Borg Warner EFR Series Turbo's V 2.0

[MBS206]

1 hour ago, Borci88 said:

 

Heres a dyno log comparing

MAP
TPS
RPM
TURBO SPEED

Each hump is 2nd, then 3rd then 4th gear. This particular log is using gate pressure with the mac valve completely removed.
As you can see it spikes to 23psi, and then drops to 20psi over the course of approx 700rpm, this is the minimum pressure the system will run using a 12psi spring. I think my next set of logs will be changing the spring to the 6psi spring and going out and doing another set of logs again and see if the spike is as dramatic.

As you can imagine if it spikes 3psi on wastegate pressure, that increases to 5-6psi of difference in the higher boost levels approaching the 28psi target with the mac valve.

I even have a few logs here where with the mac valve targetting 28psi, the haltech is seeing 38.6psi.... 

If you have a valve, set to 12PSi, and when it ramps up, it goes out to 23PSi, and then settles for a consistent 20PSi and thats the lowest it will go, then I'd be suspecting you have an issue getting enough air to flow AROUND the turbo on the hot side.

Now, this could directly flow into what GTSBoy is saying, and that's effectively that your skinny ports aren't able to get enough of the air through the head.

Remember, boost isn't a measure of air flow, it's a measure of restriction. And if the turbo at max bypass around it is still able to deliver more air than the head can ingest, your boost will be up.

 

In the NEO Head, being NA, you said it's stock, are you on stock cams, and stock springs in it?

 

Have you tried doing a run with the wastegate held fully open start to finish?

[GTSBoy]

1 minute ago, MBS206 said:

then I'd be suspecting you have an issue getting enough air to flow AROUND the turbo on the hot side.

This actually makes more sense than what I'm suggesting, which would make me feel happier anyway. I just reached for an idea on the cold side because the tests on the hot side theoretically ruled out WG problems.

But now that you mention it, it did bother me that a 12 psi spring on what is supposed to be a good WG setup is on able to get down to 20 psi. That's bullshit. Read that way, that WG is not doing what it is supposed to.

[Piggaz]

This issue has been there between twins and singles…

it ain’t the hot side.

[GTSBoy]

10 minutes ago, Piggaz said:

This issue has been there between twins and singles…

it ain’t the hot side.

That is a valid point.

[Dose Pipe Sutututu]

Post up a showing a a wide RPM range, wastegate duty, timing, TPS, MAP

Use 2x rows if you can, easier to read the data.

Or just send it to me 

[MBS206]

1 hour ago, Piggaz said:

This issue has been there between twins and singles…

it ain’t the hot side.

It's possible it's the same issue, as I described.

The twins also weren't able to bypass enough air around them, based on the wild restriction in the head.

 

OP needs to confirm how bone stock the head is.

 

Either way, on the setup, if the wastegate cant get boost eventually down to 12psi, there's an issue.

 

Heck, maybe there's some sort of restrictor installed in the air line to the wastegate system. Slow to react to open, then when boost drops it's slow for it to go back down to close the wastegate enough. This doesn't explain why it can't get down to gate pressure though.

I'd be testing the gate by slowly increasing pressure from an external air source and see how the gate moves.

If he has the type of gate I think he has from his definition, the motion of it opening is non linear too which can cause issues with getting it to play nice.

[Dose Pipe Sutututu]

38 minutes ago, MBS206 said:

, if the wastegate cant get boost eventually down to 12psi, there's an issue.

Sounds like a manifold issue

[The Mafia]

My EFR 8474 Black, made 800awhp on a roller dyno. at 25-26psi. E85.
Shaft speed was around 106,000rpm
1.01 rear. The rear is maxed. 
6 boost
Turbosmart 60mm gate
3.5inch exhaust 
Head is worked to the shithouse. Bain racing. VCam. 272 exhaust.
RB28 - RB26 foundation. 

You have an intake issue. Start getting proper data and I mean go back to the simple things. 

