Cadillac continues to bump along on sales, as the Cadillac XTS is almost on the showroom, and the Cadillac ATS is screaming in at the end of the summer.
CTS held at over 4K/month, and SRX was close to that figure. Escalade was down 100 since last year.
January – May
2012
2011
%Change Volume
2012
2011
%Change Volume
CTS
4,161
4,288
-3.0
20,437
22,807
-10.4
DTS
75
1,496
-95.0
350
7,859
-95.5
Escalade
916
1,024
-10.5
4,830
5,988
-19.3
Escalade ESV
669
612
9.3
3,089
3,220
-4.1
Escalade EXT
137
150
-8.7
672
754
-10.9
SRX
3,900
3,910
-0.3
21,190
22,249
-4.8
STS
13
142
-90.8
120
2,382
-95.0
XLR
0
1
***.*
0
3
***.*
Cadillac Total
9,871
11,623
-15.1
50,688
65,262
-22.3
The last few STS’s cleared the pattern, and 75 more DTS’s found new homes. So certainly by bleeding the showrooms dry Cadillac gave those models every chance to move inventory. Also, although sales were down 15% year over year, they were only down 2.9% for retail sales. So the big drop was in low margin fleet and rental sales.
First half sales are hopefully just the darkness before the dawn of the new models arriving in 2nd half (hey, it’s second half now).
Started shipping XTS and Dealers will start delivering those in June!
Today I took the STS-V front clip off again for some adjustments and a new tank install.
My first goal was to work on improving the lower OEM Heat Exchanger (HX1) hose routing that appeared to be crimping. Second was to transform the flow from intercooler HX2 HX1 pump to intercooler HX1 HX2 pump due to elevation differences. I also wanted to change the S3TC HX2 fittings from plastic to brass, and redo them in general to ensure no leaks. Finally, if it fit (and it does) I wanted to try adding in my AVS 1 gallon aluminum inline tank.
Here is a shot
AVS Tank initial placement
The tank seems upside down, but this placement allows the ‘drain’ to act as an air release if needed, and the tank brackets are tied off above so that the tank is ‘hanging’ in place, along with the hoses pretty much keeping it where they want it to be.
The flow now is intercooler to OEM HX to inline tank to S3TC HX to pump to intercooler. That matches the way GM did the flow for the inline tank they use with the LS9.
The tank is clearly visible in all its steampunk glory through the front mesh grill. I suppose painting it black would fade out the tank, but I am more interested in testing how it performs just now. The inline tank wants to be in the incoming air flow also to help with temperature control.
The OEM STS-V intercooler cooling system holds 2.6 quarts. HX2, the S3TC HX, holds 2 quarts. The new tank holds 1 gallon (4 quarts). So the system now has 8.6 quarts instead of 2.6 OEM quarts.
Update:
First test the intercooler temps etc and see if everything is playing well together.
First inline tank test shows lower IAT2s
The blue line is today’s IAT2, or intake air temperature after the supercharger and intercooler during a set route test drive. The red line is a previous day with the current config except no inline tank, and the HX1-HX2 flow path was different. The spikes are acceleration runs. Both days were 91.5F ambient temps, so seem comparable.
What this appears to show is that the IAT2s are lower with the new inline tank, but actually ran higher during the acceleration run. I need to zoom in on that in a different graph (below).
Overall good news for the new inline tank.
Tank vs no tank during 0-60 mph run
Conventional wisdom is that more fluid in the system provides a time buffer to IAT2. What we see in this graph is that the new tank did no better at delaying IAT2 increase during 0-60 than the system without a tank. In both systems due to the system flow rate during the 0-60 run the system never gets through all the coolant. My measured 3.5 gpm means that even with 1 gal of fluid in the system, that gallon is circulating every 17 seconds. With 2 gallons it is circulating (if the 3.5 gpm is still constant) every 34 seconds. So unless we speed up the pump (stay tuned) or measure over a longer acceleration run, one might expect to see no difference.
However, the fact that the system reached a lower temp with the new tank and configuration is a good result.
The following video shows HP Tuners gauges during the acceleration run with the new inline tank:
Coming soon:
Coming soon: jabsco intercooler pump with brass fittings
UPDATE: Re-ran the test with a change in the test setup, yielding closer to the expected results. See Below.
I hate surprising test results.
