Cadillac Conversations

I am thinking more about this graph of IAT2 over time as the Cadillac STS-V accelerates:

Let’s consider the stock, OEM Bosch intercooler pump.  This pump is rated for 8 gallons per minute (gpm) against no resistance, and likely does 5 gpm in the STS-V system.  It is overall a very good pump, and very efficient.

Now, a gpm is 1/60=0.083 gallons per second (gps).  So 5 gpm would be 0.42 gps.  The STS-V can accelerate 0-60 in under 5 seconds.  So on an average 0-60 run, the intercooler pump moves 5 sec x 0.42 gps = 2 gallons of fluid through the intercooler.

Now, keep in mind that the OEM system had 2.6 quarts of fluid, and my new HX added 2 quarts, so now my system has 4.6 quarts or just 1.15 gallons. A small part of the capacity is likely counted in the side fill loop, so we’ll say 1 gallon.

So on an average 0-60 run, the pump can move 2 gallons of fluid through the intercooler, and the system has 1 gallons in the main loop, so the coolant sees the inside of the intercooler twice in that 5 seconds.  Put another way, my current 4 quart capacity system has a circuit time of ~3 seconds — every ~3 seconds the system circulates the entire coolant capacity.

For the intercooler testing I was focused on just getting an acceleration spike and not best time.  But if we look at this graph of speed vs time vs IAT2,

What it appears to show is that the IAT2 temps are near constant for the first 3.27 seconds (looking at the exact figures in the data table), and rise dramatically after that.  Now it is dangerous to read too much into a single sample, but this seems to validate our figures that at 3.27 seconds the intercooler coolant starts a 2nd loop through the system.

From this I conclude that a system with a 2 gallon capacity of coolant would have fresh, cool fluid in the intercooler for the first 6 seconds.  Now 0-60 mph is not the end all and be all of performance.  To keep uncirculated coolant in the intercooler for a dyno run one might need 10 seconds of fluid or 3 gallons — as a thumbrule think 1 gal per 3 seconds.

Also, if you speed up the pump, you’ll need more system capacity to offset the faster circuit time.

What do you think?  Am I missing the boat?  Do you agree?  Hit the comments please!

Posted in Cadillac Performance Mods, Intercooler, Site Info / News, STS-V | 3 Comments »

This morning I took the front clip off my STS-V once again to replace the intercooler heat exchanger hoses with Spectre braided stainless sheathed hoses and then retest.

I did a first shake-down test run, then let the car sit and heat soak, then did another 20 min test capture.

The chart shows intake air temperature 2 (IAT2) after the supercharger over time during a 20 min test drive. The spikes on the chart are acceleration runs.
Today’s weather is overcast, with 72F air temperatures, similar to the historical data file for the OEM capture. What this suggests is that the S3TC heat exchanger in series with the OEM heat exchanger acts to lower IAT2s around 10F.  The end of the test was curtailed due to a traffic stackup; I stopped scanning and capturing data to save time on conversion.

Because today’s temps are similar to the historical air temps, I compared today’s run to the historical data without modification.

Overall the new S3TC Heat Exchanger results continue to be good.  The Spectre hoses are on and do appear to have better success at avoiding kinks or crimps than the rubber heater hoses did.

Here is a zoom-in on the acceleration run today, showing the trend for IAT2 vs RPM and Speed.

In this graph we see initially there is actually a decrease in IAT2, as the throttle opens, all the flow goes through Supercharger as opposed to the bypass, and the intercooler is at max cooling. As the supercharger continues to dump heat into the system, the manifold heats up more than the intercooler cooling system can sustain.

Posted in Cadillac Performance Mods, Intercooler, Site Info / News, STS-V | No Comments »

The first question for the upcoming 2013 Cadillac ATS is:  do you want the 272hp 2L Turbo 4 — starting at $35,795 — or the 321 hp 3.6L DI V6 starting at $42,090?

