Just supposin'-if a Crossfire owner only runs his car in sunny weather and by habit keeps his engine compartment really clean anyhow, wouldn't removing the splash shield keep the engine bay a whole lot cooler? I seems that there is precious little airflow through this space.

Opinions?

 

if your talking about the underbody plastic protector, it also helps with areodynamics under the car, but you've still got to worry about rocks blasting into the under side of the motor, or plastic bags, or whatever oither debri people can't find the time to throw in the trash bin

 

I kinda' figured on all of that, including the benefits of high speed aerodynamics. BUT, if one isn't too concerned with 120 mph+ speeds, is there any other benefit? I think 95% of all vehicles don't have this anyway. Am I correct?
Or as most presume: am I full of it?

 

I thought most cars do have them. On lower cars you can hear them scrape the curb or wheel stop when they pull too far into a parking space.

 

We took ours off about a year and a half ago to allow for better engine cooling during runs. It helps the engine compartment cool down a lot quicker and we have had zero issues with debris or anything for that matter.

The underside of the car is not smooth enough to warrant a big effect in improved aero from this piece. When you get under there you will notice that it isn't even secured all that well.

 

That's kind of what I observed as well. (When I had my catback installed).

I'm going to make some measurements over the next couple of weeks allowing for these 4 conditions:

1. OEM intake tubes WITH splash shield.
2. OEM intake tubes WITHOUT splash shield.
3. Underhood dual K&N conicals WITH splash shield.
4. Underhood dual K&N conicals WITHOUT splash shield.

I'll use my trusty little Nitrod meter to monitor IAT and a Fluke with a K type thermocouple to measure ambient air temp somewhere under the hood.
Any suggestions as to where the thermocouple should be placed to provide meaningful data?

Of course I'll record outside air temp during the measurements too. In E. Alabama the temps are pretty much the same day to day.

What do you think? Is this a worthwhile undertaking?

 

Think of the weight reduction!!!
Better mpg, better acceleration etc. etc.

 

To be serious, I was thinking of this while sitting at a red light for 5 minutes in 104 degree heat and remembering the concerns of many about overheating and IAT's.

OK?

 

I think this is a great idea! Good luck, and I'm looking forward to seeing the results!

 

Max, I would set your thermo-couple just behind the intake at the manifold.

Just my Dos Centavos

 

I was thinking there or under/beween the OEM airbox and the center of the intake manifold, maybe spaced so it doesn't touch anything.

Which brings up another question: has anyone tried to insulate/shield the bottom of the OEM airbox from the intake manifold? There is a goodly amount of clearance between the two with damned little airflow. Either a reflective plate or fiberglass cloth could be installed? Just trying to block infrared pickup.

Even if it resulted in 5-10 degree reduction it should help?

Whatcha' think?

 

I have mine off and zero problems, to get readings I would suggest putting the probe into the tube feeding the Throttle body. I have measured the real inlet air to some benefit, that is what counts you know, Woody ENJOY

 

OK, but isn't the IAT (Inlet Air Temp) from the ECU going to give, if not the ACTUAL SAME, at least the RELATIVE SAME readings?
What's your take on this?

 

I do not know how you would get the temp reading from the ECU. The temps at the throttle body are important as it is an indicator of how the intake air sensor readings will be. The passage thru the supercharger even at idle add to this inlet air temp and if it get too high, the ECU will pull timing / boost and therefore power.

I just know that this reading will give a general feel for the temp benefits of any alterations, such as my current grill modification post in the SRT section. Enjoy

Woody

 

But, I don't HAVE a supercharger. Just a measly Limited.

I do know, however that the IAT is one of the many ECU parameters that are displayed using a Nitrod Performance Meter. If I have it hooked up when I start a cold car, it displays near outside temperature. This quickly rises as the engine temp rises. It also will display Coolant Temp, so please don't think I'm confusing the two.
The Nitrod interfaces with the OBD II dataport. What I am trying to do with this little exercise is to see if there is a safe and easy way to reduce inlet air temps with any combination of ventilation and/or insulation. I know for instance that serious folks will wrap the CAI with an insulating weave/cloth (fiberglass). I was curious if anyone has expanded on this with the flat, exposed areas of the OEM airbox.

I'm willing to perform the experiments, but don't want to duplicate known results.

Or if knowlegable people tell me I'm nuts!

 

well I don't know if there have been previous testing for the insulation but it would slow down the transfer of heat but it would also keep heat in for a longer period after you were done driving.

 

What I have noticed is a hotter hood surface without the airbox.
I think removing the belly pan for summer is a good idea to

 

I have taken mine off some time ago. Common sense would tell you that better cooling will occur with it off, but i'm no scientist. Maybe i'm getting .001 MPG better because its not there. Who knows.

 

How Max spent his Friday:

I finally got around to making some measurements. They are with the splash shield in place. The experiment conditions were:
29 Aug 2008
Ambient temp 92 deg F.
Relative humidity 61%
Cruising speed 75 MPH
Intakes used (A) 2 K&N RC-4650 on 3" Aluminum tubes 30 deg bend. (clean)
(B) 2 K&N 33-2290 in stock configuration. (clean)
(C) Same as (B) but with 1/4" foil faced self-adhesive
foam insulation on bottom of stock air box and filter boxes.
IAT = Inlet Air Temp (Nitrod/OBD info)
OT = Outside air temp (Crossfire dash display)
ET = Engine Temp/Coolant (Nitrod/OBD info)
UHT = Underhood Temp (Fluke/Ktype thermocouple.Placed midway between radiator and front of engine)

I ran up and down the I85 for 15 miles before each test to normalize. The temps displayed were stable +- 3 degrees for 10 miles.

This cost me a day and 1/3 tank of gas. I hope you folks appreciate it!

I will try to post this in columns. (I guess cut-n-paste don't work?)

(A) (B) (C)
OT 92 92 92
IAT 134 108 106
UHT 134 137 144
ET 191 192 192

A couple of observations.
The faster you go, the lower the IAT's (duh).
The slower you go the higher the IAT's (duh).

After (B) and (C), I let the car idle for 10 minutes just to see how hot stuff gets.

(B) (C)
OT 92 94
IAT 140 131
UHT 189 188
ET 200 201

My uninformed conclusions.

Having the intakes/filters under the hood is a really bad idea. No matter how cool it looks.

If you want cool air to "launch" with, you had better keep the revs up to ~3000 for 15 seconds to cool off the intake/airbox. I saw this effect.

My cheap-*** insulation job seems to have some benefit.

If there is any interest, I'll take the bleedin' thing off again and snap a couple of shots.

I have no idea how the material I chose will hold up over time. We'll see.

I know you all think I'm a PITA, but at least I'm not a worthless PITA!

Comments?

 

it was required by MB...Chysler had to put them on because MB buyers don't want oil leakage in their garages...myself, I like knowing there is a leak....mine is gone...will never resurface again...