Most 240Z owners go about weight reduction the wrong way. The spare tire comes out, and the interior carpet gets stripped, and then they stop there. What they miss is about 150 pounds in the factory parts that most owners don't think to replace. Weight reduction beats more power every time - your car will accelerate faster, brake harder and corner with more control.
A factory 240Z weighs about 2,300 pounds from the dealer. An engine built for big power numbers will cost you thousands of dollars and stress the old metal. Weight reduction gives you better performance everywhere, and you don't touch your drivetrain at all. Your best bet is to go after the parts that give you the biggest return and keep your street reliability.
These seven modifications are the exact swaps that experienced builders use. But most weekend enthusiasts miss them. They all show weight savings in pounds (no vague estimates). Most of them can be reversed later if your plans change.
Here are the weight-saving tricks that'll make your 240Z perform better!
Table of Contents
Fiberglass Parts That Save Weight
Fiberglass hoods usually get most of the attention if you hear about weight reduction on a 240Z. The doors and hatches save you more weight. But for whatever reason, they don't get nearly as much attention. A stock steel door on a 240Z weighs somewhere around 35 to 40 pounds each. Replace them with fiberglass versions, and you're looking at just 12 to 15 pounds per door instead.
Each door saves close to 25 pounds on its own. Add the two of them together, and the total comes to 50 pounds right off the car. The hatch is another big place to drop some weight, too. Places like MSA make fiberglass hatches that weigh about 22 pounds less than the factory steel version.
Fit and durability issues are pretty common with fiberglass panels, and it's fair - older fiberglass parts from back in the day earned their bad reputation. Modern fiberglass manufacturing has come a long way since the 1970s, though. The layup techniques are much better now, and the molds produce more accurate results than what was available decades ago.
Most installations are going to need at least some fitting work, though the panels arrive much closer to ready-to-install than what was available decades ago. Fiberglass fenders are something else to look at if you're after big weight reduction. The weight savings from the fenders won't match what the doors or hatches give you. But every pound counts when your goal is a lighter car.
These bigger panels remove weight from the outer edges of the vehicle, and it helps with how the car moves. Without that weight, the car can rotate and change directions much quicker on the road. Just remember - fiberglass won't protect you in a crash the way that steel does.
Weight You Never Notice
Most owners pull out the carpet in a 240Z to save weight. What plenty of owners miss is the layer that hides underneath it.
The seats follow a similar pattern. Those original 240Z buckets pack heavy steel frames inside that weigh 35 pounds each. Replacing them with aluminum race seats like the Kirkey models drops that to just 12 pounds per seat - that's a 46-pound difference for the pair.
The door cards deserve some attention as well. The rear storage bins behind the seats have the same issue, and the original tool kit does too if it's still back there rattling around.
An owner found something pretty wild after his car had been through 40 years of regular drives and road trips - it had collected 8 pounds of dirt and old leaves behind the dash. All that debris had snuck in through the vents over time and settled into the places where you never bother to check. A careful cleanout with a vacuum and some patience pulled nearly 10 pounds of junk out of there.
Interior weight builds up fast because we don't usually think about each component individually. Every piece feels pretty minor on its own. Combine them all, though, and you have a decent chunk of weight you can shave off without ever touching the engine bay.
Lexan Window Swap
Lexan windows are one of the best ways to drop weight from your vehicle. Glass is heavy. Swap out a few panels for Lexan alternatives, and the pounds come off fast. Your windshield has to stay glass, though - that's for safety and legal reasons. The side windows and the large rear hatch are where you want to focus your attention.
The swap saves plenty of weight, and it builds up fast. A 1/4-inch thick DOT-approved Lexan weighs around 3 pounds per side window. Your original glass panels weigh in at between 8 and 10 pounds each. The biggest weight drop comes from the rear hatch glass, though. That single panel alone can save you about 15 pounds.
Lexan does have one downside - it scratches way easier than glass. You'll have to clean it with the right products and a soft cloth each time - no shortcuts here. It's extra maintenance. What you get in return for it, though, is a big weight reduction for your car.
Lexan has a long history in motorsports. Race teams were already doing this on their SCCA 240Zs back in the 1970s. Teams learned pretty early on that it was one of the easiest ways to shed pounds without gutting the whole car or compromising any of the structural strength.
Aluminum Cooling Parts
Headers and exhaust parts are usually the first place that everyone looks when they want to cut some weight on a project car. Most builders skip right past the cooling system, though, and it's actually one of the best places to find some easy wins for weight reduction.
A stock radiator made from copper and brass will weigh between 18 and 22 pounds (the exact weight depends a bit on what vehicle you're working with). Swap it out for an aluminum unit, and you're going to have something that performs just as well (if not better), as it only weighs 7 to 9 pounds. With just one part swap, you've already dropped close to 15 pounds from the front of the car.