- Pressure test your intake
- Block off the Turbo BOV, you don't need it. 
- Test pressure before and after your intercooler

If your head is pretty stock, that is your issue. Especially if it is NA. 
Take it off and spend $10k on it. 

[Borci88]

18 hours ago, MBS206 said:

In the NEO Head, being NA, you said it's stock, are you on stock cams, and stock springs in it?

Have you tried doing a run with the wastegate held fully open start to finish?

I built this engine approximately 12 years ago so my own head (brain) is a little grey on the exact hardware in the RB head, however what I recall is.

Stock RB25 NEO TURBO Intake Camshaft
HKS 260 degree Exhaust Camshaft (R34 GTR)
RB25 NEO Turbo Springs 

I ported/removed the exhaust stud humps found in the RB25 head so theres less turbulence but it wasn't ported/polished properly, just a hump removal. I've attached two pictures of the before and after to illustrate.

 

18 hours ago, GTSBoy said:

This actually makes more sense than what I'm suggesting, which would make me feel happier anyway. I just reached for an idea on the cold side because the tests on the hot side theoretically ruled out WG problems.

But now that you mention it, it did bother me that a 12 psi spring on what is supposed to be a good WG setup is on able to get down to 20 psi. That's bullshit. Read that way, that WG is not doing what it is supposed to.

 

18 hours ago, Piggaz said:

This issue has been there between twins and singles…

it ain’t the hot side.

The ECU gets its boost reference from the nipple on the rear of the head on the intake side, behind the fuel rail.
The wastegate gets its boost reference from a nipple on the cooler pipe immediately after the comp cover. 

Could a decent pressure drop across the intercooler cause the wastegate to be seeing a higher PSI than what the ECU is seeing, and thus it can't control it accurately and quick enough?

18 hours ago, GTSBoy said:

That is a valid point.

 

16 hours ago, MBS206 said:

It's possible it's the same issue, as I described.

The twins also weren't able to bypass enough air around them, based on the wild restriction in the head.

 

OP needs to confirm how bone stock the head is.

 

Either way, on the setup, if the wastegate cant get boost eventually down to 12psi, there's an issue.

 

Heck, maybe there's some sort of restrictor installed in the air line to the wastegate system. Slow to react to open, then when boost drops it's slow for it to go back down to close the wastegate enough. This doesn't explain why it can't get down to gate pressure though.

I'd be testing the gate by slowly increasing pressure from an external air source and see how the gate moves.

If he has the type of gate I think he has from his definition, the motion of it opening is non linear too which can cause issues with getting it to play nice.

We ran a line to the actuator and watched it open and close using an air compressor, while we didn't have a gauge on the line to see when it was cracking open, it was opening smoothly. 


I just removed the gate now and even though the documentation says you need to open it in a vice due to preload (which I did), there wasn't any preload on the cap, which is something we noticed straight out of the box as well when new. This silver cap internally is threaded to the actuator rod that runs out the bottom of the straightgate. Not sure how I'm supposed to get this spring out to be frank..

16 hours ago, Dose Pipe Sutututu said:

Sounds like a manifold issue

Potentially but everyone else doesn't appear to have to stop at 500kw because of 6boosts design. 

3 hours ago, The Mafia said:

My EFR 8474 Black, made 800awhp on a roller dyno. at 25-26psi. E85.
Shaft speed was around 106,000rpm
1.01 rear. The rear is maxed. 
6 boost
Turbosmart 60mm gate
3.5inch exhaust 
Head is worked to the shithouse. Bain racing. VCam. 272 exhaust.
RB28 - RB26 foundation. 

You have an intake issue. Start getting proper data and I mean go back to the simple things. 

- Pressure test your intake
- Block off the Turbo BOV, you don't need it. 
- Test pressure before and after your intercooler

If your head is pretty stock, that is your issue. Especially if it is NA. 
Take it off and spend $10k on it. 

I would, but I think I'm getting to that point where if I'm going to do the head and make another 100kw, then I'm going to need a fancy gearbox and quite a few other things and 10k becomes 20k becomes 30k within a few months.

