Over the past 6 months or so, I have had numerous questions about building a higher displacement GTR, if we will do it, pros, cons, why we don't do it, etc. I have had many conversations with members here about it, but for those who have not called in or messaged me, I sat down with my brother Tym, my father Tym Sr., and our media guy Jo to put these thoughts down on paper and place them in front of the audience that is GTR Heritage:
For those of you haven’t yet clicked on the image above, that dyno graph represents the Switzer-developed Goliath customer GTR putting down more than 1500 horsepower. To the wheels. It’s an impressive achievement in itself, more than one-thousand five-hundred horsepower at the wheels … but that dyno graph only hints at the real story. The real story is Nissan’s VR38 engine, and why we approach extreme horsepower builds the way we do.
“Goliath was all about exploring the limits of our package hardware,” explains Tym Switzer, “but it’s also about exploring the limits of some of the factory hardware – and that includes the stock VR38 engine block and rotating assembly.”
You read that correctly. Switzer’s Goliath is making nearly 4 times as much power as a stock R35 Nissan on a stock VR38 engine block with the same OEM bore and stroke dimensions it left the factory with. “It’s a fantastic piece of engineering,” offers Tym, “and we’ve been able to show, time and time again, pull after pull, run after run, and lap after lap that the factory block is able to distribute loads and temperatures very efficiently.”
Switzer began to suspect that the factory VR38 engine block might be up the challenge of extreme horsepower several years ago. In the fall of 2008, to be exact, when the first R35 came to Tym’s Oberlin, Ohio facility for evaluation and tuning. “That car had more sensors and wires on it than the space shuttle …” Tym famously said, and a tremendous amount of data acquisition went into the development of those early Switzer P700 GTRs. Data that allowed Switzer and his crew (as I wrote back then) “to see the deficiencies of certain factory components and confirm the outstanding performance of others.”
The amount of engineering that went into the VR engine was obvious, and it spoke volumes about Nissan’s engineers. The durability of the all-aluminum block and its plasma-sprayed, low-friction cylinders, however, remained to be confirmed at the power levels we intended to run. “We knew what the block and the OEM cylinder linings should have been capable of handling, thanks to our early studies. It wasn’t until our blueprinted engine program was finalized and we were getting serious miles on the cars, though, that we were able to check our early math against real-world data.” The results speak for themselves: dozens of Switzer-built engines with many thousands of hard-driven miles to their credit, and zero bottom-end failures. “My dad (Tym Sr., who runs Switzer’s engine shop and started teaching me the art of engine building at an early age) gets a lot of credit for that record of reliability,” says Tym “but I think he’d be the first guy to tell you it’s the VR38 engine’s superior engineering that makes that possible. The geometry of the VR block is constantly distributing stresses across the block and Nissan’s cylinder lining is fantastic. It was on these observations that we didn’t change the way loads traveled across the block by boring the out the cylinders, and we both adamantly opposed tampering with the block’s closed-deck structure. Even with alternate fuels, which some people thought initially might cause the cylinders to de-laminate the bore lining, we haven’t seen any evidence of this in the plasma sprayed bores.”
The outstanding performance of the VR38 engine block was only one of the reasons Switzer avoided changing the geometry of the rotating assembly. “It’s not as if we haven’t built a stroked engine – we just chose not to offer a stroked engine to our customers,” explains Tym. “Increasing the stroke in any engine increases the piston speeds within a cylinder at any given RPM. That puts greater stresses on the pistons and rods as they accelerate and decelerate that much faster. The loads the pistons put on the cylinder walls themselves increase, creating greater frictional losses within the engine. When we looked at what we’d given up, in terms of reliability and longevity, in our early test engines with different bore and stroke configurations, any low-end and initial turbo response gains we saw just weren’t worth it.”
In addition to avoiding increases to the OEM bore and stroke of the VR38 to help preserve the Switzer engines he offers his customers, Switzer is quick to point out that the added low-end torque and initial turbo response don’t do the R35 driveline any favors. “As it is, we’re already working the traction control strategies overtime to get decent launches out of the R1K and R1K-X cars with the response we have now,” offers Tym, “the only thing adding more low-end would do is make things worse.” As a result, Switzer’s crew is focused on (what Tym calls) more useful power gains in the mid-to-upper RPM range. “We’ll be able to get cleaner launches that way, and keep the loads going through the transmission and axles more manageable. That’s on a dragstrip. For our road-course customers that are concerned with response, we saw a greater improvement in corner exit speeds with software adjustments (rolling anti-lag, rolling launch, etc.) made possible with the Syvecs ECUs from our subsidiary company (Syvecs North America) than we did with the traction control fighting to keep the tires under control mid-corner. At the end of the day, a bigger stroke and more low-end power than we were already making on the 3.8L didn’t help us or our customers reach the end goals we’d set for the projects.”
I first wrote about Tym’s commitment to “the end goal” in 2009, when I quoted him as saying “We are steadfast in our stubbornness in regard to not adding any component to a project that doesn’t contribute to the end goal.” Keeping with that philosophy, Switzer hasn’t offered any components that would change the fundamental geometry chosen by Nissan by increasing stroke or cutting into the VR38 engine block and altering the distribution of stresses within the block. “We’ve always promoted a more researched, holistic approach to tuning that see the best parts used in a way that each one compliments the others. Is it conservative? Maybe – but as I’ve said before: we believe it’s in the best interests of our customers for us to be conservative in our tuning, and their interests are our interests.”
“More than anything,” says Tym, “the huge power figures Goliath is making with our standard package hardware (the same hardware we use in the P800 and Ultimate Street Edition GTRs) and Nissan’s VR38 engine show just how good Nissan’s engineers are, and why a more conservative approach is sometimes the best way to serve all parties involved. The real challenge is making the most of what they’ve given us to work with, and recognizing the right tool for the right job when it’s right there in front of us.”
The right tool? More often than not, it seems to be Nissan’s 3.8 liter VR38 engine – the little engine that can. You can check out a video from Nissan’s Yokohama engine plant (where the VR38 engine is made) below. Enjoy!
Switzer Performance News (http://s.tt/1z7cY)