This is going to sound like a stupid question but it's legitimat. How much of an affect does the IAT sensor play in performance and/or gas mileage on N/A engines?

I'm asking because i've had my intake sensor plugged in-stream on my intake, i've run it all the way to the front of the car so that it's getting nothing but cool air (IAT mod??) , now it's just sitting in my engine bay and it has made no difference whatsoever in gas milleage or performance.

It seems to me that the purpose of an IAT sensor on N/A engines is pointless really because the intake temperature is not going to vary a lot under the hood. On boosted cars it definitely makes a difference because it can be the difference of a few hundred to a thousand degrees. That means a lot of change in timing, more aggressive timing.

I guess the sensor is just pissing me off, lol, but I might be wrong about it being practically useless on N/A engines. any thoughts?

it tells the ecu how hot or cold the air is commin in, which translates to more fuel or less fuel.

also works with the first 02 sensor to accomplish this...




if you think its practically useless, take it off and run without it and then watch your CEL come on, and your gas mileage plummet.

it makes a difference, it can also cause carbon buildup inside the engine from running too rich... the main issue of the ebay BS people are still dumb enough to buy....


relocating it.... good way to get it dirty and have it read incorrectly.


and on a boosted car? a few hundred to a thousand degrees? i call BS on that statement....

what car do you know that takes in air at 1000 degree temps????

boosted is more like a few hundred degrees, not a thousand, just making the point of an extreme difference in intake temps. Running w/out an intercooler you're probably in the 3-400 degree range easily.

I guess I should have rephrased the practically useless part to this, there's not enough of a difference in air temperature to matter where the IAT is located on a N/A car. I'll explain it like this:

I don't believe cold air intakes make any more of a difference over a warm air intake. If you place you're hand on the intake pipe after driving the car for a while, the pipe is nearly as hot as the head. it doesn't matter where the air is coming from, it still has to go through the heated pipes and it will warm up to the same temperature as a warm air intake would.

The only way I can see to getting a cold air to the engine is buy making a heatsink shield along the intake piping or insulate it. Then there would be a true difference in the air intake and the placement of the IAT sensor would be important.

i unplugged mine to install a grommet in the box.. i noticed my a/c isnt blowing cold air.. im not sure if this would have an affect on it




my magnaflow decal gives me 100 hp!

boost is not that many hundred degrees dude... else detonation would be a serious ordeal.

without methanol a kit i;ve been following was doing 5psi and turbo outlet temps were 175 F and intake temps were 115 F

with 8 psi, turbo outlet temps were 225 which is only 50 degrees higher with 3 more psi....

so your "hundreds of degrees" is def WAY OFF.....



even if you rephrase it, theres not enough difference in air temp?

what stuff are you smoking?


at night in most areas it gets down into the 60;s in the day times it can get upwards of 100 degrees....

40 degrees is def a large range of temp difference....


sitting in traffic where air flow is stiffled... and some long ram intakes being next to the ground.... the ground gets upwards of 140+ degrees during the day time....

so between night time and day time, usually most people drive their cars and some even in traffic where air flow is crappy....

theres a difference of 60 degrees all the way to one sitting in traffic where their filter is taking in air upwards of 140 degrees...

right there in extremes that 80 degrees is a large range.....


as it stands this is a quote from swaintech....

Quote:

Insulated headers also reduce radiant heat and lower underhood and cockpit temperature. By reducing air intake temperature 10°F, a horsepower increase of 1% results, a 30°F drop equates to a 3% horsepower increase. This is inexpensive horsepower.
Swain Tech engineers have developed several heat management products for use on headers and exhaust systems.

Quote:



so basically by not having the sensor reading where it should be reading.....aka some sensor thats telling the computer BS

or just having it dangling in the engine bay somewhere, you can be running lean when you should be running rich, or running rich when you should be leaning out.


granted short term most people who do it, dont notice, over time it adds up....


but you are right in cold and warm air intakes not really making much difference


for starters the opposite of cold is hot. they use the term COLD AIR INTAKE as a marketing gimmick. theres alot of clueless people out there that think they are magically getting cold air into their engine.......... sad common sense really isnt that common anymore....

realistically the only way you will get COLD air to an engine is strap a fridge to the end of the intake or wait till fall/winter and take your car out....

theres really no other way around it. cold air is air usually under 50 degrees....




but when you said...

Quote:

I don't believe cold air intakes make any more of a difference over a warm air intake. If you place you're hand on the intake pipe after driving the car for a while, the pipe is nearly as hot as the head. it doesn't matter where the air is coming from, it still has to go through the heated pipes and it will warm up to the same temperature as a warm air intake would.

Quote:



totally disagree....

i;ve driven from baltimore to great falls va, a drive of about 1.5 hours with traffic and durring the late summer. non stop driving, got there popped the hood, and had everyone there feel the pipe, nice and cool on a near 90 degree day.... less than 10 seconds later i brought out the laser temp gun....68 degrees.

so in near 90 degree heat, my intake pipe was not even 70 degrees.

reason? air circulates up under the hood when the car is in motion. we dont exactly have the infinity type cars that are aerodynamically sound.


also depending if your pipe sits on the top of the engine and touches it, thermal conductivity can come into play. heat is transfered easier by touch.


however back to the iat sensor....

when your car is sitting still, in traffic, stop light, etc.... no matter where the filter is, its not taking in air as it would when you are moving...

when i car sits in idle, is when it heats up....

intake temps will prob be higher when not in motion, or in traffic, than when you are on the highway....

these are all things the computer has to account for to make adjustments. thats what the IAT sensor is there for.


so yes there is enough difference to make a difference on where the iat is located to. if there wasnt, then those ebay scam BS resistor mods wouldnt screw up so many cars....

thats proof #1


proof #2 is the ambient air in the engine bay at a traffic light, will be way warmer than when in motion... the difference in a 300+ lb block of metal giving off heat, and a constant flow of air when in motion is significant enough to warrant putting the iat in the correct spot... in the intake tube.... not in a rubber hose, or hanging somewhere, or with something on the end to make the car run extrmely rich....

on N/a it prob makes even more a difference since gains and losses are way much harder to overcome.


its like anything in life, when you are smaller and dont have as much to spare, accuracy is key...