I have a dual spectre homemade warm air intake setup "see photo" on my profile gave me great gains in MPG 3 hyw 1 city, went on this site to showcase it and got critisized that its a bad idea because of the radiant heat from exhaut manifolds and rads so I followed the advice of a couple of very knowlagble tech guys here "and still respect" and installed a direct duct system to my unit. WOW what a decrease in MPG from 15 city to 12.5 at best didnt test HWY but great gain in HP this is while being very light footed on my throttle, this was not a forced air intake just a 6'' open duct going to my filters.
Very dissapointed but really liked the HP gain.
ANYONE ELSE had same problem?
THANKS
MIKE
BRAMPTON ONTARIO CANADA

 

I cant remember your user name but you gave me alot of info everytime I asked a ? connect. and futher help me understand about cai. it was easy when I had a 650 cfm HOLLEY on my 79 camero now I'm lost on the computer controlled engines, not to say I'm dont know about computers Ive been a programmer since the mid 80"s but cant get a handle or info on the software on current units today

 

Well, the 12.5 city is about right. As for your mileage dropping, it's very unlikely it was 15 city in the first place. There's no question higher intake temps are not good for power. It's unlikely a CAI of any type will cause that much difference up or down. A ten percent difference would be remarkable and not very common.

You mention a horsepower increase, but are "light footed" on the throttle. How can you determine there is more HP and be light on the throttle at the same time? How are you determining your fuel mileage?

If you're relying on the computer to determine your mileage, you're being mislead. There is only one way to accurately determine mileage. You might want to reset the computer. That might make it more believable, but they still are optimistic to the point of being worthless in the mileage department.

 

Hot air in = lower power, better fuel economy as less fuel is mixed with it. Cold air in = better power, lower fuel economy as the colder air is more dense and requires more fuel. Your basic findings are correct, but I am rather skeptical in your numbers. A CAI alone just doesn't account for that much of a change...

 

Horsepower isn't free. More air requires more gas but makes more power as a result.

That's how those tornado devices work -- they block so much of the intake that you spray less gas as a result, but also have less power to go with it.

 

Thats one of the reasons why in the summmer I get better mileage than in the winter, when its 118* out I get roughly 2mpg better than when its in the 60's, that also goes along with the winter blend vs summer blend for gas. So if you changed the intake setup to get cold air and not hot air AND combo'd that with results in the hotter months vs colder months AND combo'd both of those with the blend changes in fuel and there you will have a heck of a decrease in mpg.

 

yea the biggest thing you noticed is probably because its getting cold outside now and gas stations are going to winter gas... thats why your mileage is dropping. no way running a duct to your air filter will do anything significant. I used to be able to get about 300 miles to a tank during the summer... now im lucky if I get 270.. thats doing nothing different.

 

The only "work" the Tornado does is lighten your wallet. They have NO other value.

 

A good buddy of mine went to one of those national mechanic institutes and he had one instructor that was big into "testing" the different devices that are marketed for better fuel economy, more power, etc.

He told me they tested a "Tornado" on a '98 Chevy V8 truck and it LOST 4 HP on the dyno and over a couple of weeks LOST 1.5 MPG, interestingly they got almost the same results with a throttle body spacer.

One problem you have when you have less power is you subconsciously know how much acceleration you normally have from a stop sign, when passing, when getting on the interstate from a ramp, etc. and your foot just wants to achieve that same rate of acceleration, so you give it more throttle without really realizing it and negate any possible fuel economy gains. That's the single biggest reason why these "mileage tunes" on tuners don't work for people, they achieve better fuel economy by de-tuning the truck and you just simply give it more gas to have the same results.

Ultimately, MORE power gives you the best fuel economy because you have to give it less throttle for the same acceleration. Of course, some people lose out here too because they just want to feel that power increase and give it more foot...

 

We need to sticky this ^