The all-new Cadillac ATS navigates through the turns and straightaways at Atlanta Motorsports Park during performance testing Tuesday, May 8, 2012 in Dawsonville, Georgia. The Cadillac ATS is engineered to be the lightest compact luxury sports sedan, reducing weight through the use of advanced materials - but not at the expense of performance. (Photo by Sam Sharpe for Cadillac)

Right behind that choice however — and the 2L Turbo is likely to be the price / performance silver lining  — will you want the 2L Turbo Performance Package (1SJ), or Premium Package (1SL)?

In Cadillac parlance, the Performance Package generally includes the key performance options in an easy selection.  The Premium package however often adds features — at a price — that are desirable even for hard core performance enthusiasts.  There is also a ‘Luxury’ model available (1SG) that combines more luxury oriented features that non-performance Buyers may prefer.

The 2L Turbo Performance package looks like this:

and the Premium package adds the full color heads-up display (!), steering wheel paddle controls for the auto trans, FE3 performance suspension, limited slip differential, and Magnetic Ride Control:

The Premium package also has navigation standard, while the Performance package has Nav as an option.

Suspensions — generally Cadillac grades suspensions from FE1 to FE3 or FE4 as the capabilities move from standard to highest performance.  The Magnetic Ride suspension on the Premium model is the most desirable setup.

The grill and parking assist items on the Performance Package list but not on the Premium Package list are a bit of a red herring, since they are standard on the Premium Package and part of the Luxury Package:

The other BIG feature standard on the Premium and optional for the Performance will be the Cadillac User Experience (CUE) system.  The 2L Sport model can be optioned up to include the HUD as well.

Both the Sport and the Premium package get the seating package standard, which adds power memory seats and rearview backup camera:

Summary:

How will you option out your Cadillac ATS?  Will you keep it clean and disciplined and stick to the Performance model, or will you write a check for the Cadillac ATS 2L Turbo Premium?

Posted in ATS / Alpha, Cadillac Models, Site Info / News | 2 Comments »

One of the great things about OEM heater systems is that they have hoses exactly bent and shaped the way needed, so that the hose is perfectly formed for the job.  Good advice for aftermarket installations like my intercooler cooling mods is to measure out exactly what type of hose you need, then go look at the big books of existing OEM hoses at an auto parts store and find the one snowflake that is similar to your needs.

Another option is the Spectre stainless steel sheathed heater hose, 39798, which is designed to allow a variety of hose turns without kinking or crimping.

Spectre hoses in their packaging

The hoses I need are 3/4″ inner diameter. These Spectre hoses are rubber hoses with a stainless steel braided sheath around the rubber.  For Spectre 39798 the hoses are 4 ft (48 inches) long.
Here is a shot out of the packaging:

Vanity shot of the hose out of the packaging

The sheathing helps prevent hose crimping. After playing with one of the hoses in various bends I would say it is helpful in resisting but does not eliminate crimping. So I will still need to ensure that the hose routing helps as much as possible to avoid crimping the hoses.

Posted in Cadillac Performance Mods, Intercooler, Site Info / News, STS-V, Test Info | No Comments »

Cadillac has a clear target in mind for the upcoming Cadillac ATS: to handle and perform better than a BMW 3-series. In order to achieve that goal they are designing a new platform from the ground-up, selecting appropriate materials, and the right power trains. If they are successful, the Cadillac ATS will be the new benchmark for luxury performance.

Engineers look over the all-new Cadillac ATS before performance tests at Atlanta Motorsports Park Tuesday, May 8, 2012 in Dawsonville, Georgia. The Cadillac ATS is engineered to be the lightest compact luxury sports sedan, reducing weight through the use of advanced materials - but not at the expense of performance. (Photo by Sam Sharpe for Cadillac)

DETROIT – When engineers set out to make the all-new 2013 Cadillac ATS as light as possible they used advanced materials to minimize weight throughout the compact luxury sports sedan but never compromised performance capability.

Lightweight parts such as an aluminum hood and magnesium engine mounts help ATS achieve a curb weight less than 3,400 pounds, and highway fuel economy well over 30 mpg. Keeping weight down also enabled balanced distribution of vehicle weight that helps delivers a world-class driving experience.

