[pdl9dp]

anyone here monitor their air intake temps pre and post install.
I got a diablo trinity where you can monitor this and and am not convinced
that my cai is doing much. I plan on putting the factory intake back on with
a k&n panel and comparing the temps. the cai seems to work until the underhood temp builds up. being that the iat sensor sits just behind the radiator on the intake tube maybe that part could be insulated.
I wonder if we are giving up hp for more air on the cai but getting hotter air
than the stock system, as they pull air from under the fender as opposed to
the engine bay. I'll post my result's as soon as I get the k&n panel and mod my factory intake elbow to accommodate the bt catch can.
PS anone got a k&n panel fs.
btw I will be comparing against a arrington cai.

An input fellas?

 

[randycat99]

Yes, you are correct...when the engine bay temps reach roasting levels, it pretty much bakes through anything/everything in there, where cold air might chance to pass through. I, too, went down the path of employing insulation to major exposed intake tubing surfaces and the IAT. The engine heat can still eventually get through, but the heat flushes out a whole lot easier when you actually put some flow through it than when it was bare. When it was bare and temps got up there, it was pretty much a permanent condition until a "full night's" cool down.

I wanted to further experiment with insulating the intake runners on the manifold, but that seemed like a major task to achieve. If you look/feel on the underside of the plastic manifold, you can see they packed it with foam insulation there, too. I presume that shields the bottom of the intake from the unadulterated engine block heat (probably quells some engine noise, too, if you can believe it could possibly be noisier ).

Oh, that reminds me to get back to my original point- all the CAI in the world won't help, if the tubing that leads to the engine is baked hot enough to turn it into warm air anyway, right?

 

[Keavdog]

Definitey get more air out of a CAI. My new roto-fab does a pretty fair job of isolating the element and drawing from the cold air port like the stock air box.

A more interesting measure would be to look at your AFR. The CAI should increase the AFR and the tune should then add fuel to bring it back down. End result is more air/fuel and ideally more HP.

This was really noticeable when I replace my stock airbox after my maggie install with a CAI. My AFR numbers got dangerously high but the Stack Performance tune got me squared away.

 

[DBDLIVES]

Most of the "cold air" intakes dont do anyting over the stock airbox. Some actually do make a few more HP but not much. As far as the intake tube getting hot itself, well, there was an engineer on the Charger forums that went into detail about that. Cant find the tread. But anyway, he said that even if the intake tube was over 200 degrees the air would not be heated up from the hot intake tube. There was not enough surface area to affect the intake charge to heat the air. Also he said that the air was moving too fast through the intake to even be affected by the hot intake tube. So basically he said keep the stock airbox with a drop in filter OR get a known good cold air intake that actually gets cold air and has true gains on the dyno with the HOOD CLOSED. As far as heat soak on the intake air temp sensor itself, that's a whole different story. Relocating your intake air temp sensor away from the engine does help for a more accurate reading. Some of the good cold air intakes do relocate the intake air temp sensor.

 

[randycat99]

A hot intake tube, itself, will not heat the air inside it up quick enough, if you are traveling at WOT all of the time, but who drives like that? If you are just driving your car around town or parking between trips, that is PLENTY of time to accumulate a plug of hot air in the induction system. It's not always going to be feasible go wide open on the throttle for 13 sec every time induction temps catch up with you. Surely a CAI should have more use than just delivering benefits on dyno and qtr mi runs, right? I'd think so, since I didn't buy my car for either of those uses, altogether.

 

[Cuda340]

CAIs, at over $300, are not a good bang for your performance buck. I bought a MOPAR CAI because it looks good, sounds great, compliments my Billet parts, and may get less hassels from the dealer.

 

[WyGoSlw]

IMO, a CAI alone will not not give you 300.00 worth of performance increase. Adding a CAI, 180 TStat and at least a canned tune will give you the best bang for the buck. Looking for more that 30 to 40 HP you're now looking at way more money and engine components like heads, cam etc.
Just my .02

 

[Devil]

Most of the "cold air" intakes dont do anyting over the stock airbox. Some actually do make a few more HP but not much. As far as the intake tube getting hot itself, well, there was an engineer on the Charger forums that went into detail about that. Cant find the tread. But anyway, he said that even if the intake tube was over 200 degrees the air would not be heated up from the hot intake tube. There was not enough surface area to affect the intake charge to heat the air. Also he said that the air was moving too fast through the intake to even be affected by the hot intake tube. So basically he said keep the stock airbox with a drop in filter OR get a known good cold air intake that actually gets cold air and has true gains on the dyno with the HOOD CLOSED. As far as heat soak on the intake air temp sensor itself, that's a whole different story. Relocating your intake air temp sensor away from the engine does help for a more accurate reading. Some of the good cold air intakes do relocate the intake air temp sensor.

You're absolutely right, AND a Dyno won't show gains or loss of a CAI because they don't have proper airflow over the front of the vehicle. Only way to show that would be in a wind tunnel.

