[Rick Reece]

After reading about John's use of a F-150 heat shield and getting a +45 degree temp increase I figured I could improve my simple dryer hose. During the Christmas Holidays I put my Insight up on Jack stands and looked at how I might improve the hot air intake. I decided that if I could get +20F from one catalytic converter using both would be even better. Since the exhaust seams to travel down the length of the car in a bit a cavity I figured I could block this off to outside air. Since the length of the intake was fairly long I figured I would put a bit of a scoop to push the air up to the airbox. THe intake consists of several pieces.

1. My 2inch plumbing elbow connected to the air box
2. A 4in dryer vent aluminum crimped over the 2inch elbow
3. A temperature probe inserted into the dryer vent at the connection of the above two items

Picture shows the above items
http://webpages.charter.net/r1957/Flipper/airbox.JPG

4. I used reflectex and aluminum duct tape to create a enclosed area surrounding the catalytic converter. This area connects to the cavity under the car moving back toward the exhaust resonator.

http://webpages.charter.net/r1957/Flipper/frontview.JPG
http://webpages.charter.net/r1957/Flipper/engineview.JPG

5. Lastly I used a home heating vent to create the air scoop.
http://webpages.charter.net/r1957/Flipper/airintake.JPG

I have had this on my car for about 5K miles and it seams to be holding up well. The lowest gain in temp I have seen is +70F but if I am in traffic or crusinging around town slow then 100F will be seen. The normal highway gain is 70-80F with uphill runs heating the temp occasionally to 90F. The gains in fuel economy are noticable but certainly not at summer levels (Guess the cold winter blend fuel) keeps a lid on how much the air temp can help with the mpg. Another advantage is that even in freezing weather the car warms up much quicker making autostop available. On the downside the scoop will scoop snow which I learned the hard way. Fortunately I didn't have to drive through very deep snow for long.

I have used a OBDII scan tool and the intake temp is usually a 5-10F below my temp sensor value. I suspect this is because the sensor is in the aluminum vent and is getting conducted heat from the metal. I have also noted that the oil temp is reading a bit high (180-190 range) and lastly the water temp stays around 197-199F.

I plan to leave it in this configuaration until mid to late spring but Robert had an excellent idea about wrapping springs around the catalytic converter. This would conduct the heat and provide a larger surface area for the heat transfer to the air. I think I may try this route next winter. Have fun, Rick

 

[b1shmu63]

Nice project Rick.

I converted the three panels under the engine into a single fiberglass plate myself. It looks like you have done something similar but have used an insulating and reflecting material and have included a fresh air scoop at the back. Pehaps I can just use some of that insulation and attach it to my plate.

Is the scoop is really necesary or effective? Wouldn't it create air turbulence and resistance? I could not use something like that myself because of the roads I drive on. Grass, stones and snow would certainly rip it off! I have installed a radiator block as well but have not done anything with the air intake. I was hoping to make something with a stainless steel sheet and a little silver soldering. Perhaps this summer.

 

[Rick Reece]

I don't think the scoop is all that necessary and yes it probably increases drag. I may cut it off in a week or two and see how just the enclosed area works. The only reason I put the scoop is that I was worried that the air flow next to the opening would work to pull air out making it hard for the engine to get enough air. Have fun, RIck

 

[Insightful Trekker]

So your seeing a 70 to 100F increase over ambient? :shock: WOW :!:

The best arctic <g> hot air mod yet :!:

FYI I think your BBcode url's are backwards the /url is the closing one and they don't display as links. A few minutes with some photo editing software to crop and compress the images would also be helpful. Not to sound ungrateful but the lighting and focus makes interpreting several of these pics difficult.

I'd be wary of IAT's in the 150F range, if that's what your system capable of. (ambient 50F +100F gain). Some of the plastic air box parts are likely to begin softening in that range.

 

[Rick Reece]

John,
Thanks I fixed the links. I also took a look at the pictures. They are very clear on my computer at home but from here (I'm in DC now) they don't look very good. As you can see I am not very efficient at posting these things. The 100F gain was noticed driving around town. I mostly cruise on the Interstate where the 70-80 range is common. The temp today got up to 138 for the intake for a high. I'll have to pull over and check the air box next time I have a really high reading. Have fun, RIck

 

[tubesguy]

Are these pics available anymore? It's getting a little cool here in Wisconsin, and I may have to get going on a hot air intake mod. Thanks - Pat

 

[Insightful Trekker]

Don't think Rick is going to pursue this mod. It appears that 100-110F IAT (Intake Air Temperature) is the maximum range a hot air "mod" has an MPG effect. So +100F over ambient is wayyy too much for all but "arctic" conditions

And his +100F mod had some underbody "problems" in regard to road hazard damage.

JoeCVT ( :?: ) had a similar mod to mine (see the url in my sig) and AFAK remember posted with pics in a ooold thread. Either of ours won't be as effective during the coldest part of what a Wisconsin winter can dish out, but better than nothing :!:

HTH!

 

[Rick Reece]

Sorry I deleted the pictures. I expect to put my hot air mod back in soon so I will take some pictures when I do. This time I think I will leave the scoop off. The goal is to have a intake temp in the 100-110 range so that you quickly get autostop in cold weather and it helps some with lean burn although the mpg numbers are not as high as a regular summer. Have fun, Rick

 

[tubesguy]

Thanks guys

 

[nortoncomando]

Small note on auto-stop: I think it looks at the outside air temp sensor (> 41 deg. F for auto stop) located aft of grill and forward of radiator. Mine was disconnected when I bought the car used and never got an auto-stop until I reconnected it.
Also, that trick with the climate control showing all the temp. read-outs in the car ( including intake air temp ) would be usefull in the set-up of this mod. Looking forward to new pics of mod.