I'm not necessarily sold on the idea just yet that the head is restrictive at 4000rpm (and what.. 300kw?) and yet doesn't seem to be restrictive at 7000rpm when it's making 500kw, however I'm obviously not closing the door on that theory.

[Lithium]

Sorry had a bit of a week and haven't had heaps of time to follow this, so apologies if I've missed something - any chance of showing a log with the rpm, turbo speed, MAP, and wgdc all in one view?

Definitely an "interesting" problem, and while it's definitely worth noting that there was a similar issue with the twins I'd not completely put all bets on the root cause being the same thing.  Keep an open mind, follow the data.

[Borci88]

13 minutes ago, Lithium said:

Sorry had a bit of a week and haven't had heaps of time to follow this, so apologies if I've missed something - any chance of showing a log with the rpm, turbo speed, MAP, and wgdc all in one view?

Definitely an "interesting" problem, and while it's definitely worth noting that there was a similar issue with the twins I'd not completely put all bets on the root cause being the same thing.  Keep an open mind, follow the data.

Not a problem at all Lithium, I appreciate your help regardless.

I've pulled a small part of a log where the target pressure was 28psi and it spiked to 36.4psi.
I've only just begun using Data Log Viewer so if I'm sending this in the wrong format let me know.

[GTSBoy]

3 hours ago, Borci88 said:

I'm not necessarily sold on the idea just yet that the head is restrictive at 4000rpm (and what.. 300kw?) and yet doesn't seem to be restrictive at 7000rpm when it's making 500kw,

While that sounds reasonable, this is definitely a boost control problem, but the real question is why are you having the boost control problem? Which is why I pondered the idea that there's a problem at ~4000rpm related to head flow. In that instance, you are not yet under boost control - it's still ramping up and the wastegate is yet to gain authority. So, I'm thinking that if the wastegate is not yet open enough to execute control, but the compressor has somehow managed ot make a lot of flow, and the intake side of the head doesn't flow as well as the exhaust side (more on that later), then presto, high MAP (read that as boost overshoot).

I have a number of further thoughts.

I use butterfly valves in industrial applications ALL THE TIME. They have a very non-linear flow curve. That is to say that there is a linear-ish region in the middle of their opening range, where a 1% change in opening will cause a reasonably similar change in flow rate, from one place to another. So, maybe between 30% open and 40% open, that 1% change in opening gives you a similar 2% change in flow. (That 2% is pulled out of my bum, and is 2% of the maximum flow capacity of the valve, not 2% of the flow that happens to be going through the valve at that moment). That means that at 30% open, a 1% change in opening will give you a larger relative flow increase (relative to the flow going through the valve right then) compared to the same increment in opening giving you the same increment in flow in outright flow units. But at 40% opening, that extra 2% of max flow is relatively less than 1/2 the increase at 30% opening. Does that make sense? It doesn't matter if it doesn't because it's not the main point anyway.

Below and above the linear-ish range in the middle, the opening-flow curve becomes quite...curved. Here's a typical butterfy valve flow curve. Note that there is a very low slope at the bottom end, quite steep linear-ish slope in the middle, then it rolls off to a low slope at the top.

This curve shows the "gain" that you get from a butterfly valve as a function of opening%. Note the massive spike in the curve at 30%. That's the point I was making above that could be hard to understand.

So here's the point I'm trying to make. I don't know if a butterfly valve is actually a good candiate for a wastegate. A poppet valve of some sort has a very linear flow curve as a function of opening %. It can't be anything else but linear. It moves linearly and the flow area increases linearly with opening %. I can't find a useful enough CV curve for a poppet valve that you could compare against the one I showed for the butterfly, but you can pretty much imagine that it will not have that lazy, slow increase in flow as it comes off the seat. It will start flowing straight away and increase flow very noticeably with every increase in opening%.

