While I was at TechnoSquare this morning Tadashi showed me this slick little device... it's called a Techtom CMX-100 N2.

What's it do? It provides the following real time info as it's seen by our ECU. It also has a peak-hold feature so you can see the maximum value the ECU has seen.

Air Flow Meter Voltage (V)
Battery Voltage (V)
Ignition timing (degrees)
Intake temp (at the MAF sensor)
RPM (X10)
Speed (mph)
Water (Coolant) temp (F)

I learned a bunch about what's going on with my car in real time. I now know that my car's intake mods almost max out the MAF sensor's voltage.

How much? $195.00 plus tax.

Their phone number is 310.787.0847.


DaveO

2003 G35 AT Sedan / DP / Willow / Premium / Sport
350Z Air Duct, Eng Cvr & T-Stat / Stillen CAI / Crawford Plenum
GG 10-Wire Kit / TS ECM / E-Fans
Street Edge TC / B&M Cooler / Stillen Exhaust

274007-CMX-100 N2.JPG

 

That's a cool little 'giz' showing some valuable info. I checked out their website for info and was impressed.
I wouldn't mind one of them myself. Did you buy one Dave? Enough interest for a G/B perhaps?

I fired off an email for info on multi-item pricing.

Colin



<font color=red>GSM</font color=red>
<font color=red>GSM</font color=red>
<font color=black>Silverstone Coupe</font color=black>

 

I'd be in on that. I'm buying one anyway as soon as they get the 2004.5 ECU reflash done.

2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5

 

In - With mph I assume this is mounted on the interior and can remain permanently plugged in?

2003.5 DP 5AT Sedan (E-thing but Nav)
14.2 @ 97.18
Z-Tube
K&N Drop In & Airbox Mod
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Polk EX-3500 Tweeters/Shock Sensor/H-Liner

 

gsedanman (with a coupe?),

That's my unit in the picture.

I forgot to mention that it plugs into the diagnostic port. Also the unit comes with double sided tape and a couple of wire ties so you can mount it if you'd like.


DaveO

2003 G35 AT Sedan / DP / Willow / Premium / Sport
350Z Air Duct, Eng Cvr & T-Stat / Stillen CAI / Crawford Plenum
GG 10-Wire Kit / TS ECM / E-Fans
Street Edge TC / B&M Cooler / Stillen Exhaust

 

TADASHI!!!!

When i was in there the other day, I said... "so, do you have any other toys for my G?"

And he said, "No, just doing the ECUs right now."

==============

So what are you doing about the MAFs sensor voltage? Is it a constant threat, or just when WOT?

-Ted



'03.5 Sedan 5a: BS/G, Prem, Aero/Body, Sport, Nav
Click for MODS or Vote at Online Showoff

 

I'd like to assume the ecu will keep things sane even with add'l air.

Will someone agree or disagree that the plenum will not change the AF per se but rather equalize the AF from front to back pairs of cyclinders making efficiency without causing much negative impact.

Thats a big softball to swat if I am wrong - lets hear from the masters...

2003.5 DP 5AT Sedan (E-thing but Nav)
14.2 @ 97.18
Z-Tube
K&N Drop In & Airbox Mod
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Polk EX-3500 Tweeters/Shock Sensor/H-Liner

 

The plenum may affect the A/F maps the ECU chooses, if that's a correct interpretation of the explanation I read posted by gurgen as well as comments Doug has made to me.

2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5

 

Ted,

I don't plan to do anything but watch it for the time being. I don't think it will be a problem.

I'll bet you may have similar, if not higher, readings since our intake mods are similar. Part of the high reading may be attributed to our Stillen exhaust's hi-flow, exhaust gas scavenging characteristics' and their impact the intake cycle's "charge". And then there's your hi-flow cats...

Another interesting observation. Even though my Stillen CAI filter enclosure (heat shield) and Z-tube are insulated, I was very surprised at the level of heated air my MAF sensor sees at idle and low speed running, as well as how long it took for the temperature to come down at 65 - 80mph.

I like to compare my system's temperature profile with the JWT Popcharger w/heat shield and the K&N SR (short ram) systems. I'm betting my system's substantially better... of course I've been wrong before.


