Sams Polo 3.0

[sambb]

ah seems breathing mods a bit too good for the APR generic tune thats in the car. It runs stock injectors but with a 4 bar rather than 3 bar fuel pressure regulator. Right at around 3000-4000rpm which is the boost peak its pulling up to 6.5 degrees of timing and then as is usual for these things is conservative in taking it out again so its really robbing power. It was 17 degrees ambient and iAT stayed rock solid at 20 degrees throughout (same cant be said of the SEAT Sport IC coupled with the K03s). The tune is actually asking for 1.55 bar (22.5psi) and I'm only giving it 1.27 bar (18.4psi) yet the timing pull is happening. It looks like its going lean in that spot, where you least want it to. ie reaching 0.88-0.89 lambda, so I think its a fuelling issue. The duty cycle of the injectors in that spot (calculated online by entering rpm and injection ms into a calculator) came back at well under 70% so the injectors themsleves arent maxed at that point. The fuel pump is a virtually new uprated APS 265lph pump that was coping just fine on 550cc injectors at 3 bar (stock are 318cc) so I doubt I'm lacking fuel pressure behind those open times. Confirming this is that at the top end >6000rpm at 82% injector duty cycle its at 0.78 lambda.
So for some reason its going pretty lean at the top of the boost ramp which may be because it is moving much more air due to much less back pressure due to the mani and 3 inch dump/exhaust. But despite less boost? not sure. The overfuelling at the top end might be APR just covering off big EGT's or the fact that stock fuel pumps were probably struggling to keep up at that point and mine is doing just fine?
So it'll rocket up through the gears aok but when you do dyno style 3rd gear pulls from 2-2500rpm it exposes it. The timing pull can really be felt down low and the richness at the top is robbing it too because its no stronger there than the modded K03s was. So if I wanted to continue in the ghetto vane I could probably get some water meth into that lean spot with a boost trigger but I think not. Instead I'll chuck the EV14 550cc injectors back in with the 3 bar, maybe go from 2.5-2.75in MAF and get Dave Howlett to do some nefmoto magic on the tune.

[sambb]

I'm going to be selling my K03s modded housings. The CHRA despite being rebuilt has seen some pretty fast rpm's over time and I wouldnt feel comfortable giving that any sort of guarantee but the housings are perfectly perfect and ideal to be swapped onto someones turbo.
Its exhaust housing was pretty comprehensively ported with the throat to the wastegate opened right out so that it could flow the required gas to stop the shaft overspeeding.
the flow to the wastegate is normally closed right down compared to this. makes a big difference.
The compressor housing has had the muffler removed and a straight pipe welded in its place so that it mimics the older K03 and K04-001 cover with the nice smooth compressor outlet. It makes a nice induction sound now and makes comp surge cho cho's if you run a stiffly sprung diaphragm DV or a piston type if you are into that kind of thing.

[sambb]

This is what I mean with the battery sub circuits panel.

The panel with the terminations/fuses etc slides sideways off the giant black plastic battery shroud. Cut off all the excess leaving just the mounting part seen in pic 1. I mounted that to this bit of nylon because it was the only non conductive bit of anything I had lying around and then that to a bracket shaped to help it clear the washer bottle. Then just take you terminations/fuse/subcircuit panel and click it back on!

[sambb]

and once you're in there hiffing the stock battery and airbox you'll most likely find this drama.

This is why Forge and most other oversizes TIP's and definitely the 'fatty' versions are such a bitch to fit. This heater core hard pipe which is mounted to the block squishes it closed some and wedges it against the gear selector cables. Undo the bolt holding it on, slip a big nut under it to space it out off the block and then grab it and give it a gentle bend outward, and it'll look like this:

your TIP will be easy to get in and out, it will breathe again without being squeezed shut in that spot and you wont be fouling gearbox cables. Lots of TIPs will sit hard against the exhaust mani heat shield which will also start to tear into them. I think part of that drama is caused by this water pipe forcing it forward as well.

[Sydneykid]

So for some reason its going pretty lean at the top of the boost ramp which may be because it is moving much more air due to much less back pressure due to the mani and 3 inch dump/exhaust. But despite less boost? not sure.

Nailed it, removing restrictions increases the airflow, which is what makes power (when combined with fuel). Boost is a measure of resistance to airflow not a measure of the airflow itself. There is also an inlet air temp consideration, maybe the higher boost level increases the inlet air temp exponentially, is their logging of that?


Cheers
Gary

[sambb]

Logs have all been coming home from night shift so 17 degree ambient and no run topping inlet air temps of 23 degrees.
I think it’s just lean everywhere and despite there being headroom in the injectors the genetic tune won’t fuel it up to meet the extra air flow.
Will have to be after xmas that I get it tuned. But by then I may have sold some stuff and be able to do the new dump pipe required for that Golf 6 gti turbo swap I’ve been sitting on my hands over.

[Sydneykid]

Logs have all been coming home from night shift so 17 degree ambient and no run topping inlet air temps of 23 degrees.
I think it’s just lean everywhere and despite there being headroom in the injectors the genetic tune won’t fuel it up to meet the extra air flow.
Will have to be after xmas that I get it tuned. But by then I may have sold some stuff and be able to do the new dump pipe required for that Golf 6 gti turbo swap I’ve been sitting on my hands over.

Assuming an intercooler efficiency of around 70% (an OK front mount) that means about 37degrees out of the compressor.
Assuming an intercooler efficiency of around 50% (an OK side mount) that means about 29 degrees out of the compressor.

That's a very low temperature rise through the compressor.

Cheers
Gary

[sambb]

I know, it does sound low. I was watching the scan gauge iAT readout and thought it looked low and just put it down lag in the display. But the logs show the same. The log was done having driven home in 5th gear at 80-90 km/h for the preceding 20 km/h so it really was cool as a cucumber when I did the pull. The sensor is ok because I see the same traffic heatsoak from the IC with iaT's getting to 50 degrees in a traffic jam on a 25 degree day as I did on the other car/IC combo.
Given the timing pull that was happening even on lowered boost, I wasnt keen to start doing back to back runs to push the IC and temps harder.

[sambb]

maybe its a unicorn intercooler!

[Sydneykid]

This is a multi temperature trace in 2017 from an Audi S4 Turbocharger Outlet Temperatures Cruising | MyAudiS4



Note Fahrenheit and MPH.

Tu_In is the temperature of the air entering the turbocharger, shown with the red line. Tu_Out, the dark green line, is the temperature of the air as it leaves the turbocharger compressor housing. The light green line is the ambient air temperature.


The Turbo outlet temp spike at ~1850 is boost to 18 psi. The inlet air temp doesn't rise correspondingly due to the intercooler being cool due the cruising beforehand. Note at cruising (little to zero boost) the otherwise fairly constant difference between the turbo out temperature and the inlet air temperature.


Cheers
Gary