Weight Reduction can be a game changer if treated respectively. It can easily be the difference between a 10 second car vs. a 9 second car as it directly affects the vehicles overall acceleration. The rule of thumb that is for every 100lbs. you remove from your car, is a .1sec improvement in your 1320 E.T.’s. If you remove 500lbs., that is a half of a second in your quarter mile time.
The biggest pro in removing weight is that it is essentially free. Of course you can only do so much without spending any money. In some weight areas, you will have to buy a lighter version of what you plan to replace. A lightweight aluminum racing seat would be a perfect and costly example. But, some weight can be removed for free like your carpet or AC system. Any weight that you can remove for free is essentially free horsepower in terms of drag racing. I say free horsepower because…it kind of is, and I’ll tell you why.
Words By: AJ Hunsinger // Images By AJ Hunsinger
I love Bench Racing, especially when we are Weight Bench Racing. Even basic Bench Racing takes precision skill, much like a Colonel in the military planning out war tactics. Weight Bench Racing takes things to a whole new perspective. We have all heard the term“Power-To-Wight Ratio” (PTWR), a simple number you get when you divide your HP by your vehicle weight, but have you ever heard of Weight-To-Power Ratio? Probably not. The two are basically the same exact thing, but are two completely different tools as they give you different information. A different “formula”, if you will.
Lets say my 1G weighs in at 2730lbs and produces 400HP. If we divided 2730lbs by 400HP, we get a Weight-To-Power Ratio (WTPR) of 6.825 lbs./HP or PHP.
(Vehicle Weight) / (Vehicle Horsepower) = (Weight-To-Power Ratio)
2730lbs. / 400HP = 6.825PHP
Now, if I removed weight out of my 1G and then it weighed 2500lbs, I would have a different Weight-To-Power Ratio. So, lets do more math.
(New Vehicle Weight) / (Vehicle Horsepower) = (New Weight-To-Power Ratio)
2500lbs. / 400HP = 6.25PHP
Now we take the old weight and divide it by the new Weight-To-Power Ratio.
(Old Vehicle Weight) / (New Weight-To-Power Ratio) = (New HP)
2730lbs. / 6.25PHP = 436.8HP
Lastly, we subtract the old horsepower from the new would-be HP.
(New HP) – (Old HP) = Gained HP
436.8HP (lets round up to 437HP) – 400HP = 37HP
What does this mean? This means that I would have to gain roughly 37HP to achieve the same thing as removing the 230lbs I just removed from my 1G. Then if you think about how much money it would take to gain 37HP more than I have currently in this example, you could easily be talking hundreds of dollars. Even a $300 upgrade for cams would struggle to net you 37HP in some instances. And here I just allegedly achieved the same results in performance by spending zero dollars in removing free weight from unnecessary items in my 1G.
When I say “it adds up”, I really fuckin’ mean IT ADDS UP! I don’t know about you, but I like me some free horsepowers! Of course, some weight reduction items will cost you some money too like I said earlier. But with a stock full weight car, you can literally loose several hundred pounds of weight that wouldn’t cost anything at all or maybe a few bucks. I would imagine gaining 50 would-be horsepower could be achieved easily. That, that is crazy.
A factory 1G AWD weighs around 3200-3300lbs roughly. When I weighed my 1G after I built it, it weighed 2730lbs by itself. Let’s say mine weighed 3300lbs when it was once completely stock. Then I built it and didn’t take weight reduction into mind, and used only horsepower adder parts, dynoed it at 400AWHP, and didn’t remove any weight. Then, I did work on weight reduction and I knocked the weight down to 2730lbs while maintaining that 400AWHP.
That is 570lbs total in weight savings. Using the above formula, my performance gain from removing that 570lbs at the same 400AWHP would be equivalent to a gain of 128HP. Mind……BLOWN! This is the exact reason why my 1G is on another major diet. My goal is to be down into the 2500lb range, or better. This will just further increase that estimated number of 128HP.
The truth is, removing weight from your car for free and spending $0 could have the same effect in performance gains as spending hundreds or even thousands of dollars in performance parts that increases horsepower would. Known as: free horsepower.
Of course, you will always have that one redneck that’s always saying “Oh, I’d rather just make more horsepower than remove the weight.” Ok…but even after you make more horsepower, there are still performance gains to make on top of your “more horsepower”. Making more power doesn’t mean the weight no longer applies. It does, it’s still a factor to consider. Like…LOL! When your 800HP full weight race car gets dragged down the 1/8th by a gutted 600HP car, don’t bitch.
