old acura rims back on and see if you notice a difference. I bet you will.

MPR

It's not so much the rolling resistance, that has more to do with the tire itself.

It's the mass of the rim and the fact that it takes more energy to accelerate and spin that mass up to speed.

Neon_Dave

iTrader: (1)

To end the debate over which is more important tire or rim weight, look up the weight of your rims here and compare them to stock sized ones. Unless they're lightweight racing wheels, you're likely going to see at least a few pounds more in weight PER rim. As mentioned before, this, combined with the weight of your tires, will have a profound effect on yor mpg and also acceleration. Some may say that yes, with a lower profile tire you don't have as much weight in tire but you can't tell me that this cancels out the increased weight of the wheels.

Here's the list mentioned earlier. http://www.wheelweights.net/wheel-weight-weight.pdf

Just my 0.02.

-Dave

XNXIXTXRXOX

I still ask what you did for the tune up... Regardless of the rims being heavier or not, it shouldn't attribute for that kind of fuel mileage. I had 17x7's on my car, that weighed more than my stock rims by about 4 pounds each. I did notice a little less acceleration, and about 40-60km's less in fuel mileage. But I still could get around 450-500kms versus my previous 500-550 kms.

Neon_Dave

iTrader: (1)

That's for sure, that's about the difference for sure. Was about the difference for me as well. The really low mileage he's experiencing is likely a greater problem than the heavier wheels, despite how much they contribute.

Maybe we all forgot to consider driving style? If you're constantly bootin it then regardless if your cars had a tune up and regardless of your wheels if you're very leadfooted your mileage will suffer greatly.

ronin_of_life

+1
Any info on the tune up? (was it just a generic "spark plug + oil change" tune up?) Were your valves adjusted? Was the throttle body cleaned?

There's so much that can affect MPG- the gas you use, excess cargo weight (maybe from your trip), driving habits...

Also remember that the fuel gauge is an unreliable indicator for gas mileage-

Want to accurately figure out your average gas mileage per fill up?

1. When you pump gas, pump it to full (I pump it until it shuts off on me once)
2. Reset your trip odometer, and drive around until you need to fill up again.
3. Pump again and this time, find out how much gas you need to pump to fill the tank (its on your gas bill or station pump)
4. Check the odometer for the number of kilometers driven, divide the Kms by the number of liters of gas pumped, and that way, you can get your mileage in km/L

http://www.fueleconomy.gov/feg/noframes/15642.shtml
If you're within 10-12 km/L, you're up to spec...

momointegra

okok wow thanks guys... soo here is the scoop.. i have 18x8's . they are light weighted momos and low pros with a 30wall.. my "tune up" was a timing belt plugs and wires. i boot my car most the time.. however when i dont i still get 300km/tank lol. I just came back from mtl (510km) hwy drive and needed to fill up at 400. ALL HWY. I smell gas sometimes like its burning rich but i passed my emissions with ease b4 i did the timing. I always fill up till it clicks never over. i 50/50 use the 94 and reg. I change oil every 5000. filter is clean. ... and like i said i always get 300km/tank

momointegra

correction... i dont smell gas when driving.. i smell it from my muffler.

Datenshi

iTrader: (3)

It might be because your car is automatic, my teg only ran about 300-350 KM per full tank and it was automatic, passed emissions too... but I always thought it may have been running rich as well.

MPR

ok, OP: you're wasting your money and quite possibly contributing to poor mpg by using 94 octane in a stock b18 non-vtec. It was designed to optimally run on 87/89 octane. Do not be deceived. All higher octane does is resist detonation, meaning it takes more energy to ignite it. If the heat and compression is not high enough, it will not be completely burning, meaning you will not be getting all the potential energy/power from the fuel. Basically, it can cause your engine to burn more fuel and make less power.

There is no benefit what so ever, to running higher octane in an engine designed to run on lower octane.

