Air intake temperature testing!
 

Well, I did some testing today regarding air intake temperatures on my car! I bought a digital indoor/outdoor thermometer that had about a 10ft lead to a remote temperature probe on it. I was going to do this with a nice digital gauge and wire it into the car permanently, but then decided there wasn't really any point, I just needed some good data to base decisions off of. Here's what I found: (all temps in Farenheit)

Location of probe: in front of airbox inlet ( approximately where a SRI locates the filter)
Ambient Temperature: 82
Temp @ ~ 40 MPH : 110
Temp @ ~ 70 MPH : 102
Temp after 2 min. idle : 135

Location of probe: in wheelwell cavity (where the CAI filter is located)
Ambient Temperature: 80
Temp @ ~ 40 MPH : 75
Temp @ ~ 70 MPH : 75
Temp after 2 min. idle: 92

Location of probe: inside air tube (just before throttle body, ONLY AIRBOX AND TUBE TO THROTTLE BODY INSTALLED)
Ambient Temperature: 75
Temp @ ~ 40 MPH : 98
Temp @ ~ 70 MPH : 98
Temp after 2 min. idle: 115

Location of probe: inside air tube w/ CAI installed
Ambient Temperature: 85
Temp @ ~ 40 MPH : 92
Temp @ ~ 70 MPH : 90
Temp after 2 min. idle: 98

Location of probe: inside air tube (CAI installed, wrapped with insulation)
Ambient Temperature: 82
Temp @ ~ 40 MPH: 86
Temp @ ~ 70 MPH: 85
Temp after 2 min. idle: 90

Location of probe: inside air tube (all stock intake, modified grill)
Ambient Temperature: 85
Temp @ ~ 40 MPH: 92
Temp @ ~ 70 MPH: 90
Temp after 2 min. idle: 99



This info just goes to show that the hole in the fenderwell provides a MUCH better location for the filter, as the temps stayed much lower, and were actually lower than the outside temp after the air started flowing. They also cooled down much faster after sitting at a light or letting the car idle for a few minutes. I'm not sure exactly how much effect airflow has over the probes accuracy, but I know that air flowing over an object will cool it some. I could see this when I measured the temp inside the intake tube, and its also the only way the temp in the fenderwell could possibly be lower than the ambient temp outside.
After I get my CAI installed, hopefully tomorrow, I'll measure the temp inside the intake tube again, and I might try wrapping the tube with some insulation with a foil outer to help repel the heat.

I've long suspected/known this about true air temps and the short ram/CAI wars that play out in these forums. I suspect far too many people equate "my car is louder when I floor it" with "My car is Faster when I floor it." Short rams may give gains over stock, but I can't see them equaling much less outperforming a true CAI. Before I changed my stock box I talked to lots of people who auto-x in STS and who've owned/tried both. To a person they all recommended CAI. My 2 cents.

Hey ES thanks so much for the info... I have an SRI already and about to order a typhoon here shortly.. but thought about opening up that spot a little just to give it more aifrlow and quite possibly cooler air... where did you find that unit for digital temp?? Radio Schmack or ? I'll probably pick one up and check it out myself too.. to see how it reacts around my area.. I'm curious.

I looked at Radio Shack, because I saw one on their website, but they said it was discontinued when I went in. I actually got it from Pep Boys, it was only like 10 bucks. I don't think it really needs anything more, although once I get the CAI in tomorrow and check the intake tube temp, I'm gonna put it down by the filter and keep it there for a few days to monitor the temps a little more long term.
As far as the Typhoon system goes, I really wouldn't waste my money on it. I picked up my CAI from ebay, it was $65 shipped to my door. The only thing I MIGHT do, is swap out the filter for one that I know is of high quality, and even if I spend $50 on that filter (unlikely), I'll have still spent less than half the price of an Injen or AEM. Aside from the filter, which probably won't make a difference, it's just tubing, nothing special. Even if you got 1 or 2 extra HP, is $120 worth it?

Well I know it is more than that.. and I had an E bay special too... and it kept hitting my master cylinder.. so I had take precautions to make sure it didn't hit anymore. You have to relocate everything etc.. and I'll be curious to see how yours performs... keep me posted.. and as for the meter.. we don't have a pep boys here, so I guess I'm pretty much SOL on that.

