The Great L28 Turbo Guide: Converting a Non-Turbo L28 to Turbo

Why Convert Instead of Swapping in a Turbo Engine?

Turbo Zs were rare to begin with: Simeo cites a forum post saying Nissan built about one turbo Z for every ten non-turbo cars. Many of those have since been wrecked or blown up, so complete turbo engines are getting hard to find, and the ones that turn up were often driven hard. Converting the engine you already have is often the easier path.

Can it be done? Yes. That's the question asked most often on the forums, and the answer is yes.

Is it safe? Nissan did it themselves. As Tony D put it, "It's called the L28ET." (Turbocharging the L28 safe?)

Is the old information still good? Tony D says nothing has really changed since about 2002, when MegaSquirt became available to solve the problem of programmable fuel and ignition with the stock ECCS. Apart from higher parts prices, the old forum threads still apply.

Using the Stock N/A Engine

The block: the stock N/A block works. Later blocks have siamesed cylinders, which are said to add rigidity, but Nissan later stated there's no difference between siamesed and non-siamesed blocks.

Four things to think about with the stock N/A parts:

• Head: the late-model P79 and P90 heads are the ones to have, for their exhaust port shape and larger combustion chambers. They help but aren't required.
• Compression: N/A engines have higher compression, which can cause detonation problems at high boost (over about 11-14 psi). Lower the compression and upgrade the fuel injection to stay safe. A 2 mm head gasket should bring compression down to about 7.8:1. You can work out your own numbers with the Atlantic Z Club L-series engine calculator (choose L28 from the engine list and click Calculate).
• Intake manifold: the N/A intake is considered restrictive. For high boost you'll eventually want a custom manifold or a ported and shaved stock one.
• Cam: the stock N/A cam is fine for low boost, up to about 250-300 hp. Past that, you'll want an aftermarket turbo cam. Before buying one, ask the manufacturer whether that cam works with your head.

Parts Lists

Two ways to go, from NismoPick's N/A L28E to turbo parts list on ZDriver.com (the original thread has more detail).

Option 1: The Thorough Route

More expensive, but more complete and more reliable. These are turbo parts from a 280ZX Turbo:

Optional parts that make the job easier:

• Intake manifold
• AAC / EGR actuator pump (only if you want those to work)
• AFM-to-turbo accordion boot
• Thermostat housing with all its sensors
• Cylinder head temperature sensor, if your chassis doesn't already have one
• Throttle position sensor (the N/A sensor has 3 pins, the turbo sensor has 2)

Option 2: The Budget Route

• Exhaust manifold
• Turbocharger
• Downpipe
• Oil feed and drain lines
• Oil tee from the oil pressure sender
• Turbo injectors

The budget route also means some fabrication:

• Oil drain: drill a hole in the left side of the oil pan and weld on a bung for the turbo oil drain.
• Exhaust: make an adapter to join the 2.5" downpipe to the stock 2" or 2.25" exhaust.
• Intake: make the pipes and couplers that carry the boosted air from the turbo to the throttle body.
• PCV: depending on the engine's year, the intake PCV valve is probably right where the turbo outlet needs to go. Cap it and move the PCV, or fit a very tight 90° bend.
• Steering box: on chassis with recirculating-ball steering, trim the turbo's wastegate bracket to clear the steering box.
• Tuning: adjust the AFM and timing to keep the air/fuel ratio in a safe range.

A Finished Conversion: bonfire79's 1976 280Z

bonfire79 (Bon) converted a 1976 280Z using mostly the original N/A parts, some of them modified. Bon's main advice: decide early whether you're doing a full turbo swap from a 280ZX or a conversion. Either way costs money, and the fuel system electronics have to match each other.

Bon's setup:

Bon reports the car is far quicker even at the stock 7 psi of boost. Bon has heard you can run more boost safely on a conversion like this but wouldn't push it, since stock boost is plenty for most people.

Sometimes the full swap is easier, because everything already matches. If you'd rather swap in a complete L28ET, see this L28ET turbo swap write-up.

More Reading

These are the links collected in the thread. They were posted in 2015, so some forum pages may have moved.

Guides and Write-ups

• Atlantic Z Club: Z car turbo tech tips
• HybridZ: The Ultimate Turbo FAQ / Beginner's Guide
• HybridZ: L28 EFI problems? EFI Bible, step 1-A (sort out the stock EFI first)
• ZDriver.com: My N/A to turbo swap (see post #3)
• ZDriver.com: Aftermarket cams, cam removal and installation (with pictures)
• L28ET turbo engine swap write-up

Fuel and Ignition

• DIYAutoTune: How to MegaSquirt your Nissan 280ZX Turbo
• zcar.com: How to install MegaSquirt and spark
• HybridZ: Pallnet aftermarket L28 fuel rails
• For a 1981-83 280ZX, also see our EFI Upgrade Guide - S130 to Z31

Video: Godzilla Raceworks' installation instructions for their MegaSquirt 2 plug-and-play engine management for the 1975-83 280Z and 280ZX.

Other zcar.com Threads on the Subject

• N/A L28 to turbo conversion question and parts list
• 260Z turbo conversion (L28ET)
• 300 hp out of an L28E N/A with a turbo
• S13 to 280ZX transmission swap
• Going ahead with a stock N/A turbo swap (update)
• Turbo on an N42 block

Looking for a bolt-on kit? Simeo's thread notes that retro turbo kits for the N/A L28 have been sold, such as the one from Turbo Tom.