Coaxing the RB, an inline-6, into an engine bay designed for a V-6 would be a true trailblazing experience. "Since I had discovered that the RB bellhousing would bolt on to the Z32 transmission without any modification, it made the motor mount process very simple," Turpin says. "I was able to utilize the stock 300ZX trans mount, driveshaft, sensors and shifter. After everything was in place I completely deloomed the RB26 wiring harness and removed all of the AWD electrical components and shortened the harness by about 4 inches."
When Turpin fired the RB to life for the first time he was running a single-turbo setup featuring a Precision Turbo GT4202 that produced 680 whp on C16 fuel. But there is more to this game than power numbers. "I decided that the GT42 was just too laggy for my tastes and began to search for something more suited to my goals. After a string of emails and phone calls, I was informed of a sponsorship offer by BorgWarner/Airwerks. I spoke with their lead Turbo Engineer, Kurt Henderson, many times and we finally made a decision on an S300 60mm turbo."
Directly after installing the new turbo, Turpin decided to make the switch to E85 due to its availability in central Illinois. Since he already had a rather large fuel system, featuring 1,000cc injectors, he needed to make zero changes to make E85 work. He took the car to Sound Performance in Chicago for the initial E85 tune and the RB belted out a solid 530 whp. After some trips to the dragstrip and some low-11 passes, with a best of 11.1 at 126 mph, Turpin figured there was more power to be had so he swapped to an Airwerks S300 66mm turbo. After fine-tuning the AEM EMS himself and setting the GReddy Profec S to 26 psi the Z dropped a 10.4 at 134 mph on its first pass, impressive considering the car has always run DOT-legal drag radials. "The Z is a solid 10-second sleeper running eco-friendly E85," Turpin says. "I have yet to dyno it, but I estimate the 134-mph trap speeds that the stock block is still holding right around 700 whp. I typically drive the Z to work on nice days without any hiccups. It drives just like a stock car until you don't want it to."
Among his favorite parts Turpin is quick to point to his Full-Race exhaust manifold. "This piece is a thing of beauty, almost worthy of framing rather than hanging off the engine," Turpin says. "I cannot speak highly enough about the quality of this piece." The Nissan's Mickey Thompson ET Street drag radials get kudos as well. "These tires grip unreal. Even with 700 whp on tap and 4:10 gears, the car hooks up without balking. I typically run through a set per year, they're worth every penny and they make the performance side of the sleeper look possible."
Turpin says he would eventually like to forge the bottom end and really shoot for some serious power-700 whp is not serious? He feels the stock RB26 has proved its strength for now and has satisfied his needs. We all know this sentiment will not last too long because committed enthusiasts like Turpin don't know the meaning of "enough."
Specifications & Details
'90 Nissan 300zx Twin Turbo
Engine
2.6-liter RB26DETT inline-6
Engine Modifications
Full-Race exhaust manifold, BorgWarner S366 turbo, Tial 44mm wastegates (2), TialSport BOV, Tomei Poncams Type A (260/252), Titan Motorsports 1,000cc injectors, Tomei 1.2mm head gasket, Precision FMIC, Custom 3" IC piping, custom 4" downpipe, GReddy SP after-cat exhaust, RB25 oil pan
Wheels, Tires And Brakes
5Zigen FN01R-C 17x8 (f) 17x9 (r), Mickey Thompson ET Street Radials
Suspension
Powertrix HICAS Eliminator, SPL adjustable tension rods, Specialty Z subframe connectors
Interior
8-point rollcage (NHRA certified), Sparco Speed Seats, RCI 5-point racing harnesses, Sparco 350 steering wheel and hub, Auto Meter oil pressure gauge, Defi Link 2 and BF Series boost gauge, Optima Red Top Battery relocated to trunk