HAI FE vs Ambient Temp

[jousai7]

So apparently the colder the outside air the worse FE i get. And ive seen the same trend pop up a couple of times across the forum. Its a proven fact Hot Air Intakes improve FE, my question is has anyone put one on a FIT yet and tested it. My theory is that it will have a profound FE boost when u can get intake temp at 120F....HAI + Grill block should have considerable FE gains. I can test my theory as im in the middle of a 80+hr work week. If anyone has tried this or wants to please post with some thoughts/results!!!!!!!!

[Tofuman]

i cut my airbox tube off (the part that runs into the fender), and i've noticed a slight increase just from ambient engine bay temps. if you route a tube to pull air from near the header, i'm sure your FE would get better, though a decrease in power.

mine looks like this:

[jousai7]

awesome, this weekend im going to setup my hai and tape off the grill be nice if i had a temp sensor there but we will see how it does. im tired of the weather killing my mileage.

[pb and h]

I have a short ram intake or WAI or HAI. I haven't tested the difference between the stock and the WAI. I do know that the grill block is a big difference........... up to 5mpg better with the full grill block..

Without the grill block my engine will get up to 173F with the grill block the engine will get up to 220F and that is in 25-30F temperatures outside.

[No_Skillz]

Why don't you just take it easy on the gas pedal? It's the same effect - better gas mileage, decreased power.

[jousai7]

"Why don't you just take it easy on the gas pedal? It's the same effect - better gas mileage, decreased power"



.........u serious...?.........hotter air = better atomization of fuel = cleaner more efficent burn = better mpg......how does adjusting the gas pedal do this again? if your not going to be helpful you can always not post

to pb & h thanks for verifying the grill block. i took a closer look at it and the grill on this car is tiny...but good to know it helps.....now when u say 220F are you talking coolant temp or?? and as for the short ram intake is that a normal one or do you actually pipe it under ur exhaust manifold?

[No_Skillz]

Originally Posted by jousai7

.........u serious...?.........hotter air = better atomization of fuel = cleaner more efficent burn = better mpg......how does adjusting the gas pedal do this again? if your not going to be helpful you can always not post

Chill out homie and hang your hater hat. Not everyone in this world is a guru at fluid dynamics like you.

Just seems kind of counter-intuitive since my knowledge is mostly performance only - we want to cram the most amount of air possible in a cylinder and that means cold is good. I've never even thought about decreasing performance for fuel efficiency.

[jousai7]

sorry about that the response, work is killin me at the moment>< but hey already got over 20 hours of overtime so far $.$ . the whole hot air is kinda hard to explain. it does the whole fuel atomization thing which is good but also when ur up to speed you only really use a small percent of the motors capabilities...hotter air gives you a bigger window to be in the "most utilized throttle position window" sorta of in a reverse sense of how cold air always insure the most power output. if that makes sense? i figure with the fit hating colder air"as far as fuel economy goes" the hot air intake would have a huge impact....i hope ..and plan to find out.

[E = Mc2]

Originally Posted by No_Skillz

Why don't you just take it easy on the gas pedal? It's the same effect - better gas mileage, decreased power.

I think perhaps that you've missed the point. The folks posting here already do that. It's about getting even better FE. I maxed out at 49.xx mpg last summer, dropping to roughly 40mpg so far this winter because I've stopped working for FE and am just driving slower. If a short ram or 'warm air' intake is worth the money spent, I might just have to replace my stock air box.

The reason that warmer air yields better FE is that the warm air is less dense than cold air. Cold air yields more horsepower but costs in fuel economy because it takes more fuel to yield the same Air/Fuel ratio. Hot air is less dense, meaning less fuel is needed to make the 'ideal' A/F that the computer is looking for.

[pb and h]

I just recently tested the Intake Air temperatures.

Stock = ~3 degrees above ambient
Stock w/ rubber attachment removed = ~10-12 degrees above ambient

I still need to see what my short ram intake will do.

[stevet47]

I actually dont even own a fit yet, but will be buying once in the next month or so, and already have a bunch of FE plans for it.

pb and h, with such high engine temps and cool ambient temps, how do you regulate the engine temp in the summer? Also, does your fan kick on more now with the grill block?
I was planing on installing an LED to tell me whenever the fan is on, and maybe an active grillblock that can open or close a bit as temps change to keep it just under the level in which the fans kick in.

[pb and h]

I don't regulate engine temps just monitor them.

I don't know when the fan comes on but I have run it as high as 220F(water temp that is) in the winter with a full grill block. It will be interesting to see how high it gets in the summer now that I have a SGII. I may put the short ram intake on tonight and she the temperature spread between ambient tomorrow.

[stevet47]

Originally Posted by pb and h

I don't regulate engine temps just monitor them.

I don't know when the fan comes on but I have run it as high as 220F(water temp that is) in the winter with a full grill block. It will be interesting to see how high it gets in the summer now that I have a SGII. I may put the short ram intake on tonight and she the temperature spread between ambient tomorrow.

Cool.
I'd be concerned that with a full grill block in the summer you might overheat, especially if you see 220F in the winter. Plus you dont want the fan on constantly, the extra draw will kill any mpg gains you get from the warmer temps.

[bkrell]

Originally Posted by jousai7

"Why don't you just take it easy on the gas pedal? It's the same effect - better gas mileage, decreased power"



.........u serious...?.........hotter air = better atomization of fuel = cleaner more efficent burn = better mpg......how does adjusting the gas pedal do this again? if your not going to be helpful you can always not post

to pb & h thanks for verifying the grill block. i took a closer look at it and the grill on this car is tiny...but good to know it helps.....now when u say 220F are you talking coolant temp or?? and as for the short ram intake is that a normal one or do you actually pipe it under ur exhaust manifold?

I thought the whole point of a hot air intake was to decrease air density and cause bigger throttle openings, thus reducing pumping losses?

[pb and h]

Originally Posted by stevet47

Cool.
I'd be concerned that with a full grill block in the summer you might overheat, especially if you see 220F in the winter. Plus you dont want the fan on constantly, the extra draw will kill any mpg gains you get from the warmer temps.

Don't worry, I don't use the grill block when temps are close to 70F. That would not be a smart thing to do.

[polaski]

I have a simple rule- I take the 2 minutes and yank that rubber attachment anytime the temps are going to be under 40F for any period of time.

When it gets warmer I just put it back in.

No altered parts, very little fuss. Less power without it, so don't pull it off if you have 3 passengers in city traffic and need all the torque you can get.

Bingo, higher manifold pressure for the same overall airflow means better efficiency. Besides it burns more quickly and reduces the need for ignition advance.

[ToFit2Quit]

Has anyone tried this? I've haven't had time to tried. But maybe someone can try it.

Why not just use parallel intake? Put a small pipe leading from the radiator into the the intake box. Therefore, the two temperature inflow will result of a warmer temperature depending on the size of the pipes.

Strip hot air away from the radiator to make your fan work less. At the same time, the system knows that warmer air is running into the intake and adjusts the fuel injectors to use less gas.

I don't think it'll overheat the engine because the hot air will be reused in the conbustion process to be released through the exhust. At the same time the heat is being stripped away again by the radiator.

[pb and h]

So, I got off my ass and put my HAI on. This mornings commute gave me the same IA as the the stock with the rubber piece removed. With that said, it is only part of the equation. Temperature, humidity along with volume of air and rate(scfm). I know the temperature and humidity but not the scfm differences. My driving conditions vary to much lately to do a valid comparison of the 2.

[pb and h]

I saw a 15 degree difference yesterday on the way home but it was 90 degrees out and my car is black.