Warm(er) Air Intake for the 1999 LeSabre - 1st Attempt
 

Here's my attempt at making a warm(er) air intake for my car. I had previously cut away a section closer to the front of the car. The current cutaway is behind the top radiator hose, closer to the engine. The old cut is closed off to ensure the intake air is coming from the engine bay. I also have a grille block, so I'm hoping the combination traps enough warm air.

Here are some photos:

Sketch, then cut:

http://i207.photobucket.com/albums/b...i/CIMG3717.jpg

Old on left, new on right:

http://i207.photobucket.com/albums/b...i/CIMG3719.jpg

Taped off for testing:

http://i207.photobucket.com/albums/b...i/CIMG3721.jpg

Installed:

http://i207.photobucket.com/albums/b...i/CIMG3723.jpg

Have not had a chance to test it yet. Feedback welcomed!

Are you monitoring IAT somehow?

Yes, with my ScanGauge.

I'm hoping this shows warmer temperatures for highway driving. Around town is all right. Highway is 10*F above outside air temperature. When it's 15*F out and the car is gulping 25*F air, the engine is not liking the cold air much. Last winter when I visited New York, the car knocked so badly that premium became cost-effective to boost fuel efficiency. Warmer air means less knock, at least for my car.

Would you be willing to try a manually controlled intake heater? I can explain the mod, though I'm not sure if it will fit in your airbox..

Please do explain.

First, I should qualify this by saying that I haven't done it to any of my vehicles yet, so the result isn't predictable 100%.

You'll need a small heater core (that fits in your airbox, or that you can mod into it), enough hose to reach from your OE heater core lines to the airbox, two Tee fittings, and a heater control valve.

You'll install the heater core in the airbox, tee off the lines to your OE heater core, and install the flow valve on the input side. Run an old choke cable into the cabin from the flow valve, reinstall your airbox as normal, and burp the coolant system.

As the engine warms up, you'll have warm coolant flowing through the heater core. You effectively have a temperature controlled heater in your intake, which will give you the option to adjust for super-hot, super-cold, etc.

IN addition, you can adjust on the fly, while watching for instant economy and faults on your SGII.

That's a neat idea! You'd let the incoming air get as hot as you wanted via scavenging the heat the engine is otherwise bleeding into the air. I think that would definitely increase efficiency if implemented.

The heater hoses are kitty-corner to the airbox in my engine bay, so it would be an octopus of coolant hose running around the engine bay. Plus finding a heat valve that was not vacuum-actuated. Not to mention getting a small-enough heater core. It'd be a challenge on this car.

Well, most Japanese base models have cable actuated heat valves. The cores are pretty small, too, but if you can braze, you can cut one down on your own to fit. The snake hoses are going to be a problem, most likely.

I still intend to try this some day on something. Eventually. :rolleyes:

Bolting together is as complex as I can do.

I tried running errands this morning, and in some cruising at 40 mph the air temperatures got up to 90*F. It's about 46*F right now, so at 40 mph cruise it's good for a 45*F increase in air temperature.

More testing will be done this weekend when I do a roadtrip to central New York.

Does the 3800 really knock when it is cold?

Some do, some don't. The SC motors, that I know of, never did, but I believe they had lower compression, as well.

3.4's sometimes knock a bit as well on 87 octane, the fix is to spray warmed water from a spray bottle into the intake for about 5 minutes after it's warm. You'll see the carbon crap come out the exhaust.

It shows up on my ScanGauge as timing pulled because of knock. I remember one 15*F night last winter blasting down the freeway and seeing a constant 2-2.5* of timing pulled because the computer was detecting knock.

I have the naturally aspirated 3800. The supercharged ones do knock as well. Battling knock is a constant struggle in the 3800 community.

My engine should be pretty clean. I've been running a dose of Marvel Mystery Oil in the gas for the past few thousand miles. I forgot it this tank, and the car's letting me know.

When I hooked my SG up to my brother's 3400 powered minivan, that thing knocked up a storm on 87 octane.

I have not had any knock problems that I know of.
 

But I don't have a Scanguage either. Want one though. I always run premium anyway, but even when I used to run regular, it never knocked.

You could try unplugging the knock sensor and see how performance/economy is affected. I don't know if the ECM requires the feedback or not. If it does, consider removing it and placing it somewhere other than the engine.