 

[Mike Dabrowski 2000]

As nortoncomando indicates, winter FAS may in fact need to fake out that outside air sensor,
I have not made any attempt to date to do any warm air mod, but am looking at doing it this winter. It seems to me that the relatively big aluminum block, when driving in cold weather, acts as a heat dissipater. Warming the air helps with the vaporization of the fuel, but probably does not help much with keeping the engine in a nice hot operating condition, thus the improvement seen with blocking the radiator. I wonder if the whole block could be coated with some of that expanding foam, to about a 1” thickness. A coating of Vaseline could be wiped over all surfaces before the foam was applied, so the foam would not stick to the metal and wires. That way it could be separated and removed if necessary. It is possible we could come up with a mold to form contour fitting insulation panels?
I like Joe CVT’s automatic Hot air bimetal adjuster, as it allows the mod to be left on year round.
I like the idea of having a small plug in block heater as well to help out on those freezing morning short trips to the store that are the real MPG killers.
:wink:

 

[Armin]

I wonder if the whole block could be coated with some of that expanding foam,
<cut>
I like the idea of having a small plug in block heater as well to help out on those freezing morning short trips to the store that are the real MPG killers.

Hi, Mike!

I have been toying with the exact same idea! Mostly to improve the effect of my block heater, and to reduce cooling of the block during stops. Actually, I was more thinking about using some sort of flexible insulation, not expanding foam. Too afraid it would go into the wrong places... Foam-in-place packaging uses PU foam, but in a bag i.e. wrap the engine in two layers of plastic and then put the foam in-between. But the biggest challenge is to find a material that doesn't cause a fire hazard. And I don't like fiberglass...

Any ideas?

 

[Mike Dabrowski 2000]

Armin
Any insulation used would have to be non hydroscopic, or the first drive in the rain would soak it.
I like that aluminum faced bubble wrap attic insulation, I think it is called Reflectrex, or astro foil.
The outside is aluminum foil, the inside is bubble wrap, then another aluminum foil, then another bubble wrap, and finally a third layer of alluminum foil. It is a good radiation barrier, but only a fair insulator. It is pretty flexable,can be cut with scissors, so several layers could be used. It is made for attic rafter insulation, and is rated at 180 f. They7 also sell an adhesive backed aluminum foil tape for joing the stuff that works quite well.
Another possibily better solution could be cork board.
http://www.mcmaster.com/
search for part# 9354K11
Cork sheets are pretty cheap, do not absorb moisture, and are good to 266F. It comes in 1/2, 1" 2", 3", and 4" thickness a 12" X36" X 4" thick piece is only $18, and the same size at 1" is only $4.61 a sheet. One could glue up a removable cover.
Heat Flow Rate: 0.27 Btu/hr. x in./sq. ft. @ 68° F

Wonder how hot the main part of the block gets, anybody know?
Obviously the exhaust manifold and cats get hotter than the rest of the block, so it may not be wise to put any insulation near there, but it is a shame to waste the heat in the winter.
Lots of possibilities, just need to get the stuff and try it out. :wink:

 

[highwater]

I had been eyeballing this stuff:

http://www.engineheatprotection.com/products.html

Middle of the page I think, called wet blanket. Comes wet and dries into formed shape. Ceramic.

Randall

 

[Mike Dabrowski 2000]

Highwater
I saw the same type of stuff in McMaster carr, It has a great 2700F max temp, is pretty heavy, is not great insulator, can be re-wet, so it will get wet everytime you drive in the rain. It is best used on high temperature furnaces and piping. It could be applied directly to the cat or exhaust manifold.
McMaster Carr has a big insulation section with lots of choices, as well as good specifications on each material.
I am going to order a few pieces of the 1"cork and see how it is to work with. :wink:

 

[ethicalpaul]

I wasn't sure which Warm Air Mod post to add this to, but this one seems pretty current and reasonable...

I was at JC Whitney buying a center console when I decided to look for 2" air intake hose for my warm air mod. I had unsuccessfully looked at a Pep Boys store and various online sources.

Whitney part number ZX501577N is for 36" length of 2" I.D. aluminum flex hose and only costs $4.99 so I ordered a couple and I'll report back to tell how well they worked.

Thanks all warm air modders for your informative posts.

One question I do have is: are you guys moving your outside air temp sensor to inside your warm air duct? This seems like the best way to accurately tell the computer what temperature air is entering the engine to me.

 

[Insightful Trekker]

Paul,

Reads like your confusing the climate control outside air temp sensor with the engine's IAT (Intake Air Temperature) sensor. No need to "move" it.

HTH!

 

[ethicalpaul]

You may be right, John.

So if I understand you, the outside air temp sensor is only used by the climate control system, and is not utilized at all by the "important" parts of the decision-making system?

I remember reading that idle stop will only activate if the temperature is above 41°F or something...does that mean IAT of 41, or outside air temp of 41?

 

[joecvt]

The outside air temp sensor (near front bumper) is used by the climate control and sends messages back and forth to the ECM (main computer) so the sensor also helps determine autostop activation. There is a temp sensor inside the air intake (In the rubber tube from air cleaner) that goes to the ECM for things like air fuel mixture stuff.

JoeCVT - Just your average CVT owner

 

[ethicalpaul]

OK, if this is true, then shouldn't we move the outside temp sensor to a warmer location in an effort to have it better match the warmer air that is coming into the engine? Any downside?