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Borg Warner R2S regulated 2 stage turbo in an NB Miata

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Borg Warner R2S regulated 2 stage turbo in an NB Miata

 
Old 10-30-2018, 12:12 AM
  #101  
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What are PM3, 4, and 5 assigned to in the IO pin list(s)?
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Old 10-30-2018, 12:13 AM
  #102  
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So for solenoids, you might actually want open drain, which would be injector outputs.

edit. To tes those you will want a pull up if you want to use the volt meter
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Old 11-01-2018, 01:48 PM
  #103  
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Well, ****.

I was told, in no uncertain terms, that I would not be able to get any additional programmable outputs from my MS today.
Wish I had known this since January.

Off to explore new possibilities with Hakan, the electronics guru here in Turkey, who builds and sells MaxiGauges.
I talked to him today, and he says we can expand the gauge interface unit in my car to allow programmable outputs to drive solenoids and whatnot.

Not. an. easy. project.
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Old 11-01-2018, 02:11 PM
  #104  
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Check out the stuff from JBperf if you have CANBUS.
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Old 11-05-2018, 07:56 PM
  #105  
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Thanks to Reverant, I now have all the programmable outputs I need, and they all work!

My MS has 2 programmable outputs, and I needed a third one.

I used the PM5 (warmup LED) output per Rev's suggestion, and used an N channel mosfet plus a flyback diode, again, as instructed by him.
Since I am paranoid about overloading anything, I also used an optocoupler relay module, packed it all in a box, and tucked it away.
The idea is removing any load and stray anything from the MS output.
Tested several times, all is good.



Red is switched 12V
Black, ground
Yellow is PM5 output from MS
Grey is the lowside trigger for the vacuum solenoid.

I am sure electronics gurus will laugh at me, but it works.
So there.
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Old 11-11-2018, 11:22 AM
  #106  
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Quick question:
I finally started the engine and did the break in run with very gentle throttle inputs and 3rd gear decels for about 10 miles, and noticed it was pretty rich all over.
My current tune was perfect with the supercharger, and I will tune it for the turbo setup.
I was expecting some change in behavior, but never thought the difference would be so drastic.
I have to take away fuel everywhere...
Gentle tip-in yields 10.5 AFR, cruise at anything over 3000 rpm is at 12.5 or below.
Idle settles down to 14.7 after ASE..
Is this normal between a SC and turbo setup?

Edit:

Another point worth noting is EGT..
Even though my observation is limited to a relatively short drive so far, EGT seems to be much lower than "before".
The sensor is in the same location, and while it is in no way an absolute value, the before and after readings can be compared.
Could be a product of the rich AFR numbers, that remains to be seen, but I am talking about 200 degrees difference (in C).

Last edited by Godless Commie; 11-11-2018 at 11:34 AM.
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Old 11-11-2018, 12:05 PM
  #107  
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Considering you just put a couple of turbines in the exhaust flow......yeah I'd expect part throttle efficiency to drop off considerably. I saw a pretty big change going from NA to turbo in my part throttle maps.
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Old 11-11-2018, 12:09 PM
  #108  
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Originally Posted by Bronson M View Post
Considering you just put a couple of turbines in the exhaust flow......yeah I'd expect part throttle efficiency to drop off considerably. I saw a pretty big change going from NA to turbo in my part throttle maps.
Please help me understand this:
You are saying efficiency has dropped, and yet I have to take away fuel (by re-tuning my VE table).
Would that not mean an increase in efficiency?
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Old 11-11-2018, 12:18 PM
  #109  
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For a given map and rpm value you move less air and therefore need less fuel. Map and load are close cousins so yes, less pumping efficiency. Now what you do with that power output factors into BSFC or overall efficiency of the engine. Since you're no longer wasting power to turn a blower over you may be at a lower map / load cell for a given amount of power.

To simplify you may be able to pull the same hill at 30kpa that took 40kpa before.
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Old 11-11-2018, 12:26 PM
  #110  
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Originally Posted by Bronson M View Post
yeah I'd expect part throttle efficiency to drop off considerably.
Originally Posted by Bronson M View Post
To simplify you may be able to pull the same hill at 30kpa that took 40kpa before.
I do not mean to contradict you, just trying to wrap my brain around this properly...
If I can do the same hill at a lower kpa (load) than before, does this not mean the efficiency has in fact increased?
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Old 11-11-2018, 12:39 PM
  #111  
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Originally Posted by Godless Commie View Post
I do not mean to contradict you, just trying to wrap my brain around this properly...
If I can do the same hill at a lower kpa (load) than before, does this not mean the efficiency has in fact increased?
Yes
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Old 11-11-2018, 12:57 PM
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Yes sorry shouldn't have said "less efficient" in my first explanation, just less pumping efficiency. Pumping efficiency and BSFC are not one and the same, but certainly related.

You're over complicating things again, give the motor what it wants, in this case less fuel for a given map/rpm point.
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Old 11-11-2018, 06:19 PM
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Originally Posted by Bronson M View Post
give the motor what it wants...
I like that. Simple.
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Old 11-11-2018, 06:27 PM
  #114  
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Now you can clearly see how much power (and fuel) you were wasting spinning that supercharger
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Old 12-18-2018, 07:09 PM
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I thought it would be best to reserve this thread for technical discussion, so I started a separate build thread:

https://www.miataturbo.net/diy-turbo...n-turbo-98818/
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Old 04-13-2019, 09:38 PM
  #116  
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Originally Posted by Godless Commie View Post
I am, however, facing some interesting challenges:


This turbo setup features three separate controls. And get this: they are all VACUUM operated. Including the wastegate.

