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As we know by fuel maps, intake air is crucial to achieving the most efficient engine operation. I know this site focuses mostly on technique, but I need some help with those with experience who can help with an engine modification.

From the Integra's computer, 80-90F IAT produces a dramatic improvement over any other temperature. I'm trying to implement a 2-tube intake design, with valves that direct the air from the appropriate source (outside cooler air, or underhood hot air) to get that optimum temp. (for example on cold starts where you want that hot air to lean out the mix and get to closed loop).

The problem is -- where can I get an actuated valve assembly? Furthermore, I know that the IAT signal can be tapped-into, design a circuit board that interprets and adjusts the valves, or even a simple manual design with a knob. I suppose it could be an electronic servo or vacuum control apparatus. :confused:

Furthermore, if a fully automatic version is designed, I'd need some basic electronic advice as to how to design the board. On another site, I've provided the full hypothesis and structure for the project and subsequent experiment (available upon request).

During testing, engine intake temps dramatically improved mileage on a test loop.

Thanks in advance for any help!

RH77

Hi Rick:

___You know Ford used to offer a thermostatically controlled intake pipe into the intake horn of the air filter housing to take warm air from the bay or somewhere under the hood to assist in maintaining an even intake temp in cold weather ops. It did not matter what the external ambient temp was for this to work once the bay was up in temp. I bet if you found an older Ford mechanic, he would know exactly what I am describing and may be able to set you up with a minimum of fuss?

___Why not head to a local NAPA store and speak with one of the old timers there as he/she might be able to help you with this controlled warm air intake contraption I remember seeing in the distant past?

___Good Luck

___Wayne

Wayne-

Oh yeah -- my old '77 Oldmobile had one of those. It would take heated air from the exhaust area using a rudimentary mechanical valve at startup, and direct it to the carb. IIRC the tube kept popping loose, and after 16 years of operation it rusted closed. I think there was a vacuum line that kept it from staying open once warmed-up. Those were the days :rolleyes: -- adjusting the carb to the weather and barometric pressure conditions. First car -- good times.

The Honda engine design is very particular to IATs. I've found a huge increase in FE around the 90-F mark, and the pulse is much easier to manage. The ECU fights against any other temps, especially below 50F.

To include cooler temps during those blistering summer temps of 90-110F ambient, I'm invisioning an electrical servo design that can be controlled in the cabin to include a hot and cool mix, or at least automated.

RH77

Why not go with a manual control? Call it a "choke". Can automate it later, when you have more data.

Hi Rick,:Banane49:

I have been working on a permanent 2 tube design also, for the Insight. Got the hot air (default/primary) part done and installed. The cold air mixing is waiting on the control/hardware to be decided on. I have found a small stepper/linear actuator motor from Hayden Switch and Instrument, that will fit inside the Insight air filter box, and regulate the ambient cold air intake. I will have to make the plunger ball thingy to fit on the end of the actuator shaft, and decide how to control it (cold air mix). I'm a bit afraid to price the little stepper.

That said; if you are thinking of something along these lines, you might be scrounging around for some defunct office machines, as there could be some small linear actuated stepper motors inside. I'm thinking along the lines of printer/copier carriages here. Might even be 12v, could be 5v.

Randall

Why not go with a manual control? Call it a "choke". Can automate it later, when you have more data.

I've been going back and forth with the decision process on this exact notion. The problem is, my time available in the garage is pretty limited since I travel for work quite often. I end up with the first stage of the project and then months later, get around to the next stage. This would be the 3rd iteration of temperature-adjusted intake air testing. I have a set of data from tests that 90F air can yield a statistically signficant increase in FE over: 60F and below (linear decrease from fuel maps and testing -- similar to open loop conditions), 100F, and 120F - 220F. So, I've decided to go "all-in" with the project :Banane17:.

Highwater: I've gotten some input on implementing a 2-tube design using scavenged throttle bodies and servos. The plan is to manually control the servos with a knob until a circuit can be designed using the IAT voltage signal. I have an old fax machine that I'd just love to "Office Space"-ize, but first, there may be actuators in there that could operate the throttle bodies. I'm a bit rusty on my electronics, though...

RH77

What kind of "significant increase in FE" are you talking about here, percentage wise?

What kind of "significant increase in FE" are you talking about here, percentage wise?

Compared to stock, Winter temps of 40-50*F IAT, I can achieve about a 10-12% increase in FE by simply getting the intake temps right (this is based on a SG verified route of 30.2 MPG at ~40*F and 34.1 MPG at 90*F.

Lately, with the increased ambient temps, IATs have been running as high as 120-140*F, which is counter-productive: the injection system attempts to cool the charge by introducing more fuel. The result is a light ping, reduced FE, and a reduction in power. I still haven't regulated the intake yet -- it's strictly from the engine bay

The ECU (from the shop manual) prefers the stated range for optimum engine efficiency.

RH77

Whoa... a 10% increase is quite significant. Anyone know if the TCH would respond similarly? This might help explain the few tanks I exceeded 45mpg with my Camry. The temps in the morning hovered in the mid 70's and afternoon in the mid 90's on the one tank I got 46.5mpg on.

RH77

Ive been playing with this in my mind also. But first I wanted to get a good feel for what was best for my Civics default tune. Just from watching my SG Ive got a seat of the pants feeling that anything below 50f and above 105f intake air temp is bad. Anywhere between 60f and 90f seem to be ideal. Ive pushed it up to 120 to 140f intake temps. It does more harm than good.

So Ive basically abandoned the thought of a auto control system for the time being. Ive found out for spring and fall driving. Just unhook the factory cai and let it draw from the engine compartment. Come winter stick in my $3.00 hose from the auto parts store. Come summer put the oem cai tube back on and keep rolling. The oem cai and wai tube both store very good with the spare tire in the trunk. The first removal of the oem cai tube kinda sucked. I had to pull the battery to get two 10mm nuts and bolts. Then a simple yank got the rest of the job done. To put it back in for summer use is as simple as stabbing it into the resonator box and slipping the rubber end back over the air box nozzle. A small amount of silicone grease on the rubber makes this a snap. One application will last years. LOL The two bolts that had to be removed now act as location pins. It works out very well. I can make the seasonal change out in now in less than a minute if I hustle.

As for how to do it. The semi/auto way.

I was going to get a good positive as possible diaphragm valve like thats used on American V-8's that pull heat off a exhaust manifold during warm up. Fit that into the wai. Then get with a buddy of mine with Johnson Control's and get a reverse acting puematic thermostat that has action on vaccume. Then cut the thermostat into the bottom of the air box. It would be best in there for a more even action and reaction. If put in any of the lines there will be velocity issues which in turn would induce a lot of stroking which would wear the unit out in no time. Set the thing for about 90f and roll. May still do it if the parts show up for free. But as easy and effective as tube change out is on a seasonal level,,, Im good right now.

Getting a auto type system on the Accord would be better than the manual system employed on the Civic. Its intake system is a lot tighter and more complex than the Civic's. So I haven't scraped the idea all together. :)

I just don't think our Honda's are as susceptible to some of the wai trickery that other cars are. Honda seems to keep a pretty tight rein on there ECU operation parameters.

I do feel wai used right say in my Civic. Is good for about a 2mpg boost when used right. Push it over the high limit and it can hurt you for 2 to 4 mpg. IMHO

Good Luck

psy