Ok, well I got my CAI on... I feel like it gained a little on top end and revs a little bit faster, but I definitely lost some low end torque. I didn't tell my wife what I had done, but she called me after she left with the car and told me it didn't feel like it accelerated from a stop as well as it used to. Also, I'm not really sure I can stand listening to the intake every time I hit the gas, it's a bit too loud for me, I had hoped the CAI would be quieter than a SRI, but I don't think it is. As far as the temps go, it did help, I added them to the end of the list.

Prote-J, as far as the ebay CAI goes, it seems to be a pretty decent piece. I am missing one of the rubber couplers for the MAF, but it doesn't seem to be hitting my master cylinder or anything else. I emailed them about the coupler, so I'm waiting to see what they say, and the only thing you have to relocate is the overflow bottle, but that's no big deal. Here's a link to the auction for the CAI that I got.

I also have the Ebay SRI and have no problems with it hitting the master cylinder. I used a small dremel and cut the left half of the coolant overflow bottle bracket off. It made a perfect fit for the new filter and maintained the stock coolant bottle location.

Also the filter is out of the way of the fan and right of the radiator. When I have the car running for 10 minutes at idle I placed my hand above the radiator in the stock location and it felt about like 110-130*.....same time I stuck my hand on my new filter and it felt like about 80*.

Just to clarify, the first location tested "in front of airbox inlet", I had removed the intake section above the radiator, all that was left was the airbox and the tubing that runs to the manifold. The probe was directly in front of the airbox in the engine compartment, not above the grill and radiator.
I think I'm going to cut out the top of the grill where the stock inlet is, and test the temp in front of the TB with the all of the stock tubing in place. Also, if leaving the stock tubing in place, it might help the temps to put some insulation with a foil outer layer on the underside of the tubing to help block the heat from the radiator and exhaust manifold.

If you compare the throttle body air temp for the stock and CAI system you will realize that the gains from cooler air from the CAI are almost entirely gone by the time it reachs the TB.

This is because the compontents used in aftermarket intake systems, aluminum piping conducts heat easily.

Yes, it may be cooler air entering the filter in the wheelwell location, but then it heats up quickly as it passes through the aluminum piping, hot from engine heat, and by the time it reaches the TB, the temperatures are near that if the stock system was in place.

The stock system made from plastic insulates much better than aftermarket aluminum piping.

Well, I feel like an idiot... I forgot to reset the ECU after installing the CAI. I just reset it, and it took it out for a drive for a little while... much better. Most of the low end torque seems to be back, although I'm sure the ECU is still relearning so I'll have to give it a few days to be sure. Its also a little hard to compare, as the noise of the CAI kind of plays with your head. I'm still not sure if the noise is worth the small gain on the top end though, my car is set up to be a driver, not a track car, hence the 50 lbs of sound deadening I added. Don't get me wrong, I LOVE a good exhaust note, but the intake seems a little obnoxious.

leungwingkei, you're right about the air temp, for the amount of drop at the filter, most of it's gone by the time it hits the TB. I'm going to try wrapping the CAI and see if that helps at all. Also, I modified the top of my grill similar to what Traveler had done, I'm going to test the TB temp with ALL of the stock tubing in place and the grill opened up in front of the inlet.

A noisy car doesn't make a fast car.

Well said!

I thought I would test the theory, and I drove around yesterday with my SRI, and then placed my hand on the tube right by the TB, and seemed quite cool in comparison to the engine. <SHRUGS> I dunno, I'll be curious to see what you find though 03.

In comparison to the temp of the engine, the tube is cool, but it definitely transmits more heat than the stock rubber tube.

Well, I completed two more tests this morning, they're added to the list above.

With insulation wrapped around the CAI, the temps took much longer to rise, and tended to drop faster as well.

After running with the complete stock system in place (I modified the grill like Traveler did, cutting out the top in front of the air inlet), I put my hand on the bottom side of the plastic, just above the radiator and manifold, and OH MY GOD!!, it was scorching hot! Some type of heat shield or insulation here could definitely help temps with the stock system in place.

My next plan is to try to draw air from the CAI location in the wheelwell, but leaving the stock airbox in place to keep the noise down. Also, leaving the resonator section that goes down by the radiator in place might help with the low end torque loss.