I have the Frankencar intake on my 2000 GXE 5 speed. These results should be the same with any other under hood filter (Stillen, Berk). Keep in mind that I still have the front scoop connected and the lower scoop/tube from my OSCAI attached. These let significant air flow to the filter area while moving. I am sure if these where not there, the temps would have been much higher. I may block these off on my way home to see the results/differences, although the outside temps will be higher then.

I used a digital thermometer that had a long wire with a sensor on it. I attached the sensor to the Monster Flow filter, and had the display with me in the car. The outside temp this morning was 48*. My commute to downtown Pittsburgh was 11.5 miles.

Miles 0-3 from my house were mostly traffic free. While I was moving (25-40mph) the temps were from about 49*-53*. Stopping at a stoplight for 10-15 seconds, the temps would get around 66*.

Miles 4-6 where mostly residential streets, with several stop signs and mostly 15 mph driving. Temps were steady around 55* going up to about 64* while stopping for stop signs.

Miles 7-8 very heavy stop and go traffic, many red lights and speeds between 0-10mph. The highest temp recorded while sitting in traffic during this time was 104.9*. Once I would start moving, after 20-30 seconds of 10mph driving, the temps would hover around 75*-80*, but once I would stop, they would quickly go up to 93*-96* and over 100* if I stopped for more than 20 seconds or so.

Mile 9 was in a tunnel leading into the city. Never got above 5-7 mph for the next mile. Temps peaked at 113* and pretty much stayed there for the entire tunnel.

Mile 10-11 after the tunnel was across 2 bridges and then onto a short stretch of highway a minute or so after the 113* temps, the temps were back down to 54.5*. Once I got to work there was about a ½ mile of 15-20 mph with a couple of stop signs. The temps got up to about 65* at the stop signs and then to about 56*-58* while driving.

So the highest temp increase was 65* while stopping, I am not sure how much more it would have been had it been warmer today. So the much hotter air at rest could be responsible for the low end power loss that some claim with underhood filters. I have not experienced this, will the underhood temps more than double like they did when it was 48*. If so, you could see temps of over 200* while stopped. I will do this test again this weekend as temps should be closer to the 70’s.

I did not try this on the stock setup, but wish I would have. I think stage 3 of the Frankencar will be very beneficial as it will always be drawing cool air through the front-mounted scoop.

--Ray

 

Good work. Sounds like it's time for some sort of heat shield... or route a shop-vac hose from outside the engine bay to the filter.

 

I did something like that but it made a lot of noise and wasn't attached very well, the heat shield will be a must for the hot Houston summers

thanks for the info.--I may do the same thing this summer--anyone have ideas for a heat shield? I wouldn't know where to start on making one

 

I still have my OSCAI hooked up, so air from outside still blows into the engine compartment right where the stock scoop would meed the stock airbox. I am going to block that off at lunch and take a drive to see what happens.

--Ray

 

Yeah, I am about to install the FrankenCar intake soon and I was thinking of leaving the front air scoop as well. I think it should direct more air towards the filter.

 

when the temp was high during the stop and go traffic
did u observe any torque loss at low end? or it is too packed to floor it?

good job on the research

thx for the info

 

There was too much traffic

 

A couple of observations.

First, it's apparent that once the vehicle gets moving with any sort of speed, the underhood temperature drops significantly. That's because there's plenty of air flow under the hood to accomplish that when the vehicle is moving at speeds as low as 15 to 20 mph.

Second, although I'm also keeping my scoop and OSCAI connected . . . principally so that I don't have to relocate my sensors . . . I doubt that doing so is adding anything significant to my air flow. Without the vacuum created by the intake, there's nothing to draw air through the scoop/OSCAI. And by the time you're moving fast enough to push air through them, you've already got plenty of air flow under the hood to cool things down.

Third, the only advantage of a true CAI is that it provides cool air for the initial launch. Thereafter, it provides no cooler air than an underhood intake does.

Comments? Criticism? Epithets?

 

I blocked off the stock air scoop and my OSCAI air scoop, and driving on the highway at 65 mph the temps were basically the same (62*-63*) with the outside temp around 55*-56*.

Driving at lower steady speeds of 30-40mph, having the scoops blocked raised temps about 7*-9* above keeping the scoops open. Having the scoops open also seemed to cool it down faster after sitting at a red light for an extended period of time.

I thought there would have been a bigger temp difference. I did not get a chance to mount the sensor in the stock scoop, but I would assume that the temps would be very close to the air temp of 55*.

