I thought some of the recent intercooler pump flow testing we have performed might be of interest to the CTSV community.
Here is data comparing the stock CTSV Bosch intercooler pump to the stock ZL1 intercooler pump and then the Varimax aftermarket pump that is similar in flow to the ZL1 pump (and is used in our upgrade kit for the CTSV).
Here are some more of the results of the recent electric intercooler pump testing performed at Lingenfelter Performance Engineering.
We have performed this type of testing before on several of these pumps but, since we recently upgraded our coolant flow measurement equipment to a much higher level of flow meter that allows us to very accurately measure flow over a very wide range of flows with very little to no impact on the system restriction, we felt this was a good time to perform this testing again and to do so on an expanded range of pumps and conditions.
For this testing we tested the pumps in two primary ways:
fixed known restriction using a ZL1 intercooler (from inside the supercharger assembly) and intercooler radiator with OEM diameter coolant hoses (3/4")
variable orifice restriction after the pump so that we could simulate any level of restriction that the pump might encounter (depending on the installed application)
We tested several different intercooler pumps including:
stock OEM ZL1 intercooler pump (this is also the GMPP LSA and LS9 crate engine pump)
stock OEM Cadillac CTSV/Bosch PCA 1150LPH intercooler pump
stock OEM ZR1 intercooler pump
VariMax 410110 DC brushless intercooler pump
a common aftermarket 20GPM inline electric pump
a common aftermarket 55GPM inline electric pump
Stewart-EMP E2512A DC brushless intercooler pump
Stewart-EMP E2512A pump reprogrammed to raise the current/pump RPM limit (revised pump part # 1030002107 when programmed with this software)
We tested a few other pumps as well but the above pumps are the primary ones we focused on.
During the testing some of the variables we recorded included:
inlet pressure (positive or negative)
differential pressure across the pump
coolant temperature (not for heat exchanger testing - just to confirm that the variable was constant from test to test)
All tests were repeated multiple times (at least three times), the data checked to make sure we had test to test repeatability and then the results were averaged to produce the data described below.
The Bosch 1150 LPH PCA pump continues to be the baseline standard pump used in many liquid to air intercooler systems in both OEM and aftermarket applications. In the ZL1 system it flowed 3.6 gallons per minute (GPM). This is the same pump used in the 2009-2013 Cadillac CTSV, Cadillac STSV, Cadillac XLRV, 1999-2004 Ford Lightning, Fort GT500 and many other OEM applications. It is also the pump used in Magnuson, Edelbrock, Whipple and many other aftermarket supercharger kits. It is fairly compact, very reliable and has low current draw. It performs fairly well against an outlet restriction but doesn't flow as well as some of the newer, higher output pumps that are available. This same pump has existed for well over 10 years without any major design changes.
As expected from our previous testing, the ZL1 pump flowed more than the Bosch pump (4.8 GPM vs 3.6 GPM) and the VariMax pump (PN TAFX410110) flowed the same as the ZL1 pump when tested in the stock ZL1 intercooler and intercooler radiator circuit. The Varimax pump is the pump that is in our CTSV pump upgrade kit (part # L330030709) that brings the CTSV up to the same pump flow specification as the ZL1. At 3.6 GPM, the Bosch pump flowed 25% less than the ZL1 and the VariMax pumps.
Also as expected, the ZR1 pump performed very well. It flowed 5.7 gpm, 19% more than the stock ZL1 pump. For its size and current draw the ZR1 pump is a very impressive pump as it is no bigger than the ZL1 pump yet flows more than pumps more than twice its size and does so with 3/4" hose fittings in and out. On the other hand it is a fairly expensive pump, with an MSRP of over $1000 and "street price" of not much under that.
The Stewart-EMP E2512A intercooler pump also performed well, matching the ZR1 pump flow when installed in the ZL1 circuit despite the fact that the inlet hose was 3/4", not the recommended 1" inlet. When we reprogrammed the Stewart-EMP pump to raise the internal pump speed and current limit, the flow was significantly increased to 7.7 gpm. That is 60% more than the ZL1 stock pump. This pump performs very well at high pressure drops but the current draw does increase significantly when the pressure across the pump is high (when the restriction is high) so you need to make sure you account for that in your wiring. The Stewart-EMP pump is a pump we have been using for several years in high horsepower supercharged and turbocharged vehicle applications including our 1250RWHP Camaro SS, our white turbo drag Camaro, and numerous 1000-1600+ HP customer builds.
The 20GPM and 55GPM pumps we tested are pumps that are commonly being used and sold as intercooler pumps so we felt we needed to test how these performed compared to the above pumps that we use on a fairly regular basis. When tested with very little restriction these pumps flowed fairly well and used little electrical current to do so. Once the restriction started to increase the flow of these pumps dropped significantly though. Both pumps, when installed in a stock ZL1 intercooler system, flowed less than the stock ZL1 pump and not much more than the Bosch pump. At higher differential pressures (outlet restrictions) even the Bosch pump flowed more as can be seen by the graph of pump flow vs differential pressure. In 2002 when we were developing and testing a turbo Ecotec engine in the NHRA Sport Compact series we had found similar results. The billet housing electric pump that we had purchased and installed in the vehicle that was supposed to be a high flow pump actually flowed less than the Bosch production pump we were using in the low boost, 500 HP supercharged customer street cars at the time. As we found out then, many pumps being sold in the marketplace are being flow rated with no pump restriction and that many of these pumps did not flow nearly as well when tested in an as installed configuration.
Here are the graphs of the test data described above:
And here are pictures of the pumps mentioned in the above data:
04-17-13, 10:47 PM
extremely helpful thank you for sharing!
No info on the JABSCO huh? That one has been widely used by the V community. Great write up with useful information. Thanks!
04-18-13, 07:13 AM
this needs to be a sticky
04-18-13, 07:59 AM
Is the ZL1 pump a bolt in for the CTS-V? Does it out flow the Bosch pump in the CTS-V's system?
04-18-13, 11:50 PM
Would anybody happen to have the GM part number for the ZR1 intercooler pump and the ZL1 intercooler pump? I'm having trouble finding them, thanks.
never mind I found the ZR1 one (ls9) and it's 15870574
expensive's right..10 notes!
very informative results,,