IS38 1.8T Info/Discussion

[Ironshade]

At what rpm are you shifting? If problem can be easily avoided by shifting 100rpm earlier, why strain motor for less power, more heat and more wear... I just don't get it. Shifting at 120-124 is wayyyy to deep into redline for 3-4 on 5mt.

 

[TwinDad]

At what rpm are you shifting? If problem can be easily avoided by shifting 100rpm earlier, why strain motor for less power, more heat and more wear... I just don't get it. Shifting at 120-124 is wayyyy to deep into redline for 3-4 on 5mt.

Bro! 7,500 rpms! Bro!

 

[8055WAGEN]

Currently running into a P0234 overboost code in 4th gear only. I can reproduce it consistently. It happens very quickly after shift into fourth right around 124mph. The car will fall on it's face spike over 30psi and set off the EPC light.

Wastegate tests fine cold and hot
Wastegate passes adaptation
Swapped MAP sensors, no change
Tried 2 OEM DVs, neither held over 15psi
GFB DV+ holds the boost without issue

Seems an awful lot like boost creep. Maybe the wastegate is failing, but still passes the tests/adaptation? Maybe it's tune related. I recall a couple GTIs having a P0234 code and it turned out it was the tune. Need to do some datalogging this weekend I guess!

I had this problem with a unitronic IS20 tune. Fixed after a tune update and new coils and plugs, not sure which was the fix.

 

[Ironshade]

Bro! 7,500 rpms! Bro!

Lolololol

 

[8055WAGEN]

Just for reference, here are a couple of logs for the unitronic is38 1.8 software off the shelf.

https://datazap.me/u/8055wagen/is38-map-0

https://datazap.me/u/8055wagen/is38-unitronic

 

[crxgator]

That’s some low boost and some decent knock. What gas are you running?

 

[8055WAGEN]

That’s some low boost and some decent knock. What gas are you running?

It's about E25, honestly I was too busy to look thru them today, just wanted to get them up on datazap.

 

[ZuMBLe]

It's about E25, honestly I was too busy to look thru them today, just wanted to get them up on datazap.

It looks like your fuel pumps are still happy at those boost/ethanol levels. Maybe kick it up to 30% and try again?

 

[crxgator]

This was me running E30 on GTI HPFP and Golf R injectors.

https://datazap.me/u/crxgator/log-1532735271?log=0&data=1

 

[8055WAGEN]

That’s some low boost and some decent knock. What gas are you running?

I may have misinterpreted this, do you mean 'decent' as in decently good or 'decent' as in decently bad knock?

 

[ZuMBLe]

This was me running E30 on GTI HPFP and Golf R injectors.

https://datazap.me/u/crxgator/log-1532735271?log=0&data=1

You still had pressure drop even with the GTI HPFP, but you're running a lot more boost than @8055WAGEN .

That's a fat timing curve. I dream of the day I'll have fueling to do that with ethanol.

 

[ZuMBLe]

I may have misinterpreted this, do you mean 'decent' as in decently good or 'decent' as in decently bad knock?

He means bad. The knock values get higher and higher, instead of lower and lower.

What's worrying is you're using E25 on a 93(?) tune and it's still doing this:
https://datazap.me/u/8055wagen/uni-is20-jb4-map0?log=0&data=1-11-25-26-27-28&zoom=28-70

 

[8055WAGEN]

He means bad. The knock values get higher and higher, instead of lower and lower.

What's worrying is you're using E25 on a 93(?) tune and it's still doing this:
https://datazap.me/u/8055wagen/uni-is20-jb4-map0?log=0&data=1-11-25-26-27-28&zoom=28-70

The log you linked to is from my initial Unitronic IS20 logging from last year. There was a problem with knock with that which was remedied shortly after with a tune update from Unitronic.

I need some education on what I am looking for here to identify knock. I am of the understanding that I look at ign2 thru ign5 to find knock, and ign1 is overall timing.

My ign1 increases as rpm increases, similar to the log from crxgator. On the two linked logs, my ign2 thru ign5 sit at zero.

https://datazap.me/u/8055wagen/is38-unitronic?log=0&data=1-4-11-25-26-27-28&zoom=20-83
https://datazap.me/u/8055wagen/is38-map-0?log=0&data=1-4-11-25-26-27-28&zoom=128-153

Zumble, I do agree that the ign2 thru ign5 look bad on the log you linked. Thank you for the education and info.

 

[Diggs24]

IGN5 is not used. IGN2-4 is cyls 2-4. IGN1 is overall timing and CYL1 KR combined. If IGN1 falls when it is supposed to be advancing you are getting KR in CYL1.

 

[ZuMBLe]

IGN5 is not used. IGN2-4 is cyls 2-4. IGN1 is overall timing and CYL1 KR combined. If IGN1 falls when it is supposed to be advancing you are getting KR in CYL1.

I'm pretty sure i've seen IGN5 light up in some of my logs. I also thought it was IGN2-5 were 1-4. IGN1 being current overall timing.
https://www.n54tech.com/forums/showpost.php?p=568006&postcount=2

Look under timing adaptation.

I think IGN5 rarely lights up is because it's the cylinder furthest from the knock sensor? Though I've seen it light up and not seen knock in 1-3. It's rare enough that I no longer have IGN5 in my phone display. I'm only showing IGN2 and IGN4 now for indication of knock.