Warm air intake. Gas mileage. Oh yeah.

[Anto]

I see weekly threads on gas mileage.

So for those experimenters, I present to you the warm air intake.

http://www.gassavers.org/showthread.php?t=244.

Look around in that thread for other links, people have increased gas efficiency by 15% - on a base B18 Integra, it went from 26 to 32 MPG.

I've read up that hotter combustion chamber temps usually result in a slightly better burn, which can equate to better mileage. Talking from a DD, strictly mileage point, running the lower temp fan switch would be counterproductive.
I'm planning to experiment with my stock KA and hotter plugs after this next oil change.

I've been keeping fuel logs since nov of last year, and i've been averaging 23mpg. I've discovered that for me, premium fuel gives me a good 2-3 mpg increase over regular. I know the KA can hit over 30 with a freshly rebuilt motor & efficiency tuning, it's just a matter of someone doing it.

Right now I'm running 0w-30 Mobil one. Going to change it to 5w-40 Syn Rotella, going to see how bad it knocks my gas mileage.

p.s.
I wouldn't recommend this to some of you turbo guys.

[derek_s13]

have you done the math on whether or not you're actually even saving money by filling with premium and spending 100% more or so each oil change?


i mean i understand you're getting better gas mileage... but are you saving money?

otherwise what's the point?

[ALEXTHESUS*PECT]

91 octane will burn better than 87, so your mpg will be higher!

go sr and run 91 all the time. your wallet will hate you for it!

[Fred Allen Burge]

I know the KA can hit over 30 with a freshly rebuilt motor & efficiency tuning, it's just a matter of someone doing it.



I hit 31.27 mpg on last week's tank, I average about 29mpg all highway. Is this not normal among the rest of you KA guys?

Mine is a 93 KA, stock everything, 172k, automatic, off brand O'reilly's 10w30oil and 87 octane all the time.

Also, wouldn't an SAFC installed and set to lean out under light throttle, low rpm (highway driving conditions) be great for this? I guess that would be fairly expensive, I think I may try the WAI though.

Fred

[94cc0rd]

I have a 98 KA bone stock except for exhaust, run 5w30 oil, and 87 octane. I get 27-29 mpg and I drive about 85% highway 15% city. Average about 80mph on the freeway...

I'm thinking it could be better since a bunch of my sensors are out (not sure if this effects efficiency but I'm assuming they do).

[MrChow]

I have 95' KA with 169k with Intake and exhaust with 2 dumb exhaust leaks. I get about 28-30MPG with same 85% highway and 15% city with 89.

[SoguRacing]

hotter intake temps can lead to failing smog ( KA guys ). higher combustion temps means higher NOX emissions. probably some other things too. or it may not be bad at all.

[Bigsyke]

interesting, so now me ridding of the airbox wasnt such a bad idea.

What about a light weight flywheel? Less energy needed to gain movement = less air&fuel needed. But would maintaining speed on the highway suffer?

[lil240sx95]

what the heck, 28-29...i barely get like 23 mpg! automatic about 110k

[Anto]

have you done the math on whether or not you're actually even saving money by filling with premium and spending 100% more or so each oil change?


i mean i understand you're getting better gas mileage... but are you saving money?

otherwise what's the point?


I actually did calculate that. It pretty much evens out, the price difference between 87 and 91 can fluctuate, but it's usually twenty or so cents higher.

.20 per gallon, 13.5 gallon fillup, it costs $2.60 more to fill up with 91.
2.5 MPG better per tank, that's 33.75 miles more for $2.60
With gas around $4.70, that means it's 20.4 cents a mile on 91(23 mpg) , and since 87 yields me ~20mpg, 22.5 cents a gallon (20mpg).

My engine is screwy though, it misfires at idle pretty bad and I did the cam swap. Once I rebuild, my numbers should go up, but for now that's what it's at.

Technically 87 burns better than 91 & has a higher energy content per gram (so I've heard), hence preignition and detonation on some motors, but some motors won't run right.

I thought of the SAFC idea as well, but steveshadows was pointing out that SAFC doesn't change your ignition maps. As far as performance goes, it's pretty bad, I'm sure from a mileage standpoint it's similar but the effects wouldn't be AS bad since you're not romping on the gas.

[HyperTek]

i got a fc turbo and just saw the fuel rating is 16mpg city 24mpg highway... shit sucks i bet this wouldnt work.. everything you know about piston engines does not apply to rotarys lol

[HyperTek]

oh maybe just turbo you car and no IC.. run straight from the turbo to the engine lol

[murda-c]

http://i238.photobucket.com/albums/ff119/williamsnc/dei.jpg

Doesn't get much hotter.

It'll work i swear.

[tt99ol]

lol i love that picture
it was on some vw forum i think

[Mr. Camshaft]

Seems like there's a chance you might lean out the AF mixture too much.

[Matej]

What about a light weight flywheel? Less energy needed to gain movement = less air&fuel needed. But would maintaining speed on the highway suffer?
Weight reduction, no a/c, lightweight flywheel, lightweight wheels, pulleys, aluminum driveshaft.
That's what I'm doing, well, except for lighweight wheels.
When I drive conservatively I already get 30mpg with no interior and no a/c, and that's with running super rich. People here laugh at me for reducing weight saying I'll gain 0.001 seconds, but they can't grasp that I never cared about going fast haha.

