240z Upgrades

A lot has changed since Datsun unleashed the 240z and some really great upgrades can be done by an average guy with ordinary tools.

Factory Service Manual

240z Factory Service Manual Before doing anything, get the genuine Datsun Factory Service Manual.

Aftermarket books are OK, but the factory manual has much better procedures, photos, diagrams and data.

You can buy an original printed copy on eBay but they tend to be beat-up and expensive. Find a scanned PDF version online and take it to someplace like Kinko's. Print the entire thing double-sided, then get it spiral-bound. With a spiral bind it'll lay down flat instead of having to be propped up like a regular book. It's well worth a couple extra dollars.

Honda Civic Heater Blower

Honda Civic Blower Motor This is the easiest upgrade you'll ever do. It only takes about half an hour.

The stock blower motor on your Z is old and obsolete. Chances are it's slow and noisy and maybe even squeaks, so replace it with a brand-new motor for an '88-'91 Honda Civic. I found a brand-new motor with the plastic fan already attached for just $38 (with free shipping). Here's how it's done:

Cut the two wires connected to the stock motor. Remove three bolts that hold the motor in the housing. Take the motor out and put the new motor into place - the hole pattern is exactly the same. Splice the wires (after making sure the motor spins in the right direction) and you're done! You can sell the old one on eBay and make your upgrade even cheaper.

280zx Alternator

280zx Alternator This is another easy upgrade. The stock 240z alternator is rated for 40 amps, which was adequate in the 70s for the ignition, wipers, heater and an 8-track stereo. Today, you can get 60 amps from a 280zx alternator, and it even comes with an internal voltage regulator, meaning you can throw that ugly stock one away. I found a new/refurbished alternator (with a warranty) for just $46.

WoodWorkerB did a great description of how it's done (better than I can do), so a link to his webpage is here .

Sound Deadening

240z Sound Deadening Take an empty aluminum can and put a few hex nuts inside. Hold it with your fingertips and rattle it around and listen to how it sounds. Now wrap your hand tightly around the can and rattle it again - it's much quieter. The inside of a Z is basically the same as a can so a good layer of sound deadening makes a huge difference.

The stuff is basically a thin layer of rubber with an adhesive coating. I used FatMat because the top is vinyl instead of aluminum foil like Dynamat (which can cut your hands) and the price was more affordable.

Installation is pretty easy but takes more time than you'd think. You cut the material as needed to fit various places, peel off the paper backing, then lay it in place and use a roller (which they include) to make it stick as tight as possible. Once it's down, it's tough to peel back up. I put it everywhere possible, including under the headliner and inside the doors. I used two layers on the firewall and transmission tunnel.


240z Header A good aftermarket header will increase your horsepower and fuel mileage but don't be led astray by wild claims. It'll take a few hours but can be done by the average guy with some basic tools. Make sure you buy a new gasket and a tube of sealer. Soak the mounting nuts the night before with some PB-Blaster or WD-40. It'll make a big difference.

Take a look at your existing exhaust before starting. Is it in good shape or badly rusted? Are there dents and/or holes? Is the muffler falling apart? If so, you might want to consider buying a complete system. There are some good, mandrel-bent kits online for less money than your local shop can do, and you can easily assemble them yourself, so give it some thought.

Heat Tape

240z Header Heat Wrap You can reduce the temperature in your engine compartment (which provides a slight increase in horsepower) by wrapping your header with heat tape. It's pretty easy to do.

You'll get the best results if the header is off the car but you can stilll do it while it's place - just remove the carbs and heat shield. Get the pipes as clean as possible with a wire brush (or sandblaster) to remove any rust or dirt. Start at the top and slowly wind your way down, overlapping about one-third of the tape with each turn. Use stainless steel "zip-ties" to hold the wrap in place where needed. I ended up using a few hose clamps because I was a little clumsy.

There's a lot of debate whether heat tape is good or not. Some people have told me it'll cause your headers to rust and void the manufacturer's warranty. Here's an article with Hooker Headers, Moroso Performance Parts and Design Engineering. They're in favor of heat tape and the rep from Hooker Headers said nothing about warranty issues. I'll let you decide.

Honda Civic Wiper Motor

240z Honda Wiper Motor A Honda Civic wiper motor makes a huge difference - it moves faster on "slow" than the stock motor does on "high". It can be done in less that two hours and the only tools you'll need for the modification is a drill and a hacksaw. I found a super-cheap used motor on eBay for just $20 with shipping (seriously) and a 12v relay for another $5. I restored the entire mechanism to like-new condition (add two more hours) for another $50.

Look here to see how it's done.

Strut Brace

240z Strut Brace Years of driving can take a toll on a unibody chassis. The pinch welds can only do so much and eventually things start to flex.

