: Aurora airbox wrapped!



Aurora40
03-28-04, 10:43 AM
So, I wrapped it all up in reflectix and cleaned and re-oiled my K&N. It looks pretty nice, though obviously reflectix isn't as pretty as the black plastic.
I first cut a large sheet that would be big enough to cover the whole bottom piece. I covered one piece at a time for a nicer flush look rather than trying to cover the entire box. Plus, I can remove the filter now with no problems. Then, I slowly trimmed away to fit the sheet to the box.

http://members.aol.com/aurora402002/airbox/airwrap1.jpg

http://members.aol.com/aurora402002/airbox/airwrap2.jpg

Gradually the sheet started to fit very well over the piece.

http://members.aol.com/aurora402002/airbox/airwrap3.jpg

http://members.aol.com/aurora402002/airbox/airwrap4.jpg

Then I put the bottom airbox piece back in the car, bolted it back in, and put the PCM back in place. I think this shielding is what will help the most as it is the bottom that is so close to the tranny.

http://members.aol.com/aurora402002/airbox/airwrap5.jpg

Then I did the same for the next two pieces one at a time. I also wrapped the flexible intake duct to help a little more (and I think it makes the use of reflectix look less strange since more stuff has it).

http://members.aol.com/aurora402002/airbox/airwrap6.jpg

http://members.aol.com/aurora402002/airbox/airwrap7.jpg

And tada, that's it. It's all done. The stuff is fairly rigid, and the hood should hold it in place. If not, I may just run a piece of string over the top of it. The stuff is incredibly light. It's like wrapping the airbox in bubblewrap. In fact, it is bubble wrap with aluminum foil on both sides. The reflective face of the aluminum reflects heat, and the bubble wrap forms an air barrier between reflective sheets. It claims to reflect up to 97% of radiant heat. I suspect most of the heat into the box is radiant, since it only has a few small contact points with the body.

I also used the reflectix tape. It is foil tape and is maintains the reflective surface of the wrap.

I guess we'll see if it really does anything. It would have been good to have an AutoTap or something to compare intake air temps (does this car even have an IAT sensor? There is no IAT in the airbox or duct). I imagine the difference would only be less degradation of performance after long operation, not anything that would be noticeable in a quick drive. So who knows. But it was easy, cheap (about $25 total), and has virtually no downside (maybe 1 lb of weight added to the car).

Aurora40
03-29-04, 04:17 PM
Huh, no one cares, ehh? I'm quite sure this would be very similar on a STS/SLS airbox. It's cheap and easy with basically no downside. It ought to help on hot days or extending vehicle operation... :yawn:

BeelzeBob
03-29-04, 04:34 PM
Just not sure what it is going to accomplish..... Nice job wrapping it , though.

There is so much airflow thru the box at full throttle that the air doesn't really get heated up much at all with the production airbox. You can tell if you put a thermocouple at the air inlet and at the throttle body that this is true. At WOT, the air temp at the throttle body will drop rapidly as the fresh air comes thru and it will stay low as the residence time inside the air box is pretty short...so it doesn't get heated up much at all when at WOT...which is the only time you are worried about the air being cold anyway.

At part throttle and idling and such the air temp really doesn't matter. Cooler air might make a little more power...but more power at part throttle and idle just means that the throttle is closed more to keep the engine at the desired operating condition....so the air temp is sort of a moot point.

Actually, for fuel economy and good part throttle torque and efficient operation hot air is actually good. At idle and part throttle there is low flow thru the ports and intake so there is less turbulence to atomize the fuel injected by the injectors. Fuel is atomized by turbulence and heat.....with low turbulence the engine relies on heat to atomize the fuel for good combustion. That is one reason that the fuel is sprayed onto the hot intake valve....so that it stands the best chance of atomization before being pulled into the chamber. Injesting hot air past the valve also helps....so....hot air is actually a good thing for most operating conditions.

At WOT and higher RPMs there is enough flow and turbulence to atomize the fuel so the engine can run with colder air....but the air cools off pretty quickly (very quickly , actually) due to the high flow rate thru the box. The plastic air box and bellows connecting the sytem has pretty low thermal density so it doesn't hold a lot of heat to heat up the air anyway. It cools down very quickly with the air flow.

So....nice mod...but I am not sure what you are really going to gain by it....

Aurora40
03-29-04, 04:54 PM
Hmm, well there are a lot of corner areas where I dont' think the air would flow as much. This would give it more time to heat up. I have had a remote thermometer in the front chamber before, and it did run up to about 120F or so. I'd think air would spend about as much time in the airbox and flex duct as it would in the intake. I believe the intake can warm up incoming air... 1/4 mile folks tend to ice it down before a run, though usually not with a nylon composite intake manifold...

At WOT, mighten a fair amount of the less moving air in the corners and such get sucked in? I mean, I dont' spend hours or even minutes at WOT, rather several seconds.

Anyway, I only hope it will keep performance more uniform. And I don't see what it could hurt. Plus, it looks kinda neat... :P :)

Olds3.5
03-29-04, 05:13 PM
Nice work. I assume that you did it to keep the intake air cooler. It's true that combustion is more efficient, fuel economy better and emissions are lower when the engine is in its desirable temp range. But for someone looking for a way to get a little more performance, a home-made CAI system might be an easy way to get the PCM to reduce knock retard or richen the fuel mixture. I have noticed that on cool days, throttle response is a little better than on hot, muggy days (I live in Louisiana).

BeelzeBob
03-30-04, 01:17 PM
Hmm, well there are a lot of corner areas where I dont' think the air would flow as much. This would give it more time to heat up. I have had a remote thermometer in the front chamber before, and it did run up to about 120F or so. I'd think air would spend about as much time in the airbox and flex duct as it would in the intake. I believe the intake can warm up incoming air... 1/4 mile folks tend to ice it down before a run, though usually not with a nylon composite intake manifold...

At WOT, mighten a fair amount of the less moving air in the corners and such get sucked in? I mean, I dont' spend hours or even minutes at WOT, rather several seconds.

Anyway, I only hope it will keep performance more uniform. And I don't see what it could hurt. Plus, it looks kinda neat... :P :)

Compare the displacement of the engine to the displacement of the entire airbox and inlet assembly. The engine will pump enough air in sevearl revolutions at WOT to completely exchange the air in the inlet system. All that "stale" hot air hanging around will be gone in the first few engine revolutions after you snap the pedal to WOT....way less than a second.... The subsequent air coming thru will not be in there long enough to gain much temp and the low thermal density of the plastic will not impart many BTU's anyway.

Once again, the idea is good but within practical limits it won't really accomplish much.