Removing weight from a car you are trying to make fast is hella more efficient than just cranking out more horsepower to achieve the same goal. Gas mileage and wear and tear are two perfect examples. The engine would work harder pulling around more weight and would use much more gas than if it were hauling less weight. You’re brakes would wear quicker slowing down a heavier car than the same brakes slowing down a lighter car. Less engine wear as the engine wouldn’t have to work harder under ANY condition. The drivetrain wouldn’t work as hard. You see where I am going with this?
This is a large reason why our 25 year old DSM’s can take on all of these newer model exotic and muscle cars. Manufactures now find it difficult to meet today’s expected levels of safety, comfort, and noise suppression without gaining weight. So, all the newer cars roll out of the factory with some insane heavy weights. And even though they come stock with 573HP, they weigh as much as a 1977 GMC pickup truck, so our bolt-on, slightly weight reduced, daily driven DSM can put buses on them. And if you also consider their price tags and compare them to the price of a DSM? Well shit. That sure as hell isn’t efficient.
Let’s do another comparison, this time between two DSM’s. Same car, different power levels and weights. Both owners want to run 10’s, which is quite a feat. One owner builds his DSM using an HX40 making 650HP and his car weighing 3100lbs. The other owner says, “Fuck all that jazz, I’m going to run 10’s on a 16G at 400HP while my car weighs 2600lbs.”
This has happened. It does happen. And it will continue to happen. Same cars, same goal, different paths, and usually different budgets.
Now, obviously if you are looking to remove weight in your daily driver, you wouldn’t remove some of the things you would if you were removing weight on a full out drag car. Use common sense when making the decision to remove something from your car based on what the car will be used for. Some things apply to one car, but not another, as well as the characteristics of the owner/driver.
Some of us can’t live without power steering and won’t remove it, even in an 8 second car. Some of us hate power steering and have deleted it in our 300HP daily drivers. Be smart about what you remove. If you’re willing to remove something that provides a safety benefit like a front bumper support, but not willing to give up you’re radio, congrats- you are medically insane. Also, don’t be dumb and remove you’re emergency brake to save weight but install a 45lb rear sub woofer.
You can use this Weight-To-Power Ratio formula backwards to see how the effects of adding weight would hurt your cars performance as well. All of this is very simple algebra.
Moving on, I have put a large list together of various different tasks and items you can remove in order to shed some weight. I will break up the list into three different stages of weight reduction. In the near future, I will try to add an exact/estimated weight or weight savings number. Enjoy!
Green denotes FREE-$1
Orange denotes $1-10
Red denotes $10+
Remove Floor Mats (up to 13lbs.)
Remove Spare Tire (up to 30lbs.)
Remove Factory Jack & Tools (up to 30lbs.)
Remove Cargo Cover (up to 5lbs.)
Remove Carpet (up to 30lbs.)
Remove Interior Plastics (up to 50lbs.)
Remove Hatch Plastics (up to 16lbs.)
Delete Emissions System (EGR, Charcoal Canister, Vacuum Lines, etc.) (up to 20lbs.)
Delete Firewall Solenoids (EGR, Purge Control, Fuel Pressure) (up to 20lbs.)
Delete AC System (up to 35lbs.)
Delete ABS System, Install SS Braided Lines (up to 45lbs.)
Replace Clutch Line Assembly with SS Braided Line (up to 5lbs.)
Remove Timing Belt Covers (up to 4lbs.)
Remove or Replace Spark Plug Cover (up to 1lbs.)
Upgrade Cooling Fan with Slim Fan (up to 10lbs.)
Upgrade Flywheel with Lightweight Aluminum Flywheel (up to 10lbs.)
Remove Front Crossmember Brace (if applicable) (up to 13lbs.)
Delete Cruise Control System, Install Non-Cruise Cable (up to 16lbs.)
Delete Power Steering System (up to 30lbs.)
Remove Exhaust Manifold & Other Heat Shields (up to 7lbs.)
Upgrade Radiator with Aluminum and/or Smaller Radiator (up to 20lbs.)
Remove Intake Manifold Support Bracket (up to 2lbs.)
Upgrade Wheels with Lightweight Aftermarket Wheels (up to 45lbs.)
Remove Battery Support & Mount, Relocate Battery onto Sub Frame or Hatch (up to 20lbs.)
Upgrade Battery with Lighter Battery (up to 30lbs.)