I recently thought about doing a very similar mod. I was thinking of taking the return line from the existing heater core, and cutting it. Then run one side of the return line to the intake of the air box heater core and the outlet to the other side of the return line. Basically put the new one in series with the return line from the existing heater core. To control the temp, I would use a flapper valve in the airbox, controlled by a push/pull cable. No need for a flow valve.:thumbup:

I can feel the engine pull timing and spark advance at times. It's staying plugged in. I'd save a bit in fuel and be spending $500 for a new engine when it predetonated hard enough to cause damage.

This engine is fickle. I'll see what this airbox does.

I respect your choice, but I will note that often, the knock sensor will pull timing "just for the hell of it". IOW - the engine runs a bit different than it did when it was new, and the new pattern of resonance just happens to fit what the knock sensor is looking for. It's happened. Alot.

But, there's nothing wrong with not wanting to risk it! :thumbup:

Thanks for the info about the knock sensors! Your statement does explain some behavior of the car. Sometimes, like when going uphill, it definitely knocks. Other times, like taking off from a stop gradually, it'll pull 12-14* of timing randomly.

Driving around tonight, the air temperature stayed pretty constant at +40 over ambient. At least for in-town driving, it's a success. Highway will wait until Saturday.

I've gotten better behavior out of knock sensors by taking them off and cleaning the sensor and the mounting surface well. (The threads in the block if its a threaded in type.)

Also if your sensor is in the head, make sure you have no rocker noise, it will casue issues.

Dave

Hmm, maybe some DynaMat around them is a good idea...

I have been thinking about something like that also.
 

I was thinking of running it parallel to the existing heater core to avoid reduced flow. I like to have plenty of heat when I want it. It would be good to have a way to disable this mod on hot days for cars that don't do well with HOT air. I think I have a tranny cooler that would fit in the air box.....

Isaac -

That's what the flow control is for. Most older Jap vehicles have them, they're cable actuated. If you're good enough with electronics, you could wire up an ARDuino or something similar to control a stepper motor with a thermostat circuit to constantly adjust the valve to keep a specific IAT setting. That would prevent the over-hot intake in the summer.

Although, if your hottest setting only gets you optimal temps, it's not going to get any worse in the summer. Your thermostat controls the engine coolant temp regardless of season.

Also, if you started to overheat to the extent that the intake heated up too much, it would act as a self-cooling device. The hotter the intake air is, the less fuel the engine injects, so the less heat is released into the engine. It's sort of self-regulating. Thats why I like the idea so much.

So the results of driving around for a few days are back. The airbox gets ~ 30 degrees warmer than ambient on the highway. It needs a duct to a heat source or a heater inside it to get warmer.

Sorry to bring up an old topic, but I have a similar car so I am interested in the mod.

Do you have any updates on this mod? Looking at mods that the average person would never know is there. Boat tails are out.

Don't have a scanguage yet do to financial reasons.

It will raise the incoming air temperature about 20*F. It helps some in the winter.

This winter I'll try getting even warmer air into the engine with a snorkel arrangement to the exhaust crossover pipe. Seeing a 30-40*F increase would be great for winter highway MPG.

Thanks, I am working to improve on my dismal 22mpg current average. I did notice that after taping of the opening in the bumper that my engine temp is slightly raised. Planning to buy a scanguage in the near future so that I can get real data. I don't trust the GM guages too much.

So tomorrows plan is to recheck tire pressure. Tape off some more of the grille and possibly change the spark plugs. I bought them last spring and still have yet to install them. Also need to check the air filter. Have just changed the oil and recent trans fluid and filter.

Allen

Check out my topic on a polycarbonate grille block for the upper grille. It's still working just fine.

Did you tape off the lower or upper grille? I'm curious because I think taping off the drivers side lower grille would be great in the winter for increased air temps, and faster warmup. The radiator outlet is in the lower left, so it would still be plenty cool with 3/4 of the grille blocked off when the temperatures are below 50*F.

The GM dash gauges are trash. The two my car has lie like criminals. My ScanGauge is much more accurate, especially for fuel economy.

I taped off the lower section completely and left the upper grille alone. I didn't hear the fan come on at all.

Also, you want a ScanGauge since a tiny pedal effort is the difference between 25 mpg and 31 mpg...

http://i207.photobucket.com/albums/b...i/CIMG3267.jpg

http://i207.photobucket.com/albums/b...i/CIMG3268.jpg

http://i207.photobucket.com/albums/b...i/CIMG3270.jpg

That's my old grille block, and ScanGauge. Right now half of the right grille block is removed to help my fans not kick on at 186*F. The computer is reprogrammed.