--Ray

 

Kul! I withdraw my second point.

I'm surprised that blocking the air scoop and OSCAI made so much of a difference in temperature at 30 to 40 mph. I would have thought that plenty of air flow existed at those speeds to provide identical temperature readings with or without the scoop/OSCAI. Now I'm glad I left them connected.

Good work, raynist.

 

What I want to know is why people are trying to make fact out of fiction? Dont we all just want to argue and assume what makes things better than others?

If you really wanted to get exteme, to test removal of hot air from the engine bay. Take the rear hood seal OFF and leave the CAI installed. See if the temp moves quicker. That way you have provided a "intake" and an "exit" for the hot air that has risen to the top. Not sure how much turbulance in in the engine bay at operating speeds to remove air. You'll have to be careful of hood flutter at this point.

Another point I would like to measure and not sure if it has been addressed yet is ambient temp versus what is going through the intake? How cool is the air in the TB vs engine bay? How quick does each cool down? I have a FC intake and extra rubber hosing that I just might experiment with...drill a hole and insert probe.

 

Go for it, Colonel. Knowledge is power!

 

Do me a favor and crank on the A/C while your stopped. I want to know if the radiator fans cool the compartment down much (fans come on when the A/C is engaged).


Dave

 

Hmm.. good point. It might be worth something, with Houston weather going up to 90's already i did notice that the car was a bit more responsive in stop-go traffic with the A/C on.

 

Let me see if I'm following your thinking, Dave. If the fans do cool the engine compartment down (and I assume they must . . . otherwise why would they exist?), would you consider wiring them so that they operate whenever the engine is running?

 

AC? You guys are !

With AC on, the ecu automatically bumps the base idle. Think about that.

AC is a heat pump. So cold air in car means what in the engine bay. Hmmmm

Also, AC automatically kicks in the radiator fans, why?? Hmmmmm

Sheesh

 

Methinks you missed the point, Jeff. The question isn't whether the A/C is running, it's whether the fans are running. In other words, do the fans reduce heat in the engine compartment when they're on WHETHER THE A/C IS RUNNING OR NOT? If they do, would it make sense to wire them so that they run all the time if we've installed an underhood intake?

 

Then why would they turn on at all? Run them all the time??? Even when you first start the car?

Methinks you are not understanding me posts.

 

Uhhhh . . . OK! Perhaps I'm being too obtuse. Does anyone else understand my question?

 

That is your question?? If yes, yes and it's been answered.

 

At the risk of appearing unable to locate the answer for myself, would you please be so good as to reiterate it? I'd be forever in your debt!

 

No way. You wanted controversy right?

Here is another kicker, when the fans are blowing, it drawing hot air from where and blowing it where??

 

Damn! Now there you've got me again. So what you're saying is that when the fans are on, the engine compartment gets hotter?

 

:spock voice: logic would dictate that if one considers the design of the fan and what it's purpose is, one should be able to come to a decent theory. Especially when temperatures regarding CAI and HAI have been discussed in length. :spock voice:

 

Thanks for your input, Jeff. Now back to my original question. If the fans reduce underhood temperatures, would it make sense to hook them up so that they're on all the time in order to (1) increase air flow and (2) cool the air being fed to an underhood intake?

Intelligent guesses only, please.

 

Are you deaf?! I answered that! The answer was intelligent, mabye too intelligent. hehe

 

The fans draw air through the radiator and would only add more hot air to the engine compartment.

 

Then if that's the case, why are they there? I was under the impression that a fan is designed to cool things down, not heat things up. Or is it simply an air flow issue?

PS: I appreciate the fact that you're willing to take time to explain things, Anachronism. Your maturity is noted.

 

The fans are there to cool the engine coolant (IE Antifreeze) when the car is not moving by drawing air through the radiator, when the car is moving enough air is forced throug the radiator to keep things cool. The engine coolant keeps the rest of the engine 'cool', at normal operating temps I belive the coolant is around 180 deg. The radiator transfers heat from the coolant to the air drawn through it, so any air drawn through the radiator will be heated significantly if the car is at operating temp.

 

And in some cars (not sure if it applies to Maxima's), the radiator also has the ability to cool down the transmission fluid.

As in Anachroism's post above, would it make sense to put a heatshield behind the radiator fan to funnel that hot air out elsewhere instead of hitting the engine directly?

 

Got it. Thanks for the explanation.