Cold Air Intake-Fuel Economy

[Cajun]

Does anyone have any before and after results on CAI effect on fuel economy?

[QUIKAG]

Depending on how much you're hitting the happy/go pedal, the mileage should stay the same or even increase. I got 29.5mpg on a leisurely drive to/from Austin from Dallas this past weekend. I never got on the gas hard, but I did cruise at speeds between 70-85mph depending on traffic conditions. I was pretty impressed. Also, the A/C was on the whole time!

[Sub-Vibe-R]

quote: Also, the A/C was on the whole time! Ok, no mre details, Here we kept freezing...

[Triton]

Must be nice to be using the A/C. We won't need to worry about doing that for another two months at least!

[DABEAR95]

quote:Must be nice to be using the A/C. We won't need to worry about doing that for anoter two months at least!Hey now, a little hope please!! I can't wait to take the snow tires off my Vibe and take a cruise in the Camaro on a nice Saturday...Jason

[DopeVibeGT]

I hear ya. I cant wait to get the GA out and finished. Being a snowplot isnt good for a car.Anyway, I didnt really take notice of any increase/decrease that can be related to the intake. I got my best mileage so far at 25 MPG.

[Triton]

Same here. My miles per gallon are getting better the more miles that are on my car. My dealer told me that you really shouldn't look at your fuel economy until after a couple thousand miles. Looks like he was right.

[Lancer]

At my last oil change 4 months ago I could go almost 300 miles on a tank. Now 2 days after my last oil change and over 12000 miles, I was suprised when I filled up with a 1/4 tank left and had gone 310! And can you believe the gas prices now?!?! $1.85 for med octane.

[kdd5ltr]

I know I run my vibe GT hard but my MPG is sucking right now.Maybe 20-22 mpg.The car is alot better performer with the CAI.

[St. Martin]

Guys, I run the GT pretty hard and get near 30 on every tank. I've even gotten 345 miles out of a tank on the highway through the mountains. No exaggeration. Not sure why you guys are only getting 22. Its all about the right gear at the right time.

[Lorin]

quote:....Its all about the right gear at the right time.The old school of thought was to go for the highest gear /lowest rpm. I wonder if that still holds or if there is an rpm target range to shoot for?

[St. Martin]

quote:....The old school of thought was to go for the highest gear /lowest rpm. I wonder if that still holds or if there is an rpm target range to shoot for?Actually,I've found that RPM's are the secondary variable in gas mileage. More important than road speed or engine speed (rpm's) is how far down the pedal is. There's no point to running 6th gear at 1000 rpm's if the pedal is to the floor. You're much better off in 3rd at 5000 rpm's. The pedal is the mechanical control that lets the gas into the engine. When the pedal is floored, no matter how fast you're going or in what gear, the valve is completely open and gas is pouring in. First gear doesn't burn a whole lot more gas than 6th, unless the pedal is to the floor. That's what I've found anyway. Drive like a grandma if you want to get milage. Then, when that 16 year old pulls up beside you in a neon, there's still enough gallons in the tank to smoke his (removed)!

[atom]

St, Martin, Consider yourself lucky @ 30m,pg. You're the only case I've read about w/ #s so high. Currently my mpg sucks. Granted I'm still "breaking-in" with 1400 miles. Last tank I hit 23.9 mpg, that's the best I've gotten. My big block GTO got pretty close to that ( 20 ). We, my wife and I, bought this car for a number of reasons, one of which was efficiency. Have yet to see efficiency for a 1.8 liter.An aside: Just recently hit lift and it put a grin on my face. Now if lift could come 2000 rpm sooner so that we could enjoy it more w/out beatin'the (removed) out of her.

[Lorin]

Last week I completed a road trip to Indiana and back. 1006.5 miles. I got 29.6 mpg for the trip. Speed was 75-85 miph 95% of the time. 82 mph + 10%. A/C in use 5%. Cruise 15%. Crossed the Alleghanies twice (out and back). Car went from 3,000-4,000 miles on the trip.For the speed I was driving and mostly w/o cruise, I can't make any complaints. EPA sticker was 30 mpg and I got nearly that. p.s. - Commuting - I am getting 27 mpg. Twisty turning mountain roads, several stop signs, average 45 mph but periods where I hit 65 mph (brief!). Economy jumped 1.5 mpg after I put on the exhaust.

[mu_ohio]

I've always came close to 29 mpg with my GT after a few thousand miles. Typically, I put in 10 to 10.5 and get around 300 miles per tank. I have not noticed a difference with the intake though.

[viberator80]

your ecu (engine control module) is programmed to run your engine very rich for the first few thousand miles. This is to protect your engine and get all the crap that my be in there from the manufacturing process. so yes you should see a increase in MPG as you drive

[viberator80]

the cold air intake will decrease you fuel economy for the simple fact that more air will get into the engine. So your maf sensor will tell your ecu "hey we are getting alot of air" and the ecu will respond and give more fuel to keep the mixture the same.

[mu_ohio]

quote:your ecu (engine control module) is programmed to run your engine very rich for the first few thousand miles. This is to protect your engine and get all the crap that my be in there from the manufacturing process. so yes you should see a increase in MPG as you driveI have never heard that. Going back before computers cars experienced the same effect. As I understand a new engine is very tight and once it settles, it takes less gas to do the same work. Pretty much the same reason why the hp will increase after a few thousand miles. Also, a dirty air filter has shown a decrease in gas mileage. This contradicts the fact that additional air flow will increase gas usage during normal driving.

[johnsoax]

I have just over 950 miles on my car, and I've put 3 tanks of gas in it (plus one from the dealer) I got the car at 60 miles, over 300 miles (362) on the tank from the dealer, put 10 gallons in (30 MPG), then filled up the next time at 649 (286 miles, 26.43MPG), and then filled up on Monday at 913 (264 miles, 28.27MPG, Premium was on sale ). So if your telling me that my milage will increase after a few thousand miles, I will be a very happy camper.(I'm not that (removed) about fuel milage, I have a program for my Handheld that I put the odometer reading into and how many gallons and how much the total was and then it calculates everything for me. It is called FuelLog and you can get it at http://www.palmgear.com)

[MadBill]

viberator80 is correct, but the reason is a little more complicated. (The mileage discussion here relates only to part-throttle operation) What happens is that because cold air is denser, the throttle needs to be opened less to meter the required mass of air to generate the power to maintain a given speed. This means the pistons are doing more "negative work" (termed "pumping losses") during the intake stroke in order to overcome the resulting higher intake manifold vacuum, and this in turn means higher fuel consumption. (one of the three main factors contributing to the better economy of Diesel engines is that they are unthrottled.)* Example: Years ago, a friend of mine commuted ~100 miles a day in his '70 Pontaic GTO, which had a cable operated "Ram Air" (& cold air) hood scoop. One winter the linkage stuck in the cold position, and his fuel economy dropped by over 2 MPG until he was able to free it up.*(For the record, the other two are the 18 to 22:1 compression ratio and the fact that Diesel fuel contains ~15% more energy per gallon than gasoline.)PS: New vehicles must meet emission standards from day one; no provision exists for changing the calibration after some mileage is reached. (Possibly the confusion arises because the EPA does permit 4,000 miles of mileage accumulation to break-in mechanical parts before running official emissions tests.)

[Lorin]

I just got 29.6 mpg on a 1006.5 mile highway road trip with 3,000 miles on the Vibe. Lots of cargo (heavy Dell servers) going both directions, with average speed on the road 80 mph. The epa highway rating of 30 mph seems to be on the money for me.

[NovaResource]

Bottom line: my mileage increased with my "short" CAI over the factory air box. So much for your theory.