“We designed and engineered ATS’s vehicle architecture to deliver quick, nimble and fun-to-drive dynamics,” said David Masch, ATS chief engineer. “We distributed mass to key areas, much like an athlete builds muscle where he needs it most. This enabled ATS to achieve the performance characteristics that luxury sport sedan buyers demand.”

One seemingly heavy way the ATS engineering team achieved its performance goals was using cast iron in the rear differential instead of aluminum, a learning taken from the performance-tuned CTS-V.

The differential provides torque and rotation to the wheels, and ATS’s cast iron design helped distribute weight equally between the front and rear wheels to provide agile handling while reducing noise and vibration. Cadillac benchmarked it against world-class competition to deliver a driving experience that is as well-tuned for sound as for ride and handling.

Unlike a differential made from aluminum, which expands and contracts twice as much in response to temperature change, a cast iron differential is stronger and retains its shape better under temperature extremes, which allows the ring and pinion gears to operate more quietly. As a result, a cast iron differential also requires less energy to operate, contributing to higher fuel efficiency. To the consumer, this means more miles between fill-ups.

The ATS team also achieved significant weight reduction in the rear suspension by using specially engineered straight steel links with lightening holes instead of using aluminum.

“The team focused on grams, not pounds, every day of the ATS’s development,” Masch said. “Even the smallest of changes could contribute to the overall mass goal.”

ATS’s wheels also benefited from 50-50 mass distribution between the front and rear. While heavier cars need larger wheels, tires and brakes to account for heavier mass, ATS’s relative light weight enabled the use of optimized high-strength aluminum wheel forgings and Brembo brakes that deliver stopping distance of approximately 129 feet decelerating from 60-0 mph, which is expected to be best in the segment.

Inside the ATS, the vehicle team took advantage of a new process that places sound-absorbing material between two layers of laminated steel. By doing so, Cadillac refined a part and process it pioneered on CTS.

These sound-buffering materials help reduce noise coming into the cabin from the powertrain and fine-tune the sound to a sporty growl that communicates powertrain response and road characteristics to the driver.

ATS also uses an acoustically laminated windshield and side windows that are lighter than standard tempered glass and provide better wind and powertrain noise reduction for a quieter interior. Acoustically laminated glass also offers almost double the amount of ultraviolet ray protection.

“Smart material selection and styling modifications that reduce complexity are key enablers in our quest to reduce vehicle mass,” said Bob Boniface, Cadillac exterior design director, who spoke Thursday during a panel discussion on lightweighting at the Automotive Press Association.

“As consumer demand for more features, space and comfort continues to increase, so too has our proficiency in designing vehicles that offer aerodynamic performance and efficiency equivalent to lower vehicle weight,” he said.

The ATS, which starts at $33,990, goes on sale this summer.

Posted in ATS / Alpha, New Technology, Site Info / News | No Comments »

Got the AVS tank I ordered in the post today.  Very interesting.  Previous mention:  Cadillac STS-V inline flow-through intercooler tank

AVS tank in the box

I ordered this as a possible inline tank addition to my Cadillac STS-V intercooler coolant loop. Additional coolant would act as a buffer to temperature changes (both up and down). The stock system has 2.6 quarts. My system has the S3TC heat exchanger added, which holds 2 quarts, so it is running 4.6 quarts. The new tank would add 4 quarts, for 8.6 quarts total.

The tank has a drain at the bottom, 1/2″ NPT fittings that handily I have 1/2″ NPT to 3/4 inch hose barbs from my 45321 experiment to fit, and a 1/4″ NPT fitting for a gauge which I will either stick a stopper in or a temp gauge.

1/2" NPT to hose barb attachment added

I will have to decide whether to add the tank during in this weekend’s big install adjustments session, or wait and test with the new Spectre hoses in place first so I have a clean baseline, then redo the circuit with the tank in place. Notionally with the angle brackets on the bottom, this tank would just sit directly on top of the S3TC.  Choices are good.

Update:

This temperature gauge, with 1/2″ NPT fitting, 2″ probe length, and 0-220F temperature scale could work and hopefully be visible through the grill on close examination.  Hmm.

