Ten Pounds of Shit in a Five Pound Bag - Twin Turbo LS3/DCT Daily Driver

[shainiac]

Minor update – car has been running great. I’ve been daily driving it the last few weeks. I think I went 2 weeks without even starting my daily driver Lexus lol.
I’m still chasing EMI issues with the DCT. The speed sensor for the DCT output shaft is a 2-wire VR sensor. The nice and expensive harness I bought for the DCT is all DR-25, Tefzel, and concentric twist, but they didn’t bother to use shielded wire on the speed sensor.
Apparently the majority of their customers have no issues with EMI, but I’m one of the unlucky ones.
It currently doesn’t effect drivability, but the DCT controller manufacturer keeps teasing a new closed-loop update that would use the speed sensor as one of the parameters and should greatly simplify tuning. The car drives pretty well as-is, but there are a few spots that could be better with more time and effort tuning open-loop.

This weekend I redid all the grounding an power for the battery, ECU, GCU, etc. I ran new 4AWG from the engine block to the battery, new 4AWG power from battery to just ECU/GCU (preciously shared with starter/alt), ground for GCU/ECU straight to battery.
I noticed these changes did have some improvements in voltage stability. It previously had +/- 0.5V of variation when the engine was running, and now less than 0.25V. Noise on the DCT speed signal is exactly the same. A buddy also lent me his 2-year-newer HTG GCU and that also had the same noise, so it’s not the GCU.

Another annoyance – the car started running at 205-210F consistently. I could still hear the fan running (PWM at 100%), battery voltage was fine and the coolant level was fine.  Turns out one of the Ford Contour dual fans crapped out. I was able to verify the PWM controllers and wiring were fine, just one fan no longer works. Ordered another fan and can hopefully just swap the motor/blade into the modified shroud I currently have installed.

I also have started sourcing parts for the LS3 turbo kit. I was planning on using Pulsar G30-770 twins. They’re Garrett clones for about 1/3 the price and come in reverse rotation for mirror-image hotness.
Leaving the EFRs for a Garrett knockoff had me a little worried, but they’re supposed to make great power (not that I need or can use a ton more). Luck was on my side and I ended up finding a Indycar EFR 7163 on eBay. Now I need to find a second unit.

The EFR 7163 is the 57/56mm version compared to the 54/51mm EFR 6758s I currently have on the 5.3. It should mimic the response and spool of my current setup, just +20% power. Borg Warner also sells “SX-E”-style compressor covers for the EFRs, which have 4” inlets instead of 2.5”, and anti-surge slots. I don’t have issues with surge on spool-up, but they do get surgey if I back off the throttle, but don’t go into enough vacuum for the BOV to open. Also, more whistley noises. Someone with a ~500whp STI swapped from the standard EFR comp cover to the SX-E and picked up like 40whp and 30wtq on the same tune. Seems like a no-brainer.

EMI, blue is DCT output shaft speed, green is engine RPM. DCT output should be a smooth line at stead speed, but you can see all the little blips that are signal noise. the duration of the spike is basically just 1 period of the signal refresh rate, but it still makes the DCT's calculated VSS worthless for traction control.


New EFR

[digitalsolo]

Score on the EFR.    Noise on the VSS is annoying.   Any way you could shove a signal conditioner in the path?

[shainiac]

Score on the EFR.    Noise on the VSS is annoying.   Any way you could shove a signal conditioner in the path?

What kind of conditioner are you talking about? The DCT harness terminates at the GCU with a Molex CMC connector, so I could probably add one there. From the CMC connector-out, everything is concentric twist and DR-25'd. The bulkhead for the DCT is a Autosport connector and booted.
Rumor has it the GCU manufacturer added some additional signal filtering to the newer batch of GCUs, but the one my friend lent was from very recent and exhibited the same issue.

[spacevomit]

Shield the wire externally.

[shainiac]

Shield the wire externally.

Like metal mesh sleeving over the DCT cable?
I'd either have to de-pin my entire connector (Molex CMC suuuuuck), or get a sleeve that expands large enough to go over the Deutsch Autosport connector.
My only reluctance with sleeving is, I don't know where the noise is coming from and it could very well be the solenoids inside the GCU. There's maybe 18" of Raychem'd harness inside the trans that goes from the Autosport connector bulkhead to the mechatronics. From the mechatronics, the sensors and solenoids are wired through the OEM DCT wiring, which I believe are shielded conductors.

Here's the harnesses I have:
https://www.domi-works.com/products/dct-wiring-kit

[spacevomit]

I would just wrap some aluminum foil or something around it to see if it makes a difference lol.

[cholmes]

Just a thought, what spark plug wires are you using? Some of the "High Performance Ultra Low Resistance" wires can be a problem.

[MPbdy]

Typically you would add capacitance right before the GCU, but software filtering would be way more commonplace.  Is there really no software filtering you can setup?

Are you sure your airgap is consistent all the way around your reluctor?  Could you back the sensor out a little bit?  I read that VR sensors get noisier with higher voltage signals.

Are the sensor wires twisted?

The ground is an isolated ground from the GCU correct?  The GCU should have isolated I/O for any analog sensor input.  Grounding the GCU directly to the battery should do it.  You could try powering the GCU from it's own battery to see if the voltage quality improves.  If not, the GCU is noisy, you're picking up noise from your PWM/ignition, or you have an issue with your sensor.

If you're picking up noise it must be your PWM signals.  Also, ignition wiring is super nasty.  Are you close to any of that with your sensor wires?

[shainiac]

I would just wrap some aluminum foil or something around it to see if it makes a difference lol.

Definitely worth a shot.

Just a thought, what spark plug wires are you using? Some of the "High Performance Ultra Low Resistance" wires can be a problem.