A strut brace is a bolt-on stiffener that keeps the strut towers from moving back and forth. It's one of those things where you don't realize how much you need it until you bolt one in place.

The downside is having to remove it when you need to take off the valve cover. There are some braces that use heim joints at each end and the pin holding them in place can be pulled easily, but from an engineering viewpoint those type braces have a flaw - they prevent the towers from moving closer or further apart, but do nothing when the towers are moving in the same direction. I bought one where each end is solidly mounted and should add some additional rigidity. At the center is a threaded adjuster that allows you to put more pressure against the towers or pull them closer together.

Stitch Welds

240z Stitch Welds This is an option that goes along with the strut brace. As mentioned above, the pinch welds can only do so much, so racers often add a series of stitch welds everywhere the sheetmetal overlaps. Typical spots are the strut towers (front and rear) and the frame rails. It requires some grinding to remove the paint, a welder to do the "stitches", and then the area has to be repainted. If your is already finished, it might not be the easiest upgrade here, but it's certainly cheap.

I did a series of small spot welds 1" apart on the towers and rails. Typically the welds are longer but I was nervous about blowing holes the sheetmetal. I'm not sure how much of a difference it will make for street driving, or even the occasional track day, but while I had the car apart it didn't take a lot of time.

Air Dam

Admittedly, an air dam won't make a huge difference around town but I think they look great.

An air dam forces air to go around the car instead of underneath, where it can cause turbulence, which in turn can reduce the top speed. It also has an agressive appearance. Some air dams come with cooling vents for the brakes (like this one), but I opted for the smooth version. They're available in urethane, which is less likely to be damaged if you tap a parking lot block, or fiberglass, which doesn't flex at higher speeds.

It's an easy upgrade, typically only requiring a wrench and a drill and about two hours of time.


240z Spoiler Like the air dam, a spoiler won't make a huge difference around town but if you're planning on any high-speed driving don't get one without an air dam. A spoiler will push down the rear of the car, which means the front will be higher and that can result in more air going underneath and potentially lift the front further, leading to decreased control.

Thankfully that won't happen if you're going less than 100 mph.

It's another easy upgrade. The one I bought only required two holes in the rear hatch. If I decide to remove it later, a pair of black rubber plugs will seal the holes and very few people will know they're not stock.

5-Speed Transmission

240z 5-Speed Transmission

Changing your 4-speed transmission to a 5-speed makes a big difference at freeway speeds. The toughest part might be finding the transmission itself because it's a very popular upgrade. Any Z transmission can attached to any Z engine without an adapter. The support mount underneath is the same and the driveshaft doesn't have to be modified. If you own a '70 or '71, you'll need to slightly enlarge the hole in the transmission tunnel where the shifter passes thru.

You also need to make sure you have the right clutch release bearing and you might have to change a tiny pinion gear to keep the speedometer accurate. Fortunately, you can look here to see how.

Toyota Dual-Piston Calipers

Toyota 4x4 Front Brake Calipers The stock front disc brakes are a single-piston design which works very well for daily driving and the occasional track day. I had no problem locking up the front brakes on my previous '72. However, if you race (or just want to impress your friends), the dual-piston calipers from Toyota pickups is a relatively easy and cheap upgrade. The calipers bolt right into place, but you'll need to trim the dust plate and a larger master cylinder is recommended but not required.

If you want to keep your stock solid rotors, use the calipers from a '79-'85 4x4 pickup. I found new/remanufactured ones for $33 each and a set of pads for $24, for a total of $90 (+tax). Add about $150 if you want the larger master cylinder.

If you want slotted/vented rotors, use the calipers for an '86-'88, rotors for a '85 300zx and a pair of hub spacers. If you want the ultimate best performance, use the calipers for an '89-'95 4x4 or an '89-91 4-Runner.

To see how it's done, look here for step-by-step instructions from WoodWorkerB, or here for the write-up from Driven Daily.

Window Track Rollers

240z Window Rollers If your windows are difficult to move up or down, it's probably because the rollers and washers inside the regulator mechanism are frozen or jammed or broken (or maybe even missing).

To see how to fix it, look here .

Power Steering

240z Power Steering This is something new - genuine power steering for your Z. Instead of the traditional hydraulic system, it uses an electric motor connected to the steering column, which is typical for most modern cars. A clever guy on one of the Z forums made one from scratch and hopefully in the future I can add his design to my site. In the meantime, take a look at one of the kits here .

A Word of Caution

K&N is a great company and their filters increase horsepower by reducing the amount of air restriction compared to a stock filter.

Look at one of their filters. You can see right thru the mesh and foam. Yes, spraying the mesh with oil will catch a lot of dirt and grit, and being able to reuse the filter is great... but a K&N won't come close to cleaning air like the stock filter. Is gaining a few horsepower at the expense of your engine's lifespan really worth it?

The choice is yours.

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