timing pull

[sambb]

Just a question for the guys that have delved into lemmiwinks, unisettings and nefmoto etc. A lot of what I read has people talking about 'acceptable' amounts of timing pull with figures anywhere from less than 6 degrees being 'ok'. Just hoping for your take on that because to my mind isn't any timing pull at all, even one schmidgen of it a decent drama. I mean knock sensors have been shown to be pretty random ie I've seen a couple of tests where tuners can hear knock in an engine well before sensors register that its happening let alone trigger a reaction to it. I was always under the impression that in a tuned motor that it only took a few knocks and you were screwed.
I'm getting small amounts 0.8-3 degrees of pull on an increasing load sometimes and am curious how much of a drama that is going to be until I can get the AFR's checked. I dialled it out for now by upping ch02 "increasing load fuelling" in lemmiwinks but I'm just curious what you guys reckon about timing pull in general.

[seangti]

You really need to get your hands on a complete logger as it's hard to give context in isolation.

Timing pull is typically not desirable, advancing timing is desireable and will lower exhaust temps to a certain degree too - which was news to me until not long back. If you can get some complete logs a few of us can understand what your car is currently doing. I like the nefmoto ME7 logger as it gives you everything in one run.

[sambb]

Yeah I'm working on getting the VCDS lead and doing a tonne of nefmoto research, so can't really log meaningfully at the moment. Just noticed very slight pull which I find unacceptable but I found it really surprising that people on forums are even saying up to double digit is ok and they dont seem to be kidding!
Weirdly some of the pull is in the moments right after I lift off. Throttle plate angle will go from 100% to say 20% but the next few lines might have 0.8 of pull. Whats that mean - suddenly so lean on lift off that there's a tiny pre ignition? Never seen it on 3rd gear logs but will see when I log a run out of a valley or something.

[seangti]

If you PM me with your email address, I'll send you some of my logs so you can compare. I can send you logs of both cars which have recently been custom tuned.

How are you accessing lemmiwinks/unisettings, guessing with an OBD cable, or is it bluetooth? The all blue ebay OBD cable works with nefmoto for logging, they are like sub $10. The silver/clear lead OBD cable has a slower latency with VCDS (for me anyway), but still works. This cable has some extra features (i.e. drivers) to allow you to upload some tunes from nefmoto. I have both cables, both from ebay, I use the all blue one for logging as it works better in VCDS to check active read outs prior to a log with ME7.

[sambb]

Makes perfect sense but for some reason It didn't dawn on me that the cheap cables were sufficient for nefmoto. I have a couple so I might forget the $100 vag cable for now then. So yeah its been with a cheapy ebay OBD cable that I've been changing things in Lemmi - I have ebay blue and ebay clear, so I'll juggle them around. I'll PM you. thanks for that mate.

[noone]

6deg is nothing. So small you won't notice it. The reality is you could push it harder but the more timing that is pulled, the less power you create.

The balance with timing is that a tiny pull on 1 cyl at a specific RPM shoudn't stop you from adding timing across the range. This is way you cant just 'tune' the car with lemmiwinks, a tune should be matched to the engine design and to a lesser extent, mods.

More timing = more torque = more fun.
More timing pull = less consistent torque = less fun

hitting 6's is not a drama.

[sambb]

Yeah but the ECU only pulls timing because a knock sensor has sensed knock ie. not because timing settings are optimum, but because they've gone too far. Knock is not good. I've seen mates cars rolling roaded after big HP rebuilds and the tuners using head phones (which pick up knock more reliably than sensors which give false positives and worse, false negatives) were striaght off the power with very serious looking faces the moment they even heard the first signs of it. "She knocks a bit but don't worry the ECU should catch it" are not what I'd want to hear after a full custom tune. I've just never known it to be tolerated as something that can exist more or less regularly in a modded car.
With our (mostly) flash tuned cars, I know that common practice when 'next stage' tunes go in is to incrementally add timing till the first signs of timing pull and then move back from there. But to leave it in a state where its pulling great chunks of timing often is going to do damage eventually.
Remember the ECU is designed to detect and react to knock when our car had 12psi max and 110kw. A bit of laxity in the reaction to knocking might not kill a motor at that level of tune and will adjust things for the motor when wifey puts in 91ron. Once its pumping double that boost and cylinder pressures become more serious and you wouldn't even think of putting in less than the best 98ron, knocking becomes a different ball game. I don't know flash tunes might alter the knock sense/reaction loop making it more sensitive as the tunes and consequences of knock get more serious but I wouldn't bank on it?

[noone]

The knock sensors are there to stop knock, correct.
Timing pull does not mean knock is happening, it means the sensors are picking up on something that indicates the engine is approaching knock. I cant talk about it on engines as a whole, just the 1.8T which is a resilient little engine.

The reason you can add timing until it pulls it out and then pull back the timing a little is the engine has these sensors, making the rough final tune easier. It would be better to amend the map, but tuners are generally looking at off-the-shelf maps or broad changes rather than making minor adjustments every 200rpm.

I get your want to understand the technical side, I read a lot on timing when I was tweaking, quite interesting.

[sambb]

No, knock sensors are piezo sensors (or atleast used to be when I knew stuff) and they pick up on the particular frequencies of sound that are caused by knock. Knock by definition is not even spontaneous combustion its a spontaneous explosion. Things don't kind of explode they either do or they don't. There is no grey area before knock happens that knock sensors are able to measure. The sensors aren't predictive, they are a dumb sensor that can't detect knock until it happens -unless they are faulty, fooled by strange harmonics at certain rpm or I suppose maybe by pre ignition which is a bit different to knock. Setting your timing so that the ECU regularly pulls 6 degrees means your engine has well and truly pinged already.

[noone]

Yes, that is better put. My description is incorrect, knock is happening. Knock to me is audible or strong detonation, semantics...
An occasional mild detonation from strong timing that is only triggering a slight timing pull is different from audible or strong detonation which would cause issues and or pull more timing.

Much of my experience is from reading on forums, sounds like you know more than I.

[h100vw]

Within the scope of the timing offset within custom settings. I think pulling 5 degrees isn't a biggie. It's wot. To refine a tune for no pull ever would take ages. Obviously you can use numbers that will never cause timing to be pulled, how much potential are you missing out on though. At least the ecu will let you look over the edge and as long as you don't jump off the cliff, it will hold on to you, so to speak.
I often see timing pulled when the throttle has closed for a gear change, is that dangerous to the engine. I doubt it.

[sambb]

Yeah I agree. If you can only offset the base timing curve you'll be leaving power on the table if you're not pushing it in some spots. It just seems risky to live in that zone and erode that much of your safety net.
The 0.8drgrees on throttle lift is weird
I've even seen it on lift and coast. Yeah surely not risky - the ecu using it to stabilise engine speed and re idle the engine?