Poking around on NAM and reading some of the sound insulation threads, links lead me to a variety of products, some of which were applicable for heat insulation. So I thought, why not find something to put on the underside of the exhaust manifold shield to reflect heat away from the coolant reservoir? The theory behind the choice is to apply the product as close as possible to the primary heat source. The products I selected were from Design Engineering Incorporated (http://www.designengineering.com/), Floor and Tunnel Shield and Cool Tape.

I bought a handheld IR temperature sensor to take data from the following locations as indicated in the two images:

1 - exhaust manifold shield left
2 - exhaust manifold shield center
3 - exhaust manifold shield right
4 - tunnel shield
5 - coolant reservoir
6 - tube to coolant reservoir

I'm taking data after my commute to and from work. I'll stop, shut off the engine, pop the hood and take measurements. I will also take a few numbers with the engine running. My goal is to get at least 20 measurements per location since based on the numbers I have already recorded, they vary significantly. The numbers for the tube should be taken lightly since I could not get close enough to measure only the tube. I will provide averages and the variances when the collection is complete. I will apply the exhaust and tunnel shield and retake numbers from the same locations.





Inputs and comments are appreciated.

 

Sounds like a winner, look foward to seeing the end results.

 

I hope so Phillip. It is cheap (~$50 for materials) and easy (only two bolts to remove the exhaust manifold shield) so why not? I figure to have tunnel shield material left over from the manifold, so I will eventually also cover the forward part of the MINI shield. I have a hunch it may lower temps incident to the console.

 

Science rules.

 

What exactly are you trying to accomplish here? Changing the temperature of the overflow/expansion tank isn't going to affect the bulk temperature of the coolant that's actually flowing through the engine.

Or are you trying to protect the plastic bottle itself from heat? I know some of the reservoir bottles on the earlier cars were prone to cracking/leaking (not necessarily because of heat, though), but you already have one of the later bottles.

 

My goal is simply to reduce the heat from the exhaust manifold into the engine compartment. I realize the coolant temperature is not going to change. I appreciate the information on the coolant reservoir itself, I was not aware of that change.

Like I said, this is a cheap and easy process. I figure it is not a bad idea to reflect heat away from the aft engine compartment.

 

Have you looked into the M7 aero gel shield. there was a great article in MC2 in the May June 2007 issue.

 

harryo, I'm aware of the M7 product. The concept is similar except that "my" solution does not alter the airflow at all. And it is a lot cheaper, although, to be fair I have no idea how to compare effectiveness.

 

Maybe you can take 4 additional readings on each corner of the motor, just to see if overall underhood temp is reduced. Also record ambient air temp for each set of data. That will allow you to rule out a hot day vs a cool day.
Thanks for being methodical!

 

I will certainly be interested in your solution, I haven't purchased the M7 and if you come up with a better "Mousetrap" , I'm sure there will be alot of us beating a track to your door. Thank you for your determination.

 

Was there a final outcome on this?

 

Not yet, but I do have some data for folks to chew on.

The chart below shows data points (with high and low values removed) for the engine running for the 6 locations shown in the first post. There were 13 sets of data taken, so the plot shows 11. The plot is location temperature (recorded by a handheld IR temperature gun) versus outside temperature (reported by the gauge in the car). Statistics are also provided for the outside temperature and the 6 data locations.

I am only gonna make some general observations based on the statistics. The temps did not seem to be proportional to the outside temperature. Not surprisingly, the highest temps were on the manifold shield. I was surprised that the right side of the shield was consistently hotter than the other shield locations. The shield data was also the most varied, with the highest standard deviations. The coolant reservoir and the tube recorded the most stable temps.

 

Hmmm. Very interesting. Good science. Shows me very little tendency for the coolant to boil(?) -- Please correct me if I'm off base on that conclusion!!

If you plan to do more measuring in higher ambient temps, I would find it interesting also. Most of your observations are in what I would consider, as a SoCal resident, on the "cool" side. My system frequently loses coolant and turns the fan on due to what I think of as "overheating," even though I have the M7 aerogel heat shield (over the header in the rear of the engine bay). I have been concerned that it actually does not help due to reducing air flow, but I have not devised an experiment that would help to determine the "truth."

