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Let's talk about weight

Joined
30 November 2000
Messages
59
Location
Prescott, AZ, USA
In a current thread which discusses the relative qualities of an NSX and BMW M5, a number of wagging fingers have been pointed at the M5's 4000 lb weight. I'm a little puzzeled by this. Not only is the porky M5 as fast as the latest NSX in acceleration, it is within a tick in skidpad performance (.90 vs. .91) and very close going through a slalom (64.7 vs. 65.8). In fact, according to data in Road and Track, the heavy M5 is quicker through the cones than an M Roadster or a Porsche Boxster. It is also interesting that the new 580 hp Lamborghini Murcielago, which everyone whould agree is a sports car, weighs as much as an M5 (4020 lbs). I'm sure there are other examples of extremely high performing cars that weight over 4000 lbs.

My question to all gear-heads out there is this: If the power to weight ratio is held constant, will a lighter car always be faster in the corners than a heavier one? I think weight alone is not the critical factor here- suspension and tires are. Am I right or wrong?
 
To grossly oversimplify, power-to-weight ratio is incredibly important to acceleration at low speeds (e.g., 0-60) where aerodynamics don't dominate. At high speeds, HP and Cd*A are much more important. And powerful heavy cars require incredibly good throttle modulation so as not to liquify the tires.

I just spent last week driving > 100 HP and < 1100 lb. cars around Laguna Seca and I personally think that the lightweight cars are much more nimble and fun. Heavy cars can be made fast, but not nimble - just the laws of physics in conjunction with the state of the art in tire technology...

--twc
 
One thing that gets overlooked in tests is how a car preforms thru a section of turns. The magazines can test on skid pads & slalom courses all day long, but when your on a section of a road course of varied radius turns with equal pwr/wght ratio's the lighter car will out preform most generally because of less body roll and lower center of gravity in addition to weight. A good driver can hustle a heavyer car through a series of turns and may be able to hold his own against a lighter car and then pull'em coming out of a turn to a straigh portion of a road course. I would guess an M5 would hold its own due to their suspension and weight distribution alone, but I would bet you a driver of an NSX or similar weighted car work work less. Several years ago at Heartland Park (Topeka, KS)which is a 2.4 mile road course a 125cc gearbox kart was timed in a section of the track and was faster in time to a 911. Don't know the percentages as far as pwr/weight but the kart was about 1/2 HP per pound. Of course the 911 would dust a kart down the 1/2 mile straight. Dramitic illustration yes, but you get the picture.
 
Case in point - "The Get a Grip" write up in June 2002 Road & Track will help to answer the question you have asked. They use a GPS system to track corner entry speeds, speed at breaking points; apex speeds, corner exit speeds, and segment times. When you break up any track/cornering event into small pieces you can learn what effect HP, torque, weight, corner grip, and driver can really have. One of the most interesting things to compare is the Lotus Elise, Corvette Z06, and the 360 Modena.

After reading this article the one thing that I could not believe is that the NSX was not included. It just goes to show you that Honda/Acura did not do enough to excite the press (or update the car) when a handling article includes a Mitsubishi Lancer (not even available in the US) over a NSX.

Dave
 
when a handling article includes a Mitsubishi Lancer (not even available in the US)

Dave[/B]

Go to your local Mitsu dealer, they should have some sitting on the lot. Pretty good performance for the price (start under 14k)



------------------
1994 Red/Black NSX #418
 
The Lancer sold in the States is an inexpensive, low-performance (120 hp) subcompact. Think cheap.

The Lancer sold in other markets (notably Asia) includes some models not available here, some of which have pretty decent performance.
 
The Lancer EVO VI Extreme has 340hp!
eek.gif


You can check it here: http://www.mitsubishi-cars.co.uk/

It is on sale for about 40'000 UK£ = 75'000 US$.
 
I have a 17MB Windows Media Video file (.wmv) that has a Lancer drifting rally-style at every single turn on a paved road course somewhere outside the US. =)

Good video. Must see. (He eventually has an incident.)

If any one has some server space, I can send the file over.
 
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