The mechanical fan and its clutch assembly are another place where you can save a lot of weight. Those two parts alone add about 8 pounds to your engine bay that don't need to be there. An electric fan setup is much lighter - the whole setup usually comes in at around 3 pounds or so. Weight isn't the only benefit, either. When your engine doesn't have to spin that mechanical fan the whole time, you're going to free up between 5 and 7 horsepower that would otherwise just get wasted.
The overflow tank is another part that's worth swapping out during your build. The stock metal tanks are actually pretty heavy. A plastic racing tank does everything that you need and saves another 2 to 3 pounds at the same time. Add up these cooling system mods, and then you're talking about a real drop in your total vehicle weight.
Remove Weight From Other Car Parts
The stock battery sits up front in the engine bay and weighs about 40 pounds. Relocating it to the rear trunk area and swapping in a lightweight AGM battery will save between 15 and 20 pounds. This swap also helps to balance out the weight distribution across your car, and it makes the car drive better on the road.
The factory alternator is another heavy component that tends to get forgotten about when weight reduction comes into play. Your stock one weighs around 12 pounds. But modern compact alternators come in at just 6 pounds or so - it's a chunk of weight you can pull from the front of your engine bay without giving up any performance at all.
Your wiring harness should be looked at more closely, too. Most 240Z cars still have some leftover wiring from old emissions equipment or air conditioning systems that quit working decades ago. These unused sections are just dead weight at this point. You can remove them safely. But you need to be extra careful about what you're cutting and double-check everything first.
The exhaust system is another place where the factory added more weight than they needed to. A lighter exhaust sits lower under the car, and it helps - the weight down low doesn't hurt how it drives nearly as much.
Most owners forget about bumper support brackets, and they add around 8 pounds of weight that you just don't need. Plenty of owners will remove their bumpers to drop some weight. But then they leave the mounting brackets still bolted in behind where the bumpers used to be. Without the bumpers on there anymore, those brackets don't serve any purpose.
Wheels and Spare Tire Weight Reduction
A stock 240Z comes with steel wheels, and each one weighs between 18 and 20 pounds. Fortunately, you'll find plenty of aftermarket options that weigh quite a bit less - Panasports and Konig wheels are two proven picks that have been around forever, and most of them weigh around 11 to 13 pounds per wheel. Dropping 6 to 8 pounds per corner like that will make your 240Z feel more responsive and quicker to respond. Unsprung weight matters on these cars, and lighter wheels are one of the best ways to improve how your car drives.
Check out your spare tire situation as you make these changes. Most 240Z owners still haul around the full-size spare, the jack and the whole tool kit - that sits behind the rear axle. Pulling everything out drops about 30 pounds from the back of the car. Your weight distribution will get better, and the rear end will feel more stable and planted when you drive hard through corners.
Removing the spare tire does trade away some roadside security. A tire plug kit in the glove box works as a decent backup, or you can have a can of fix-a-flat on hand for punctures. Either one barely takes up any space and weighs almost nothing. The choice depends on what you care about more - saving those 30 pounds or keeping that sense of security that comes with a full spare mounted and ready to use.
Build Your Dream Car
Between all these modifications combined, you can expect to shed somewhere around 200 to 300 pounds off your street-driven 240Z. That might not sound like a big amount at first. But weight reduction is free horsepower, and it changes every part of how the car drives. Acceleration down the straights gets noticeably harder. Turn-in gets way sharper and even more responsive. Even your brakes won't have to work nearly as hard to scrub off speed. These changes add up, and they change how your 240Z performs without ever having to crack open the engine bay.
The best way to approach this is to start with the easy, reversible modifications first. That way, you get to feel what weight reduction actually does for your car, and you won't be stuck with any permanent changes if you go back later. You should keep a basic weight log, too - just jot down each change and how much you removed. Tracking everything like this makes the whole project more rewarding. It's actually pretty satisfying to watch those numbers add up and translate that into performance gains.
Bob Sharp Racing and their driver, John Morton, applied the same strategy to dominate SCCA racing back in the day with their period-correct 240Zs. Weight reduction turned out to be one of the fastest ways to make a race car competitive, and their track success backed up what plenty of racers already suspected. If it worked for championship-winning teams at that level, it'll work for your street car, too.
For anyone working on their own build (maybe you want to cut weight, improve how it handles or just squeeze more performance out of your 240Z, 260Z, 280Z or any other Datsun), at Skillard, we have what you'll need to make it happen. We specialize in custom parts that are made for Datsun cars, and our catalog includes everything from lightweight aluminum door cards and center consoles to performance bumpers and aerodynamic spoilers. Either way, we have the parts that'll work for your build. Check us out at Skillard.com to browse the full catalog and to find what you need.