I'm using brand new OEM Delco wires and NGK BR7EF (resistor) plugs. Just changed everything a couple weeks ago to see if it'd help and it did not.

[shainiac]

Typically you would add capacitance right before the GCU, but software filtering would be way more commonplace.  Is there really no software filtering you can setup?

There's no software filtering that I'm aware of. I've had to add pullup resistors for VR CAS signals in my old Megasquirt days. Not sure if that would work here.

Are you sure your airgap is consistent all the way around your reluctor?  Could you back the sensor out a little bit?  I read that VR sensors get noisier with higher voltage signals.

The speed sensor is the OEM BMW speed sensor, which is a flange-style. I've not made any adjustments to it's airgap. The noise seems doesn't not seem RPM dependent, so not sure that's an issue.

Are the sensor wires twisted?

Concentric twist in the harness, but not twisted pair.

The ground is an isolated ground from the GCU correct?  The GCU should have isolated I/O for any analog sensor input.  Grounding the GCU directly to the battery should do it.  You could try powering the GCU from it's own battery to see if the voltage quality improves.  If not, the GCU is noisy, you're picking up noise from your PWM/ignition, or you have an issue with your sensor.

If you're picking up noise it must be your PWM signals.  Also, ignition wiring is super nasty.  Are you close to any of that with your sensor wires?

GCU is grounded straight to the battery with 6awg welding cable. It does have it's own dedicated "sensor ground" in the concentric twist loom. I like the idea on powering the GCU with it's own battery. GCU loom comes through the trans tunnel and into the radio cubby where the GCU is located. All ECU-related wiring is 2'+ away. The only wires that come close are the GCU power and ground, which go to the fuse block and battery.

[shainiac]

I ended up ordering a whole new turbo setup. Going to sell the Indy EFR 7163 I just bought, and eventually sell my EFR 6758 turbo kit that’s currently on the car.
The 7163 wasn’t a great fit for the larger LS3 and compressor efficiency was going to be in the low 60%s. The larger 7163 turbine also wasn’t proportional in flow to the jump in displacement from 5.3 to 6.2L.

I’m probably being pickier than I should be, but I want low boost-threshold, great response, and a setup that revs out. The whole setup is hamstrung by the stock DCT clutches. I can’t really go over 650-700wtq, so the plan is to add boost past peak TQ to carry power to redline.

I bought some VS Racing knockoff Garret G30-770s, mirror-image with 0.83AR turbine housings. 58/55mm wheels aren’t that much an of an increase from the 57/55mm EFR7163, but the compressor flows 20% more (72lb/min vs 60) and ~25% more on the turbine.
The twin G30 turbines also flow about 15% more than a single G42-1450, which I was also considering. The low-mount twins package so well, I didn't want to change to a single and deal with less space and more hot pipe.
The G30s should be more compact that the EFRs and the mirror-image housings should simplify fab work quite a bit.
The 4” inlets on the G30s means I likely won’t be able to fit hydro power steering, but I already bought an Equinox electric column to retrofit.

Also picked up VS’s new “Gen3” 50mm wastegates. They’re a weird hodgepodge of designs. They have a piston-style dome like a JGS instead of a diaphragm and are pretty compact, albeit tall.
The goal is to build a new “turbo-fold” setup like my current turbos. I’d like to run as light of a spring as possible for the lowest-power base setting.
My current turbofolds with Tial 44mm gates will hold 4psi to redline on the 5.3L. The G30s should have less EMAP, so less drive pressure for the gate priority, so hopefully the 50mm gates help.

[kinger]

You got a lot going on there 

[shainiac]

Not a ton to update. I've been driving the car as much as I can before the salt hits the road. The Integra speedo/odo in my car died, so I don't know exactly how many miles I've put on the car, but I've put  less than 1000 miles on my DD Lexus since the end of June (last oil change).

I've been trying to get the ball rolling on winter upgrades. The LS3 block I bough ("new" Chev. Perf. LS3 block) has enough flash rust on the bores that it unfortunately needs honed over. It's getting dropped off at the machine shop this week, along with the LS3 heads, crank, LT4 rods, and I'll order pistons when the machinist confirms the final bore. Should be a stout little rods/pistons LS3 when it's all done. I'll end up having the block and heads decked, bores honed, and crank polished and balanced with the new rotating assembly. The pistons I'm looking to buy should put CR around 9.5:1. Should be nice for pump gas and low-ish boost.

VS Racing G30-770s showed up and look surprisingly nice also. They're a bit bulkier than the EFR's, and definitely heavier. I still feel like I'm making a mistake ditching the 5.3 and EFRs. They've been super reliable and flat out work. Now that the weather's getting colder, the R888Rs can't really put down what the little 5.3 makes anyways lol.

[Esser]

wow that's a surprising amount of rust for a new block. Wonder if they just cast a bunch of them up to 2015 then stopped.

[shainiac]

wow that's a surprising amount of rust for a new block. Wonder if they just cast a bunch of them up to 2015 then stopped.

I got it cheap-ish third-hand. I dunno how long it'd been sitting, but it's filthy and had never been stored properly. I dingle-ball honed it a much as I felt comfortable and it didn't clean up completely, so I'm just going to have it honed hopefully 0.005" over. Ironically it's going to cost me more after machinework than a good stock-bore block would have, but at least it'll be fresh. It also has a fairly deep scratch right next to the sleeve, so it'll get decked. Gen4 blocks look like the decks were cut with a hatchet to begin with, so probably not a bad move for an MLS car regardless.
On the plus size, Summit LS Pro pistons are back-ordered in stock-bore size, but I can get 4.070" pistons today. $750 with rings.