Topic: Twincharged Solstice = Turbocharger + Supercharger

[Steelmesh]

That's exactly what zzp did on their initial twincharger setups.  It made for a much smoother power and when it switch over to the turbo providing boost..  I'm pretty sure it's also what I recommended a few pages back but you shot me down bc "you were running too much boost" or something.

I'll find the post so I can say I told you so. Lol!!!!

Ohhh you got me....wait are you sure?  I don't see why though 

[Steelmesh]

Here it is....lol...told you so haha!!!

Here was my reply to your comment above from Feb 19:

"Thanks for digging this up and sharing.  I should be able to get away with using the factory bypass actuator passively with a boost signal.  If this works out using the Precision 5557, my pathway would be to go with a much bigger turbocharger and add a secondary throttle body to feed directly into the intake manifold, larger volume tract compared to the smaller factory bypass port.  If you look at the LSJ bypass port system, on the intake manifold side (part of the water adapter), it is quite restrictive considering my power level."

I just went through all those links, every page in those posts and searched "bypass" on every page and failed to see anything related to the bypass controller I independently designed above.

[MattM]

Huh?!  I quoted the part where they talk about saying the bypass to open on a specific psi either quickly or slowly and setting it up for a smoother power curve.  It's in there somewhere.

Anyway it's ok I was just giving you a hard time anyway.

[MattM]

 The other point is you only need the boost pressure switch to activate the bpv you don't need anything else.  It works well that way.

[MattM]

Oh I see what you are saying now.  What I was referring to was the fact that zzp utilized the stock bob on the supercharger to control boost delivery.  In your post after that you were saying you wanted to go with like two throttle bodies etc...  Now though...you are seeing the light and using the bpv which is good.  Just in how you want to do it is different.

[Steelmesh]

Oh I see what you are saying now.  What I was referring to was the fact that zzp utilized the stock bob on the supercharger to control boost delivery.  In your post after that you were saying you wanted to go with like two throttle bodies etc...  Now though...you are seeing the light and using the bpv which is good.  Just in how you want to do it is different.

Using the existing turbo I agreed that using the stock LSJ BPV was a good idea.  If I go to a gigantic turbocharger I am still proposing the better idea is a large bypass using a secondary throttle body which would more efficiently equalize pressure across the SC reducing the parasitic losses once the turbo spools up and more importantly reduce heat ending up in the charge going into the cylinders.

DDM Dave shared his positive experience that using a boost controller to control the BPV.  I assumed it was an electronic boost controller.

This style here dumps the top of the wastegate to atmosphere to open the wastegate, the top has spring pressure too but the bottom port will over come the spring pressure once you start dumping the top.  The wastegate is analogous to the BPV in this series twincharger setup, it "opens some valve once a PSI is reached" sort of thing.  I took this concept of dumping the top to atmosphere (ATM) and came up with the controller concept using a boost switch, valve, and flow control.  I have microcontrollers, pressure transducers, and programming skills in stock so I should be able to overcome issues if this doesn't work out as planned (like hysteresis with the analog switch bouncing on and off).


Otherwise MattM, keep trying whahahahaha!! 

[MattM]

Lol....yeah I tried.

You might try contacting zzp about the bpv.  I don't think they ever had to get go past just utilizing the bpv with a boost switch.  Wouldn't hurt to ask.

[MattM]

Might save you time and complexity as well

[MattM]

In this link they talk a little more about their BPV setup.  In one post Ryan says they "have a regulator set up to open the bpv at a certain psi."

https://www.cobaltss.net/forums/2-0l-lsj-performance-tech-47/interesting-twincharge-dyno-testing-194098/

They also talk about the need to tune HOW the bpv opens up (so as not to introduce an obvious pressure loss) instead of just having the bpv slam open quickly.

[MattM]

Here is some more information on how the bpv worked on the stock lsj...
"to clarify the bypass actuator is the black diaphragm device attached to the side of the supercharger. The bypass solenoid is the device that sits up on top of the engine with wires and vacuum lines going to it. The solenoid has a boost/vacuum signal coming into the back of it from the intake manifold. It works by having a constant electrical charge sent to it which blocks the vacuum/boost signal from the manifold from proceeding onto your bypass actuator under normal conditions. If this electrical charge is either disconnected or cut off by the ECU it acts just like a flow through coupler and allows the signal from the intake manifold to place pressure on the actuator which if you are boosting will open up the bypass butterfly valve in the supercharger.You can bypass the function of the solenoid by disconnecting and plugging the line on either side of it. The only reason you have to plug it is because if you leave it open it will be a boost/vacuum leak as when the solenoid isn't energized and is open it is basically just a open line connected to your intake manifold.

Now the bypass actuator that connects to the supercharger has hose barb fittings on both the top and bottom side of the diaphragm. The top line places vacuum on the top side of the diaphragm when your throttle plate is closed off enough to create a vacuum in between the supercharger rotors and the throttle body. This prevents the supercharger from trying to boost and suck air through a closed throttle body when you aren't on the throttle hard and must stay connected. The bottom nipple works the same way but on the opposite side (bottom) of the diaphragm so that boost will push the diaphragm in the same direction as the vacuum signal (on the top side) for when the computer is telling the solenoid to pull boost or your bypass solenoid is unplugged or broken. So while you can disconnect the bottom line to prevent the solenoid from modulating boost the bottom nipple must remain open to atmosphere so it can breath and allow the vacuum signal on the top side of the diaphragm to actuate the bypass butterfly valve."



