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LT1 Electric Water Pump - High Volts Low Temps Redux

Testing Meziere's LT1 Electric Water Pump

Jay Heath Nov 1, 2008
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One needn't boast an advanced degree in thermodynamics to understand that wedging a largish V-8 powerplant into a tight, poorly ventilated engine compartment is bound to pose cooling problems. And indeed, the Corvette aftermarket is chockablock with specially designed radiators, thermostats, and fan assemblies that purport to effect a meaningful drop in vehicle-operating temperatures.

In our August issue, we achieved spectacular results by installing a Meziere electric water pump on a lightly tweaked C6 Z06. In addition to slashing the big LS7's coolant temperatures in everyday driving, the beltless Meziere unit reduced parasitic losses sufficiently to tack on an extra 13 hp at the rear wheels. In the realm of performance-parts testing, outcomes don't get much better.

Based on our success with the LS7 Meziere, we decided to try out one of the company's electric pumps on our '96 automatic coupe. We felt the evaluation would serve as the basis of an interesting follow-up article, inasmuch as the C4's LT1 engine was both significantly less powerful than the LS7 and driven by an unconventional, cam-driven (as opposed to belt-driven) water pump.

Lacking the requisite wrenching skills, we entrusted the installation and testing to Sarasota, Florida-based Vette tuner RevXtreme. The highlights of the job follow, along with test results and driving impressions.

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The pump assembly is lowered into place. Although the electric unit sticks out a little farther than the stocker, there should still be plenty of clearance. (Note, however, that some aftermarket camber braces may not fit.) Once all the ancillary hardware is reinstalled, it's time to move on to wiring.

With the cooling system buttoned up, Briese and company strapped the C4 down onto the shop's Dynojet chassis dynamometer and performed a series of pulls. While we didn't expect the car's mildly modded LT1 to register improvements as large as those observed on the LS7, we were slightly disappointed to find that our new electric water pump had only increased rear-wheel output by 3 hp and 3 lb-ft of torque.

Could it be that the LT1's cam-driven pump saps less power than a conventional system, making improvements harder to come by? Or maybe our C4's relatively modest output (290 rwhp) is to blame. Whatever the reason, we should point out that we have heard of LT1 Vettes making as much 10 extra rear-wheel horsepower when equipped with the same Meziere unit.

Where the electric pump really paid dividends was out on the road, where coolant temperatures in typical use dropped from a scorching 210-220 degrees F down to a comparatively gelid 185-195. Installing Hypertech's Power Programmer tuning, with its lower fan-engagement thresholds, slashed those temps by another 10 degrees in all but the knottiest stop-and-go snarls.

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Briese wires the electric pump to run with the ignition in the "On" position. This will allow us to cycle the pump with the engine off-perfect for cooling things down between passes at the strip.

The effects of such a significant reduction in operating temperature aren't hard to grasp. At the strip, we've found that the car makes its best runs at 180 degrees or below; keeping temps in that range on the street is sure to improve real-world acceleration while also extending engine-component longevity.

While we didn't unlock big power gains with the Meziere LT1 pump, the marked increase in cooling efficiency it offers makes the unit well worth its $240 asking price. Throw in an ECM programmer or fan switch, and keeping your cool in a C4 has never been easier.


Tampa, FL 33619



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