Tags: AVS Tank, Cadillac STS-V, Intercooler cooling
Posted in Cadillac Performance Mods, Intercooler, Site Info / News, STS-V | No Comments »

The intercooler cooling system for the STS-V is self-bleeding, although it can take a bit to complete. I have been considering using a system like the Mityvac 4535 with a compressor to both leak check and refill under vacuum to ensure all air is out of the system.

This system takes a vacuum on the coolant system to pull the air out, and clean fluid in. I would attach it at the Tee reservoir.

The Mityvac 4535 is around $108 but perhaps can be had on loan from O’Reilly’s Autoparts. Then I’ll need to get a better air source to draw a vaccum. Either would be a seldom use item for me so that makes them dear to purchase. It is possible a local shop could do this also but the fee might have paid for one of the tools.

;

An alternate appears to be the UView 550000 Airlift Cooling System Leak Checker and air purge kit.

Thinking I will add this process after I replace the intercooler hoses with the Spectre stainless kink-free hoses planned for this weekend.

Update:

I ‘cheated’ and ordered the Mityvac 4535, and will have to shop a larger air compressor. Should made my intercooler experiments easier and more controlled.

Tags: Intercooler cooling
Posted in Intercooler, STS-V, Test Gear | No Comments »

Quick pricing summary:

• Standard 2.5L Four: $33,990
• Turbo 2L: $35,795
• 3.6L V6: $42,090

This will likely make a Premium 2L turbo around $45K and a Premium 3.6L around $52K. The big seller for numbers however is likely to be the 2.5 L, and making is available as close to 30K as possible is crucial for sales.

DETROIT – The all-new, rear-wheel-drive Cadillac ATS compact luxury sport sedan with a fuel-efficient 2.5L engine and next-generation six-speed transmission will be priced starting at $33,990, including destination charges. Highway fuel economy will be well over 30 mpg.

“The ATS enters a vehicle segment this year that’s one of the most competitive in the market, from both a price and performance standpoint,” said Don Butler, vice president of Cadillac Marketing. “ATS will bring a distinctive presence and compelling value while offering quick, nimble, fun-to-drive dynamics that will appeal to the lifestyles of modern luxury buyers and challenge the segment’s status quo.”

A mid-level model with a lightweight and powerful 2.0L turbocharged engine costs $35,795 including destination and will offer automatic and manual transmissions, and rear- or all-wheel drive.

Topping the engine range is a 3.6L V-6 with a preliminary rating of 320 horsepower, costing $42,090 including destination with an automatic transmission and standard content that includes CUE, leather 8-way power seats with memory, adaptive start and more. All-wheel drive will be available.

A full breakdown of availability and pricing of packages and options will be available later.

ATS goes on sale this summer, but already the new sport sedan is positively impacting Lansing, Mich., where more than 410 new employees have been hired at Cadillac’s Lansing Grand River plant where the ATS will be assembled. A total of 600 new employees are expected to be part of Cadillac’s $190 million investment in the facility.

A dedicated engineering team has traveled the globe refining and advancing the ATS to meet customer demands. The addition of advanced materials has reduced curb weight to less than 3,400 pounds, more than 100 pounds less than an Audi A4 or Mercedes-Benz C250.

Time spent at premier race tracks around the globe, including Road America, Road Atlanta, Phoenix International Raceway and the Nürburgring in Germany has enhanced the ATS’ sporty ride and handling and engine tuning. The 3.6L model is expected to have a 0-60 mph acceleration time of well below six seconds.

Cadillac’s new CUE user interface, standard on most ATS models, offers the first automotive use of capacitive touch to create an intuitive, modern way for drivers to interact with the car. This technology, used for most smartphones and tablet computers, uses electrodes to sense the conductive properties of objects, such as a finger.

Tags: Cadillac ATS
Posted in Site Info / News | 1 Comment »

Got an early start on my Saturday install Friday evening.

Front clip wins by a nose

Getting the car up the wheels off and the front clip off went well. Replacing the OEM Heat Exchanger was a breeze.
The new S3TC goes under the bumper supports, but I didn’t visualize that part correctly and prepare to either drill and bolt through the 6″ boxed bumper support, or cut a hole in the top of the support to allow me to wrench on a bolt inside the bottom of the boxed support. So I’m delayed for a trip back to the hardware store for a long bolt or a hole saw or both, and it has started to rain here which puts a damper on the fun in the driveway.

