10mm vs 11mm alh injection pump

[burpod]

actually, i should be doing this... well at some point anyway when i have more time. i've got several 10mm pumps, a spare 11mm and 2 cars with 11mms... but then i'd have to get retuned *SIGH* LOL

 

[ToxicDoc]

I've read here and a few other places that as long as the timing is set right you don't necessarily need to retune. I just had a 10/11 hybrid installed and it works great without having touched my original tune. No smoke, just extra power.

 

[burpod]

I've read here and a few other places that as long as the timing is set right you don't necessarily need to retune. I just had a 10/11 hybrid installed and it works great without having touched my original tune. No smoke, just extra power.

well, i as i "roll my own" now i was being a little shamelessly silly. if your your tune was *perfect* before such a pump change, your tune will most definitely be out of whack afterwards, because the fueling will most definitely change and that will affect boost for sure, and also timing. the "timing" you speak of being "spot on" is totally different than the timing set by the tune, completely different things. i'm not really sure myself how much this pump modification would make. but taking logs would surely tell a more accurate story.

without good VCDS data logging you really have no idea how good your tune is doing. i've seen people driving their cars thinking they are just fine, but boost logs show +8psi spikes and the usual big drops below target after! like a target of 15psi but spikes to 22-23 on a vnt15 (with a name-brand pro tune on it) and they had no idea. perhaps they had a feeling something was off or saw some smoke sometimes but it usually gets brushed off as "varying conditions". boost control is completely out of whack if you know how to read the n75 values in the log. and surprisingly, to most, it still feels fine and good - at least until they've driven something that actualy has good boost control, and then you will feel the difference. and the difference in the logs/graphs will be obvious.

if you haven't taken logs i would urge you to at the very least take a good long log of 011 only on a commute to work or grocery store etc, from start to finish, and post it up to be analyzed. you may be rather surprised what you may find....

 

[PakProtector]

So then burpod, to paraphrase and make sure I understand this, the tune has a set of N75 data that it goes to, and from there the 'adjustment code" aka PID makes adjustment on the fly to try and hit the demand. When the N75 command off the table/map is not good the PID attempts at adjustment overshoot/undershoot results. So...a log file shows this and the N75 table gets adjusted so as to reduce the adjustment the ECM has to make and the over/undershoot goes away( because the initial 'guess' at where the N75 should go is better in the first place).

I had no idea...and from what you say, turbo/pump/nozzle combination leaves a difficult job for the PID adjustment to do if the original look-up is not any good.

Douglas

 

[burpod]

So then burpod, to paraphrase and make sure I understand this, the tune has a set of N75 data that it goes to, and from there the 'adjustment code" aka PID makes adjustment on the fly to try and hit the demand. When the N75 command off the table/map is not good the PID attempts at adjustment overshoot/undershoot results. So...a log file shows this and the N75 table gets adjusted so as to reduce the adjustment the ECM has to make and the over/undershoot goes away( because the initial 'guess' at where the N75 should go is better in the first place).

I had no idea...and from what you say, turbo/pump/nozzle combination leaves a difficult job for the PID adjustment to do if the original look-up is not any good.

Douglas

yes, that's how it works. if rod length is exactly "right" (as expected by n75 map in tune - the pre-control map), boost works much better and is easily seen in the boost log graphs. the pid controller uses this to calculate it's first guess as to how much to close the vanes when you first step on the pedal and goes from there depending how boost changes.

so if rod length is right (say 18hg), 50% in the n75 pre-control map means say 50% vanes closed. if rod length is say 19hg, 50% will now mean something like vanes only 45% closed. so now the whole pre-control map is off by 5%.

BUT also when fueling is off, eg, 30mg is actually 40mg of fuel, the pid controller's first guess (and the rest of its calculations) isn't going to be right, because it uses tables based on fuel consumption. this is why there is a FUNDAMENTAL flaw in all of the name-brand tunes, none of them uses real IQ values - they all stick within the stock ALH 0-51mg limits. how much depends on the pump/nozzles you have and how they fudged the pump map and where your QA is set (hammer mod). it's not hard to imagine that with 11mm and .230s for example, boost control may suffer horribly when 50mg actually means 80mg. turbo spins up quite a bit quicker with such a larger amount of fuel

so when rod length and IQ are both mismatched, boost control can really suffer if the errors are compounding each other, or they could cancel out a little bit depending. it's basically a mess... and then of course mismatched timing, temperature changes and other varying conditions, all thrown into the mix....