Return of the Twincharge: 2/18 - Datalog comparisons!

[anothernord]

A long time ago, I cobbled together a twin charger system using an Eaton M62 and custom-mounted TD04. Since then, I've done a full WRX hybrid build complete with forged pistions.

I also got a degree in Mechanical Engineering, so I'm planning on using some of those skills to make this all work...

The goal is to increase low end power and reduce turbo lag.

Phase 1 will set the the wastegate to control the compressor speed to match the mass flow of the M62: a balanced system.

Phase 2 will get trickier, and will involve an Arduino-based control system to bypass the supercharger once the turbo starts to overtake it. I'll be copying the setup VW uses:




UPDATE:
Datalog results and video proof:



UPDATE: The initial changeover code works: Quick video:




I've written some pseudo-code for how the control system will work. But I'm still working out whether to use static pressure measurements before and after each air-handling device, or mass flow. The latter seems more reliable since it'll account for changes in air temperature.

Anyway, this'll be a drawn-out project since this is my only vehicle, and daily driver to and from work.


So, I picked up another Mercedes M62 from eBay, and started thinking figuring what needs to move and how to mount it.


The current status of the car:


More to come...

- Nord

[chevyman1968]

I am going to be waiting to see the outcome of this. I am glad you are working on this again. I am loving your wheels!


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[meepers]

Nord, you are a twisted beautiful bastard.... I always love watching the Nord Skunkworks appear. You have some awesome designs. Cant wait to see how this works out.

[anothernord]

Nord, you are a twisted beautiful bastard.... I always love watching the Nord Skunkworks appear. You have some awesome designs. Cant wait to see how this works out.

I got a good laugh from this. Thanks!

A few more updates:



I also ordered most of the electronics to actuate this Bosch electronic throttle body I found. Coincidentally, it's also from a Mercedes C230. It uses a simple PWM single that should be easy to get working with the Arduino.


The new AOS (IAG Performance) will go where the washer fluid bottle was. I'll probably get one from a newer Impreza that goes in the fender.


She's a little taken apart, but things will be coming together a little more quickly in the coming weeks.


Oh, I finally bought another vehicle to drive while I work on the Subaru. 2001 Tacoma with 254,000 miles.

[meepers]

Haha, Glad I could give you a laugh! I really do love your builds as they are always pure awesomness!

[nepbug]

So what is the engine management plan?

Are you building an entire arduino-based ECU? It kinda sounds like the arduino is just controlling boost, right?

Megasquirt? ECU conversion? RRFPR and cross fingers?

[anothernord]

So what is the engine management plan?

Are you building an entire arduino-based ECU? It kinda sounds like the arduino is just controlling boost, right?

Megasquirt? ECU conversion? RRFPR and cross fingers?

My car is EJ205/EJ257 swapped, so I just use a Tactrix cable and Romraider.

The Arduino is only controlling the supercharger clutch and it's bypass. So really it will be an independent system.

And a small update:

I got the Bosch throttle body (mostly) working with the Arduino. It's crude and there needs to be some refinement in the code, but it'll do the job for now.

The Bosch throttle body has 2 variable resistors that read opposite of eachother, so it's easy to build a voltage divider circuit. A voltage divider circuit is basically the same way that your typical potentiometer circuit works, so the Arduino ends up just reading a 0-5V signal.

The valve's motor uses a PWM signal provided by a TIP120 transistor. It basically just switches the power to the motor on and off at whatever frequency is applied to the base pin.

In the video, I'm just using a 10k potentiometer to control the valve. On engine, I'll have a simple switch, as well as the aforementioned pressure sensors that will provide the signal to open/close the valve.

*** Click for video ****

[lord flashheart]

Lol hey anothernord its been a while! Your still crazy as ever i see!

[lord flashheart]

Anothernord please post up here
https://sl-i.net/FORUM/showthread.php?t=19038

[anothernord]

Status report:

The pulley adapter plate has been designed and sent out to the machine shop. I went with Proto Labs, which charged $218 for the plate with a 3 day turn around.

Everything will get held together with these handy shoulder bolts from McMaster. I found that the lightning pulley has holes that provide about .004" diametral clearance on with these bolts, so the pulley will located nicely to the plate with minimal runout.




The Kartboy crank pulley will still need holes drilled and tapped in it, so that's the only thing left to do with the pulley.

I also have ordered all the piping, so that will be getting fabbed soon as well.

[anothernord]

Well, I had to get brain surgery for a minor hemorrhage, but I'm ok and recovering.

And here's the pulley adapter plate that came in.

[anothernord]

I found a random piece of metal at work that pilots both my adapter plate and the Kartboy pulley pretty well, then used a 10mm center punch to pretty accurately locate the six holes to be drilled and tapped on the pulley. I think I got it fairly close to concentric, but one of the 6 holes didn't quite line up with the adapter plate holes, so I'll have to enlarge that hole.





Some work got done on the piping as well:

[anothernord]

A little more progress...

Inlet flange + pipe (not pretty but it will work)


Charge piping to the inlet:


You can see where the last piece of the puzzle will go: A flange for the Benz throttle body, and a "Y-pipe" to spit incoming air to the bypass throttle body or supercharger inlet


Hood clearance... err, what hood clearance? If I'm livin' right, I'll be able to just cut out some of the support and have the piping clear. Otherwise there will be an awesome charge pipe out in the breeze.

