You know the name Scott Clark. His handiwork has helped MANY racers of all different stripes go faster, be more consistent, and make more power. Scott is a professional engine tuner and he works at DIY Autotune, the company that sells the wildly popular MegaSquirt EFI system that literally anyone can build at home. Scott gets to lay his hands on some amazing iron, like Larry Larson’s truck but this one may top them all.

Last week Clark was summoned by the Lingenfelter Performane Engineering shop to come up and aid in their dyno testing of a unique and awesome engine. Essentially a prototype LT-5 motor that Lotus was helping to develop for the General Motors which was to be used in the ZR-1 Corvettes from the 1990s but was never used, engineers have had questions about how well it worked because they never got the chance to run it. . Graham Behan was an engineer with Lotus and worked on the project. He is now the chief engineer at LPE and he assembled this engine with his own hands.

Scott tells the story better than we could so here goes!

I spent a few days last week in Decatur, IN helping on a super cool project worth sharing.

Graham Behan, the chief engineer at Lingenfelter Performance Engineering, invited DIYAutotune to help with a special project engine he had been working on… since the early 1990s!

Way back in the 1980s, Graham worked for Lotus on the design team for the LT-5 engine found in ZR-1 corvettes of the era. That engine was a radical departure from small block Chevys of the time as it featured 32-valve heads, staged injection, variable geometry intake, and a ton of other details that were pure science-fiction on anything but the most exotic of cars during its development. The engine was rated at 405hp in it’s last configuration, and has quite a following still today (Zr1.net)!

However, what few people know is that GM had the Lotus team working on a *2nd* generation of the engine. This one was to make more power, and be yet another step up the technology ladder. This was a serious supercar engine for it’s time and ultimately it was perhaps ahead of it’s time. GM sadly cancelled the program right before the Lotus group got to test it on the dyno.

Graham tells me the target power on a reasonable (pump gasoline) tuneup was 500hp with a peak at 7200rpm. Remember that this was the late 80s, early 90s, and a small group of people were handling all the work – CFD, FEA, even 3D drawings were in their infancy and not really used on this project. Most of this was hand calculated and drawn.

Fast forward 20 years. Graham now works at LPE and has a pile of castings and most of the parts from the Gen 2 program to build one of these engines. With the 25th anniversary of the LT5 engine and a presentation to give at the Corvette Museum, they decided to FINISH it.

Fortunately for me, my company makes the only plug-ang-play Mega Squirt ECU that works with the first generation LT5 engines, so it was the best candidate for running their new Gen 2 LT5. Huge thanks to Graham, Jason, and Brent for trusting us with your extremely rare powerplant!!

With 2 days to spare we all met at the LPE dyno facility, wired and fired the engine to see if the original Lotus folks hit their target or not. In this particular configuration, on this dyno, and the correction factor used (SAE J607) the target was 500hp.

On the first pull to redline it made 501.1. Power peak at 7200rpm.

By the time Rob, LPE’s dyno operator and a skilled EFI tuner, was done working the MS3Pro fuel and timing tables, the engine belted out 528hp!

Nice work, Dudes at Lotus!!!