good hands

I recently had a discussion with another racer that said each 100lbs of increased or decreased ballast on approximately a 2900 lb car is equal to 1 second a lap at my home track of Summit Point. I found that hard to believe.

I realize there are many factors on what makes a car faster down the straight ( aerodynamics, speed at corner entering straight, gearing etc. ) but I have found consistently that cars with the same supposed HP to weight ratio but start with more HP and then add ballast seem to pull me on the straights...... So is adding weight really an equalizer ?

kurt M

Weight hurts most in the corners. Weight does not change things evenly around a track. You might see 1 second drop off but the second might all be lost in corners with little change on longer straights. This was my beef with the new GT rules. Add weight to a big hot $$$ motor/car combo to have the highest HP in a class. Anyone can work a pass in a HP drag race and then be a fat wide *** pig in the next corner.

If you need to win in class figure out which car is best and buy the right car for the class. Most every class has a car that is the sweet spot.

Bolt a 200# instructor into the right seat and see what happens to your total lap times and to your T.V. at the end of long straights. .

M758

Weight hurts plain and simple. Now the arguement is always how much weight is right weight. The is never a clear answer on that. Weight will make a car slower in theory, but in pratice might help a unbalance car achieve balance such that it is faster due to improved balance vs extra weight. However you go to a different track and the impact will change. However I never subscribe to the idea that 100lbs = 1 second or stuff like that. It is far too complex for that.

Now two cars with same power/weight are not going to be making the same lap times on track. Their are too many other factors. However when you are on track also realize that how well you get out of a corner makes a huge difference. Heck even aligment makes a difference as well as weight of tires. This past weekend I was racing another spec car. We had the same hp and same weight (with in 20lbs) and was killing him in one area on the track. I was using a different line and this gave me more exit speed so I would appear much faster on a straight section of track. To some it may look like I had more hp or less weight. In fact it was all due to corner exit speed. This was clear when you look at another straight on that track where we were dead even on acceleration.

Lemming

background here http://www.nasaforums.com/viewtopic.php?f=44&t=28149

Bob Rouleau

If ballast can be placed at any location in the car, then being underweight and ballasted is an advantage. Some classes dictate where the ballast can be placed to prevent it being an advantage due to a lower center of gravity for example.

I do not subscribe to 100 lbs = 1 second. Fact is, it varies but I do believe that light weight plus ballast makes for a better handling car.

analogmike

I am looking at a Bonneville top speed car, and they ballasted it to make it FASTER...

Brian P

I'm sure that being underweight and ballasting is an advantage, but I doubt it's a huge advantage (at our level). I.e., in most cases the better driver is going to overcome the ballasting advantage.

A long time ago, I did a regression analysis of class winners at Watkins Glen and came up to the conclusion that 10HP was worth about a second and 100 pounds was worth about a second. The one thing to realize is that there was a TON of variance in that equation. In other words, driver skill is going to far outweigh this simple equation.

For example, as we all know a good driver can overcome huge HP differences. In addition to that, some drivers may think they are driving at the limit, but they are really only driving at their own personal limit. In these cases, changing the amount of weight in the car is not going to make a big difference. They are going to corner at almost the exact same speed and probably have the same braking points. The only difference weight will make is in the different acceleration capabilities.

Bob Rouleau

I guess I should have added the (obvious I thought) "all else being equal".

Jim Child

I suspect they added ballast to keep it from taking off. You can't break any speed records if you can't keep your driven wheels on the ground.

Brian P

Sure, but my point is that unless the driver is driving at the car's limit, then he probably won't observe much difference in lap times due to weight changes. However, if the driver is driving at the limits, then the lap time changes are easily observable.

So, even with "all else being equal", the effect is still driver dependent.

2BWise

Its easiest to see in touring cars where they add success balast to even the field. Top drivers in top machinery in a sprint race format. Ultimate lap time is only slightly diminished, but the big disadvantage is in tire degradation. After a few laps drivers with success balast usually start falling back little by little as they start to overwork the tires. Depending on the car and driver some can drive around the weight penalty and still finish up front, but it always makes for a more exciting race as it brings him closer to his competition. And usually with touring cars the penalty ranges from 20-60 kg, which is in the range of 100 lbs.

mark kibort

Thats a entire different animal!

balance and grip can be gained with ballast at Bonneville. weight just means it takes longer to get to top speed, at a slight increase in rolling friction but at Bonneville, thats what you want. Grip is at a premium. My WR setting stock class production car went 172 at Bonneville and 180 on pavement at Nardo, Italy.

As a note, i finally got a chance to test this theory with 200lbs. It cost about 1.5 seconds at sears point, ca. It was a open track time trial sesssion I was doing for fun and giving rides in the race car. So, I could take a few open laps with no traffic, blast into the pits and pick up a passenger and then hit it again. all things were very equal. I pushed pretty hard to equal my prior times. 1.5 seconds was the best I could do. However, I know if that weight was lower and strategically in position, and I didnt have to worry about freaking out the passenger, Im sure I could have shaved .5 seconds but it would have been on the edge.

chrisp

Wouldn't aero drag play a role?

If two cars have different aero but the more aero one has been ballasted to an equal hp/weight, the aero car would be faster on the straight in both accleration (assuming a somewhat high exit speed for the previous corner) and top speed.

FredC

Chris, don't tell me that you have to add balast!!!!! See you in 2 weeks.

chrisp

No worries...I've been adding ballast all winter.