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LeanBurninating 06-15-2009 03:11 AM

warm air intake mod ('98 Civic HX)
Sup guys.

Ive been running a PVC pipe intake for a while now, and im getting ready to swap it out for one that will soak up more heat. Im having trouble staying in lean burn mode, and this is likely one of the culprits.

So far, Ive had a friend of mine at his muffler shop take a bit of steel 2.5" exhaust tubing and crush bend it to make a good pipe that will work well. We pressed out the irregularities that the crushing caused as best we could. It doesn't look like a nice mandrel bent piece but it does look decent. The size and bend should be perfect.

I was just going to do only this, but then an idea came to me. I have been doing a bit of part time helping out at this performance shop for diesel pickups. One of the popular mods is called a heater grid delete. Check it out.

They remove this heater grid for a more free flowing setup. The result is a bunch of used factory heater grids sitting around at the shop. Yes!!!

Im going to look into it more and see how much one of these used factory units will cost, how well I can fit it in, and how hot this thing really gets. My intake requires some rubber fittings and stuff, I just want to make sure Im not gonna melt anything.

Im sure it probably runs on +12 dc volts, but I don't know if I need to put a fuse in line or?? Will I be wiring it right up to the battery? Is it possible to rig it up for variable intensity? I guess we'll find out.

If it works out I would like to have it on a toggle switch next to my e brake.

What do you think?

LeanBurninating 06-18-2009 02:10 AM

88 views and no responses? Hmm... maybe you people are starting to pick up on how many projects I like to talk about vs how many I actually go through with and get done. :o

Well I really should be getting this done very soon.

I had some good convo with the diesel guys today. I thought this header grid ran continuously, but in reality its only on start up, and on a big truck with two full size batteries it sucks out enough current to make it harder to start and dim the lights and everything. Apparently those batteries will drop from 12v to 9v when that heater grid lights. So for me and my one little battery this would not work well.

As an alternative, one guy suggested I use an $8 glow plug, since its cheap, its simple to hook up and integrate, and it makes lots of heat. Only drawback is that if it runs long enough, I've been told that it will get hot enough to melt itself after about 12 minutes.

I really like this idea because it allows me to run a (theoretically) very effective warm air intake, and also toggle it off for a regular intake. Ideally I would like to have two functions:
1) some heavy duty heating power, like one or two of these glow plugs that I can turn on for cold starting that will heat up to 1500 deg. F for the aforementioned ~12 mins, this working to get the car into closed loop faster, and then in addition to these I would like
2) some type of glow plug / heating device that I can run continuously while I drive. I thought about maybe making a hot coolant line wrap around the intake pipe, but I'd rather have something electronic that I can click on and off. Plus toggle switches are where its at. yo.

Some kind of continuous heating device... a glow plug that wont melt itself that I can run non stop. Warm enough to make a difference, but not hot enough to start melting stuff lol. Any takers??????

Keep in mind that whatever I use will be mounted into a steel exhaust pipe, so it will be heating the air passing by inside the pipe, but also heating up the pipe itself, then heat soaking the air even further.

I need your brain powa!!!!

Thanks for reading.

dcb 06-18-2009 04:29 AM

using electric power, from the alternator, to make heat, in a car? Don't know what to say. :)

What was wrong with collecting air from around the exhaust manifold?

Daox 06-18-2009 08:28 AM

Ditto. You're trying to use more power to gain efficiency... Why not use wasted power (exhaust heat)? The gains are guaranteed to be better.

stevey_frac 06-18-2009 06:17 PM

If you really want to get hot air, can't you put a heat exchanger on the exhaust, and let the intake air flow over it before it enters the engine? at low load, i bet that would be very effective.


Christ 06-18-2009 07:02 PM

You could put a heater core in the intake box (if you still have a stock intake) and run tap lines from your original heater core into it. The control would be as simple as a cut-valve on a cable from any older car... (88-91 Honda Civic for sure has them) or you could make a simple flap in your air box that would still allow cooler air to bypass the heater core, so you can somewhat accurately control temperature.

LeanBurninating 06-18-2009 10:44 PM

Thank you, oh voices of reason.

Unfortunately, none of these options include toggle switches. That just won't do.:D:D

Im using a modified intake with a cone filter, and I do agree that the best option is using exhaust heat...

However, first of all I can't switch it on or off like I can a glow plug. Also, I want to keep a short ram intake design, I want to avoid the power losses that come from snaking an intake hose all around the engine bay. The way I have it now its almost a straight shot.

A heater core would work well although I fear it is too restrictive on the air flow, and also a bit more troublesome to adapt to an intake pipe than just drilling a hole in the side to insert a plug.

Christ 06-18-2009 10:49 PM

A small heater core should almost fit directly into your intake's filter box (provided you use the original filter element). It also won't restrict enough airflow to make a difference, unless you drive at somewhat high RPM's on a regular basis... however, with the "fresh air" flap, you could easily get colder air and better flow for "performance" driving, as it were.

Just an idea though, and not fully thought out, by any means.

bgd73 06-18-2009 10:54 PM

that is a good idea..although, if late model enough, is there a means to hack maf sensor or other thermal sensor? could be as simple as finding on the intake to wrap to stay warm..or wherever it is.

LeanBurninating 06-19-2009 12:08 PM


Originally Posted by bgd73 (Post 110740)
that is a good idea..although, if late model enough, is there a means to hack maf sensor or other thermal sensor? could be as simple as finding on the intake to wrap to stay warm..or wherever it is.

Im sure there is a way to fool the sensors, and I don't know all the intricacies of how lean burn works, but I am pretty sure that lean burn engages only when it does because its safe to do so.

In other words if you fool the sensors into putting the motor into lean burn mode when it normally would not, you could be damaging things.

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