I don't know if this will be helpful or not.

[Steelmesh]

Okay from that they're saying the boost solenoid connects between to the outlet side of the SC and bottom port of the BPV, so boost pressure would be higher than the inlet side of the SC (top port) overcoming BPV spring pressure to open the [normally closed] valve.  In my case, I think this function goes out the window because the inlet side of the SC will be at some higher than ambient pressure from the turbocharger.  Also note I am running an E67 LE5 engine controller, this does not have a BPV control even if I were to use the LSJ solenoid.  What I assume you're thinking is use a boost switch on the SC outlet side to perform the same function, where the boost switch lets SC outlet pressure open the BPV when a pressure setpoint is reached.

I will draw out some concepts of this system when I get home later to visualize this better.

The other day when I came up with the first concept, I broke out my vacuum tester and set my air compressor to 15 psi and played with the BPV to try out different scenarios.
- Apply a vacuum to the top port and leave the bottom to atmosphere it will open the valve, this would be idle/cruise
- Apply pressure to the bottom port and leave the top port to atmosphere it will open the valve, this could happen if I put the top port to atmosphere like using the solenoid I proposed
- Apply pressure to the top port, it will keep the valve shut, this would theoretically be like punching the throttle from a no load condition, the SC should produce higher pressure than the bottom port keeping the valve shut

Based on the above assumptions, I formulated the twincharger BPV control system concept.  Only one way to find out if it works, 1) Instrument the crap out of everything, 2) Run It!  I'll take a look at the other idea too first hehe

[MattM]

Or...You could just run it with the bpv entirely closed the whole time.  It would still work fairly efficiently that way.  ZZP did that on one of their dynos and the performance was at least very comparable vs. utilization of the bpv...

Anyway, yes you are right!  My thoought was to use the boost switch in place of the lsj ecu.  It would work the same way theoretically only open with boost reference instead of vacuum etc.....

[Steelmesh]

Couldn't fit the dipstick, tried two different LE5 styles.  This dips*** really wanted a dipstick, I identified a near straight shot to the bung, cut both ends off the OEM tube with the bottom on a slight angle. Got a friend to weld it to a straight stainless tube.  He used 9-20 amps, pretty sure my welder doesn't go that low and he is also professional welder so no issues burning through like I would excel at.

[Steelmesh]

I think the OEM strategy will not work because it falls apart in the face of a series twincharger system, the LSJ engineers expected there to be atmospheric pressure before the SC under WOT, but the twincharger boosts this circuit.



I think this is technologically beyond anything a forum post can solve, this is a 'go out and do it in the real world' and see what happens deal.  Also, this is more of a reason to run a custom microcontroller operated secondary throttle body to deal with bypass, with code you can make it do whatever you want compared to analog systems that can be a dynamic puzzle of variables and limitations.

[MattM]

Hey man...this is your setup and ultimately your decision..  You should go with what makes you comfortable.

[Steelmesh]

Hey man...this is your setup and ultimately your decision..  You should go with what makes you comfortable.

I appreciate your inputs 

Got a big car to-do list, a 4 day weekend, and smack talking Mustang owners at work.

[Steelmesh]

Among a bunch of small details taken care of, the intake and supercharger are torqued down.  Intercooler coolant system is now 100% plumbed. Nearly finished the surge tank fuel system last night.

[MattM]

Very cool!!!!  I'm excited for you! 

I have one more run at the Dragstrip I want to do with just the Trifecta base tune, and then I will be changing to the E-47 Trifecta tune (330 whp 410 ft lbs of torque)  Once that's done, and you have your setup done we should plan to meet up at a drag strip to run our cars!  Obviously, by the numbers you should kill me, but it would be a cool friendly competition! 

[Steelmesh]

More water/meth please, second nozzle added:




Beading the tubes:




Arts and Crafts with Steelmesh (custom blanket for the turbo intercooler core):




Hardline tube added for the return line coming from the surge tank:

[Steelmesh]

Biggest filter I could fit without clearance issues. Ebay new old stock: 3" tube, 7" long with 5" base.

[Steelmesh]

It's alive, fired up and it didn't experience a rapid disassembly.  New fuel system works great and the 044 style fuel pump is not annoyingly loud since it is partially submerged.  The tune needs some work though.  I got a 3-bar MAP/IAT sensor that fits in the LSJ intake manifold.  I took the IAT wires from the LE5 MAF sensor and put those on the new IAT, then wired up the 3-bar to the LE5 MAP sensor input. 

[Critterman]

No rapid disassembly is always a good thing.

[MattM]

It's alive, fired up and it didn't experience a rapid disassembly.  New fuel system works great and the 044 style fuel pump is not annoyingly loud since it is partially submerged.  The tune needs some work though.  I got a 3-bar MAP/IAT sensor that fits in the LSJ intake manifold.  I took the IAT wires from the LE5 MAF sensor and put those on the new IAT, then wired up the 3-bar to the LE5 MAP sensor input.

Very awesome!  Glad it's coming around!

[Steelmesh]

It wasn't running great, felt like there was a restriction.  I removed the turbo pipe and fed the supercharger air directly, still didn't feel right.  The car was smoking significantly.  I checked compression everything look good.  I was having trouble burping the water intercooler circuit, so I decided to pull the supercharger and inspect the intake for a coolant leak and that is exactly what I found.



Intake manifold






Ordered new o-rings and I guess I'll use some silicone or anaerobic sealer when I put it back together. 

[MattM]

That really stinks!  Hopefully everything with that supercharger intercooler works out...