Improving MPG

5

Asked by Jul 13, 2008 at 08:50 PM about the 2008 Honda Civic Coupe Si

Question type: Car Customization

If I have an AEM cool air intake and a Catback exhaust, will that improve my car's MPG. If so, by how much?

17 Answers

45

No, this will not improve your mileage. It will improve your cars performance, but not the mileage. Performance parts improve power, not mileage. If you plan on any serious upgrades, plan on sacrificing mileage for power.

4 of 4 people found this helpful.
3,325

haha are your serious? you bought an si and you want to improve the mileage? you should be modifying it and not worrying about the mileage its a damn si

4 of 4 people found this helpful.
3,325

you should of bought the civic hybrid if you were going to worrying about mileage

1 of 1 people found this helpful.
90

lol... i think hes looking for an excuse so his mommy and daddy will pay for mods

2 of 2 people found this helpful.
45

Yes, modifying your car does increase gas mileage, because it allows the engine to flow a lot better than a restricted exhaust and air box. The engine doesn't have to work as hard. It's not going to be a noticeable difference around town, but on the highway you can add a mpg or two. As long as you keep your foot out of the gas you will increase your gas mileage.

1 of 1 people found this helpful.
105

at most just a little the both the mods help but its hardly going to be noticeable.

2 of 2 people found this helpful.
10

actually it will improve your mileage... especially if you don't reflash your ECU. However, you will *really* improve your mileage if you drive more smoothly (less hard accelerates and then hard brakes; shifting into neutral when coasting to a red light). Also if you're short shifting (like below 3000rpm) you'll save mileage as well. I have an Si sedan... get around 31mpg just going to work and stuff... (even with dipping into VTEC about 2-3 times a day).

1 of 1 people found this helpful.
115

put in an electric fan purty much tru dual exaust not glass packs

5

Swap the motor into a 94 civic hatch, you will probably get around 40MPG and still run 12's in the 1/4 mile.

90

hella BAD information in this thread... go to honda-tech.com and search for answers yourself...

1 of 1 people found this helpful.
90

yep, pretty much *thumbsup*

265

first off any mods that are not HKS approved will void your waranty to that section you modded. did you buy an extended warany? Is this a track car or a red light warior?( which i do not endorse) is this a six speed stick you already have a fast car! stick with factory approved mods for you may need your warenty unless you have unlimited bankroll

265

car is stock in si with electric fan

265

thats crazy dude!!! how about a crx swap if your that nuts

www.mileagewillvary.com..... Check it out. I get 33 with my 2008 SI on the highway. Your car will compensate for the extra air it is taking in, as well as the exhaust flow, and add fuel which will actually decrease gas mileage.

8,985

good idea in theory, but I think you fail to understand what the additional fuel results in... Thats the same as saying... if you step on the peddle more it will use more gas... Well yes, of course that is obvious, but it also results in more force(torque)/speed. The idea of better mileage is to reduce the amount of work the engine has to do to pull air in. The principle is easy to understand.... Grab two straws with the same internal diameter. Breath in through a 5 inch straight one and then through a 6 inch curved one... Which one did you waste more energy trying to breath with? The curved one right? Same principle as a 4-stroke engine on it's intake stroke. This just makes it easier to breath... The problem with most CAI is the fact that they are open element and tend to pull hot air into the engine... This defeats the entire purpose since hot air is less dense.

90

the air intake is actually working against you if you want to increase gas mileage you should probably change your oil more often and try not to be so heavy on the gas. by puting in a high performance air intake and exhaust you will make more air go through the engine and the engine will have to work harder to pump the fuel through the car. in effect you will have to have oil changes more often and you will lower your gas mileage. Aem is a good brand though but you are just using it for the wrong purpose!!!!!!

Your Answer

Civic Coupe

Looking for a Used Civic Coupe in your area?

CarGurus has 10,849 nationwide Civic Coupe listings starting at $1,800.

ZIP:

Honda Civic Coupe Experts

  • #1
    deb5deb5deb5deb5deb5
    Reputation
    1,790
  • #2
    elmerenzo
    Reputation
    1,490
  • #3
    kd5qhr
    Reputation
    1,210
View All

Related Models For Sale

Used Honda Civic
590 Great Deals out of 52,285 listings starting at $1,500
Used Honda Accord Coupe
142 Great Deals out of 5,071 listings starting at $2,000
Used Honda Accord
858 Great Deals out of 87,670 listings starting at $1,444
Used Ford Mustang
344 Great Deals out of 42,036 listings starting at $1,488
Used Toyota Corolla
907 Great Deals out of 69,857 listings starting at $1,479
Used Toyota Camry
1,107 Great Deals out of 76,352 listings starting at $1,100
Used Mitsubishi Lancer Evolution
13 Great Deals out of 594 listings starting at $12,700
Used INFINITI G35
61 Great Deals out of 2,881 listings starting at $1,200
Used Toyota Tacoma
566 Great Deals out of 40,726 listings starting at $2,500
Used BMW 3 Series
1,119 Great Deals out of 33,866 listings starting at $1,209

Used Cars For Sale

2017 Honda Civic Coupe Si For Sale
378 listings starting at $21,692
2014 Honda Civic Coupe Si For Sale
4 Great Deals out of 85 listings starting at $12,972
2013 Honda Civic Coupe Si For Sale
8 Great Deals out of 148 listings starting at $8,996

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.