Just think of the rotational mass these things would save. We can hardly imagine how quickly this setup would rev but we’d love to find out.
At its core, hot rodding is all about the never ending search for lighter, stronger components. Whether that’s wheels, engine components, or driveline gear, it’s a never ending quest. And while carbon fiber technology has come a long way, even making its way into wheel technology lately, we never thought we’d see the day where carbon fiber would be used inside the engine. But here we are.
A recent startup called Naimo Composites is looking to bring carbon fiber technology into the engine with the creation and implementation of the very first set of carbon fiber connecting rods ever. Chris Naimo, the company’s founder and namesake, thinks it’s about time someone took engine composite technology one step further and he has chosen GM’s LS platform for its maiden voyage.
“I was looking to get my name out there and get my engine development business off the ground in terms of finances,” Naimo explained. “My original idea was carbon-ceramic pistons. There were a few companies that tried, but they never got off the ground. But as I was thinking about that, I took a look at connecting rods and decided that would be an easier area to start with and more than feasible.”
Obviously, a connecting rod made of carbon is completely solid. It almost seems like it would be a shame to hide these beautiful pieces inside an engine. Image via Naimo Composites.
Naimo says he originally heard that Lamborghini would be attempting something similar but that the components wouldn’t be available in a production engine until sometime in the 2020s. With that, he set out to beat them to the punch and began development on his own connecting rod design made completely from carbon fiber.
“When we started designing it, we weren’t even sure that it was possible with the available materials, but once we really got looking into it, everything was pretty reasonable and it will work,” Naimo told us.
There are several hurdles to be overcome when using carbon fiber in an application such as a connecting rod, mainly heat. The resins used to give carbon fiber its form are typically not especially heat resistant—though carbon fiber treated with more high-performance resins have been used in high-heat applications such as missiles.
The wrist pin and rod journal diameter are all stock LS meaning they would swap right in without a problem.
However, using high-performance resins have some drawbacks and introduce additional cost to the production of any such component. This, along with many other variables just may be why we haven’t see the technology brought to the aftermarket just yet.
“Most common carbon fibers use an epoxy resin, and in terms of handling heat there is what’s know as a glass transition temperature,” Naimo explained. “At room temperature, the epoxy resin is very strong, but as you begin to raise the temperature, it loses strength and if you were to chart it out, strength versus temperature, as the temperature increases, it would start to curve down and settle out low and become a horizontal line. That range, where it decreases in strength, is known as the glass transition temperature.”
“To get the epoxy resin to take high heat, there are additives which you mix in to allow it to handle heat better. But it’s also a function of the curing process, which when done at a higher temperature over a longer period of time, also increase the glass transition temperature,” Naimo said.
Hours of computational analysis have gone into ensuring the rods are capable of taking the forces Naimo Composites plan to place them under.
The proprietary polymer that Naimo Composites has designed allows the carbon fiber to maintain stability up to 300 degrees Fahrenheit operating temperatures, according to Naimo. But he adds that means the glass transition temperature is much higher and it would take considerably more heat to compromise the component.
But what are the advantages to running a carbon fiber connecting rod? Well, first and foremost, there is weight. Any gearhead knows that taking weight out of the rotating assembly will allow it to come up to speed quicker, giving faster throttle response, freeing up horsepower and allowing higher RPM.
“Our connecting rods should be half of what a traditional alloy connecting rod weighs,” Naimo said. “We’re not ready to release the final numbers just yet, but obviously they are going to be substantially lighter than a conventional connecting rod.”
Currently, Naimo’s designs have centered around naturally aspirated applications, with the rods being developed to handle the cylinder pressure of a high-revving LS7 (around 100 bar), though boost-ready carbon fiber rods could be not so far off. Naimo says that the rods have been “designed with a safety factor of around 1.6.”
The rods are designed to take the standard 0.927-inch wrist pin with a 2.225-inch rod journal diameter—standard for LS engines. And if you’re wondering when you can get your mitts on a set of these bad boys, that’s where the good and bad news comes in. Naimo is currently looking to drum up funding to get a set of them made for testing. All of the design and computational analysis is done, but a prototype set has yet to be produced.
If you’d like to help turn these into a reality and get your hands on the first set, Naimo’s crowd fund campaign over on Indie Go Go is set to go live on Dec. 1. Update: The campaign is now live here.
While we’re not sure what benefits they will offer to initial investors, you can rest assured that it would move you name up the list to be the first to try a set out for yourself.
We’d love to see what they are capable and put a set in an LS ourselves. According to Naimo, if all goes well, the company will began expanding to more carbon fiber components for engines, such as pistons. Who knows? Maybe one day you’ll be able to put together an engine made primarily of carbon fiber. What do you think? Would you run them? Leave your thoughts in the comments below.