Project Nissan Skyline R33 GT-R – Part 3: Borg Warner turbo and Full Race exhaust manifold

With small pistons and a short stroke, the RB26 is not known as a torquey engine. However, this Borg Warner 8374-C turbo (the “C” denoting its one with an internal wastegate and a .92 AR divided housing), should ramp up the boost fairly quickly. You can’t quite see it here, but the external wastegate is equally divided between the two halves of the turbine housing.
To mate the 8374’s divided housing, we also went with a divided flange for the Full-Race manifold. It, of course, was ordered with no wastegate piping either, which should further cut on MKC’s installation time.
These are robotically TIG-welded manifolds.
For those of you who enjoy weld shots, here you go. These manifolds are real beauties. Both the turbo and exhaust manifold were coated in Full Race’s optional hi-temp black finish. While our engine bay should look drastically different as a result, the coating will also help keep the heat where it needs to be—inside those pipes and away from everything else.
Full-Race has a partnership with Solidworks, using their CFD (computational fluid dynamics) and FEA (finite element analysis) software to design their thick-wall stainless steel turbo manifolds. Full-Race also specs a custom stainless steel alloy for the unique high temperature and high vibration environments found on modern turbocharged engines. According to Full Race founder and engineer Geoff Raicer, “This stainless steel alloy is optimized for our robotic welding process. It’s most similar to the alloy known as 316H, but with more chromium, nickel, and sulfur. We’ve had zero robotic weld failures in 17 years.”

When you look at a Full Race manifold, it’s easy to place it into the “equal length” category, which is a popular design in the racing world. What people don’t realize, however, is that Full Race isn’t just a company with expertise at building manifolds, it also really knows the RB26 and its reported tendency to run slightly leaner in cylinder #6. Full Race’s manifold uses a runner geometry that is adjusted accordingly. Says Raicer, “the Full-Race RB26 manifold is designed with a differing pressure drop. The lowest pressure drop starts from cylinder #1 (which is the longest straight at the head flange) to an increasing pressure drop all the way to cylinder #6. This gives a +7% pressure drop [at cylinder #6] compared to cylinder #1. This is a big part of the reason why equal-length is not the end-all that most think it is–pressure drop is the key metric; and it should be tailored depending on the unique operating parameters of each individual engine.”

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4 comments

  2. I am really glad that you are not going for an all-out TQ number. There’s so much more to an engine than it’s TQ/HP number. Most people don’t really know that there’s much more to an engine than how much TQ it produces.

    Case in point: Gordon Murray’s T.50 NA V12 revs at 28,400 RPM per second.

    Reply

  4. hi guys, thanks for the replies. Next two articles are in the works as we speak!

    Joe, I think I understand what you’re saying with the 28400 RPM “per second”, as in the rate of RPM acceleration. Just so others aren’t confused, it’s like–when free-revving in neutral–it’ll *theoretically* rev to 28400 RPM if you floor/free-rev it for one 1sec. Murray’s actual [beast of a] car has a 12100 RPM rev *limit*, which is still insane for that size of a motor. And thanks for the compliments. Yes driving this car is so different from the Supra in every aspect, I’m just having so much more fun in it. I very much want to floor it more often than in the Supra (which is more of an “event”) since it is more top-end based. And I just love the RB’s sound, even moreso now with the wastegate plumbed back into the exhaust. Stay tuned as that’s what I discuss in the next one! 🙂
    thanks guys.

    Reply

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