NefMoto > Technical > Tuning > Need help with low airflow/power 1.8t
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Author Topic: Need help with low airflow/power 1.8t  (Read 1546 times)
maxwell_ck
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« on: February 01, 2024, 09:38:54 AM »
Hi!
I am having some problems with low power increases and timing retardation kicking in too early.
It does around 260g/s of airflow with up to 1.6bar boost.
Please find the logs. Do you see anything suspicious that could potentially cause the timing to retard and prevent power output from increasing?

Setup:
1.8t AUQ
630cc Bosch injectors
4bar FPR
3" MAF
Sytec 300l/h fuel pump
K04-064 - TTE480

Logs attached
« Last Edit: February 01, 2024, 03:32:38 PM by maxwell_ck » Logged
prj
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« Reply #1 on: February 01, 2024, 09:49:31 AM »
Fuel not mentioned, compression ratio not mentioned.

How do you think anyone is going to be able to tell you anything?
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maxwell_ck
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« Reply #2 on: February 01, 2024, 10:12:19 AM »
Thanks for pointing this out.

CR was only affected by using BAM pistons.
Fuel is 98-octane E5.

Let me know if anything else needs to be clarified.
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prj
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« Reply #3 on: February 01, 2024, 10:23:07 AM »
BAM pistons are not for a small port head...
So who knows what compression ratio you are actually running.

From the looks of it, way too high. You're done.
You need to run the car on ethanol or build the engine with a reasonable compression ratio for your power target. 9.5:1 or 10:1 is not it.

8:1 pistons are more like it on small port head... 8.5:1 on a big port head.
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Blazius
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« Reply #4 on: February 01, 2024, 10:37:15 AM »
Quote from: prj on February 01, 2024, 10:23:07 AM
BAM pistons are not for a small port head...
So who knows what compression ratio you are actually running.



BAM is small port head.

BAM pistons are 9:1 in the BAM engine.

IMO 9:1 is high for 1.6bar+ if you wanna get decent timing out of it on pump fuel..
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prj
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« Reply #5 on: February 01, 2024, 11:10:56 AM »
Quote from: Blazius on February 01, 2024, 10:37:15 AM

BAM is small port head.

BAM pistons are 9:1 in the BAM engine.

IMO 9:1 is high for 1.6bar+ if you wanna get decent timing out of it on pump fuel..
Yes you are right of course, I have no idea what I was thinking when writing the post.
But anyway CR is too high for power target. And if you want to run over 1.5 bar boost you need forged rods as well, stock stuff turns into bananas after that...
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ratosluaf
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« Reply #6 on: February 01, 2024, 01:58:53 PM »
in this log you are doing ~240g/s with 1,3 bar of boost and timing goes from 6 to 14 degree during spool

tbh, you can lower boost and add more timing, will result in lower egt, less stress on turbo and same airflow, you'd be in better point of compressor map
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prj
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« Reply #7 on: February 01, 2024, 03:20:07 PM »
Also can set more sane lambda, at around 0.8-0.81, that will make more power too.
This will make around 290-300hp.

"But it's a TTE480" - well if you want to make more power you need engine with correct compression ratio for the fuel and turbo that you chose.
Also intercooler could use an upgrade.
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aef
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« Reply #8 on: February 02, 2024, 03:04:19 AM »
http://nefariousmotorsports.com/forum/index.php?topic=22084.msg161742#msg161742

Check out this post and change your lamfa during spoolup. This made a big difference for me with a similar turbo size.

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maxwell_ck
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« Reply #9 on: February 02, 2024, 06:07:51 AM »
I have checked the boost presure supposing that  intercooler might be the main reason.
The pressure was 2bar before the intercooler, and 1.6bar after.
What do you Think about it? The delta pressure seems to high and may potentially cause some backpressure.
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aef
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« Reply #10 on: February 02, 2024, 06:59:13 AM »
Bar and Plate or Fin and Tube?
Which Car and which intercooler is this?

Are you running some kind of 5120hack or just bigger sensor because your boost is /2 ?

Your current boost and maf is more like a stock k04-064.

If your boost drop over the intercooler is too high you are pushing the turbo out of its compressor map but you will see only small boost @ the mapsensor.
In your case i dont see a big problem at the moment because your boost is reasonable compared to the low wgdc.
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maxwell_ck
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« Reply #11 on: February 02, 2024, 07:48:58 AM »
Bar and plate. One sided (this makes me wonder if there is enough flow)
Yes, I am running the 5120 hack with bigger sensor.

So what do you think about the pressure drop values over the intercooler?
Isnt it too high?
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aef
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« Reply #12 on: February 02, 2024, 08:12:16 AM »
With one sided you mean its a fmic but with inlet and outlet on the same side?
this is shit
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prj
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« Reply #13 on: February 02, 2024, 12:57:29 PM »
Quote from: maxwell_ck on February 02, 2024, 06:07:51 AM
I have checked the boost presure supposing that  intercooler might be the main reason.
The pressure was 2bar before the intercooler, and 1.6bar after.
What do you Think about it? The delta pressure seems to high and may potentially cause some backpressure.
Sounds completely normal to me. Remember that the air gets cooled down in the intercooler.

20% delta is completely normal, when you get closer to 35% then you have a problem.

Your problem is high compression ratio and then intercooler will make problems later when you increase boost.
Not flow wise, just it does not seem to cool that well.

But this is like 1% of the problem right now and not worth talking about. The high CR is the main issue.
Either rebuild the engine, fit CR lowering headgasket (not ideal) or fit WMI, or convert to E85. No other way around it.
If your rods are stock, then you are gonna have to rebuild it anyway.
« Last Edit: February 02, 2024, 01:00:11 PM by prj » Logged
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maxwell_ck
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« Reply #14 on: February 03, 2024, 10:56:02 AM »
Update: I lowered the boost yesterday to 1.5 bar, so it  does  around 310hp/430Nm and  at least puts less stress to the turbo. Nevertheless I will replace the cooler first as I will have to do this sooner or later as the ambient temperatures get higher.

I totally get the idea of reducing the compression ratio too, I will think of what would be the best way to do so. Do you have any idea about the proper head gasket to fit in? Or should I use the spacer?

Ps
I already have forged rods.
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