I mean, this setup is used in a diesel engine. Diesels have vacuum pumps, and the vacuum level never changes with RPM and such. So, a controller sends signals to some vacuum solenoids to activate the said controls...

The trick is figuring out the reasoning/triggers behind these individual commands.


Here is a short video of how the system operates, and you'll understand what I mean:





Small turbo is called High Pressure Compressor (HP), large one if Low Pressure (LP).

In the very beginning, HP spins and starts spinning the LP.

After that, LP starts blowing into HP.

Then, HP and LP blow together for a BRIEF period.

Following that, LP takes over, its bypass valve opens and LP continues to provide boost till either wastegate opens, or I lift my right foot.


The largest actuator operates a valve or gate between the two turbos.

This is an important step, because when and how it opens determines the boost ramp and how much the HP has to work:

Too little, and boost transition will be laggy and there will be a noticeable dip in the boost graph.

Too much, and EGT will rise due to restricted exhaust flow and there will be IAT issues, as well.


It is entirely possible to run this thing solely on the HP. This would just ruin the unused LP.


Next, there is the opening of the bypass valve (after the LP). That valve ensures the LP is no longer blowing through the HP and just providing boost in the traditional sense.

Apparently, there is a HUGE advantage to have the LP feed into the HP for a while to ensure maximum efficiency and cooler temps.


I am ultimately planning on maybe 14-16 psi boost pressure with this system.

I will run it in stages after the install.


First stage will be at the absolute minimum boost pressure that will ensure a "handshake" between HP and LP turbos.

That way, I can learn the intricacies of the system.


Also, I am planning on using a pressure driven (normal)wastegate actuator and linear motion DC motors for the remaining two.

I can drive those using my MS.


Question:

Can I find a pressure driven WG actuator that PULLS instead of pushing?

That would make my life much easier.

I have been building my project car since 2016 with a set of these turbos. From my conversations with BW and a couple other diesel places, in a diesel vehicle the wastegates are in the opposite state while the car is off. When the car is turned on the vacuum starts and pulls them to the opposite position. You can swap them to pressure actuators and they will work exactly the same way but use the normal pressure system used in a petrol car.


Nice project
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Old 04-14-2019, 11:58 AM
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Originally Posted by LOL650 View Post
I have been building my project car since 2016 with a set of these turbos. From my conversations with BW and a couple other diesel places, in a diesel vehicle the wastegates are in the opposite state while the car is off. When the car is turned on the vacuum starts and pulls them to the opposite position. You can swap them to pressure actuators and they will work exactly the same way but use the normal pressure system used in a petrol car.


Nice project
Not necessarily.
A diesel engine does not inherently produce vacuum, you need a vacuum pump.
That pump operates all the time and provides vacuum regardless of manifold pressure, so you can use and deliver this vacuum where and when needed.

A gasoline engine provides manifold vacuum in closed and part throttle operation only. A turbocharged gasoline engine provides vacuum to a point, then pressure.
Given the fact that one needs one or the other to operate the said controls for turbo operation, I chose vacuum for several reasons:

* The system already comes with properly sized and calibrated vacuum controls on it, why spend the time, effort and money to find matching pressure actuators...

* Some of the operations are carried out in off-boost conditions, meaning, manifold vacuum is readily available to that end. (I keep the internal wastegate open in off-boost cruise conditions, for example. This allows better exhaust scavenging etc...) A pressure actuator would be damn near impossible to use in off-boost conditions.

* I opted to build a large vacuum canister to have the vacuum needed under boost. Please keep in mind that the car spends a very small fraction of its running hours under boost. Maybe 5 to 30 seconds - at most - at a time before a gear is changed or throttle is lifted to restore vacuum in the reservoir.

Also, I drove this thing with this setup for 1000 Km with no problems whatsoever.

Yes, electric actuators would be a hoot to use... But... They are pretty expensive, and programming them is a bit beyond my abilities at this point.
So, vacuum it is for me.
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Old 06-12-2019, 02:56 PM
  #118  
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Hi, I have been Googling for info on R2S set ups and your post came up. I have got one on my PT Cruiser crd in the UK but it blows a lot of oil in the intake pipes. A mess when a pipe blows off as I can push it to 2.5 bar. I am controlling it using factory wastegate controllers. How have you done your return to sump? I can only use a 2 into 1 until I can pull the motor and put a second return in.

Tight.
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Old 06-12-2019, 03:17 PM
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Originally Posted by John F Latham View Post
Hi, I have been Googling for info on R2S set ups and your post came up. I have got one on my PT Cruiser crd in the UK but it blows a lot of oil in the intake pipes. A mess when a pipe blows off as I can push it to 2.5 bar. I am controlling it using factory wastegate controllers. How have you done your return to sump? I can only use a 2 into 1 until I can pull the motor and put a second return in.
Here's the build thread:

https://www.miataturbo.net/diy-turbo...n-turbo-98818/
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