[Silverbullet]

this is an interesting thread.

I've read up that hotter combustion chamber temps usually result in a slightly better burn, which can equate to better mileage. Talking from a DD, strictly mileage point, running the lower temp fan switch would be counterproductive.

kind of... The thermal efficiency is determined by a ratio rather than just saying "hotter is better". On paper, the efficiency can be determined by calculating temp of after combustion (T4) MINUS temp of before compression(T1) DIVIDED BY temp of before combustion(T3) MINUS temp after compression (T2):
eta=1-[(T4-T1)/(T3-T2)]
There are other methods that this model can be translated into like in terms of work and heat energy, or compression ratio and specific heats; which may be more useful for engineering purposes, but this is the simplest way used with every dayish terms.


here is my thought:

I would imagine that increasing the intake temp will raise the temp for every process in the engine resulting in the ratio staying the same. But of course in a real world situation ideal processes are never true... only close for estimation purposes.

Book marked. Interested to see what new stuff we can learn =)

[C. Anderson]

I put an s14 sr in my s13 a few months ago and I get 30mpg taking it easy at 9 psi. If I drive at an event I get about 9mpg.

[jackjack]

my car (ka) drinks gas like its going out of style.

i love it.

:yum:

[INeedNewTires]

Another point i'd like to add is that alot of you mentioned stock engines, etc. But what wheels are you running? Because i noticed a huge difference in mileage when i put my 19's on, couldnt figure out why for a while, then realized the odometer is off now because my overall tire diameter is changed drastically.

I'm not the best a math and conversion formula's so i didnt attempt to calculate the difference, but if some of you could figure out a percentage increase or decrease then that would help us out alot.

I used a tire calculator to figure out how much of a difference it was in terms of diameter. http://www.1000rims.com/rt_specs.jsp

Stock S14 is what 205/55R16 right? and i'm now running 245/40R19 in the back (which is where it reads right?) so a difference of

Tire diameter Stock :632 mm (24.9'')
Aftermarket :679 mm (26.7'')
Difference of 47 mm (7.4%) taller.

But thats not going to change my gas mileage 7.4% right? thats where i got confused and stopped. So some of you math or engineering majors figure this shit out

[white92_s13]

my gas mileage sucks on my ka. i avg like 20-22mpg.

all i have is injen cold air intake, new filter, hotshot header, and custom 2.5" blast pipe exhuast.

all the egr works great, only emissions item i have removed was the evap canister, and i plugged the throttle body with caps.

i avg. 20mpg. mostly highway driving.

[Mr. Camshaft]

Another point i'd like to add is that alot of you mentioned stock engines, etc. But what wheels are you running? Because i noticed a huge difference in mileage when i put my 19's on, couldnt figure out why for a while, then realized the odometer is off now because my overall tire diameter is changed drastically.

I'm not the best a math and conversion formula's so i didnt attempt to calculate the difference, but if some of you could figure out a percentage increase or decrease then that would help us out alot.

I used a tire calculator to figure out how much of a difference it was in terms of diameter. http://www.1000rims.com/rt_specs.jsp

Stock S14 is what 205/55R16 right? and i'm now running 245/40R19 in the back (which is where it reads right?) so a difference of

Tire diameter Stock :632 mm (24.9'')
Aftermarket :679 mm (26.7'')
Difference of 47 mm (7.4%) taller.

But thats not going to change my gas mileage 7.4% right? thats where i got confused and stopped. So some of you math or engineering majors figure this shit out

Let's say we drive 100 ft. On stock tires it would take 15.33 rotations and 14.31 on the aftermarket ones. For 15.33 rotations, the aftermarket tires would take you 107.16 ft. Your odometer is gonna be off by a factor of 1.07 so just multiply whatever you've got with that.

[sldbyuramg]

disclaimer says it all... anyway you would be better off not driving like an ass around town then making a warm air intake.

[thatdrifterguy]

your mpg also depends on how much you let the car coast down the road.
are you guys calculating that into your mpg??? cuz thats kinda cheating between other people that dont

when i dont let the car coast i get around 20mpg but when i do it can go up to around 30

[INeedNewTires]

your mpg also depends on how much you let the car coast down the road.
are you guys calculating that into your mpg??? cuz thats kinda cheating between other people that dont

when i dont let the car coast i get around 20mpg but when i do it can go up to around 30

yea but you have to coast in gear.... Anytime you are 'down revving' or 'engine braking' in gear the injectors are completely shut off. I have a PowerFC and i constantly monitor the injector duty. Its pretty sweet, i'll leave it in 5th and coast to red light, and i'll down shift to 3rd but keep off the gas and i'll basically shut down the injectors the whole time. So I know some people will throw it in neutral and coast but thats actually less efficient than leaving it in a higher gear.

[corwin]

I had heard that coasting in neutral was less efficient than coasting in gear, and now I know why. Luckily I do that anyways. I still only average about 23 per gallon though =/

[beeracing s14]

what are the stuffs needed to be checked to get this ka perform at better gas mileage?