Testing: WAI's effect on engine warm up
 

I don't know about you guys, but its been cold here lately. As I type, its about 5F and dropping for the night. This brings about a certain problem with driving more efficiently, your car doesn't heat up as quickly as it used to. In fact, on my 21 mile drive to work, even with my full grill block and highway driving, the Paseo never even gets warm enough to open the thermostat most of the time.

So, this has got me thinking. Everyone claims that even if their WAI doesn't give them better mileage, it at least helps warm up times. I thought that sounds great for my heat problem, so I decided to do some testing.

I did three different tests. The first test was setup #1. It is what I have been running. It keeps the intake air a bit warmer than ambient (remember I have a full grill block that helps). Setup #2 was a simple flexible aluminum duct run up close to the exhaust manifold. Setup #3 was that same duct slightly repositioned, but with aluminum foil around it as a shroud in an attempt to scavenge more heat off the manifold. Pictures are below:


Setup 1:
http://www.tercelreference.com/downloads/paseo043.JPG



Setup 2:
http://www.tercelreference.com/downloads/paseo044.JPG



Setup 3:
http://www.tercelreference.com/downloads/paseo045.JPG



The test was simple, idle the engine for 10 minutes (long warm up time, I know, I'd be at least 1/3 the way to work by then) and log intake temperature and coolant temperature every 30 seconds. This is what resulted.


http://www.tercelreference.com/downloads/wai_test.jpg



As you can see, setup #2 (WAI 1 on the chart) was pretty much useless as a wai, it didn't heat the air noticeably at all. The coolant curve between setup 1 & 2 is nearly identical. My reasoning for #2 being somewhat slower to heat up is a very slight breeze outside. Setup 3 was done in the garage with the door open to correct this mistake.

I talked it over with Darin and he suggested the foil option. I just tested that setup (3) tonight. It was much colder starting out (15F vs 31F), but you can see the intake air did warm up. However, it really didn't have a noticeable effect on coolant temperature even after 10 minutes of idling! Again, the curve is nearly identical to the other two.

So, I am still trying to decide if there is a way to make an even warmer WAI, or if it is useless. I'm thinking, if I make it much warmer, it might help with warm up a tiny bit, but once the engine is up to temp the intake air is going to be scorching hot and may harm mileage. I think its at least semi-safe to say that WAIs don't really help with warm up times all that much, at least on this car.

It's a bummer when you go to all the trouble to set something up and actually test it, and don't see any significant change.

Still worth posting the results though - thanks.

How about a radiator block?

regards
Mech

That could work. I know Tim's already got a near 100% grille block, but the engine compartment is still open to the underside so there could still be flow through the rad.

Should add: Tim is violently opposed to the idea of using a block heater in this car. Don't ask me why. Ask him!

Another idea: electric water pump. Leave it off (or cycle it slowly) until coolant temp starts to rise.

Could also try insulating the engine. I know you know the value of insulation from all the work you've done on your house. Relatively cheap & easy, plus the unmodded cooling system can still get rid of excess heat if it needs to.

It stands to reason that he is getting almost twice the normal EPA mileage, so the heat losses would be reduced by probably 50%.

At those ambient temps with hypermiling, he could probably cool the car with the heater core, considering the engine and all the coolant heater and radiator hoses, as well as the exhaust are all radiating heat to the atmosphere.

I would leave a small opening of some configuration for the electric cooling fan to draw some air through if it did come on with a full radiator block. At least some way to monitor if it did come on at all. Careful with a full block because it could block any airflow that the cooling fan would need if it engaged.

I also wonder if the thermostat is working properly. If he is reading temps at the thermostat area, it may be that the thermostat is not closing completely, at least as much as it is designed to close.

Nissan factory stats would fail open, and the engine would never warm up properly.


regards
Mech

The thermostat was replace 2 years ago with a higher temp thermostat. Not to say it couldn't be bad, but I did have this problem last year too.

I can cool the engine with the heater blasting, haha.

There are vent slots on the underside of the bumper cover that let air in if the coolant fan turns on, and I am running an indicator light that tells me when the fan turns on. It rarely turned on the summer (only the warmer commute home in the afternoon), so in winter I'm quite sure it'll never come on.

I think I might try insulating the engine itself. Ideas on that would be great.

You've seen the images of the custom 1st gen Insight insulation "suit", right?

I think they're in this thread:

http://ecomodder.com/forum/showthrea...tion-6052.html

Apparently even your President wants you to do it.

"Obama Says Insulation is "Sexy"

(OK, he said "home" insulation. Same idea.)

Daox -

I'm thinking that if you want to start with insulation, maybe the end tanks of the radiator and the hoses would be a good place to start. The hoses could be insulated with dead air by putting larger hoses over them and taping off the ends with heat-resistant tape.

Insulating your intake box and tubing might also help, marginally.

If you wanted to insulate the block itself, and don't mind replacing a couple gaskets, you'd have an easier time getting something in there if you removed the intake and exhaust manifolds. If you didn't want to replace the gaskets, you could still get some fiberglass or something in there to pack the block and wrap it all together with aluminum foil, if you wanted quick and dirty. The other approach would be to make an attempt at actually sealing the engine compartment, with a full belly pan, engine cover/blanket, etc.

You might not want the exhaust manifold in your engine sandwich, but then again, if you drive really conservatively, maybe it won't hurt?