[DWR]

Originally Posted by zackz

Our k26 turbo for sure isn't listed in the sheet, it should be able to handle a little more boost and air flow, but less speed too...

That's why we should ask borg warner for our part number turbo compressor map.

Following up on this post a little while back -
Borg Warner said the compressor and turbine maps are property of the OEM. So, I did a little comparision work given the dimensions provided by zackz. Just matching up inducer and exducer dimensions with other available turbos should put us in the ball park. A Garrett GT2871R with a 50 Trim would match up nicely. No such beast exists. I've attached 48 and 52 Trim as reference. Unfortunately, that ballpark is still a little small for slugging out over 400hp.
DO NOT reference the speed lines. Without the A/R you don't know if rotational speeds are equivalent. These speed are much lower than the AsMod parameter for turbine speed, even at moderator boost and exhaust pressures. As an aside, the AsMod calculation is closely correlated with airflow. So, at the choke line it probably is not accurate.

[DWR]

TDIwyse has shared many graphs of EMP vs Boost. So here's one he asked for, a stage 2 Jarek tune with modified stock wastegate. Enjoy

[iaknown]

Originally Posted by DWR

TDIwyse has shared many graphs of EMP vs Boost. So here's one he asked for, a stage 2 Jarek tune with modified stock wastegate. Enjoy

Look at those sexy curves!

[DWR]

Yeah, before she had 'surgery' she looked like this. Looks like it was all worth it.

[TDIwyse]

Excellent. Thanks for sharing. Looks like you've converted the mbar data into psig? If so, is that EMP touching ~4200 mbar at 4500 rpm?

Also interesting that the boost dips so much at the handoff between the HP and LP turbo's. That area looks a lot different than how my system is behaving.

Questions...

1. What is your exhaust configuration? Open? SCR/Diffuser?
2. Is this with just the tune, or are you adding H2O/methanol and/or more fuel? I'd be curious to see the point where the ported internal wastegate can't keep up with exhaust flow as additional fueling is burned in the cylinders.

Thanks again for sharing the data.

[TDIwyse]

Originally Posted by DWR

Yeah, before she had 'surgery' she looked like this. Looks like it was all worth it.

It's interesting that stock the EMP was reaching the same level. Although, was that with the extra back pressure of the DOC/DPF/SCR/Diffuser in the system? If so, then I'd expect it to be less drive pressure across the turbo in the stock case even with the same EMP.

[DWR]

Originally Posted by TDIwyse

Excellent. Thanks for sharing. Looks like you've converted the mbar data into psig? If so, is that EMP touching ~4200 mbar at 4500 rpm?

Also interesting that the boost dips so much at the handoff between the HP and LP turbo's. That area looks a lot different than how my system is behaving.

Questions...

1. What is your exhaust configuration? Open? SCR/Diffuser?
2. Is this with just the tune, or are you adding H2O/methanol and/or more fuel? I'd be curious to see the point where the ported internal wastegate can't keep up with exhaust flow as additional fueling is burned in the cylinders.

Thanks again for sharing the data.

Peak EMP is 4600 mbar. I don't like the boost curves for any system I've seen, including stock. Exhaust system in the Stage 2 graph is custom, using non stock components. Don't know what the pressure after the turbo is, yet.
It is just tune. Rough order of magnitude, fluid to gas expansion ratios are similar for many compounds. Since fuel is @ 7% max by weight of the mixture in the cylinder, it is acounts for a similar percentage of exhaust gase volume. The gas expansion is primarily a result of the heat of combustion. As you know, Stage 2 does not have a lot of room to add more fuel because of the AFR limit. So, additional exhaust flow from methanol or rail pressure manipulation would be proportional to % HP increase.

For complete transparency, I am getting data from a number of sources now and what I share with the forum may not be from a single vehicle. Unless the owner's give me explicit permission I will be keeping certain information confidential.

[Smonkey09]

Originally Posted by DWR

For complete transparency, I am getting data from a number of sources now and what I share with the forum may not be from a single vehicle. Unless the owner's give me explicit permission I will be keeping certain information confidential.

All your data are belong to us.

[TDIwyse]

Originally Posted by DWR

Peak EMP is 4600 mbar....

Thanks for clarifying. But I'm confused on how we get from 4600 mbar to the graph psi for EMP. It appears from the boost # that the graph is gauge psi. Which would make the peak EMP on the graph ~46 psig, which would be about 60-61 psi absolute, which would be about 4170 mbar. Or am I missing something?

[DWR]

Looks like we are having technical issues with logging. Here's EMP vs Boost without the strange dip, from a second run. Unfortunately, there is a 1.5 second gap in the log in mid rpms - best I can do for now. Oh, and iaknown says I can tell everyone this is his car.

[DWR]

Originally Posted by TDIwyse

Thanks for clarifying. But I'm confused on how we get from 4600 mbar to the graph psi for EMP. It appears from the boost # that the graph is gauge psi. Which would make the peak EMP on the graph ~46 psig, which would be about 60-61 psi absolute, which would be about 4170 mbar. Or am I missing something?

