WAI vs CAI test results

[JanGeo]

Ok that all sounds reasonable and yeah lowering the intake vacuum with wider throttle helps but all the timing implications could and seems to make it a lot more complicated.

The water injection that I needed was to prevent carbon buildup in the head - I controlled when it was injected. The engine was running with 195psi compression in the 12 to 1 compression ratio or higher so it needed a little cooling. Actually I used to get ice forming on the intake manifold - couple of times the throttle locked up on the ice.

[rh77]

Originally Posted by JanGeo

The water injection that I needed was to prevent carbon buildup in the head - I controlled when it was injected. The engine was running with 195psi compression in the 12 to 1 compression ratio or higher so it needed a little cooling. Actually I used to get ice forming on the intake manifold - couple of times the throttle locked up on the ice.

That kinda sounds dangerous. Before you joined, there was a discussion thread on the best way to clean away the carbon deposits in the system. We found that water works well, but Seafoam works pretty well too. The thread.

[MetroMPG]

more on the IAT vs efficiency mystery...

just heard back from a fellow metro owner with a factory service manual for the 1998 1 liter car:

The PCM uses the IAT sensor in order to calculate incoming air density. The PCM uses air density information in order to adjust fuel delivery and ignition timing.

so that confirms the role of the sensor in the Metro: the IAT DOES control fuel trim (for air density), and it's likely doing just what i want it to as a result of the WAI.

however, the PCM is also adjusting timing based on the IAT. generally, the timing is advanced with decreasing air density:

from http://www.stealth316.com/2-ignitionsystem.htm: (though it describes the Mitsubishi 3000GT and Dodge Stealth)...

Intake Air Temperature Correction
When the air temperature is low, for example in cold weather, ignition timing is delayed. Colder air means denser air-fuel mixtures, which both combust faster and can be more prone to knock, and so ignition must be delayed. When the air temperature is high the ignition is also delayed because hotter air-fuel mixtures are more prone to knock.

so it appears possible (likely?) that there's a "bell curve" effect for efficiency vs. IAT.

timing is initially delayed from a cold start, then advances as the IAT warms, and then it's delayed again as the air gets "hotter".

lately, i've been seeing IAT around 110-120F at around 35F ambient. i may adjust the shroud on the manifold to drop that down to 70-80, where the SVOboy's AIT/fuel trim plot shows a 0 correction.

[diamondlarry]

timing is initially delayed from a cold start, then advances as the IAT warms, and then it's delayed again as the air gets "hotter".

In light of that staement, I may have to start experimenting with different resistor values in my IAT sensor mod. Right now the ECU "sees" 242-247 degrees F.

[krousdb]

Yep, it took all of 5 minutes. And the best part was that I had what I needed laying around. Last year I bought 3 of those accordian type 1 1/2" tubes from NAPA for my Prius WAI. I had one left over so I used that.

Starting from my air filter box, the existing CAI goes straight down, then does a 180 and comes straight up. Then there is a tee shaped piece. On one end it is closed with a resonance chanber. The other end pulls air from befind the passenger side headlight. The first thing I did was to yank it off and turn it 180 and popped it back on, press fit, no fasteners. This puts the air intake right at the distributor. Thats better, but not close enough to the exhaust manifold. So I popped the tee back off and shoved one end of the accordian tube where the tee was and liberally applied duct tape. I routed the other end between the exhaust manifold and the engine block/transmission. One wire tie secures the tube to the upper radiator hose. Viola. Done. Hope see some difference.

Honda didn't have a 195F thermostat so I will try pep boys. Thermostat and recirculating ebh next.

There you go.

[SVOboy]

Post up some pictures, y0! I am especially interested to see the grille block on the del sol.

[krousdb]

Originally Posted by SVOboy

Post up some pictures, y0! I am especially interested to see the grille block on the del sol.

Grille Block from cardboard wrapped in duct tape and painted. Fastened in place by wire ties. Plug is for 200W magnetic heater on the oil pan.



WAI, connection to existing CAI where you see the duct tape.




WAI ends up between the block and exhaust manifold. All held in place by wire tie to upper radiator hose.

[krousdb]

I just got back from running errands, about 20 miles in all. Post office, a few auto parts stores and honda dealership looking for the 195F thermostat. No luck on the thermostat, all were listed as 172 or 180F. Anyone know where I can get a 195F?

Anyway, with the new WAI, after the engine warms up, it idles lower (600rpm) and a bit smoother that before. I assume that the WAI is working. Maybe the ecu enables a lower idle speed when the AIT is warmer. Before, the lowest I had seen it idle was 650-700rpm.

[SVOboy]

Autozone near me claims to keep a 195 in stock for my car, I imagine it's the same for yours but if you want I could check on yours and send it out with your ecu.

[rh77]

Nevermind, figured it out. I guess I just need to actually read the post...

RH77