I was expecting to see around 3-4 PSID system head, and the Bosch OEM intercooler pump doing 5-6 gpm.
Cadillac, in bucket, out bucket, extra coolant
This morning I ran a bucket test on my Cadillac STS-V. A bucket test is a simple way to measure gallons per minute of flow in an operating system. To do the test, measure how much fluid comes out of the system over what period of time. Record the result in gallons per minute.
First I calibrated my bucket. I used a “TO” bucket that was shaped like a cylinder, with no slope to the sides. That simplifies measurement. I took a large 1/2 gal kitchen measuring cup and put 1/2 gallon of water in “TO” my bucket. Then I measured how many inches of depth were in the bucket. My bucket measured 1&1/4″ per 1/2 gallon. I added another 1/2 gallon and noted that the bucket was at 2.5″; good.
Next, I put the STS-V up on jackstands, and removed the undertray. I disconnected the hose from the hard pipe out at the bottom of the V coming out of the intercooler, and put a “out” hose there leading to my “TO” bucket. I put the hose that had been connected there in my “FROM” bucket. I added coolant to my “From” bucket, and ran the test.
The pump in the test is the Bosch OEM intercooler pump. It is pumping through the intercooler, and pulling from both heat exchangers so that the flow should exactly model what the pump sees in operation.
What I measured was a meager 1 & 1/2″ of flow per 60 seconds. Since 5/4″ was 1/2 gallon, 6/4″ is 20% more or 0.6 gallons per minute (GPM). That means that the current pressure head in the system as tested is nearly 7 PSID. The Bosch pump can only pump against a max of 7.3 psi.
I plan to test with a Jabsco pump next. The Jabsco pump is rated up to 8 PSID, and at 7 PSID might be able to push 4 or 5 gpm.
What would you change in the test setup? Hit the comments!
Did my test setup effect the outcome? If the “FROM” bucket was elevated to the same level as the intercooler at the top of the engine, would that be more fair? Or does the down force from the intercooler height to the bucket get ‘counted’ in the flow out the “TO” hose already and so is not ‘lost’?
Next:
Re-run the bucket test
Check all hoses for crimping
Raise the “FROM” bucket to intercooler level
Test with the engine on, not just battery/pump on with engine off as before — full voltage
Update — Raise the Bucket:
Re-ran the test with the from bucket at intercooler height. New pump flow 3.5 gpm, much closer to expected. 40″ of water height is a static 1.4 psi into the system that is there in operation but missing from my initial result.
For this test I put the “FROM” bucket at 42″ height, or the intercooler height in the car. I did that because the hoses and pipes leading to where I put the “FROM” bucket are the downhill flow from the intercooler. I pushed water through the FROM line to prime the line and ensure that I got gravity siphon flow through the line and into the car. With the bucket and line in place the system actually flowed 1.2 gpm with NO pump running. So the height of the bucket makes a difference — each foot of height of water gives 0.42 psi, so 3.3 feet equates to 1.4 psi or so. My original test had the FROM bucket on the ground, so inadvertently took away this 1.4 psi of system pressure.
FROM bucket at intercooler height, TO bucket at ground level
I ran the engine at idle when I was testing the pump. With the pump on in the retest the system did a steady 3.5 gpm flow.
This suggests that at 3.5 gpm the system pressure head is around 6 psi assuming the OEM bosch intercooler pump is operating to spec.
It also ties with the first test result given the setup difference.
The test perhaps also points to the system psid curve versus flow — 1.4 psi at 1.2 gpm flow, and 6 psi at 3.5 gpm flow. We expect psid to go up as a function of nearly the square of the change in flow, so this also seems appropriate.
Pump rated flow vs head pressure and system pressure curve
Now, my system resistance of 6 psid may still be higher than it should be; I am looking at the fittings to see if they can be improved further.
If the system numbers are correct than the system flow resistance would be shown by the green line on the chart above. The Y axis shows pressure head. The X axis is in gallons per minute of flow. The blue line is the Bosch OEM pump spec. The red line is the Jabsco pump spec. Where the system flow line crosses the pump lines are where we would expect that pump to operate in gpm and PSID in this system. So in other words, if the Bosch pump is doing 3.5 gpm against 6 psid, and the system characteristic curve is correct, then the Jabsco pump will do 4.3 gpm which will raise the system pressure head to 7.7 psid.
