Remove Beauty, Free the Beast: @Cadillac STS-V LC3 Thoughts

For my upcoming Spectre Intake install the beauty cover on the LC3 4.4L DOHC VVT V8 in my 2008 STS-V will need to go.  Technically, it can stay with less underpadding, but good excuse to remove it.

The top of the engine — the intercooler on top of the supercharger on top of the engine — is capped with this nice Cadillac beauty cover.

In my opinion, a beauty cover misses the point.  I get that it cleans up the engine compartment nicely and all.  But the beauty part should be the engine, not a molded cover hiding the engine.

Here’s what it looks like with the covers removed: (click on images for larger versions)

STS-V Engine with Covers Removed

With dirt, part of the underside of the foam from the beauty cover, et al.

This actually is MUCH more interesting to me, and you can see the air intake piping, the intercooler and cooling lines, and even down to the right the belt drive for the supercharger.

Cadillac STS-V intercooler coolant reservoir

This is a close-up shot of the intercooler coolant reservoir.  Yes, it looks like it is just a filler neck because that is what it is.  The fill cold line is near or at the top of the tube.  You can just see the actual coolant in the tube just at the bottom of the tube before the insulated covering.

The tube coming out of the top of the reservoir is a vent drain to an empty spot in front of the battery.

It strikes me that replacing this small tube with a larger but sized to fit in the space reservoir would add more fluid capacity to the system and if selected appropriately bolt in.

It is very hard to photograph the front heat exchangers, but here is a shot and bear with me because we’ll switch to diagrams after the photo:

STS-V heat exchangers engine shot

There are three different heat exchangers in view at the front of the STS-V.

STS-V LC3 Engine Coolers; Radiator, A/C Condenser, Intercooler

The are in order from back to front, 22 the radiator, 21 the transmission oil cooler, 19 the A/C condenser (CONDENSER,A/C ACDelco #15-63240), and 17 the intercooler front-mounted heat exchanger (FMHE), (RADIATOR,CHRG AIR CLR, 25770419).

STS-V LC3 Intercooler Heat Exchanger

So looking at that, this view looking forward in the engine compartment probably shows the item 19 (black); the intercooler heat exhanger is a smaller item ahead of that and not visible.

This diagram shows just the intercooler flow paths and parts:

STS-V LC3 Intercooler Flow path & Parts

This gives me pause — the assembly diagram shows a reservoir (1) and the line from the tube running to that reservoir.  My STS-V does not have this item (1) at all, so I’ll have to check with other owners to see what they have.

The intercooler pump part number and info is

018 22718756 PUMP. Turbocharger/Supercharger Cooling.
PUMP,CHRG AIR CLR COOL(LESS CLAMP). Required: 01For: DX 4.4D(LC3) (2006-2009) (2006 – 2008).

STS-V LC3 Engine Compartment with side covers and front cover on


The front center cover over the heat exchangers strikes me as perhaps functional, and used as a shroud to keep air flowing through the radiator.  I put that one and the side covers back on for every day use.

Questions to ponder:

Is there an easy way to expand the intercooler coolant reservoir at the overflow and so add more coolant to the system for heat buffering?

The standard front mounted heat exchanger for the intercooler appears to be large and very functional.  Is this really a weak spot and needing to be changed, or is the issue really the amount of fluid in the system?

Next Project: Get out there and clean up the engine compartment!

@Cadillac STS-V Supercharger & Intercooler Ideas #Motorama

The Cadillac STS-V (2006-2009) featured the 4.4L DOHC VVT LC3 V8 with a custom Eaton M122 Supercharger and integrated intercooler.

This photo shows the Cadillac LC3 engine without the ‘beauty cover’, looking from the rear of the engine — so the front of the Cadillac would be right and away.

Air flows in the black tubes at the top of the engine to the ‘back’ of the engine, and into the supercharger.  Note the noise baffles in the intake tubing intended to isolate the whine of the supercharger.

This view is of the supercharger+intercooler from the back:


and the next view is the reverse angle or ‘front facing’ shot of the coolant in/out tubes flowing to the intercooler (black part).  The ‘snout’ is the drive for the supercharger.  A belt runs from a pulley below to turn the Supercharger, pressurizing the incoming air.

Once you open and separate the supercharger and intercooler they look like this — note the intercooler is flipped upside down here, as if you simply removed it by ‘opening it up’:

STS-V Intercooler removed from Supercharger

The intercooler is an air to water system, and features Laminova laminar flow heat exchange tubes.

The air flows into the back of the supercharger through the long intake.  Then it is pumped up from the center of the supercharger through the intercooler past the Laminova tubes, and then it flows down the sides of the intercooler casing and the supercharger casing and into the engine.

