Cheapest Way to Go Faster, Oct 2011 Gearhead Answers

Your answer that weight savings are the cheapest way to go faster is only true for weight savings that are free. Removing A/C, stereo, carpet, etc. are all great ideas and are free for the taking. However, suggesting that swapping out lighter parts is a cheap way to go faster is incorrect. For example, a third gen fiberglass hood costs about $300 and saves about 20lbs. A carbon fiber hood is about $1000 and saves an additional 5 lbs. As you can see there are diminishing returns. If I spend that same $1000 on a quality nitrous system with a modest 100 shot I've dramatically changed the PWR and will have a much larger gain for the same amount of money. Using the corvette example and being generous with the weight changes.

c6 Corvette w/ carbon fiber hood: $1000: 3133 - 10 (for carbon fiber hood) / 505 = 6.18 lb/hp
c6 Corvette w/ 100 shot nitrous: $1000: 3133 + 40 (for nitrous system) / 605 = 5.4 lb/hp

Weight is the enemy of speed so take all the cheap weight off you can (I'm sure I have 30 lbs of driver weight to shed.) But once money is involved, it soon becomes a very expensive way to go faster, just like adding more horsepower.

Jay Hoskins, Rockford, IL  

Hey Jay,
Good point, and you're right on the HP/$ formula; but that only takes straight line acceleration into account.

Our stance on getting the best all-around returns for a car by dropping weight is based upon reducing the mass that forces are acting upon. For example, that nitrous system won't help you brake faster or deeper into a corner (possibly eliminating the need for upgraded brakes), but that carbon fiber hood along with dropping other dead pounds probably will while also working towards acceleration.

Of course the answer will always depend upon your specific goals for your car.



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Christopher Campbell
Technical Editor
Popular Hot Rodding Magazine

Hi Christopher,
I do more road racing than drag racing so I was considering all aspects of performance. I race a 88 Camaro in American Sedan class. Our minimum weight is 3000 lbs. and I still have around 300-400 pounds to take off.

My only point is that it won't be cheap to shave off the rest as I start replacing body panels with fiberglass. I also will only get a modest PWR improvement.

To your point, I also race a E production 240Z which weighs in at 2200 lbs but only has about 200hp. It has braking points a couple of markers beyond the Camaro and gets around the track with about the same lap times. It also goes through the turns faster and generates more G's. In many ways it's more fun to drive because it is so light.

If your familiar with NASA racing they use the Power to Weight Ratio for their muscle car class as the limiting rule. Racers in that series need to decide if they spend money on new heads or lighter wheels. It would be interesting to see if the heavier, higher horsepower cars do worse than the lighter, lower horsepower cars. My gut says the lighter cars should win, but alas, I don't have the science to prove that.  

So we do agree that weight is the enemy of speed and a significant factor of the price/performance equation.

Jay  

I think you're underestimating the power of the cut-off wheel my friend! You'd be amazed how much dead weight you can remove from the unibody- especially if you have a good cage installed.

Also, sell those steel panels you take off to offset the cost of glass or CF.
On the flip side, you can also make your own panels. Stay tuned to PHR to see how it's done.

I am familiar with NASA & SCCA rules. Kertz Fabrication & CorteX Racing, the two companies helping put project Max Effort together, maintain several cars that run in the American V8 SuperCar Series and I've had a chance to be up close and personal with them. Their main goal is always less weight- sprung, unsprung, and rotational.

Now in your case where there is a horsepower/lb limit, the choice will come down to the layout of the course. If its wide open with lots of long straights go for more hp and more weight. If it's tight with lots of kinks and chicanes, opt for less power and less weight.



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Christopher Campbell
Technical Editor
Popular Hot Rodding Magazine

jhoski 1st off welcome to the CC forum... N20 will only be good for how ever long the bottle is charged, the lightening of the car is every lap or every pass not just when the bottle is full, don't get me wrong, I have used the N20 for many years now, but taking weight off the car any were will help for the hp/weight ratio & after all that's what your doing by adding bottle power albeit temporary, it can be expensive at times depending on what your working on, but reducing reciprocating & sprung weight will benefit you the most long term... lightweight rims & tires, lightweight suspension components, aluminum - carbon fiber or titanium parts to replace steel were ever possible also will help, lightweight brakes & drive shafts... Speed is pretty much relative to cost! (to an extent) how fast do you want to go? how much do you want to spend? those are the questions you need to ask your self, then live with your ultimate decisions of were you choose to spend the money... Good luck with your ventures in performance & speed...  
"Fill Your Library Before Your Fill Your Garage"  3836bbl alias Budnicks

Jay, if you are "going in circles to find the finish line" as drag racers tease the circle racers, chances are, I'll assume, Nitrous isn't allowed, but losing weight until meeting the minimum requirement, then spreading it to where it'll do the most good in a car, is.  also, a carbon fiber hood doesn't burn the piston tops  

on the flip side of the equation, "speed costs money, how fast ya wanna go kid?"    once you've done the cheap things (tune, cut up the car, etc), then you run into money chasing after a tenth here and a tenth there.  
Just because you can't do it...doesn't mean its impossible

It's all relative to money, it always come down to how to spend your money most efficiently, "lighten car 1st" it make everything you add after that work better...  
"Fill Your Library Before Your Fill Your Garage"  3836bbl alias Budnicks

While waiting for power to return, I was reading a 1967 issue of HotRodMag,Bud Moore was talking about how some of his NASCAR Fairlanes were running 427 blocks with 361 truck cranks for 396 cid (imagine the breathing comparted to a Chevy 396).  the reason, on short tracks like Riverside, was the smaller engine allowed for a lighter car, which meant fuel economy...and pit stops were even back then, a way to lose a race.

so, weight loss on a race car may help the fuel economy, which on a track with few straightaways, the fewer pit stops may offset the lower top-end HP that gives you speed on those straights.  Lower weight loss may help acceleration off the curves, which could also help the racecar get up to speed sooner and leave the pack behind by the next corner, allowing for a better path into the brake zone and apex.

just a thought...  
Just because you can't do it...doesn't mean its impossible