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

[paul_3rdgen]

And here I am with my lowly 7.2L and oil never goes over 93C. Haha I've not taken it to the track with this motor yet though. Pretty sure I'll find out I need more cooler.

The track changes everything, oil temps would always be lower then 90C on the street.  At the track oil temps get to 120-130c, no oil cooler but I have 10 litres of oil due to the drysump.  Tank is in front of the right side grill opening for cooling.


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[shainiac]

I've been driving to/from work the last few days and getting the tune more dialed in. Most of my closed-loop lambda corrections are +/- 2% or so. Accel Enrichment still needs tuned, bad lol.

The DCT self-learning is getting better as I drive it more. It's pretty smooth at low loads and quick when I want it to be. I've yet to turn throttle blips back on, but I may this weekend.

Boost control wasn't working quite right but that ended up being a scaling error. I converted all of my sensors over to kPa and accidentally rescaled the dome pressure sensor as a 150psi instead of 100, so all of my dome targets were 33% lower than target. I am finding that I have more EMAP than I would have expected. I also need quite a bit of dome pressure at higher RPMs to counteract the EMAP trying to open the wastegate valves.

The weather currently in the 40s, so traction control is yanking tons of timing. Which is not helping my EMAP issues lol.
With boost control turned off, the dual 50mm gates will hold less than 1psi to redline with 3psi springs

On 4psi, the LS3 feels as rowdy as the 5.3 on 8-10psi. Check out the 3rd gear datalog below:

In the middle graph, the highlighted yellow line is wheel slip. TC is targeting 7% and doing a pretty good job.
The bottom graph, the yellow is TC timing correction. It's pulling a LOT of timing to wrangle in wheel speed. I haven't changed my throttle targets since I had the 5.3, but I think I'm going to have to pull more throttle out of the car until later.  I guess only making 1psi might be a perk for power management lol

[shainiac]

I done fucked up...

Looks like a fender washer was somehow hiding in the pleats of the driver's-side air filter and came dislodged after a 3rd gear pull.
I thought I blew off a couple because the car was making a wooshing noise under any amount of load and wouldn't make boost. Couldn't find an obvious leak when I pulled over, but I was an hour from home so limped it back. At least these are cheaper Chinese turbos and not $2800 Garretts. I already ordered a new CHRA. $350 shipped and I'll have it this week.

At this point, I think I'm going to park the car for the winter and get an early start on the projects I wasn't able to get to this year.
Short list of winter projects:
Water-air intercooler, new rad, heat exchangers for oil and DCT
Change over to MaxxECU DCT control (ordered)
MaxxECU PDM (ordered)
Clean up some cosmetics and do some refining.

I'm bummed I only got a few weeks of driving after almost a year of wrenching, but at least I was able to shake out some of the bugs on the new engine. Hopefully none of the turbo metal made it through the intercooler and into the brand new engine  I'm scared to borescope it lol.

[Venom13132]

Ouch.  Something similar to that happened at work this year but it was a Jet engine that ate the washer.

[shainiac]

Damn, I'm sure that wasn't a cheap bill.
Do you work for Rolls? I went to school in Indy and I think a couple classmates went there after.

[digitalsolo]

Shit.  That really sucks man, super sorry to see that.

[Venom13132]

Damn, I'm sure that wasn't a cheap bill.
Do you work for Rolls? I went to school in Indy and I think a couple classmates went there after.

yeah I do.  We are like the 3rd or 4th biggest company in Indy so lots of people work here ha

[kinger]

Ugh, sorry man, this sucks!  This is the part of car building that stinks.  Lot of nice upgrades for winter though! 

[Cobranut]

Bummer.
Hope you got lucky and there's no engine damage though.

[shainiac]

Couple things to update. I sold my whole DCT setup and bought a new setup. Now that MaxxECU can control the Gen2 DCTs (overdrive), there's no reason for me to have a standalone controller that adds complexity and tuning challenge. I bought another used DCT, a new Domiworks adapter kit (dampened input spline this time), and a MaxxECU DCT harness. MaxxECU worked with an existing BMW tuner (xHP) to use their OBD flash tuning with the DCT and MaxxECU. I bought a bluetooth OBD dongle and will be able to change a few transmission settings and flash different tunes to the DCT from my phone.


I'm getting started on the new cooling system. I 3D printed the first design over the weekend. Because my printer is limited to 10x8x8", I split it into quarters and printed everything into 2 24hr prints. It fits pretty damn well for a first pass. I designed it as sheet metal in Solidworks and converted to a solid for printing.

The cooler uses two Garrett '750hp' water-air intercooler cores in series.
I split the inlet in half left-right for each turbo and they outlet is a common end tank with a 3.5" outlet.
Still not sure if I want to plumb cooling in dual pass or single pass, or what size hose to use.

There's a glut of used Nascar radiators and oil coolers on eBay. I'm planning on buying a used oil cooler, which are almost the exact size of my radiator, and using it for a IC heat exchanger. 26x18x1.5 and high-end C&R, PWR, Setrab cores.

I'm planning on using a Pierburg CWA200 water pump. They're brushless and OEM quality, and the MaxxECU can control it out of the box.

I also bought a Howe 27x19" radiator with a pretty large oil cooler built in. My plan is to use the rad oil cooler for engine oil and add the 300mm Laminova oil cooler to the lower rad hose for DCT oil.

I've already ordered a manual tube bender and some 3/4" DOM tubing to make lower radiator supports. The rad/HX will also get ducted to the front bumper opening once everything is mounted.

[digitalsolo]

I adore your ultra compact packaging in this stuff.   The level of effort to address thermal management across all of the systems is pretty crazy.

I'll snag those fan measurements today;  I keep getting distracted in the garage when I go to measure. 

[spacevomit]

I wonder if theres a difference between two cores in series, and two cores in parallel with an internal divider or guide.

[shainiac]

I wonder if theres a difference between two cores in series, and two cores in parallel with an internal divider or guide.

Two cores in series would probably be less efficient than parallel. Series will have higher pressure drop and lower deltaT at the end of the cooler / less heat transfer in those final inches vs front.
The Garrett 750hp cores I have are 3.8"x3.8"x11.7". 3.8" of flow length may also not be enough to get all of the benefit, but I don't have the patience or data to confirm that lol.
The real challenge with running the coolers in parallel would be packaging. I'd have 23.4" of cooler width, plus water manifolds. Which would basically take up the entire frame rail width and block my turbo inlets. Or it'd be 7.6" thick and hit the radiator. You also can't rotate the cores 90* and change which paths are for water vs. air. The core design is dedicated for each. The air-side has wider tubes for more flow.

[gnx7]

Nice update!  I run an ex NASCAR oil cooler in my '69 Chevelle turbo LS as the a/w heat exchanger also.  It is massive! 

[shainiac]

Nice update!  I run an ex NASCAR oil cooler in my '69 Chevelle turbo LS as the a/w heat exchanger also.  It is massive!

Oh nice! Do you have any pictures of it? How are IATs?
Did you pick one up with Wiggins style fittings or AN? I'm having trouble finding the proper Wiggins style fittings that'll work with rubber hose.