Thread: Under-hood Temperature Profile
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Old Sep 21, 2008 | 02:45 PM
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jbomar
Joined: Aug 2008
Posts: 73
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From: Edwardsville, IL
Default Under-hood Temperature Profile
Decided to instrument under the hood and record temperatures during actual driving conditions. I used a National Instruments DAQ module and my laptop along with (4) thermocouples to read temps. The instrument pack was setup so each thermocouple read and recorded 3 times per second.

https://www.crossfireforum.org/galle...4/ppuser/21897



The "Flight Engineer"!!
https://www.crossfireforum.org/galle...6/ppuser/21897


The thermocouple locations are shown in my gallery and are located in the following:
https://www.crossfireforum.org/galle...5/ppuser/21897

1.) Passenger Side Stock Intake Port Behind the Grill
2.) Driver’s Side Stock Intake Tube
3.) Passenger Side Stock Intake Tube
4.) Slightly Above and Behind the Throttle Body

Positions 2 & 3 were chosen to simulate many of the DIY intake systems I have seen on the forum.

I live in St. Louis and today’s test drive ambient temperature ranged from 76 to 81 degrees F. I will try to conduct this same test during colder periods and hotter as environmental conditions allow.

The test drive consisted of a “warmed car” beginning with stop and go city driving, followed by 60 – 70 mph interstate driving, another city driving segment, a second interstate segment and wrapped up with a final city driving segment. These segments are very apparent on the attached graph.

Notables:

1.) Stop and go radiant heat increases all temps dramatically during stops
2.) The Driver’s side intake tube runs cooler at speed but hotter at stops
a.) At stop the increase in Driver’s side temp is most likely attributed to radiant heat from the radiator hose, oil filter and power steering box
b.) At speed there must be additional air flow on this side of the engine compartment that leads to cooler temperatures
3.) Throttle Body Position maintains elevated temperatures through driving range
4.) At speed, the Passenger and Driver’s Side Intake Tube locations are approximately 40 deg. F hotter than the Stock CAI position
5.) Each of the spikes in CAI readings represents a vehicle stop.

I see the entire air intake discussion as a two pronged one: 1.) How much less restrictive are the DIY intake systems that stop behind the radiator than the stock system; 2.) With actual temperature data in hand, how detrimental is the 40 deg increase in behind the radiator systems versus stock? I think I may have access to some instrumentation that could measure the difference in airflow. If so I will add that to this discussion as time permits. I would certainly be interested in “performance savvy” opinions of this data!
 
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Temperature Profile.pdf (205.4 KB, 76 views)
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