Try running straight regular 87, drive the car the same, and I bet your fuel consumption will improve.

momointegra

ill give that a try, i know what your saying. but i highly doubt that its the gas doing this. I say that cus i went for a while without it then decided to use it a couple times for the cleaning purposes.

MPR

It dosn't clean anything. In fact, as a result of incomplete burning, it could be junking up your engine with deposites....

Run a can of seafoam through it to clean it out. lol.

momointegra

seafoam is? lmao

momointegra

i was going to say.. is there anything that cleans my engine and cat?

MPR

Click here: http://www.seafoamsales.com/motor-treatment.html

There's even a how-to video there.

momointegra

looks good.. my buddy here did it.. and actually told ma about it but forgot lmao. ill try it out. Anything else i can do?

MPR

You say you hav 18x8 rims. typical stock rims for a civic or integra are 6-7" wide. yours are 8" wide. What size (width) tires are you currently running?

momointegra

215/35/18 i believe. love em.. i know thats the typical size as u mentioned and everyone said these wouldnt fit. but they do and give a nice modern look to my ride. plus the grip is amazing. although i dont think i can lower it

XNXIXTXRXOX

Thats a bigger rim/tire diameter overall from stock.... that also could be causing the fuel mileage issue.....


So it seems you have a few things against you....

- 94 octane (yes it does contribute slightly to decreased gas mileage)
- Larger rims/tires
- Possibly running rich
- Plus myths say that standard cars (because of less horsepower drawn away from the tranny) get better mileage than autos....

Neon_Dave

iTrader: (1)

-Your vtec goes BWAAAAAAAAAHHHH (often)

SOR

iTrader: (2)

if he's running 94 thats why it smells like he's running rich ^^^ drastically incomplete combustion

what oil are you using? i've heard of that being a contributing factor.

and i've heard some horror stories about seafoam... i would research the hell out of it before you run it through your car if i were you.

Vida

iTrader: (2)

Arent you running 18 inch momos on your car? and using 94 octane? Man youre doing overkill

momointegra

Ive heard mixed reviews. what have you heard?

Vida - yes 18's n the 94 i used to run mainly when i was going on a hwy drive. like my montreal missions.

Vida

iTrader: (2)

Yea i recommend not to use it. For me at least. I used 89 at shell and i got 480 to the tank. I felt rich one day and put 91 and i got 420 or less. So for you doing 94 its just way too much and its a waste of money and gas.

As for the 18's....i get what youre saying that it gives the car a modern look...but really thats for bigger cars. Tegs are small all around and giant 18's make it look like a boat, but a really weird boat. PLUS its just killing your suspension and gas mileage. I suggest switching to a 16 or 15 inch, car will look nice and low, wont look like a boat, it'll feel nicer and your suspension and gas consumption are saved

momointegra

it most def does not look like a boat, check out my pix. or come to the meet. a few of the guys have seen it a few weeks ago. As for fuel.. yea im gona take it back in and see if there is anything my mechanic can find.. the seafoam makes sence but i wanted to know if there are other products that can clean the crap out of my car

Vida

iTrader: (2)

Hell. you know what though. Try this for 1 tank. If you have any smaller rims around, from 14-16 inch. Fill up your tank, and drive with the small rims until your tank is empty. Then come and tell us what the mileage is. If its still bad then its a problem. But if its back up where it normally is for tegs (450+ kms) then you found your problem. It'll save you the trouble of doing something like Seafoam.

momointegra

very truuu. I will try that but my stock rims have winter tires lol. theyre gona melt in this LAVA we call summer weather. lol

XNXIXTXRXOX

dont bother. just correct your gas, dont drive so hard, and see what you end up with.

No sense in putting your smaller rims on, cus your gonna keep your current rims on regardless right? hell, if those are what you want, then you just gotta live with the gas mileage

momointegra

yea if i put my old rims back on it would be only for testing purposes. I am most def not riding on stock rims in the summer lol

ronin_of_life

Alright, now let me get this straight... you guys all pump 89 or less octane in your ride, and you get BETTER mileage? Hmm... so let me ask- where the hell do you guys pump your gas, because you all probably found a place that has very little ethanol in their regular and mid grade gas, and that, imo, is harder to find than a rust free DA...

