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Is Injector Modification Worth It?

Racers often choose to modify their fuel injectors. Industry experts weigh in on the merits of this approach.

By Ilona French

Some racers may ask about having their injectors modified, but is this the right solution for your customers?

“There was a time when very-high-flow-rate injectors, needed when you make big power, just didn’t exist or didn’t exist at a reasonable cost,” explained Matt Cramer from Suwanee, Georgia-based DIYAutoTune. “Some went to modifying existing designs, sometimes done well, but some of the crudely modified injectors out there just have some components drilled out. The result is a bad spray pattern and inconsistent fuel delivery per cylinder, often leading to catastrophic results.”

“In previous years, racers and others in the automotive aftermarket were modifying due to a lack of availability of injectors in the size and flow range that some consumers were seeking,” said Dan Caciolo from Continental in Allentown, Pennsylvania. “Today, this is less common as OE fuel injector manufacturers are engineering and producing new products. For example, with our VDO racing injectors sold into the automotive aftermarket, we are now filling that gap in flow rates and expanding our product offering. It is very important to note that tampering or modifying injectors reduces the life of the injector, widens the variance or flow rate between injectors, destroys the targeting or mapping of spray pattern and, most importantly, is dangerous for your engine system.”

“Sending your injectors out for ‘modification’ is like playing Russian roulette,” said David Deatsch from Oklahoma City, Oklahoma-based DeatschWerks. “Sometimes you will get good results, sometimes you won’t. What you will never get is proper injector characterization data, which is essential in properly tuning your car. The small amount of money you save by having your injectors modified is quickly offset by tuning frustrations and possible engine damage.”

“Professionally, one is OK if it replicates or improves the OE manufacturer’s original design,” said Phil Ellisdon from Bushey, Hertfordshire, United Kingdom-based ASNU, “but when you have a system when the end is just off to increase the flow without any control, this is not the best result for a performance engine. The use of LPG injectors, which Bosch have outlawed the use of with oxygenated fuels, is commonplace and dangerous, as it has been found to cause damage to the engine, catastrophic in some cases.”

“An injector is a complex piece,” said Doug Flynn from Bowling Green, Kentucky-based Holley Performance Products. “If they are modified, one wants to make sure that the entire dynamic flow curve is matched within the set of injectors. Having injectors that only have matched static flow is only a small part of the overall injector performance.”

“While modifying a racer’s injectors to achieve higher horsepower is the least expensive option, the lack of fine control in flow sizing and the inability to match the offset is a clear disadvantage over buying a brand-new set of data matched injectors,” said Jens von Holten from Hobe Sound, Florida-based Fuel Injector Clinic. “Modifying your OE injectors is seldom (if ever) worth the savings where expensive, high-horsepower engines are at risk.”

For full coverage of the latest in EFI Hardware, see our feature article in the May 2014 issue of Performance Racing Industry Magazine.



Performance Racing Industry