OEM HX back in the Car, S3TC on the ground in front of the STS-V

There is also a power steering cooler bolted to the back of the bumper in the area that should stay out of the way after everything gets re-arranged but we’ll see. I’m going to focus on getting the hx hung then the hoses rigged then address the power steering cooler.  Also, hoping the front clip fits back over everything.  Did I mention the hose routing?  I’m sure it will all be more clear in the morning light.

Update:

After a long day Saturday with at least 3 installs in 2 locations to get the various parts to play together the new HX the OEM HX, and the Power Steering HX are all in the STS-V and functioning.

The S3TC is mounted on the bumper supports, with the PS HX above it.  Normally one would run flow to the aft HX, then to the forward HX, since the forward HX has the coldest air, but the hose routing didn’t work for that so mine goes to the S3TC then to the OEM HX.  Minor difference at best but worth mentioning.  I have been running the intercooler pump and refilling the system.  I am really missing the RX Performance fill tank today!

I am going to take a long break then I will go over everything again and get a test drive in.

Update 2:

Took the STS-V for a shakedown drive to monitor IAT2, the temp after the supercharger.  For the first trip out, the temps went steadily up to 170F.  This obviously concerned me, but I grabbed dinner on the way home.  I had the farmhouse salad, the STS-V had another 1/2 gal of Dexcool 50/50.  Yes, that shake-out drive burped up even more air and the intercooler loop gulped down a lot more coolant.

Next I waited until the thirst for dexcool had slacked, and went to retest.

This time the IAT2s came right down to 125-127F at coolest.  They also recovered quickly after acceleration runs back to near the 127F baseline.  This seems a good result to me for today’s weather — it is 92F outside with ‘effective’ temp coming off the highway hotter.    This makes the graphs harder to compare, since our ‘before’ graph had an ambient temp around 77F (3/26/2012 7:58pm) and today is around 92F, or 15F hotter.  The ambient temperature has a direct effect on the ability of the heat exchanger to cool the air charge.  So for this graph I have taken the ‘historical’ OEM HX data and simply added the temp delta of 15F across the boards.  If you have not read the previous posts on this topic, the graph shows IAT2 sensor readings, which is air temp in F after the supercharger and intercooler, over time for the same test loop, about a 20 min drive and 60k data points for each.

S3TC plus OEM Hx vs OEM alone (adjusted for air temps)

What the graph suggests is that the new S3TC plus OEM is more effective than the OEM alone.

Further, look at the size of the data spikes, and the width of the spikes.  The spikes are acceleration events.  The size of the spike shows how far up the IAT2 went under acceleration.  The width shows how quickly it recovered.   What I think this shows is that the S3TC+OEM is more effective at limiting increase during acceleration, and recovers more quickly.  Those are the key characteristics I am hoping for in the upgrade.

I will keep burping and filling the system, and testing.  Hopefully we’ll get one more 72F day comparable to the history file.

S3TC Front Mounted Heat Exchanger visible in the lower grill

Posted in Intercooler, Site Info / News, STS-V | No Comments »

Got a nice but surprisingly light box delivered today, with the new front mounted heat exchanger.

ZZP S3TC FMHE

This one will go below the front bumper, and I plan to use it in series with the OEM heat exchanger.

Here is a shot of my new intercooler cooling team together:

OEM Heat Exchanger and S3TC Front Mounted Heat Exchanger together

Sorry for the rapid image cropping, but I knew you’d want to see it sooner than if I took the time to fix it perfectly.

The new HX arrived with hoses and fittings, so the install should be getting the front clip off again, drilling two holes in the bumper to mount the new HX, putting back in the OEM HX, and then connecting hoses etc.

After the install we’ll get new IAT2 numbers over the test area, and see if I get the expected improvement, or we have some new factor at play here!

Tim C can be contacted at t_coel@yahoo.com for inquiries on the Heat Exchanger, STS-V upper pulley, and new cold air intake.

Posted in Intercooler, Site Info / News, STS-V | No Comments »