C4 Corvette Fuel Injectors - Gimme Fuel

It may not have the coolness quotient of a high-lift cam or a rowdy exhaust system, but a properly functioning set of fuel injectors plays a critical role in optimizing overall engine performance. Fortunately for those of us on salt-miners' salaries, a well-maintained octet of factory injectors is more than capable of meeting the fueling demands of a typical bolt-on performance build.

How, then, to make sure your stock squirters are performing up to snuff? In-tank cleaners such as Chevron Techron are fine for routine fuel-system maintenance but aren't concentrated enough to break down heavy deposits. Pressurized systems that use a solvent routed directly into the fuel rail are better, but cleaning solutions alone can only do so much.

For a serious injector-scrubbing, you'll want to use a system that supplements the cleaning-fluid component by bombarding the injectors with ultrasonic (high-frequency) sound waves. We don't have the space or the acoustical-engineering degree to get into the science of it here, but suffice it to say it's like the difference between working over your teeth with a Sonicare Elite and simply swishing around a mouthful of Listerine.

After a baseline dyno test,... 

   

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After a baseline dyno test, AntiVenom tech guru Greg Lovell begins the operation by removing the LT1's fuel rails...

For now, what we can do is show you the results of a real-life injector-cleaning test conducted recently on this author's 77,000-mile '96 C4. As in the past, the work went down at Seffner, Florida-based Corvette tuner AntiVenom, which earlier this year took delivery of an ASNU-01 (the name refers to the machine's purported ability to restore injectors to "as new" condition) Ultrasonic Cleaning System and Tester.

If you like what you see-and we think you will-AntiVenom can provide you with the same service on a mail-order basis for $125. A full rebuild-including new O-rings, filters, etc.-will run you $185. With most aftermarket injector sets currently selling for $350 or more (not including the requisite PCM recalibration), that qualifies as a bargain.

...and gently prying loose...        read full caption ...and gently prying loose the injectors. In proper operating condition, these 24-lb/hr Rochesters will supply enough fuel to support around 350 horsepower.	If you're following along...        read full caption If you're following along at home, be sure to hang on to these retainer clips. You'll need them in order to reinstall the injectors on the fuel rail.	Next, the injectors are secured...        read full caption Next, the injectors are secured in the ASNU-01 for baseline flow testing.
This image shows the flow...        read full caption This image shows the flow testing in progress. Tests are conducted using a custom-formulated fluid that has the same specific gravity as gasoline, without the pesky flammability.	With the 30-second test cycle...        read full caption With the 30-second test cycle complete, we can record each injector's flow rate by observing the hash marks on the side of its test cylinder (shown in cubic centimeters). You'll find our injectors' pre- and post-cleaning flow numbers in the accompanying data box.	Prior to cleaning, Lovell...        read full caption Prior to cleaning, Lovell fills the injector tank with a unique (and pricey), biodegradable cleaning solution.
The injectors then spend around...        read full caption The injectors then spend around 10 minutes soaking in the ultrasonic bath.	Here's one of our injectors,...        read full caption Here's one of our injectors, post-cleaning. The dark half-circle near the author's thumb shows a portion of the injector body that was not submerged in the cleaning tank. Quite a difference, no?	After a follow-up flow test,...        read full caption After a follow-up flow test, the injectors are reinstalled on the engine.

With the fuel system buttoned up, Lovell makes another set of pulls on the dyno. In the end, our C4 picked up almost 5 hp and more than 7 lb-ft of torque at the rear wheels-a deeply impressive result given the relative cleanliness of the injectors prior to cleaning. In addition to the extra power, the car's fuel economy jumped by 0.8 mpg on an improvised city/highway driving loop. Even idle smoothness was markedly improved. These are improvements you'll appreciate on the street, at the track, and at the pump.