So, in your application, you're coming up onto boost, the wastegate is closed. Boost ramps up quite quickly, because that's really what we want, and all of a sudden it is approaching target boost and the thing needs to open. So it starts opening, and ... bugger all flow. And it opens some more, and bugger all more flow. And all the while time is passing, boost is overshooting further, and then finally the WG opens to the point where the curve starts to slope upwards and it gains authority amd the overshoot is brought under control and goes away, but now the bloody thing is too open and it has to go back the other way and that's why you get that bathtub curve in your boost plot.

My position here is that the straight gate is perhaps not the good idea it looks like. It might work fine in some cases, and it might struggle in others.

Now, back to the head flow. I worry that the pissy little NA Neo inlet ports, coupled with the not-very-aggressive Neo turbo cam, mean that the inlet side is simply not matched to the slightly ported exhaust side coupled with somewhat longer duration cam. And that is not even beginning to address the possibility that the overlap/relative timing of those two mismatched cams might make that all the worse at around 4000rpm, and not be quite so bad at high rpm.

I would be dropping in at least a 260 cam in the inlet, if not larger, see what happens.

I'd also be thinking very hard about pulling the straight gate off, banging a normal gate on there and letting it vent to the wild, just as an experiment.

Edited May 25 by GTSBoy
typos n shit

[Dose Pipe Sutututu]

1 hour ago, Borci88 said:

Potentially but everyone else doesn't appear to have to stop at 500kw because of 6boosts design. 

it's not the issue with making power, it's the issue with controlling boost, and this isn't the first time I've seen a 6Boost having issue with controlling boost down low.

 

43 minutes ago, Borci88 said:

I've pulled a small part of a log where the target pressure was 28psi and it spiked to 36.4psi.
I've only just begun using Data Log Viewer so if I'm sending this in the wrong format let me know.

The boost control here looks interesting.

 

Looking at your logs, looks like it's set to open loop boost control strategy (which is fine). We can see VCT being kept on till about 6600RPM (no issue with that). Ignition timing (I'm assuming this is E85, seems within reason too, nothing too low, causing hot EGTS and boost spiking). There's about 15 degrees of advance when your boost shoots up, however can't be this as the timing isn't single digits.

I'm assuming there's no EMAP data, as I wasn't able to find it in the logs. We can see your tuner sets the WG DC to 0% after 4300RPM, trying to control boost.

 

My thoughts, what frequency is your wastegate set to?  AND why aren't you using both ports for better control?

[Dose Pipe Sutututu]

This is the other log file, if only we had exhaust manifold pressure - would understand what's going on a bit better

 

Can you take a screenshot of your wastegate setup in the Kebabtech?

 

Engine Functions --> Boost Control (looks like this):

 

[Borci88]

1 hour ago, Dose Pipe Sutututu said:

This is the other log file, if only we had exhaust manifold pressure - would understand what's going on a bit better

 

Can you take a screenshot of your wastegate setup in the Kebabtech?

 

Engine Functions --> Boost Control (looks like this):

 

Not in front of a computer until later tonight so this is probably the best I can do for now.

 

We are using both ports on the wastegate eith the 3 port Mac valve, I've just changed it to single in the photo as I was trying it out on gate pressure 

 

 

[MBS206]

1 hour ago, GTSBoy said:

While that sounds reasonable, this is definitely a boost control problem, but the real question is why are you having the boost control problem? Which is why I pondered the idea that there's a problem at ~4000rpm related to head flow. In that instance, you are not yet under boost control - it's still ramping up and the wastegate is yet to gain authority. So, I'm thinking that if the wastegate is not yet open enough to execute control, but the compressor has somehow managed ot make a lot of flow, and the intake side of the head doesn't flow as well as the exhaust side (more on that later), then presto, high MAP (read that as boost overshoot).

I have a number of further thoughts.