DaveO

2003 G35 AT Sedan / DP / Willow / Premium / Sport
350Z Air Duct, Eng Cvr & T-Stat / Stillen CAI / Crawford Plenum
GG 10-Wire Kit / TS ECM / E-Fans
Street Edge TC / B&M Cooler / Stillen Exhaust

 

"as well as how long it took for the temperature to come down at 65 - 80mph."

That explains alot for me. When I go out to the county roads with my G Tech, it takes me awhile to get there and my first run is always my best. As I turn around and recalibrate the G Tech my engine bay must be heating up, thus each run it just gets hotter and hotter under there, resulting in slower and slower runs.

It was true with my pop charger and true with my Nismo CAI, although less pronounced with the latter.

2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5

 

DaveO where is the Diag port and also where did you mount yours - I'm guessing the best place may be the nav-less cubby lid back....

PS mine will be here tommorrow - I cannot wait for this any longer as I have wanted AF guage for a while now.

Thanks for the head up on this - BIG find

2003.5 DP 5AT Sedan (E-thing but Nav)
14.2 @ 97.18
Z-Tube
K&N Drop In & Airbox Mod
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Polk EX-3500 Tweeters/Shock Sensor/H-Liner

 

I'd be interested in a group buy

 

Also this may be good for those of you with nav already.

http://www.technosquareinc.com/vlogger.htm

2003.5 DP 5AT Sedan (E-thing but Nav)
14.2 @ 97.18
Z-Tube
K&N Drop In & Airbox Mod
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Polk EX-3500 Tweeters/Shock Sensor/H-Liner

 

SixFive,

Here's a picture of the diagnostic port. I don't have my unit mounted at this time.

Please note that the CMX-100 N2 unit does not provide an air/fuel ratio reading. It does provide MAF sensor voltage.

Since there seems to be a little confustion on how our MAF sensor works, perhaps a brief review is in order.

The mass air flow (MAF) sensor is the hot film type that only measures a portion of the total intake air flow. The ECM (ECU) provides power to the hot film. The temperature of the hot film is controlled by the ECM to predetermined values over an established operating range (Approx. 1V to 5V on the 2003 cars). The heat generated by the hot film changes as the volume of air flow changes. The more air flow, the more heat loss. The more heat loss, the more power the ECM must supply to maintain the hot film at temperature. Less air flow, less heat loss, less ECM power required.

I believe that if the amount of air flow is great enough to exceed the ECM's maximum value (> 5V) for very long the ECM could go into the limp mode. This seemed to be a problem with some early FI installations.

While I'm not a master by any means, I do have an opinion on the effects of the aftermarket plenums on total air flow.

I agree that they improve the balance the air flow to cylinders. With air flow to the front (and middle?) cylinders "freed up", there's now less backpressure. Therefore, total air flow to the engine will increase unless there's some other limiting factor. This therory is supported by the fact that our engine's run rich above 4k-5krpm with the stock plenum and lean with an aftermarket plenum.

Most aftermarket hi-flow intake systems lean out the A/F ratio. One air flow bench test showed an 50% increase in air flow when placing a velocity ring in front of the MAF sensor. If the ECM's fuel map(s) can't keep up, the engine will lose power. If lean enough, the engine will run hot and may exercise the knock sensors.


DaveO

2003 G35 AT Sedan / DP / Willow / Premium / Sport
350Z Air Duct, Eng Cvr & T-Stat / Stillen CAI / Crawford Plenum
GG 10-Wire Kit / TS ECM / E-Fans
Street Edge TC / B&M Cooler / Stillen Exhaust

274474-100_0017.JPG

 

You know I mis-took Air Flow as Air Fuel - (speed reading has its dis-advantages).

It seems as though the info from Air Flow reading will give some good info about the ratio in redefined terms. It seem like a good investment since there doesn't really seem to be a better way to get accurate AF readings without a laptop.

I just went out to the office garage to check out the location but thanks for the pic...yer quick.

And in any event, it sounds like the mods we make should always be tempered by the ECU/MAF to a good safety level if they could otherwise do damage.

Thanks for the info again.

2003.5 DP 5AT Sedan (E-thing but Nav)
14.2 @ 97.18
Z-Tube
K&N Drop In & Airbox Mod
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Polk EX-3500 Tweeters/Shock Sensor/H-Liner