Q MAF inlet temperature

[Q45tech]

Just for drill I rigged a accurate temp probe at the inlet of OEM air horn and another one in the air path infront of MAF.

the ambient was 90-93F AC on after 10 minutes to stabilize:At 60 mph the temp rise was 22F ~~ 113FAt 70 mph the temp rise was 15F ~~ 107FAt 80 mph the temp rise was 10F ~~ 101FAT 90 mph the temp rise was 6F ~~ 97F

Driving off the expressway after 10 minutes of traffic and 35-40 mph average speed with 2 red light stops of 2 minutes each the air into MAF had risen to 42F above ambient ~~ 134F.

Need another set of temp recorders to simultaneously record underhood at a few spots and to measure air temp in plenum....which is what really counts.

Within an hour rerigged to measure some of the radiator output air flow temp 164F - 157F at 60-90mph. This would be a rough and dirty estimate of a cone filter without CAI ~~ 50F higher at 60 mph and ~~ 60F at 90F..........the amount of hot air from the rad overwhelms any cooler air that might come in the the firewall air slot.........really need to mount a K&N to get more precise but it will not change more than a few degrees.

Couple of years ago tested a car with a K&N cone and a homemade air insulated air box being feed from the air slot.........it leaked air badly [no matter how hard we tried to fix leaks] sucking in HOT under hood air.

I wonder how well these aftermarket CAI work temperature wise.

Think I will spray some insulating foam on the black plastic parts of oem system.

The reaction time of the temp probes is not fast enough to accurately measure short WOT bursts.......my guess is no more than 10F hotter than ambient after a second or two of acceleration........at MAF input.

[maxnix]

the ambient was 90-93F AC on after 10 minutes to stabilize:At 60 mph the temp rise was 22F ~~ 113FAt 70 mph the temp rise was 15F ~~ 107FAt 80 mph the temp rise was 10F ~~ 101FAT 90 mph the temp rise was 6F ~~ 97F

Great data. I assume the above temperatures are from the probe immediately before the MAF Sensor?

[Q45tech]

No the temp probe was dropped down my existing pressure testing hole in the top of air box, so that the tip rested in top of panel air filter.

This was just a test of the heat pickup of oem from air horn in front of condenser thru resonators thru firewall and the airfilter box itself..........all the rigid black plastic stuff.

This is a low air flow test since even at 90 mph cruise [3000 rpm] the throttle is still 75% closed. The air flow is only around 55-60 CFM compared to 215 CFM at WOT [impossible to measure exactly because transmission would down shift and you would be in 3rd with higher rpms].

Read an interesting article about using temp probes on input , out of turbo, on intercooler metal, after intercooler in air path, to measure the heat sink ability of an intercooler. The author had 14 years of accurate data............to help one understand the effects of time vs temperature rises in intercooled applications.

Quarter mile racing 15 secs is quite different from 3,4,5,6 second highway passing [50-80 mph].......at 80 mph each 0.1 sec is 11.7 feet.....average in a pass might be 9 feet so 0.2 secs or a car length is meaningful.

Summer heat [AC shutoff delay, air density, etc] adds about 3 car lengths to a 50-80 mph pass.

Heat soak even in plastic.

Where and how to get the 4-8 grams [4%] x 5 seconds of chilled vaporized water for injection.

[HeavyDuty]

That's very interesting Dennis. I am surprised how much of a difference there is particularly at highway speeds.

Very interesting.

I'm working on a sealed box from another application, but for now it's just sitting on the shelf.

[Q45tech]

Actually the horn placement is at a pressure maximum so there is also a tiny boost at 90 mph.....[from a previous test] almost 1" WC =1/27.7=====0.036 psi ~~1/4% more power hey every 3/4 HP helps............this is at WOT only.In theory it would rise to over 1% at 150 mph.

This is not a positive pressure* just less restriction in the flow in front of MAF.

Well the outside air is always at pressure, what I'm saying is the 14.7 [29.92] is only reduced to 5/27.7=........14.7 minus 0.18.....14.52 psi at MAF.......then 14.52 +0.036= 14.558 psi at 90 mph.

Boy a 1.0 [much less 6 psi] supercharger look BIG when we discuss 0.036 psi boosts.

Some one invented the term [NEGATIVE BOOST] to describe the pressure losses from the air and filtration system.From the ouside air to the plenum the {neg Boost losses} are roughly 0.6 psi at WOT max rpm 14.1/14.7=0.9592 or 4%.........whereas the other 10-16% is from valve restriction and flow time/friction in the heads.

The temperature density variations over 80F ambient represent 7%..........hard to do much about air temp.