I have a tune that I know runs the car a bit leaner than stock, but I'm not sure what sort of exhaust temps or AFR's I am actually reaching on the high side.

I need more gauges!!

 

I recorded a few temps on the coolant reservoir (engine on and off) that were at and above 212F. I have no idea how long that temperature persisted.

I also do wish that temps were higher, but I want to put the material on now, just to finish the project. If I had a spare manifold shield, I could easily record more baseline temps when the weather gets hotter.

 

Keep up the good work, and thanks for sharing.

 

No problem Mark. NAM has been good to me so if can actually input content, it's pleasing.

BTW, since I see you're local (I work in Long Beach), I'll show you the shield when I'm done.

 

Very interesting. Like said above, Science rules. Will be watching for the after affects of the modification.

 

GREAT! I didn't notice you were a Beach person too.

I look forward to it. PM me when you're set. I'm off from this Saturday- 1/6.

 

I finally put the material on, the before and after images of the underside of the exhaust manifold shield are shown below. If nothing else, it looks a lot shinier! The material adds less than 1/4" thickness to the shield. It didn't take long, but its nice to be able to take your time and do a job right. I'll start data logging this week and when I get a similar number of data points to the compare with the before case, I will post them.

 

...finally!

The chart shows the data plotted in the same way as the baseline (Before) set. The table below repeats the baseline statistics, shows the numbers with the heat shield treatment, and lists the deltas (delta = after - before). I am pleased to report that there was a measureable reduction in the coolant tank temperature (column 5), an average of 9 deg F. The temps on the right side of the exhaust manifold shield were knocked down a lot, 82 deg F (column 3). I have nary a clue why the center and left heat shield temps were not reduced to a similar extent. Additionally, the standard deviation was less for the coolant tank temps with the treated heat shield.

Lastly, I am going to put the same heat reflection material on the front part of the tunnel shield to see if there is any further benefit. The minimum coolant tank temperature should be the temperature of the coolant itself. As the days grow hotter, I will take more readings to get an idea of temps under extreme conditions.

 

I don't think your approach will do much. What you need to do is ventilate the engine compartment. I have found (on 2 different cars, an Audi TT turbo and an '08 corvette) that if you allow air into the rear of the hood at the base of the windshiled (a natural high pressure area) you can reduce engine bay temps by 20 degrees. You can do this by simply removing the gasket between the hood and the firewall...Very simple. You're pulling cool air into the engine bay and it exhausts out the bottom of the car, taking the heat away form the items you're attempting to shield. On my Audi, I used USB style Temperature dataloggers to get the data. I did this while verifying the efficiency of an airbox I make for this car.. If you have any interest, check out this thread with data: http://forums.audiworld.com/tt/msgs/1574191.phtml

 

Wow...the results are impressive. It obviously is keeping some heat directed away. I look forward to seeing your future results. This is definitly looks like a cheap and easy way to significantly lower underhood temps

 

Modshack, this was a what-if exercise. I had no idea what to expect for temperature reduction. As you can see though, the application of the DEI material to the heatshield reduced the temperature of the coolant reservoir.

Your idea is very interesting also. Have you done this on a MINI? Is there any rattle with the hood?

 

After looking at the hood design of the Mini I have to conclude that this particular trick will probably not be effective. it is on the other cars I've tested because the hood ends at the cowl, sealed only by the gasket allowing for plenty of flow into the compartment. on the mini the hood shuts against the cowl trim and there is only a thin body line there for air flow. A better approach would be to provide Vents in the firewall between the engine bay and the HVAC plenum at the base of the windshield. This is already fed by the 2 cowl vents and an approach used on several cowl induction style intakes. Most of my experiments were done on a turbo'd Audi TT where the heat from the turbo at the firewall was literally baking components. Over time Vac lines and Wiring harnesses were deteriorating from heat. It was effective in this application. I don't think it's quite that bad a problem on the R53. The Bay is already ventilated somewhat by the Intercooler scoop.. The Mini does not seem to run particularly hot so I'm doubting any real long term benefit here...

 

I modified my M7 shield to help with the air flow and I have noticed lower temps as well. The concerns about airflow are valid, but can be addressed with just a bit of re-arranging.