Yeah, few people think about pressure in absolute terms or even mbar. The reason I graph in psi is to show the data just as if you were looking at a gauge.

[TDIwyse]

Originally Posted by DWR

Yeah, few people think about pressure in absolute terms or even mbar. The reason I graph in psi is to show the data just as if you were looking at a gauge.

Understood. But since TestO is reporting mbar, and we're comparing data, it would be one less step in conversions.

And I still don't see how to get from the graph of EMP in psig to the 4600 mbar EMP TestO data that was mentioned as the peak EMP...

The latest graph shows higher EMP for the psig, but even with that I calculate back to a ~ 4350 mbar. So where did the 4600 mbar peak EMP come from?

[DWR]

Originally Posted by TDIwyse

Understood. But since TestO is reporting mbar, and we're comparing data, it would be one less step in conversions.

And I still don't see how to get from the graph of EMP in psig to the 4600 mbar EMP TestO data that was mentioned as the peak EMP...

The latest graph shows higher EMP for the psig, but even with that I calculate back to a ~ 4350 mbar. So where did the 4600 mbar peak EMP come from?

My fat fingers! I didn't even notice my typo. You are correct.

I'm less concerned about the mathematical conversion, my concern is the mental step. Not convinced we should let TestO decide how to present the data. I am convinced, however, that we should do what is best for the audience. As an audience member, I personally don't like seeing the data in mbar. It was distracting trying to match your boost gauge findings with mbar logs. Just one man's opinion. I would appreciate others chiming in here so we can present findings in the besy way possible.

From my point of view, the power of the graphs is you can see relationships.
If we want to compare the numbers then we should probably do that explicitly. I'd like to suggest we find a good way to share data, so that we can literally plot the comparison data on the same graph, tables, whatever. I am not an expert on how to do that in this forum - I'm at the top of my game when I can insert an image, lol. So, I'm open to suggestions. Anyone?

[gtp900]

+1 for psi

[iaknown]

Doesn't matter to me. I'm so used to seeing mbar now it doesn't phase me. Everything so far has pretty much been in mbar so I don't know if it's better to stick with it...

What would be nice is a way to make the graphs show up similar, psi or not. The dip in boost above probably looks worse because of the x-axis in the graph being stretched more compared to other graphs. I don't know enough about graphing though, does other graphing software offer a better way to standardize plots?

[TDIwyse]

Originally Posted by iaknown

Doesn't matter to me. I'm so used to seeing mbar now it doesn't phase me. Everything so far has pretty much been in mbar so I don't know if it's better to stick with it...

What would be nice is a way to make the graphs show up similar, psi or not. The dip in boost above probably looks worse because of the x-axis in the graph being stretched more compared to other graphs. I don't know enough about graphing though, does other graphing software offer a better way to standardize plots?

I like exporting the data to excel and then processing there... you can keep stuff in mbar or convert to psi and psig as well. you can also grab sections of pulls and do an xy scatter plot with rpm as the x axis, and then set the min/max range for the various scales. But that's just my preference.

[DWR]

Originally Posted by TDIwyse

I like exporting the data to excel and then processing there... you can keep stuff in mbar or convert to psi and psig as well. you can also grab sections of pulls and do an xy scatter plot with rpm as the x axis, and then set the min/max range for the various scales. But that's just my preference.

Yep, you and me both. Big scatter plot fan because it normalizes the axis (I say that but I did not do it the last couple of plots ) A funny thought occurred to me, who else is submitting graphs?

[zackz]

Many thanks for those interesting graphs DWR!

That's what I was firstly looking for from the beginning

[zackz]

Now we clearly have the proof that the stock wastegate mod works well!

I will see in my case if that's enough for 400 ++ hp....

[iaknown]

Originally Posted by zackz

Now we clearly have the proof that the stock wastegate mod works well!

I will see in my case if that's enough for 400 ++ hp....

We had clear proof quite a while ago when I posted the log from my piggyback showing the boost in check but this TestO log was posted for comparison purposes for those that wanted to see.

Will be interesting to see if 400hp can be reached!

[DWR]

Originally Posted by iaknown

Will be interesting to see if 400hp can be reached!

We must be talking RWHP, because some have already achieved this at the crank. It depends on the driveline loss, because max airflow indicates it is a close call. Efforts to move more air in the upper rpm's is the key. Just 5% more air would get you there.

Maybe I should say 5% more oxygen, food for thought.

[zackz]

Originally Posted by iaknown

We had clear proof quite a while ago when I posted the log from my piggyback showing the boost in check but this TestO log was posted for comparison purposes for those that wanted to see.

Will be interesting to see if 400hp can be reached!

Sorry I missed that I think

Thank you iaknown of course for starting that thread!

Well I'm already around 400 hp at the crank, the limiting factor is currently the overboost...

My Mods: straight downpipe, wagner ic, k&n filter, straight egr tube, and of course the remap!