05 base w/auto....Is it possible to improve both hp and mpg?

[wisvibe]

I have an 05 base w/auto and was wondering if it was possible to improve mpg and hp with exhaust, chip or air intake. Thanks for your opinions.

[ragingfish]

the two are inversely proportionate. to make extra horses, you need more fuel. certainly an exhaust or chip are not likely to do that. SOME have reported mild economy boosts from a CAI, but in most cases it drops a bit (mostly because the driver takes advantage of the additional power).

[drunkenmaxx]

actually fishy, exhaust can increase economy as well. anything you do to make the engine more efficient will, it just makes sense.

[sagekai]

By having more power, if you kept the weight of your foot the same, wouldn't the engine consistently be at lower rpm's resulting in better mileage?

[drunkenmaxx]

actually, that is a common misconception. the rpms will be the same at X miles per hour no matter what, that can only be changed by getting different gears.and that is why i laugh when people say, "since i got my CAI, i am 500 rpms lower at 55 mph" or something to that effect. lies i say!

[ZubenElGenubi]

Yup; I admit that after I installed my CAI I thought the RPM's dropped. Nevertheless, after a couple of tanks of leadfooting it, my gas mileage did improve by a couple miles per gallon. For the sake of disclosure, I also switched from Super Unleaded to Regular Unleaded exclusively.

[drunkenmaxx]

it does idle at lower rpms, that should make you feel better.

[northvibe]

after my cai my mpg went up 1 or 2, course I had to not drive hard for a couple weeks to find this out TB spacer may help too

[joatmon]

The relationship between RPMs and MPH depends on the transaxle and wheels.If a mod, like CAI or exhaust increases the power output of the engine, then theoretically it would take less gas to generate the power required to move the car at the desired speed, so you might see a change in throttle position to RPM relationship.A CAI or performance exhaust will let the engine breathe easier, so you should get more power out of it for the same amount of gas. However, wouldn't the car's computer adjust fuel injection to try to keep the fuel air mix where it wants it to be, so would more air cause more fuel?Also, the best fuel economy is going to be at low throttle, RPMs under 3K. THe power band is at higher rpms. I am not sure if the factory intake/exhaust restrict air flow at engine speeds under 3K to make much of a difference. Maybe a before/after dyno chart would show if there was any appreciable power/torque gains at cruising rpms.

[djb383]

I thought we had some posts about CAI that showed dyno results indicating maybe 5 hp gain at 6500+ rpm and virtually 0 hp gain at 3500 rpm or less where we drive 99.999% of the time.

[sagekai]

just an observation... since i put my cai in last week, my auto is making every shift at 5 miles an hour higher than it used to... is this possibly because it requires less work on the part of the engine to go faster now... meaning better mileage?

[ramenboy...]

Quote, originally posted by sagekai »just an observation... since i put my cai in last week, my auto is making every shift at 5 miles an hour higher than it used to... is this possibly because it requires less work on the part of the engine to go faster now... meaning better mileage?hmmm...5 mph higher? does that mean its shifting later? to get better gas mileage, the engine would have to shift out of the lower gears earlier. it seems that if the engine shifts at a higher speed (later), the engine is revving longer. i could be wrong

[sagekai]

my feeling is that its shifting later because not as many rpm's are required to reach the same speed, so by the time it gets to the rpm point to shift, the mph are higher. its still shifting at the same rpm point so basically it seems like you can get to a higher speed with less efforti could be wrong too though

[ProtonXX]

Pulleys work great. Found 2 OBX pulleys for $120 & put them on myself. I felt more power than a CAI & Ram Air Intake & my transmission wasn't dropping a gear gears to accelerate as much.Exhaust might too but Im not ready to throw down the money for one yet. (I unscrewed my 2nd O2 sensor & pretended I have one . My mileage appeared to went up 1-2 mpg & power went up, but that could be a effect of a bad 2nd Cat.Lightweight Rims(upgrade from steelies), Syn Oil, hydrogen injection are other ideas.