This is my understanding of fuel mechanics and chemistry. I may be wrong, and if I am, I'd appreciate it if someone were to point out where I've spoofed.

Theoretically, 87 octane gas is supposed to give better mileage:
- n heptane, a straight chained hydrocarbon (no branches), is found in larger quantities in 87 octane gas than in 91 octane gas (remember, a gas with straight n heptane has a 0 octane rating). Needless to say, a straight chain hydrocarbon isn't that compact- meaning that it has a lower melting and vaporization point- ideal for fuel injection engines, which must convert the gasoline into a vapor before initiating combustion. (Why vapor? well, try burning a log of wood and sawdust- the log will burn slowly, the sawdust will literally explode- its the surface area of the molecule that determines combustion. The same applies for molecules, n heptane can easily separate into a more vaporizable form, easily initiating combustion.
- 2,2,4 trimethyl pentane (isooctane), has secondary and tertiary carbons present on both ends, so due to a higher number of carbons, and a more compact structure, it has a much higher melting/vaporization point than n heptane. Thus, it is much harder for fuel injectors to vaporize isooctane for combustion- small droplets with less surface area and more fuel results per burn, yielding an incomplete burn.

So why, when I pump 87 or 89 octane, do I get less mileage? (last tank I got 12.1km/L using 91- the 89 brought it down to around 10km/L (average of 4 fill ups). I have a 91 integra RS, 1.8 L non VTEC engine, stock timing.

Its in the ethanol. Compared to n heptane and isooctane, it is hard for ethanol to vaporize. Despite ethanol being a smaller straight chained molecule, ethanol has an OH group, which enables it to form hydrogen bonds, thus drastically lowering vaporization.

So although the n heptane slightly increases vaporization and mileage of the 87 octane, the addition of 10% ethanol in the gas will lower it (unless the ethanol molecules are evenly dispersed, thus reducing the chances of the ethanol molecules in bonding with each other).

***I currently use ethanol free Shell 91 octane- I tried the ethanol laced 89 and 87 stint for a month or so, and I didn't like it. I absolutely wish that a gas station that sells ethanol free 87 gas would open up, but now with Ontario Ministry of Environment mandating a push for up to 15% ethanol in the gas... soon the ethanol free 87 of yesteryear will be harder to find than crack!***

momointegra

I cant answer that but i want to say that i get about 7.5km/L and 10km/L hwy! sooo bad. gona try synthetic on my next change.

Datenshi

iTrader: (3)

I agree with Vida, it would be a good idea to test it out. Worst comes to worst.. you drove for 2-3 days with regular rims but atleast you'll know if your gas mileage is affected by your rims.. (which I think it will be) and as everyone has said, bigger rims = less mileage and not recommended for integras.. but we can't argue with the style you want for you car, so if thats the rim you want then all the power to you.

ronin_of_life

I use castrol syntec- to cut down on the pricing though, don't buy it in Crappy tire- there's a lot of people on Craigslist who sells it in bulk- I got 4 4.4L jugs for 90$.
There's also amsoil for 10$ a liter if you're willing to spend 600$ and buy 60 bottles...

Oil has a pretty long shelf life, so stocking up for a couple of years ain't a bad idea...

MPR

If all you do is daily regular driving and have a non-vetc lower revving engine, don't waste your money on full synthetic oil. You won't notice a difference. What is more important then the type of oil you use is that you change it regularly.

You have many factors acting against your fuel consumption: 94 octane gas, heavy 18x8 rims, wider 215 tires = higher rolling resistance, larger then stock overall wheel diameter, and auto transmision.

You can't change the transmission of course, but you can change many of the other factors and see what kind of effect they have on fuel consumption. All those things in combination can have a huge impact on fuel consumption.