GTR 101: The Basics - Injectors, Turbos, and Clutches
Now that we've covered the small stuff, it's time to start preparing for more power. In this installment, we dive into the simple items that should be addressed as you plan your horsepower goals. There are an abundance of brands out there who produce these parts so use this guide as technical information to help you make the best decision based on your goals and budget.
All conventional petrol powered engines need three basics things in order to make power; spark, air, and fuel. A reliable and calculated supply of the three will ensure the longevity and capabilities of your engine. We've covered the spark plugs, and in GTR 201 we'll go through intakes and other bolt-ons. Here, we'll touch on injectors: an item that is for maintenance as well as for upgrading.
Stock injectors are top-feed 440cc injectors. While injectors aren't a frequent failing item, on cars this old it's worthy to see if they've been replaced or upgraded. Build up over time can lead to inconsistent flow and will result in loss of power and terrible fuel efficiency. A general rule of thumb for 6 cylinder engines like the RB is that 1cc would be safe for 1 crank horsepower. So in essence a stock injector can handle 440 horsepower and 1000cc's can handle 1000 horsepower however it is always safe to run your injectors at 80% capacity or less. When it comes to considering injector upgrades for more horsepower, also look into fuel rails. All big horsepower builds will also feature upgraded fuel pumps, fuel pressure regulators, fuel lines, and surge tanks.
Boost is fun and turbo upgrades will always be the core of horsepower gains. Stock R32 turbos tend to fail at 16psi (1.1 bar) so we wouldn't recommend upping the boost too much. Stock boost pressures are as follow: R32 11.5psi (0.8 bar), R33 13psi (0.9 bar), R34 14.5psi (1.0 bar). R32s and R33s featured journal bearing turbos, whereas R34s got faster spooling ball-bearing turbos.
We'll cover popular aftermarket turbos in a later post, and for today, here are the part numbers for Nissan and Nismo offerings:
BNR32 stock ceramic – 89-91 (14411-05U20)
BNR32 stock ceramic – 91-93 (14411-05U21)
BNR32 stock ceramic – 91-93 (14411-05U22)
Nismo BNR32 - 14411-06U00
BCNR33 N1 - 14411-24U10
BNR34 - 14411-AA300
BNR34 N1 - 14411-AA401
BNR34 N1 - 14411-AA402
BNR34 N1 - 14411-AA403
Nismo R1 - 1441A-RSR45
Nismo GT, Le Mans - 14411-RR581
Having a ton of horsepower is useless if you can't get it through the transmission and into the drivetrain. As you go higher in power, you'll need a clutch with more grabbing power. You will have to trade off drive-ability and comfort, but most available options are a still easy to drive on. Early R32s are push-style clutches, 93's and beyond are a pull-type so shop accordingly. While looking into clutch options, you'll want to look into flywheels as well. Generally, the lighter the flywheel, the more freely the engine with rev. Go too light and it'll be too rev happy for regular use.
A popular upgrade over stock is the Nismo Coppermix twin-plate clutch. It's lighter than stock and the "non-competition" model can hold 640 horsepower. The Ogura Clutch twin-plate is a couple of hundred bucks cheaper. OS Giken's twin-plate is a good option as well, and is in the same price range as the Nismo.
We hope this installment was helpful. Hopefully it helps you plan your horsepower goals and equips you with GTR-nerdism. Check back at the end of the week as we give our recommendations on brakes, brake fluid, and lines.