I use butterfly valves in industrial applications ALL THE TIME. They have a very non-linear flow curve. That is to say that there is a linear-ish region in the middle of their opening range, where a 1% change in opening will cause a reasonably similar change in flow rate, from one place to another. So, maybe between 30% open and 60% open, that 1% change in opening gives you a similar 2% change in flow. (That 2% is pulled out of my bum, and is 2% of the maximum flow capacity of the valve, not 2% of the flow that happens to be going through the valve at that moment). That means that at 30% open, a 1% change in opening will give you a larger relative flow increase (relative to the flow going through the valve right then) compared to the same increment in opening giving you the same increment in flow in outright flow units. But at 60% opening, that extra 2% of max flow is relatively less than 1/2 the increase at 30% opening. Does that make sense? It doesn't matter if it doesn't because it's not the main point anyway.

Below and above the linear-ish range in the middle, the opening-flow curve becomes quite...curved. Here's a typical butterfy valve flow curve. Note that there is a very low slope at the bottom end, quite steep linear-ish slope in the middle, then it rolls off to a low slope at the top.

This curve shows the "gain" that you get from a butterfly valve as a function of opening%. Note the massive spike in the curve at 30%. That's the point I was making above that could be hard to understand.

So here's the point I'm trying to make. I don't know if a butterfly valve is actually a good candiate for a wastegate. A poppet valve of some sort has a very linear flow curve as a function of opening %. It can't be anyelse but linear. It moves linearly and the flow area increases linearly with opening %. I can't find a useful enough CV curve for a poppet valve that you could compare against the one I showed for the butterfly, but you can pretty much imagine that it will not have that lazy, slow increase in flow as it comes off the seat. It will start flowing straight away and increase flow very noticeably with every increase in opening%.

So, in your application, you're coming up onto boost, the wastegate is closed. Boost ramps up quite quickly, because that's really what we want, and all of a sudden it is approaching target boost and the thing needs to open. So it starts opening, and ... bugger all flow. And it opens some more, and bugger all more flow. And all the while time is passing, boost is overshooting further, and then finally the WG opens to the point where the curve starts to slope upwards and it gains authority amd the overshoot is brought under control and goes away, but now the bloody thing is too open and it has to go back the other way and that's hy you get that bathtub curve in your boost plot.

My position here is that the straight gate is perhaps not teh good idea it looks like. It might work fine in some cases, and it might struggle in others.

Now, back to the head flow. I worry that the pissy little NA Neo inlet ports, coupled with the not-very-aggressive Neo turbo cam, mean that the inlet side is simply not matched to the slightly ported exhaust side coupled with somewhat longer duration cam. And that is not even beginning to address the possibility that the overlap/relative timing of those two mismatched cams might make that all the worse at around 4000rpm, and not be quite so bad at high rpm.

I would be dropping in at least a 260 cam in the inlet, if not larger, see what happens.

I'd also be thinking very hard about pulling the straight gate off, banging a normal gate on there and letting it vent to the wild, just as an experiment.

What is shown here by GTs is what I was getting at about the gate being non linear.

It's like the throttle in your car. Roughly 80% of your power is controlled with 20% of the throttle blade movement. Same same for your wastegate which makes control very hard.

[acsplit]

It looks like there is room to fit a traditional wastegate with a basic screamer to perform a test.

You just don't see people using these straight gates on mass still. 

[Borci88]

19 minutes ago, MBS206 said:

What is shown here by GTs is what I was getting at about the gate being non linear.

It's like the throttle in your car. Roughly 80% of your power is controlled with 20% of the throttle blade movement. Same same for your wastegate which makes control very hard.

13 minutes ago, acsplit said:

It looks like there is room to fit a traditional wastegate with a basic screamer to perform a test.

You just don't see people using these straight gates on mass still. 

I spoke with Turbosmart on Friday and they said the uptake in Australia has been quite slow because it's not a known item, however they've been selling in huge numbers in the USA so we should have heard reports by now if they were no good surely. 

While it may be the gate it still begs the question, why did this happen very similarly with the Twin turbos... 

[acsplit]

Did it happen before you changed ECU's?

[Borci88]

20 minutes ago, acsplit said:

Did it happen before you changed ECU's?

Not that I could tell no however we also only used racepaces version of a boost controller, and not an actual Mac valve.