tocho1

Yes, I'm a "big" guy and I like racing...and I keep hearing about the importance of weight in cars but not so sure how do you translate that into time.

Say two similar "fast" drivers, one that weights 250lbs (like me) and another one that weights say 150lbs, race each other in similar cars..what would the time difference be? Does it vary with the track? Does it matter what type of cars they drive? Etc...

I'm not looking for an excuse not to diet, which I need to (), but just curious...

Any thoughts or comments?

Thanks in advance

Juan Lopez

Let's just say that we spend thousands in lightweight body panels to save weight. Why not try to loose weight (God knows I have to...). Its all about power to weight ratio.

NJcroc

A good number of groups weigh the car with the driver, so weight would not matter unless you couldnt get to the weight needed

wanna911

That would only pose a problem with a small co-driver. I can only get to about 210 lbs which would be 3% or so body fat and I'd pass out after lap 1. For some of us there is no hope for being 1XX so we have to count on total weight with the car.

Leh seems to do ok, and he's a big dude, has to be in the 200's, and Dirk Werner (his teamate) is lighter but they are still similar speed. I don't know if they account for that somehow. Personally I don't think 40-50 lbs will hurt you much in short sprints, but only in long races wear consumables wear faster.

Sure hurts me at Andretti's Karting though with the little buggers that weigh 125. I can keep up, but 100 lbs in a kart is like 1000 lbs in a car.

Bryan Watts

Since many (most) racing classes include the driver in the required minimum weight of the car, ultimate weight isn't necessarily a problem. That said, a lighter driver will be able to distribute the weight better in the car, and perhaps have additional weight headroom for larger coolers and more fluids (radiators, oil, etc), driver comfort systems (shirt cooler, water bottle), etc. Further, weighing more likely means you will wear out and become less precise in the car as the race goes on...the G-forces wear on you more the heavier you are. Lighter weight is also an advantage if you crash. I say all of this as someone who has packed on some extra pounds the last few years since I haven't been racing seriously and became a dad.

rcc55125

IF everything were equal and the only difference was 100 lbs. for the driver, it would take an additional 7.8 HP to accelerate the additional 100 lbs. to 100 MPH in 1/4 mile.

HP = Wt x (Vel/234)^3.

Veloce Raptor

In an SRF or open wheel/formula-type car, driver weight is a major factor. In a sedan-type car, not so much, unless the driver is 500 lbs, IMO.







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srf506

Not only getting up to the minimum weight, you can always add ballast, but it's a problem if you can't get down to the minimum weight where a lot of those little skinny buggers are! I don't have to ballast the car up, I have to strip stuff down, including me!

It definitely impacts you for car handling and performance, especially if you're in a spec series in the HP/lbs metric. The bigger that number the better.

Cory M

It all depends what you're driving and if the minium weight includes the weight of the driver:

In my 944 spec my body weight is ~8.5% of the overall weight, but the car is light enough that I am right at the minimum weight requirement despite my size. In this case it shouldn't make a huge difference although if I weighed 100 pounds less I could put that ballast in an optimal location to help the CG and cornerbalance.

In my kart my weight is ~52% of the overall weight and I'm 15-20 pounds over the minimum weight requirement. In this case it is a massive disadvantage, and there isn't really anything I can do about it.

mark kibort

Only if the class weight is with driver like speedGT/Touring. But, in Indy, look at the advantage Danica has with being 90lbs vs 200lb guys! 100lbs trying to get to 220mph is significant, in either a HP measure or rear wheel Torque!
(not to mention cornering and braking)
They should toss Mika into Danicas car for her races to make it fair for the big men of the series.

mk

Veloce Raptor

Um....not true. A hugely heavy drover is much worse for center of mass, etc. than ballasting to the same total weight, or than a light drover in very lightweight or underpowered cars, IMO.






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SundayDriver

So are you getting ready to run SRF? You seem to mention it a lot all of a sudden. Fun class. BTW - the weight in SRF is with driver (as are the other SCCA classes) so driver weight is not always a big deal. In some classes, like DSR, no one seems able to get to min weight so driver weight makes a real difference. In SRF, unless you crash a lot (and have a lot of repair material built up) not so much.

If you are planning on racing SRF, my advice is - Go Long Bondo.

Bob Rouleau

To meet minimum weight carry ballast is better than body mass since the ballast will be placed low and in a location which helps improve the balance of the car.

Veloce Raptor

Sunday: I have raced SRF's, including in a 6 hour enduro, and thought it was the most pure racing fun I have ever had.







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Veloce Raptor

Yup, you posted this as I made post #11.







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