[Yamazaki]

Hood clearance... err, what hood clearance? If I'm livin' right, I'll be able to just cut out some of the support and have the piping clear. Otherwise there will be an awesome charge pipe out in the breeze.

I don't know why, but I laughed when I read this. But why have an open bit of hood? Why not fab in a little bump in the hood like in the older Eclipses?

[anothernord]

Here's what I ended up doing with the hood:


And more updates: I'm very close...

Here's what happens when you don't lubricate and torque your turbo's fasteners enough:


DIY turbo inlet with a piece of 3" pipe and HPS offset coupler (2.25" - 3". Requires bending of the fuel lines.


Looking more like an engine:


Idler/tensioner support:


Close-up of the pulley:


Bracket:




Belt, all tensioned and check for clearance:

[anothernord]

Woot woot!

It's running! I shook it out over the weekend and it runs pretty well. The last thing to do is get the controller working with the bypass; right now I'm just switching the SC off and on manually.

Video proof:

[meepers]

super sweet. I hate that I can BARELY fit a stock 06 Top mount under my hood let alone that GIANT beast you have. Stupid stock non turbo intake manifold!. I had to cut a space for my BOV to fit through the hood scoop. lol. Looks good. Once you have all the finishing touches on, that thing will look the business!. How is off the line pull with the SC running?

[anothernord]

The low end is very nice to have. I used the SC a bit going over Trail Ridge Road (highest cont. paved road in the US) the other day and didn't have to downshift at all at 12,000'.

I have the code working to open and close the bypass right now, so it's basically just a 2-mode system: SC mode, or turbo mode.

[dynonacht]

pics with hood closed?

[Dead91silvia]

Been a while since I looked at this build but this is some amazing work! I'll admit, I'm a bit confused on a some bits, but super cool anyway!

I do agree that it would be kinda cool to do what @Yamazaki said, do a small bump in the hood, like an old Eclipse would have.

I'm sure this will be a bit of a noob question, but whats the MPG you are getting and what fuel are you using?

[Alucard]

Questions (and let me know if I'm asking the right or wrong ones):

1. Does each forced induction appendage (turbo and supercharger) have their own unique tunes, considering that they operate and generate power different ways? If they're working together, how will that particular tune pan out for them?

2. Will they still be able to work together as one in the midrange rpm area like your last twin setup? With the way you have the intake piping set up, I can't imagine the Supercharger getting in the way of the turbo psi pressure once it gets going.

3. Have you thought about a destroker EJ25 of some kind? This way, you could attain the high rpm and relieve some stress of forced crank acceleration, and cram even more air in those chambers without the aforementioned added stress of trying to get the 257 crank to spin high.

[anothernord]

Questions (and let me know if I'm asking the right or wrong ones):

1. Does each forced induction appendage (turbo and supercharger) have their own unique tunes, considering that they operate and generate power different ways? If they're working together, how will that particular tune pan out for them?

2. Will they still be able to work together as one in the midrange rpm area like your last twin setup? With the way you have the intake piping set up, I can't imagine the Supercharger getting in the way of the turbo psi pressure once it gets going.

3. Have you thought about a destroker EJ25 of some kind? This way, you could attain the high rpm and relieve some stress of forced crank acceleration, and cram even more air in those chambers without the aforementioned added stress of trying to get the 257 crank to spin high.

There's no way to change tunes with the stock WRX ECU, so I have to have one tune for everything. The supercharger simply lets the engine get more airflow at low RPM, so, in this case, for example, I just have to make sure the cells for the high-load, low-rpm have good timing and air-fuel values. They both give air to the engine, so it's just a matter of what load conditions they give air to the engine.

The supercharger most definitely creates a restriction to the turbo above a certain point. The turbo will, very quickly, outflow the supercharger, so there isn't very much of the operating range where they can work in true series mode. The turbo in this setup is much bigger than my previous one.

The valvetrain is really the limiting part of this engine for high-rev operation. All the EJ crankshafts have pretty similar inertias, if that's what you're talking about, so they don't really care as much about how fast they're accelerated. As long as oil clearances and flow rates are there, all is well on the bottom end. Plus, these cams don't really offer enough duration at high RPM's to create power very efficiently. And my tach only goes till 7,000 anyway.

[anothernord]

Alright folks! I finally got around to working on the "crossover code", which controls the bypass and SC clutch during WOT.

Basically, when the throttle is floored, and the manifold pressure is below the setpoint, the SC turns on, and bypass closes. As soon as the turbo starts trying to take over, the pressure will go above the max that the SC provides, and the system will disconnect the blower and open the bypass.

[nepbug]

Nice, but the video is so shaky and short that it's hard to catch anything.

You can't leave this thread without a good quality video.

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[anothernord]

You can see that the boost jumps up right away with the SC, then increases more after it opens the valve!

Datalog results:

[dahoseman]

You can see that the boost jumps up right away with the SC, then increases more after it opens the valve!

Datalog results:

Do you have a boost plot or a dyno plot? I'm very interested in your results. Sent you a very long PM about a similar (potential) build.

[anothernord]

Here's a still crappy but better video. Low boost, ~13 psi.

[SilverLegacy]

awesome build