Now I know what my tC is thinking!

[2dot4]

I love it when things work like they should.

I got my USB-serial adapter today ($18 shipped from directron.com) so I hooked up the laptop and took my car for a drive. I started at a stop sign, made a left turn, and took off at WOT through all 5 gears. It's wet outside so I didn't go nuts, but I just wanted to get a basic idea of my current airflow settings. After I hit 5th gear, I let off and coasted in gear for a while, then hit WOT in 5th gear to get an idea of my airflow under gradual acceleration while at WOT. Then I let off the gas, slowed down and turned into a parking lot.

The reason I explained that is so you have a reference when looking at this graph. Keep in mind, this is my airflow input graph - it shows how much air is coming into the engine - it's NOT my a/f ratio (AEM UEGO will be here monday and I'll use the serial port and post a graph then). My peak airflow voltage is 4.3V - in 4th gear at redline. My idle is 1.2V at 752rpms.

http://i193.photobucket.com/albums/z99/2dot4/MAFmap.jpg

I forgot to turn the airflow adjustment value off for the graph, so just ignore that yellow line. Since I haven't tuned the car yet, the airflow input and output are the same. Just note the correlation between the red rpm line, and the blue airflow input line.

I think it's cool how the e-manage can log this information and it's awesome that I can finally see what's going on while I'm driving.

If anyone knows how to interpret this graph to offer insight as to where I need to make adjustments, I'd appreciate it.

[2dot4]

here is my injector duty cycle and duration graph.

Right now, it peaks at 88%, which is good I guess...leaves room for improvement so to speak.

This graph shows me cruising in 4th at about 40mph, then dropping it into 3rd and taking it pretty close to redline. I'm going to run this again when it's not wet outside.

http://i193.photobucket.com/albums/z99/2dot4/dutycycle.jpg

[Krdshrk]

88% is pretty heavy on the duty cycle.. You're on the stock 370cc's right? I'd upgrade!

[2dot4]

yeah I'm on the stock injectors...I'm looking at the RC 550cc injectors.

I'm gonna wait until I get tuned and see where that puts my duty cycle. The idea is that as long as you're under 100%, you're fine...over 100% and you're shorting yourself on fuel, causing a high-rpm lean condition, which isnt good.

Now, I have a question - since we have a MAF system, the ecu will always make sure there's enough fuel, as long as it's within the stock injectors duty cycle, right? So running untuned on a tC, as long as you're under 100% duty cycle, you can never run too lean, because the MAF sensor and 02 sensors work together to automatically adjust fuel. Correct me if I'm wrong, but that's what I've come to understand.

I've made an appointment with a local dyno tuner to get my car tuned. I gotta wait til I get paid, but I'll post my new graphs and a dyno chart afterwards.

[fightinsk8ers]

sounds good cant wait to see your dyno results!

[Krdshrk]

That's why I run so rich, Eric. The car will overestimate on the amount of fuel to dump into the engine. Getting the GReddy MAP sensor and putting that on and tuning will help prevent that. You won't lose the power from running too rich.

Also - Injectors are ok if they're under 100% duty cycle, but they're not supposed to run at high duty cycle for a long time - that shortens the life of the injectors.

[TinCan]

Is that the basic E-mange?

[2dot4]

Is that the basic E-mange?

Yep - e-manage blue wth support tool software and injector harness.

the software is BEAUTIFUL! It lets me tune almost everything - I can add fuel, I can tune airflow plus or minus 50% - I can check injector duty cycle and duration, I can get specific idle rpms....it does so much.

The e-manage alone only allows you to tune airflow plus or minus 20% in 1000rpm increments . With the software, I have data logging capabilities, injector and airflow monitoring in real time, and the ability to tune airflow and injectors more precisely. The software turns the blue into an ultimate, minus a couple features here and there. I'm happy with everything so far - $450 for the emanage, software, and injector harness. TOTALLY worth every penny.

[TinCan]

I'm going to look into this a bit more:hiding:

[Mr_Meaty]

It is my understanding that you don't want to go over 85% duty cycle. And just cause your injectors aren't maxing does not mean you cannot go to lean...that all depends on the tune with fuel and timing. I have one map on my car that gives me partial throttle at 10afr (to rich), one at 13afr(a little lean) and one at 15afr(way lean...I don't use that one!)
btw, I'm using the AEM F/IC for fuel manegement.

[2dot4]

the stock tC runs 14.7 at idle - which is the higher end of stoichiometric, but not dangerously lean - 13:1 is perfect - anything over 16:1 is dangerously lean.

I wasn't saying it prevents me from running lean - I was saying it prevents me from running dangerously lean. And that was also coming from the fact that I have no tune - so I'm running on ecu compensation right now.

I just got my AEM wideband today, so I'm gonna install it sometime this week when I get a break from work. I'll have an even better idea of what my tC is doing. I like knowing everything I can about my engine lol.

[Krdshrk]

Actually you want about a 12.3 AFR I believe.

[2dot4]

stoichiometric is stoichiometric (whew, try saying that three times fast lol)

anything between 11.5 and 14 is supposed to result in complete combustion...so technically 11.5=14, and the same goes for all values in between. Granted they're different values, but the idea is that any value between 11.5 and 14 results in complete combustion, so it doesn't matter as long as it's between those two values (which may vary slightly, I dunno)

[Mr_Meaty]

OK. I'll agree with that if you were saying "Dangerously Lean" and not just "lean" I just didn't want you to ASSUME that all was well cause your on stock injectors. But you'll find out for sure as soon as you get your wideband in.

Oh, and the numbers I posted were at partial throttle, not at idle. My idles are around 15 but I'm not to worried about that since it's not putting any preassure on the motor. Saves a little gas, and as soon as I gas it it goes down.
14.7 is desireable at idle, 12.3 at partial and 11.5 at WOT, but those are general guids that you want to try to get around.

Let us know when you get that wideband in so we know where you're at.

[2dot4]

I got the wideband installed today - I just gotta run my 02 sensor to it. I installed it just to see what it looks like