Intake air temp data (Stillen Gen 3, need stock)

wstar

I got bored today with nothing else to do to my car today, and I logged some info on intake air temps with the Stillen Gen 3 intakes just to validate that they are in fact drawing cold air (not that I expected any different). Results are unsurprising. I was using a little handheld OBD-II unit that can log a minute or two of data at a time for review, so it took a few passes (and a few minutes of just watching live data as I drive).

Outside temps were around 61-65 F through the drive according to the Z's little info display. Intake air temp (IAT) dropped to about 66 within two minutes of getting on the highway at 70mph+ speeds. Coolant temps were around 195, oil temp similar, maybe 5 degrees higher on average (this was a very non-aggressive drive). Even when I slowed down onto the feeder road (~45mph), the IAT stayed down. When I got down to parking lot speed, the temps went up a few degrees, but still stayed under 70. A couple of WOT runs didn't phase the IAT either (just in case the increased engine airflow caused them to suck hot air from the radiator fins or something). Nothing I could do driving seemed to raise them. I was looking for ways to cause some kind of airflow or pressure problem - very high speeds, long slow curves, driving behind another car vs not, etc.

The only way to get them to raise significantly was to park the car and idle. Took about 12 minutes of sitting in a parking lot idling to get the IAT up to 115 degrees (and the coolant temp was cycling between about 200 and 214 as the fans kicked in and out). Leaving the parking lot and driving again, it takes a minute or two for the IAT temps to get back down to "normal". I suspect this is because the sensor responds slowly to rapid changes like that, as there's really no other rational explanation.

If anyone else has a generic OBD-II tool that can show them live IAT on a stock 370Z intake, it would be interesting for comparison to see how it does. I'm kicking myself now for not thinking of this two days ago before I installed my intakes. Given the design of the stock inlets (which is really pretty good for factory stuff), I imagine it does pretty well, although perhaps not as good as the Stillen setup.

__________________
7AT Track Car!
Journal thread / Car setup details

semtex

Cool info! Thx for sharing.

__________________
"There are no small accidents on this circuit." -- Ayrton Senna
316.8whp & 248 ft/lbs (Dyno Dynamics) | 319whp & 256 ft/lbs (DynoJet) (04/23/10)
Stillen G3 CAI, CBE, Pulley / F.I. LTH / GTSpec Ladder Brace / Setrab Oil Cooler / UpRev-tuned by Forged Perf.

RCZ

Yeah thanks for sharing.

Namir

Good to hear. I hope someone is able to do a similar test with the stock airbox as you suggested.

__________________
Ambition is the path to success. Persistence is the vehicle you arrive in.

G37S|6MT|PREM|NAV|Eibach|Ichibia|Injen

LiquidZ

And I think that's why the Stillen setup is going to be extremely hard to beat in terms of performance.

I am definitely getting the Stillen intakes in the future.

tranceformer

Thanks for the info. I've got cipher on my laptop, I'll try to get some datalogs of the stock airboxes this week. Although it's a bit warmer in TX than in NJ, it's worth a shot anyway.

__________________
Ray
2009 370Z Base Sport 6MT / 12.860 @ 109.09mph / 1.921 60ft / street tires
official 1/4 mile track times

Modshack

On My New 370 I've been monitoring temps also.. I'm a big CAI fan and have designed a few for other cars.. I have a Scangauge on my car so I can get a constant readout of both Water temps and IAT temps.. We did a little run through the country on Sunday..

Ambient temps were about 60 degrees.

Water temp runs consistently in the 180-183 range as long as the car is moving.

IAT's with the stock intakes ran between 72-75 degrees or between 10 and 15 degrees above ambient.

I'll be doing more testing in the future. I have a pair of standalone Temp Dataloggers that you can place in different locations and have them record data every few seconds or minutes. Might be fun playing with them.

__________________

Steal my car! (SOLD)...Now Porsche Cayman S
Oil Cooler DIY: Here!

t-ray

Be sure to datalog what happens to the temps(coolant and IAT) relative to ambient at idle as well, with the a/c on and off. That's always interesting to watch.