 

[SpudRacer]

A hot intake tube, itself, will not heat the air inside it up quick enough, if you are traveling at WOT all of the time, but who drives like that? If you are just driving your car around town or parking between trips, that is PLENTY of time to accumulate a plug of hot air in the induction system. It's not always going to be feasible go wide open on the throttle for 13 sec every time induction temps catch up with you. Surely a CAI should have more use than just delivering benefits on dyno and qtr mi runs, right? I'd think so, since I didn't buy my car for either of those uses, altogether.

I'm going to have to call this one... I agree with the previous poster that a hot air intake tube is not going to SIGNIFICANTLY increase the air intake temp. Even at idle you've still got a decent airflow through the tube. As stated, there is not sufficient surface area on the air tube to make a significant difference in the temperature of the air travelling through the tube. If it were water flowing through, do you really think cold water would flow in one side and hot the other... OK, bad example. A buffer of warmer air may lie in close proximity to the tubing, but the majority of the air isn't going to be affected by a hot tube unless the temperature of the tube were extreme.

 

[randycat99]

It's not an issue of the tube rapidly heating up the air inside. Unless you are standing on the throttle all of the time, there is just not enough inflow to displace the accumulated air that did get a temp rise from sitting along a hot wall long enough. The overall mixture of air that gets into the engine is decidedly warmer than than ambient. It may not be 200 deg that the tube is heated at, but it certainly won't be the 70 deg ambient. The overall mix may get to 110-120 deg during hot engine bay conditions as read by the iat. If you let it sit long enough (with very little vehicle motion and throttle doing not much more than idle) the air may get to 150-160 deg.

It all comes down to how rapidly you are displacing air inside there. Chances are an induction system designed to support almost 400 up is going to see very low air movement relative to its capacity if you are just moseying around town. The engine will then become "soggy" until you find some place to open it up, even if you have a magic cai on the end of the tube. Once you are back to crawling around town, the hot air then resumes accumulation inside the tube.

I've read this right off the iat so either you believe me or not. If not, it doesn't effect me in the slightest because I've already used the knowledge and information to my benefit. If something different works for you, then be well...

 

[Christovich]

It's not an issue of the tube rapidly heating up the air inside. Unless you are standing on the throttle all of the time, there is just not enough inflow to displace the accumulated air that did get a temp rise from sitting along a hot wall long enough. The overall mixture of air that gets into the engine is decidedly warmer than than ambient. It may not be 200 deg that the tube is heated at, but it certainly won't be the 70 deg ambient. The overall mix may get to 110-120 deg during hot engine bay conditions as read by the iat. If you let it sit long enough (with very little vehicle motion and throttle doing not much more than idle) the air may get to 150-160 deg.

It all comes down to how rapidly you are displacing air inside there. Chances are an induction system designed to support almost 400 up is going to see very low air movement relative to its capacity if you are just moseying around town. The engine will then become "soggy" until you find some place to open it up, even if you have a magic cai on the end of the tube. Once you are back to crawling around town, the hot air then resumes accumulation inside the tube.

I've read this right off the iat so either you believe me or not. If not, it doesn't effect me in the slightest because I've already used the knowledge and information to my benefit. If something different works for you, then be well...

This is just faulty logic, air does not "accumulate" in the tube, otherwise your engine would stop running. Even at idle the engine is sucking air through your tube so there is constant air flow. Now as for how much then obviously the farther away from idle you are the more the air is flowing, but it is always moving until you shut the engine down.

 

[Sndsgood]

right air is always moving thru the tube. when slogging around town sure allot less air is moving. but when your doing that your not really needing or making use of the power of yoru car anyway so it doesnt matter. when you want that cooler air and more volume of air is when your actually getting on the gas to go fast. so does it really matter if the air is warmer when your idling thru town?


most of these units sold i call warm air intakes. onlything i call a cold air intake is an intake that is pulling the air directly from outside the engine bay.

for most intake systems i think the biggest advantage your getting is a larger quantity of air over the tempature of it. if yoru filter is in the engine bay its going to pull in whatever temperature there air is in the engine bay.

 

[randycat99]

This is just faulty logic, air does not "accumulate" in the tube, otherwise your engine would stop running. Even at idle the engine is sucking air through your tube so there is constant air flow. Now as for how much then obviously the farther away from idle you are the more the air is flowing, but it is always moving until you shut the engine down.

I was saying that *hot* air accumulates in the tube, not just "air". This is all dealing with scenarios where the engine is NOT drawing in flow at WOT. If you are barely flowing air through a large tube, it's entirely possible the net heat flux into the tube may be comparable to the limited cooling effect of new air being drawn through at a relative trickle. The end result is overall air temp that is warmer than anticipated just by the ambient reading.

Think of it a different way, if you are piping in air at a slow rate into a hot attic, is the air coming out going to spontaneously be "cool"? No, it is going to be a composite temperature that relies on how much the hot attic air dominates vs how much the piped air dominates. If the pipe flow is a trickle, the outflow is going to be hot like the attic. If the pipe flow is a gusher, it will eventually displace all of the attic air, and the outflow will fall from attic hot temp to something near cool pipe temp. If the pipe flow goes back down to a trickle, the heat flux into the attic will slowly heat up all of that stored air mass faster than it can be displaced by the cool air trickling in. Eventually, the outflow temp will be dominated by the hot attic once again.