Each of the four Laminova tubes look like this up close:

Laminova STS-V Intercooler Tubes

The science of the Laminova design is to create huge surface area with minimal air flow restriction.  The very thin fins, 0.2 mm each, along each Laminova tube collect the heat from the air passing through the 0.3 mm gaps between the fins.  The surface area presented to the air flow is approximately 5 times greater than a conventional plate-style intercooler according to Laminova, as well as reducing noise and pulsation.

The heat is conducted to channels surrounding the solid core of each Laminova tube, where liquid coolant is passing through to remove it.

It appears that the coolant flows into the intercooler, circulates through all 4 Laminova intercooler tubes, and then flows back to the intercooler heat exchanger.  The heat exchanger is like a small radiator.  The intercooler coolant system is completely separate from the engine cooling system/radiator.

The advantage of the Laminova design is that they have a very good efficiency with low pressure disruption and light weight.   A disadvantage is cost.

The CTS-V LSA engine uses a finned box air to water intercooler:

This shot shows the CTS-V LSA intercooler upside down.

How can the STS-V intercooler be improved?

An interesting ‘science project’ for the STS-V intercooler would be to replace the intercooler endcaps that direct coolant flow through one Laminova core after another with a custom endcap that directed coolant flow in parallel with all 4 Laminova cores and out after one pass.

One expert mentions that it is helpful to ‘index’ the 4 Laminova cores, so that the large fins are facing the air flow.  I am not clear looking at the images what is intended, as the Laminova cores appear to be uniform and symmetrical, unless the intent is to rotate the ‘sleeves’ the cores are contained in?

Owners are also experimenting with larger heat exchangers at the other end of the system, larger fluid reservoirs to allow more fluid to circulate and absorb heat, and higher capacity intercooler coolant pumps to circulate fluid.

On the slots that allow flow across the Laminova tubes, are the cross-pieces structurally needed?  If removed, so that the slots were just continuous single slots — flow would be increased.

Do you see other avenues to explore?


A tale of two Blown 4.4L V8s – BMW & @Cadillac

The new 2012 BMW M5 uses the twin-scroll, twin-turbo 4.4L V8 from the BMW X5M/X6M SUVs.  In the 2009 BMW trucks this powerplant made 547 hp, in 2010 555 hp, but in the new M5 makes 552 hp.   This all seems to need a bit more sorting.

This engine is the BMW S63, which is a twin-scroll version of the N63 V8.  For the 09 trucks it makes 547 hp at 6000 rpm and 500 lb ft of torque at 1500-5650 rpm.  As in the N63, the turbos are mounted in the V of the engine.  The engines do not appear to use the BMW valvetronic (variable valve timing used instead of a throttle), since there is a perception that it is not needed with a turbocharged vehicle, but are double Vanos systems (variable valve timing,  abbr. from German variable Nockenwellensteuerung, or variable camshaft control).

BMW S63 Engine

BMW fansites were predicting 585-600 hp for the S63 in the M5, so 552 hp is a bit of a surprise.

A blown 4.4L V8 seems familiar — ah yes, that’s what I have in my 2008 Cadillac STS-V!  Of course, mine is supercharged and not a turbo model as in the BMW, and makes only 469hp instead of 552 hp.  The Cadillac uses 12 psi of boost, while the BMW pushes that dial up to 22 psi of boost.  At around 4 % improvement per PSI, a LC3 running 17 psi would make similar numbers, but would run out of the boost range for the custom Eaton M122 supercharger in the Cadillac V8.  (The Stiegemeier snake bite kit does hit 17 psi however…)

[Updated] The BMW N63 makes similar boost pressure to the Cadillac LC3, at 11.6 psi but with a 10:1 compression ratio for the BMW.  The N63 was rated at 400 hp vs the 469 for the 12 psi Cadillac.  Both the N63 and S63 are direct injected engines.  The S63 uses twin-scroll turbos, cross-flow turbo plumbing, lower compression at 9.3:1, and higher boost to build to 552 hp.

The BMW SUVs have launch control, so hopefully the M5 will benefit from this as well.

A bit surprising that BMW stopped short of exceeding the Cadillac CTS-V’s 556 hp.  A shame really, as I would love to see Cadillac turn up the wick on the LSA 6.2L Supercharged V8 in the CTS-V a bit further to 600+ hp.

More on HP: Confusingly the BMW engines are still rated in PS (German: Pferdestärke = horse strength), which is a DIN standard mathematically different from British hp used in the USA.  PS has been replaced by the kilowatt, but is still used.  The 2010 BMW X5M made 414 kW, or 554 hp. is quoting the new M5 at 560PS which converts to 552 hp, but is actually less than the 563 PS in the 2010 X5 M.  Autoblog and Jalopnik are quoting the X5M at 547hp, but that was the 09 model.  I’m sure this will get sorted, hashed, and be more clear presently.