In my g, I found that with the a/c on the temps stayed close to ambient, because the electrics fans kicked on earlier. With the a/c off, apparently the temp threshold for the fans was greater, so the IAT's and coolant temps soared before the fans kicked on.

Its for this reason that I always have my a/c on at the drag strip while in the queue.

Modshack

Yup...I was in a store the other day and left the car off sitting in the sun...60 degree day. Switch on and the IAT temps read 156 degrees!

Within an eighth of a mile it was down to 100 degrees and continued to drop as the car aired itself out.

I have an intake system on my Vette that runs IAT's at ambient as long as the car is moving. On that car, timing starts getting pulled when it hits 86 degrees. Wonder what it is on the Z??

__________________

Steal my car! (SOLD)...Now Porsche Cayman S
Oil Cooler DIY: Here!

juld0zer

i relocated my IAT sensor to the pre-airbox duct (aircon compressor side). it's mounted about 2 inches from the mouth of the duct. My IATs and fluctuations are very similar to wstar's findings.

However i do notice this sensor responds very fast and as soon as i come to a stop, IAT starts rising quite quickly. Once moving again, it drops fairly quick and i've gotten it to within 1*c of the onboard ambient sensor temperature reading.

Car is stock with heat shielding tape wrapped stock airboxes & airbox outlet pipes wrapped in heat resistant mitt material. Filters are stock Nissan ones.

I'm attributing the standstill IAT climb to radiant heat from the radiator. Stick your hand thru the front grille when she's full warmed up and u can feel the heat radiating without sticking your hand in too far.

This is probably why motoIQ quoted a higher dyno output with the front fascia removed.

With the factory sensor, the IAT climbed slower when standing still and dropped slower so i'd say it's quite slow to respond or that may be due to distance from the intake mouth. When testing with hairdryer aimed into the airbox (filter holder removed, it seemed to respond quite quickly though.


NB: sensor is one from a Mazda3. @ 20*c air, it has the same resistance as the factory IAT sensor. I have it mounted in this duct because someone on the forum said the ecu takes IAT readings from the (US) driver's side bank. This is incorrect. According to the FSM and my own hair dryer test with scanguage to monitor, the ecu does indeed take IAT readings from bank 1. ie the side closest to the alternator. Either way, the coolant hose on bank 1's side seems to be radiating a lot of heat while bank 2's side seems cooler without this hose nearby.

showme99

This is pretty interesting stuff. Thanks for sharing, everyone.

SouthArk370Z

What are you calling the "airbox" - the box with the filter or the box on top of the engine? Ie, are you measuring temp at the inlet to the ductwork (near the radiator) or after the throttle body?

__________________
Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub
Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

juld0zer

hi there, i have the sensor inside the inlet duct to the air filter box. (the bit that gets removed during a Gen 3 intake install.

Putting it inside the plenum (that's what it's called right?) would get you a pretty good idea of air temps almost immediately before it enters the cylinder. but that would be heatsoak galore... and i'd need a different sensor capable of being in the hostile conditions of this region (vacuum, oil blowby, heat) which would be a covered sensor, ie one which reacts slowly compared to the bare bulb style type.

Plenty of debate over the effectiveness of IAT sensor relocation, where is the 'ideal' place to mount it etc but let's leave that to the GM guys. concept is the same though - reduce bogging to improve driveability & improve standing starts whether simply keeping up with civics or at the drag strip.

I dont have the gear to measure air temps using an independent sensor/device but i'd be interested in getting an idea of how much the air gets warmed as it passes thru the blazing hot pre-throttle body pipes. Does plastic really radiate less heat into the air inside? Does the air inside get heated at all due to the velocity it travels thru en route to the cylinder?
If the heating is minimal then i'd say mounting the sensor outside of the engine bay is a great idea on a n/a engine. FI guys would most benefit from a post intercooler mounted sensor though

SouthArk370Z

I'm experimenting with the same thing. I bought a spare set of ducts (from radiator support to TB on both sides) and am in the process of insulating the spares and hunting down an inexpensive multi-channel thermometer. You can check on my progress at this thread.

__________________
Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub
Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma