Before I get started....for those of you who are not aware.......IAT stands for Intake Air Temperature. Glad we got that cleared up.

We had a car pull up into our shop that just happened to have a Scangauge 2 inside it plugged in so I took the opportunity to do a little comparison test on the IAT of my car vs one of our stock Mazda 3s

Now the second thing I want to mention is that YES i am aware that the comparison car is not another Civic Si; however I just thought it would be somewhat relevant to do this comparison since both cars operate off of the same principle in regards to the air intake.....both draw their air from the front bumper area. When I get a CAI I will run another test directly comparing the two intakes from my vehicle alone. But this should give you a somewhat generalized impression of the effects.

Outside air temperature during this test was 83 degrees and the tests were done immediately one after the other. Both vehicles were initially sitting in broad sunlight for several hours prior to the test and both vehicles were warmed up before the test was performed. And both tests were done with the A/C off to prevent the radiator cooling fans from distorting the actual results. Intermittent stops did occur during the tests on both cars however they didn't last any more than about 10 to 15 seconds. Both cars were driven on the exact same route and encountered the exact same number of stops for roughly the same amount of time.

The Intake Air Temperature on this device is abbreviated ( "IA" )

I have highlighted the exact spot where the Mazda 3 draws the outside air into the engine. How do I know this? Well I just happen to work for a Mazda dealership. Kthnx

And I know the pics are crappy....but you can still see the results. Aside from the idle pics they were taken from a moving vehicle with one hand on the wheel and an iPhone in the other hand trying to gauge the shot while watching the road as well. Not to mention this was a spur-of-the-moment thing so I didn't have my fancy schmancy 200 dollar Canon with the ever-so-useful image stabilizer with me. So cut me some friggin slack okay. Kthnx

So anyway here you go..........

2010 Mazda 3



Mazda 3 Stock IAT at near-consistent 30mph speeds for 5 to 10 minutes



Mazda 3 Stock IAT after 15 minutes of idling after being driven.



My '06 Civic Si w/ Fujita SRI IAT at near-consistent 30mph speeds for 5 to 10 minutes



Civic Si Fujita SRI IAT after 15 minutes of idling after being driven.



So there you have it. Not much of a difference in the final results from the two cars. Could the results be different when I put my CAI on.....of course they could....but do you really think it will be a significant difference?? Maybe.....or maybe not. Keep in mind to that the stock intake on the Civic Si and this Mazda 3 is supposed to be less conductive to heat because of the material its made out of vs the metal tubing on my SRI. But the stock material doesn't seem to offer a dramatic reduction in air temps....at least not in this comparison.

We'll just have to wait and see the results when I get a CAI on my car.

In the mean time what are the two lessons we should learn from this given the present data. (1) It seems like the stock intake on a car is just as susceptible to significant heat soak as any aftermarket SRI....just on a slightly slower scale............and (2) The cruising speed IAT between the two is pretty much almost insignificant. Is 10 degrees (give or take) really worth the risk of hitting that unsuspected puddle and drowning your filter? Maybe it is for some of you. But while 10 degrees may feel like a big difference when you're at the beach.....in terms of your car's power output.....you're only gaining about 1HP for each 10 degree drop in IAT. And with this Mazda 3 drawing air directly from outside the engine bay and yet only being 11 degrees cooler than my SRI positioned INSIDE the engine bay....how much colder air do you really think the Si with a CAI is really going to be able to pull in?? Think about that. The results from the vehicles being in motion would lead me to believe that even with the intake being positioned inside the engine bay....there is more than enough airflow coming in to filter out a good amount of the internally heated air in the engine bay.

So the negative aspects of owning a SRI really become irrelevant unless you just happen to be sitting at a stoplight for 15 minutes with the guy next to you ready to burn some rubber with you or if you just happen to be at a McDonalds drive-thru for 15 minutes with the intention of immediately racing the first person you see after pulling onto the street.

Just a thought! Have a nice day.

 

LOL!

 

We've known this, also it's for every ten degrees celcius you have potential to gain one hp.

 

You're probably right. Or maybe the results from my CAI will be very similar. Like I said....i'll be doing another test that isn't so apples-to-oranges. Just for you!

 

Really? I would think that all the people cursing SRIs because of their heat soak and swearing by CAIs would be somewhat surprised at this. Like I said earlier....i know it's not a direct comparison with the same car....but it's just a temperature comparison from two intakes drawing their air from different places. Take it for what its worth and move on. I understand that most of you wont be satisfied with just these results and I'm working on that....but this is the best I could do for now and considering I haven't seen any other comparisons like this on this forum I figured it would be of some benefit to at least some people out there. If its not then oh well. At least I tried....it's alot more than I can say about some of the bland threads we've been getting lately.

If you're right then all it does is further enhance my point.

 

no thats a good comparison in a sense. But there have been test on 8th that are CAI to SRI temp test. I remember reading it and I can tell you that the CAI temps are much lower.

 

Well I was just looking through the site and the results seem to vary. One thing that caught my attention was a guy who did a datalogging comparison before and after wrapping his CAI in insulation. His cruising temp. at 65mph (before insulation) was still nearly 10 degrees higher than the ambient air temp. of 88 degrees.

 

Yes cai's collect colder air. The key word is celcius here, for every ten degrees celcius you have potential to gain one hp. Ten degrees celcius is equal to 50 degrees fahrenheit.

 

I seriously think you are incorrect. If I am wrong please tell me how.....but 50 degrees F seems a little to high.

 

Yeah your right. For every 10 degrees C is like 18 degrees F, I think I'm right this time.

 

lol Im not doubting you T3KNIQe. I was just trying to reference Rico to the info that was sort of given on 8th.

 

Its all good just had to throw that out there, now I'm done thread jacking!

 

lol. No I was referring to Celcius vs Fahrenheit. I was mistaken myself to........I believe it's 10 degrees Fahrenheit to 1PERCENT hp instead of 1HP.

Are you sure it's 10* C and not 10* F??

 

Short rams are total garbage on the 6th gen Si. The filter element is literally right next to the exhaust manifold, so if you've got a race header on there that isn't insulated, temperatures are going to be even higher than stock with a heat shield.

I'm not surprised to see the Fujita SRI running 32 degrees higher than ambient at speed, and a whopping 80 degrees higher at idle. When I used to own a Cobb AP, I used it to give a live readout of my AEM cold air's IAT -- on an 80 degree day, IAT is around 80F at speed, and never goes more than ~15 degrees higher at extended idle.

 

29 degrees higher....not 32. But look at the comparison to a stock intake piping its air from the front bumper...18 degrees higher than ambient and the idle is 76 degrees higher.....showing that even factory intakes are just as susceptible to significant heat soak.