Remove or Replace Front Bumper Support, Install Tubular (save up to 35lbs)
Remove or Replace Rear Bumper Support, Install Tubular (save up to 35lbs)
Remove Door Panels (up to 30lbs.)
Remove Headliner (up to 5lbs.)
Delete FIAV, IAC System (up to 4lbs.)
Delete Balance Shafts, Install BSEK (up to 22lbs.)
Delete MAF, Install Speed Density (up to 5lbs.)
Remove Windshield Wiper Fluid Reservoir(s) & Lines (up to 30lbs.)
Remove Windshield Wipers Assembly, Front & Rear, Install RainX (up to 30lbs.)
Delete Hood Latch Assembly, Install Hood Pins (up to 30lbs.)
Delete Hatch Latch Assembly, Install Hood Pins (up to 30lbs.)
Remove Radio Antenna Assembly (up to 20lbs.)
Remove Door Locks (up to 5lbs.)
Remove Hatch Lock (up to 3lbs.)
Remove Radio, Speakers, Factory Amp (if applicable), Wiring (up to 30lbs.)
Gut Doors (up to 40lbs.)
Remove or replace Passenger Seat (up to 30lbs.)
Remove Passenger Seat Belt Assembly (up to 35lbs.)
Remove Rear Seat (up to 30lbs.)
Remove Rear Seat Belt Assembly (up to 25lbs.)
Replace Driver Seat with Lightweight Aluminum Seat (up to 30lbs.)
Replace Driver Seat Belt Assembly with Racing Harnesses (up to 35lbs.)
Remove Head Lamp Assembly & Wiring (up to 10lbs.)
Replace Sunroof Glass with Lightweight Plug (i.e. Carbon Fiber, Aluminum, Fiberglass) (up to 10lbs.)
Remove Sun Roof Assembly, Add Sheet Metal (up to 20lbs.)
Wire Tuck, Depin Unused Wiring, Fuse Box Relocation (up to 30lbs.)
Remove Dash, Metal Supports (up to 20lbs.)
Remove Center Console & Supports (up to 11lbs.)
Remove Exhaust & Hangers, Run Front or Hood Exit (up to 60lbs.)
Remove Pop Up Headlight Motors & Misc (if applicable) (up to 30lbs.)
Remove Sound Deadening on Firewall, Front an Rear of Firewall (up to 10lbs.)
Remove Sound Deadening on Chassis (use Dry Ice) (up to 30lbs.)
Remove & Cut Spare Tire Hump/Hatch Floor (up to 5lbs.)
Remove Full AC System (up to 35lbs.)
Delete Heater Core & Hoses (up to 30lbs.)
Remove Defogger Relay (up to 2lbs.)
Replace Big Brake/Dual Piston Front Calipers with Single Piston Caliper Assembly (up to 8lbs.)
Upgrade Brake Rotors with Drilled & Slotted (up to 20lbs.)
Remove Ignition Assembly, Install Push Button Start (up to 3lbs.)
Remove Passenger Air Bag (up to 13lbs.)
Remove Full Air Bag System (if applicable) (up to 50lbs.)
Remove & Drill Out Spot Welds for Rear Seat Support (up to 8lbs.)
Remove & Drill Out Spot Welds for Rear Seat Belt Mounts (up to 2lbs.)
Remove & Drill Out Spot Welds for Hatch Latch Supports (up to 2lbs.)
Remove Rear Speaker Mounts (up to 3lbs.)
Replace Roll Stop Motor Mount Bracket with Tubular (up to 15lbs.)
Remove Splash Guards (up to 9lbs.)
Remove Hatch Struts (up to 5lbs.)
Upgrade Gas Tank, Install Fuel Cell (up to 40lbs.)
Remove Gas Fill Door and/or Latch Assembly (up to 9lbs.)
Gut Hood (up to 12lbs.)
Remove Emergency Brake Assembly (up to 15lbs.)
Remove Spoiler Assembly (up to 10lbs.)
Replace Window & Hatch Glass with Lexan (up to 40lbs.)
Replace Fenders, Doors, Hatch with Carbon Fiber (up to 60lbs.)
Remove Front & Rear Sway Bar (drag racing only) (up to 25lbs.)
Remove or Replace Power Windows, Install Manual Window Cranks (up to 5lbs.)
Replace 91-99 Transfer Case with 90 DSM Transfer Case (uses an aluminum cover/housing, weighing 8lbs. less than 91-99 Transfer Cases. Requires the use of a 22 spline output shaft to make it work)