2 questions about tuning and timing

[Cazzo]

I just got a datalogger and I have a couple questions.

I noticed that my timing starts off at 25deg or so and then drops off accross the rpm range to about 4 deg. Does timing get pulled for too much fuel too? I was getting .96v on the o2's BUT my EGT's were also high at around 860C, so I'm kind of thinking that leaning it out won't help me much. I could probably drive around and tune by trial and error, but if you have any advice on which way to go first (rich or lean) I would appreciate it. Currently on the AFC high settings, I'm at about -33% accross the range.

As for the datalogger: Do 2g's have slower sample rates than 1g's? The data I get is kind of useless because the sample rate is about 2.5sec. I could go through a whole gear in that time, and miss all the data I'm looking for. In fact, when I graphed everyhting out, It didnt even pick up the 2nd-3rd shift and rpm increase in 3rd. The whole rpm spike was missing, and I'm positive I got to 3rd because my vehicle speed for that missing rpm point was 70mph.

Im using the OBD-2 scanner tool http://www.obd-2.com . Are there any others for 2g's that have a higher sample rate, like 0.2sec, or am I screwed on this because of OBD-2? Or does anyone have any tweaks for the scanner to make it sample faster?

thx-cazzo

[Peter 92TSI]

Hey,

Datalogger rocks. :)

First off, there has to be a way to change the sample rate on your datalogger. 1 sample every 2.5 seconds? Something is wrong, because my 1G datalogger does 18 samples per second. There has to be a way to modify that, because the logger would be worthless.

Since, you have a 2G logger, you can only tune by timing advance. 1G dataloggers show knock sum too. Anyway, good timing advance is around + 25% degrees at least. So you are pretty set in terms of that.

Running rich can cause knock. Ideally what some of the faster DSMers do, pick a stable boost setting like say 15 psi, then do runs, and lean the car out right before timing starts dropping below 25 ks. Then they turn up the boost, and add a bit of fuel, and start leaning the car out again until the timing starts dropping again. To be honest with you a lot of fast DSMers don't mess around with 02 voltages, or EGTS, nope a lot of them only tune using boost and datalogger. If your timing is right, EGTS should be perfect.

Peter

[Nick 92 TSi AWD]

Most people just make sure egts don't peak 900c and then just watch for knock. 1v o2 sensors are useless for tuning.

[TheHondaKiller]

I don't think 02's are useless at all, I use them to help get the fuel in the ballpark for my Haltech. I don't say that any or all cars should run .85V or anything like that, because each 02 is a bit diffirent in how it reads. But once you get a good idea of the sweet spot of the o2 you can use it quite succesfully to put the a/f where you want it. EGT's are just a last warning device of severe combustion chamber heat. And I think turning the car to a safer boost setting (15psi) and then added fuel and recording all the gauge info and interpreted acceleration and then leaning it out and doing the same thing you can really find the sweet spot for your 02, then it will become a useful tuning tool. Another thing to keep in mind is the voltage drops after the sensor is very hot.

[Nick 92 TSi AWD]

Originally posted by TheHondaKiller
Another thing to keep in mind is the voltage drops after the sensor is very hot.

Yes and it can throw mine off by as much as .5 volts.

I still don't consider a 0-1 volt o2 sensor very useful at all. .01V is such a small variation, if you are constantly shooting for a certain o2 voltage your car will never get tuned. I just make sure mine is in a certain range and that's it.

I'm going to be using a 0-5v sensor on the dyno....that's useful.

[TheHondaKiller]

just like there is no exact a/f ratio that is perfect for all engines there is no exact voltage that is perfect either. But using the voltage as a general a/f tool is exactely what you should do, buying a $1000+ uego sensor is out of the question for most people, and so is dyno time. I think that you can safely use the 1v 02 sensor as a general guideline, due to its relatively good accuracy and economic price, and for that reason it's a useful tuning tool.

[GSTSpyder]

To answer some of your questions Cazzo, you should be able to change the software's sample rate goto Options->Gateway and lower the number to around 10 or so, it will log alot faster.

A severely retarded ignition timing such as yours can send the EGTs through the roof regardless of fuel mixture since the exhaust gas is still partially combusting on it's way out.

Try leaning the mix out a little at a time.

Also, the 2g ECU retards the timing in the upper rpm band. They actually seem to perform better that way, the rule of thumb for 2g's seems to be: aggressive timing in the lower rpm band, less aggressive timing up top.

[Cazzo]

ok thx ill try that out...I did lean it out a bit and noticed higher timing....it's around 13 degrees or so.. thx again

[pablo0321]

OK i am hearing all this talk about reading your volts, and i see thats pretty much what a A/F gauge does. Also, i see so many sites on hoe to make an A/F gauge with the little LEDs, but if i wanted to actually see my volts 0-1V could i simply buy one of those digital volometers and hook it up to the 02 wire??

[TheHondaKiller]

Yes you can do that, I used to do that before I put my Haltech in the car, I would hook up the voltmeter to 2 wires (signal, ground) every time I changed a part or would change the boost to help keep the a/f good, so I would get maximum timing on the stock ECU.

[pablo0321]

hey "TheHondaKiller" if I used just a digital voltometer would it be bad to always have in on when driving the car?? Or is it something that should just be temporary, like just to check now and then?? If you could do this, i dont know why people go out and spend all the money on those little LED gauges.
thanks

[TheHondaKiller]

Jumptronix is just a digital voltmeter, like you are thinking of using, I found it useful to hook it up every now and again instead of having an ugly voltmeter in the car. The usefullness of the LED meters is for closed loop and light throttle where the voltage changes drastically over short periods of time, it a lot easier to read an analog style LED than to look at a digital readout. That's why I use an Autometer A/F with a 20 LED readout for light throttle and crusing, then I use my laptop for datalogging full throttle because of the .001 resolution it has.

[ProjectGSX]

2G's are entirely different beasts when it comes to tuning, than the 1G's are.

First and foremost, put your damned honeycombs back in. You cant properly tune a 2G without the honeycombs.

First off, YES, 2g's have HORRIBLE sampling rates. Log as few parameters as possible. When I tune, I JUST log timing.

Here is what you should see for timing:

Cruising and part throttle, your timing really doesnt matter. the ECU is still controlling fuel and such anyways, so your tuning shouldnt affect it. Timing will be really high, generally in the high 20s low 30s.

Timing, like o2's are only really important at WOT.

Tune for 3rd gear. Why? Well, Its not safe to do freeway pulls in 4th gear till redline while staring at your laptop. :)

Start your timing pulls at 3500RPMS. Floor it, and boost should be full on by 4k. Your timing is going to drop like a rock, from the 30 or whatever you had cruising.

With great tuning, your timing will still drop to 9-10 degrees advance.

As you progress through the RPMs your timing should NEVER drop. With good tuning, your timing will climb steadily as RPMs increase.

By redline (I generally rev through 7200 rpms) you want to see 20-22 degrees advance.

You will get lower timing if you are lean OR rich. EGTs are not important to tuning. The EGT gauge should really only be used as a safeguard to make sure you dont melt anything. It should also be a good indication that your tuning is VERY far off. Even with +-10% off on the AFC, I have not seen crazy EGTs.

o2's ARE a good indication of tuning. However.. you need to make sure that your o2 sensor is WARM before you start paying attention to what its telling you. Also, you have to get your car properly tuned BEFORE you can decide what o2's your car likes to run at. .92 doesnt work for everyone. But, if you get your car tuned and see its pulling .92 at WOT all the way to redline, you now know your car likes to run at .92! I am not sure how the o2 voltage will change over the life of the sensor, however.

If you find you cannot get proper timing no matter how you do your fuel settings, you are probably either running some bad gasoline, put in the wrong octane gasoline, or you are running too much boost. Also, if you have boost leaks, you are effectively changing the efficiency of your turbo. It is having to work harder to maintain boost levels, and will then push hotter air. Hotter air makes knock more likely, which gets your timing pulled. Lower octane makes for more knock, and gets your timing pulled.

So, if you are having trouble tuning properly, drop your boost down to 15psi. Keep in mind that once you are tuned, you should be able to up the boost a few pounds and probably wont even need to adjust the AFC. The MAS will see more air, and will respond with more fuel on its own.

The limiting factor to how much boost you can run (assuming you have a fuel system capable of supplying enough fuel) is the temperature of the air it puts out. You can compensate for more air with more fuel. Compensating for HOTTER air is much harder.

You can run higher octane gasoline.
You can run water injection.
You can put together a more efficient intercooler.

All of those things will lower the temp of the charge air and let you run more boost. (Again, assuming you have a capable fuel system.)

Did I miss anything?

[Cazzo]

thanks project GSX- i was looking for a more in depth answer. I think I need to drop my boost some since I'm using crappy 91 octane in CA now. YOur info will help me alot this weekend when I go for some test runs.

thanks everyone else who also helped..=)

I am going to try and put some logs on my website this weekend so people can give me some suggestions and tips.

Thx

Cazzo

[ProjectGSX]

Originally posted by Cazzo
thanks project GSX- i was looking for a more in depth answer. I think I need to drop my boost some since I'm using crappy 91 octane in CA now

Check different companies in your area. I am still able to find 92 (Im in Cali also).

Im moving to Texas next thursday, 93 octane here I come!

[95TsiAWD]

Another thing to try is replacing your 2G Cam angle sensor with a 1G one. It's outlined on Magnus Motorsports page
www.magnusmotorsports.com
Marco says he picked up 4 degrees at redline just by replacing the sensor, and then you'll be ble to pick up even more timing if you set your base timing higher than 5 (I think 8 is about as high as you want to go on pump gas).

[ProjectGSX]

Originally posted by 95TsiAWD
Another thing to try is replacing your 2G Cam angle sensor with a 1G one. It's outlined on Magnus Motorsports page
http://www.magnusmotorsports.com
Marco says he picked up 4 degrees at redline just by replacing the sensor, and then you'll be ble to pick up even more timing if you set your base timing higher than 5 (I think 8 is about as high as you want to go on pump gas).

That is an excellent suggestion.. but do it AFTER your car is properly tuned. Your ECU is not advancing timing for a reason, after all. Once you get your ECU happy, feel free to fudge a few more degrees of advance.

Ive got a sensor on the way from Marco now, actually. :)

[GSTSpyder]

Also keep in mind that the oem o2 sensor is only accurate around stoich, for performance tuning a wideband o2 sensor should be considered mandatory

[ProjectGSX]

Originally posted by GSTSpyder
Also keep in mind that the oem o2 sensor is only accurate around stoich, for performance tuning a wideband o2 sensor should be considered mandatory

However if your idea of "tuning" involves a S-AFC or something similar, dont bother. :)