Whether you believe any of this goes on over 6-7 net feet of air passage at low average throttle over time prior to entering the cylinder head, I can attest that employing insulation on my car has certainly made a change to its heatsoak behaviors. That's all I really needed to know that I had achieved a benefit when it came to city driving beyond 25 min or successive trips between parking instances. It was never really about achieving max hp at WOT on demand. It was about maintaining fresh and perky performance no matter how I was running the engine. That means a WHOLE lot more to me in quality of the experience than simply hitting some number on a dyno and then ignoring how well it runs in any other use scenario.

 

[hdsoff]

Nope. We have "speed/density" sensors not "mass air flow". Sensors are sensors regardless of brand. Read here, Speed Density Verses Mass Air Flow - Why Should You Convert?

The horsepower figures marketing is feeding you is more like horse-s$!^. Just because you hear a load roar under the hood doesn't mean you are going faster..There is a Dyno sheet somebody did a couple years back on LXforums with a 5.7 Mag. Just sayin..

 

[06ssmc]

people over analyze the crap out of this with seat of the pants engineering and no r & d .
air temp is only one aspect of function. doubt that you will get as much volume with less turbulance with your stocker. these company,s have been around for decades , spent more than we will ever dream of on r & d , doubt any one here has more resources available to them !
JMO !

 

[Keavdog]

Anyone have the CFM flow by RPM? That would be helpful - but its my opinion that there's no way any air sits in a CAI long enough to be significantly heated even at idle. I would wager that the air temp at one end of the tube is nearly identical to the other end of the tube.

Drawing HOT air from the engine bay is an issue - hence my recent switch to Roto-Fab which does a better job of sealing the element in an airbox which draws from the same 'cold' air port infront of the fender.

I still belive the CAI is more about providing more air flow.

My car was running an AFR in the high 11s. I added an Arrington CAI (Carbon Fiber tube - for sale now btw ) and my numbers were up around 15 or so at Stack Performance. These number are amplified by the super charger but they still represent the fact that there are CAI systems that will move more air than the stock airbox.

 

[randycat99]

All I can say is put an obd reader on to monitor your iat in various driving situations (assuming it is still in a stock location), then decide if engine bay temps have zero effect on induction parts.

 

[DBDLIVES]

I think the whole point is that even if the tube was negative 500 degrees the air will still be hot because the air under the hood is hot. The "hot tube" is not the problem, its the heat that the engine is making. Even a good cold air intake does not work at idle in traffic because it will still pickup heat from the engine and road. I did a test last night at the track. I loaded the stock tune in and let the car cool down. I ran a 13.24 @ 105. Not bad for a stock R/T. I then hot lapped it and idled 15 minutes in the staging lane so the engine was fully heat soaked. Guess what, I ran a 13.27 @ 105. For some reason my car does not care if its hot or cold. I tested all the Diablo tunes and they all ran the same as the stock tune. 13.20's @ 104-105. My car could care less if its got cool air. Needles to say, I took the Predator off the car and its now back to stock with an SRT airbox.

 

[MoparTen]

I think the whole point is that even if the tube was negative 500 degrees the air will still be hot because the air under the hood is hot. The "hot tube" is not the problem, its the heat that the engine is making. Even a good cold air intake does not work at idle in traffic because it will still pickup heat from the engine and road. I did a test last night at the track. I loaded the stock tune in and let the car cool down. I ran a 13.24 @ 105. Not bad for a stock R/T. I then hot lapped it and idled 15 minutes in the staging lane so the engine was fully heat soaked. Guess what, I ran a 13.27 @ 105. For some reason my car does not care if its hot or cold. I tested all the Diablo tunes and they all ran the same as the stock tune. 13.20's @ 104-105. My car could care less if its got cool air. Needles to say, I took the Predator off the car and its now back to stock with an SRT airbox.

Think maybe the Mopar 10 hood scoop with direct air flow makes any difference? You must be a pretty good driver, those are real good times.
Congrats

 

[runner2go]

I think the whole point is that even if the tube was negative 500 degrees the air will still be hot because the air under the hood is hot. The "hot tube" is not the problem, its the heat that the engine is making. Even a good cold air intake does not work at idle in traffic because it will still pickup heat from the engine and road. I did a test last night at the track. I loaded the stock tune in and let the car cool down. I ran a 13.24 @ 105. Not bad for a stock R/T. I then hot lapped it and idled 15 minutes in the staging lane so the engine was fully heat soaked. Guess what, I ran a 13.27 @ 105. For some reason my car does not care if its hot or cold. I tested all the Diablo tunes and they all ran the same as the stock tune. 13.20's @ 104-105. My car could care less if its got cool air. Needles to say, I took the Predator off the car and its now back to stock with an SRT airbox.

Ok... 13.24 for the Classic is too close for comfort...

Time to get that Mopar'10 back to the track and shoot for a 13.0

Need to widen that gap a bit more than a measly 0.04 :disgust: