Timing Logs Graphed

Since I was all up in Mike's (Noside) Thread, I thought I would go ahead and move mine into a separate one. With that said, I have spent some time reading about engine timing this morning and I still can't make sense of my logs. How do I have negative overall timing values when my CF's are almost "0" across the RPM band? Any thoughts?

I would be curious to see a AFR log. The only thing i can see is that when your rail pressure hits about the 120bar mark, thats when you finally see positive timing advance. When your in the negative, rail pressure is somewhere around 110bar. Thats if i am reading your logs correctly. I am not sure about GIAC, but even 110bar would seem to be enough.

The other thing is that if you take out the numbers for the timing, it's a nice advance to redline, no big spikes, except for the very end. It would look like a healthy timing curve. I would call GIAC and ask them, because it looks like a mapped curve, rather than the ecu doing something on it;s own to protect itself or something. And, even then it should not go negative in a nice progression like yours, but rather big spikes between negative and close to 0 or positive.

Also, i would think if it's the ecu, you would show cylinder timing delay, and the ecu reacting. I think the rest looks good, so i think it could be a GIAC file problem or the way it's designed. Which does not make sense to me, because negative timing means no power, the combustion starts after the piston is allready moving down. Anyway gotta go back to work, but i would call GIAC.

Yet GIAC continues to claim that they do not run ATDC timing . . . .

BS flag?

Have you logged your EGTs?

Dave

wannagofast said:

I would be curious to see a AFR log. The only thing i can see is that when your rail pressure hits about the 120bar mark, thats when you finally see positive timing advance. When your in the negative, rail pressure is somewhere around 110bar. Thats if i am reading your logs correctly. I am not sure about GIAC, but even 110bar would seem to be enough.

Click to expand...

Ask and you shall receive (I couldn't remember if I mulitply the A/F Lambda by 14.7 or 13.7...sorry brain lock. I used 14.7, the values are exactly the same between Requested and Actual, so only Acutal Values have been graphed.)...

wannagofast said:

The other thing is that if you take out the numbers for the timing, it's a nice advance to redline, no big spikes, except for the very end. It would look like a healthy timing curve. I would call GIAC and ask them, because it looks like a mapped curve, rather than the ecu doing something on it;s own to protect itself or something. And, even then it should not go negative in a nice progression like yours, but rather big spikes between negative and close to 0 or positive.

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This is exactly why I'm stumped on the whole thing. The actual slope of the line looks perfect IMO. It's just where it drops down to that has me confused. With that said, I'm a little worried that if it didn't drop that low, then I would be around 30 near redline...not good.

wannagofast said:

Also, i would think if it's the ecu, you would show cylinder timing delay, and the ecu reacting. I think the rest looks good, so i think it could be a GIAC file problem or the way it's designed. Which does not make sense to me, because negative timing means no power, the combustion starts after the piston is allready moving down. Anyway gotta go back to work, but i would call GIAC.

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I have not contacted GIAC yet, but will soon enough...just curious to hear what you guys had to say. Please LMK if there are any other logs you would like to see.

crew219 said:

Yet GIAC continues to claim that they do not run ATDC timing . . . .

BS flag?

Have you logged your EGTs?

Dave

Click to expand...

Dave, I thought I would catch you in here. Don't see you around the 'Tex Tech Forums anymore, so I thought this might grab your attention. No EGTs, but I will grab those in about a week or so...have to leave town tomorrow. Please elaborate a little on your ATDC comment if you don't mind. Make sure you play nice...LOL!

What revision fuel pump do you have? I am impressed that you are getting 120bar for the last 1,500rpm's. What's odd is that the program is asking for it, as you still have the stock pump, and i thought 110bar was the accepted limit. You deffently don't have a fuel pump problem.

Your AFR looks in line with you having a full exhaust. What are you seeing near redline, low 11 something? So, if the timing curve was a result of something the ecu was reacting to, i would expect to see a lower number (10.5-10.4 is stock).

ATDC means after-top-dead-center. Which is the negative number in the timing graph. It means that at the start of your timing run, the spark is not igniting till 12deg. after the piston has passed top dead center, on it's downstroke. Normaly the complete combustion process is done a few deg. ATDC, to push the piston down.

Dave may be on to something by asking your EGT's. It looks like GIAC is worried that the engine is going to get to hot. Which does not make sense, because you are not running alot of boost, looks like you can supply plenty of fuel, so if anything it could be much more aggressive all around. I know they use 2.5" exhuast and you have a 3", but that's no expanation for negative timing. By keeping that timing so low through the main boost time, it's keeping the cylinder temps. down, by not having complete combustion take place. If thats what there trying to do why not give a richer AFR and increase the timing map.

Personally it looks like your logs are correct. Apparently thats what GIAC designed. I had never heard that GIAC went with such a bizzare timing map, but dave has been around a lot longer than me and he mentioned it. And, your logs are showing it. If you call them and they confirm that is the program design, i would think about switching to another company. Not trying to pitch a product, but if you went apr, even stg.1 would give you more power than your tune now. Plus you have mods to go stg.2 way more power than it looks like your getting now.

Anyway good luck. I'll be interested in what happens. By the way, what's your gas mileage look like?

wannagofast said:

By keeping that timing so low through the main boost time, it's keeping the cylinder temps. down, by not having complete combustion take place.

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You have backwards. Increasing timing will lower EGT's.

Arin, I would actually like to hear your spin on this...not from an APR perspective, but what you personally have seen. You have been around these technical forums much longer than I and you, Dave and WannaFast have a great deal more knowledge than I do.

After reading some more about ATDC, it seems that EGT might be higher than I think due to part of the combustion process occurring outside of the cylinder and moving into the exhaust manifold. I have noticed that that my intake (and engine bay for that matter) becoming very hot...wonder if that's due to the additional heat coming off the exhaust manifold and DP?

Fuel mileage seems to be okay, but I haven't gotten on my car much lately...really only time I every see above 10 psi boost is during logging sessions. Highway mileage and regular city driving seems to be normal. Currently I have the F pump and I'm sure both Dave and Arin can attest that previous GIAC maps have shown fuel cuts in my car. Best thing that could happen is if another GIAC user could post some other logs just to verify that this is indeed their correct timing map.

Arin@APR said:

You have backwards. Increasing timing will lower EGT's.

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Yep, because increased timing = more complete burn of the fuel. Running ATDC timing = unburnt fuel igniting as it is being expelled into the exhaust manifold. Great for spooling up the turbo . . . not so great for component longevity or economy.

Dave

Dave, have you seen other GIAC logs representing the same behavior?

rbradleymedmd said:

Dave, have you seen other GIAC logs representing the same behavior?

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I saw the logs that Austin posted trying to disprove my claim of them running ATDC . . . . those logs Austin posted were in ATDC so it makes me wonder if he understood what I meant.

He later claimed that they were an anomaly once I pointed out his error.

Dave

Arin@APR said:

You have backwards. Increasing timing will lower EGT's.

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That's not really what i meant. I know i was talking about exhaust before that sentence, but i am talking about actual cylinder temps. and the relationship to the knock sensors.

My question here is why in the hell are they going so conservative with the timing. As far as i can tell by the op's logs they are not going conservative anywhere else. Plenty of requested rail pressure, boost, leaner afr. Does not seem they are worried about high egt's. I think GIAC is trying to prevent knock with that timing map. I don't know why, and why so extreme. It does not seem to be necessary. So, they must be concerned that the tune is so aggresive, that if they advance the timing to much, to soon, there will be detonation and overheating.

Bump...are any other GIAC users a little intrigued by this??? I mean WTF, my old X+ File (fuel cut or not) had power throughout the band, now I have nothing until about 4k RPM...I own a k03, not a GT series turbo!!!

/Subscribed

I've also noticed some weirdness in my power band I didn't have with the old file... sometimes my car feels very fast, and sometimes it feels majorly heat soaked or something... It's been pretty hot lately, that might have something to do with it as well. I also feel that the power band isn't aggressive enough in third gear... 2nd and 4th feel fine, but 3rd feels worse than I remember it...

I wish I had some logs or something...