is Light not right?

[Jeremy Blaze]

  Please excuse me for my salt ignorance.

  I know in most other forms of racing, the lighter the better.  Is this true or not with LSR?

 

[Peter Jack]

Within reasonable limits weight is not critical. Often times increased weight helps with traction.

Pete

[Bville701]

I agree with Peter. It usually helps with traction. We ran a firebird that weighed 5K lbs. and the weight helped us keep lots of traction at very high speeds.

[Stainless1]

Weight is good within reason, still need to be able to accelerate to top speed within the required distance.  So balance weight and power.

[Dean Los Angeles]

Lighter is always better until traction rears its ugly head.

Loyd "Hooley" Huffman's Studebaker went through a development cycle that included spinning at high speed because the horsepower came on BANG and high speed loop-de-loops ensued. Adding 800 lbs of weight allowed them to stop doing that and set a record. I think it was something like 1,200 lbs total. Sumner will straighten me out.
http://purplesagetradingpost.com/sumner/hooley/hooley-construction-2006-1.html

[Peter Jack]

Remember too that distribution of said weight can also be rather important.

Pete

[Sumner]

............. Sumner will straighten me out.................

Actually I wish I could straighten the Stude out as we (Hooley) tried to spin it again last year..........

http://www.youtube.com/jp.swf?video_id=uSrGmZC2M1M&eurl=&iurl=http%3A//img.youtube.com/vi/uSrGmZC2M1M/default.jpg&t=OEgsToPDskIdM3ro7UHSuNOqVj4lmsZ5

............... after that run that Hooley qualified on ............... but on this one......

http://www.youtube.com/jp.swf?video_id=VyWUfWaWEDQ&eurl=&iurl=http%3A//img.youtube.com/vi/VyWUfWaWEDQ/default.jpg&t=OEgsToPDskJt-jgG709YPCBCF6T4oIeZ

We were 3000-3100 lbs. the first year when we ran over 200 with the junkyard alky motor and never got into trouble since we were still accelerating and got close to 219 on the 4th run and the last run as we were pumping all the oil to the top end and had no oil pressure.  One lesson learned.

Then next year (2005) we went back and made four runs before blowing a seal in the blower.  I think the best mph was 212 as the course was terrible and we weren't able to get 100% throttle.  We were finally getting the suspension working when the seal blew.  I almost felt good about that as I thought Hooley was really trying too hard and bad things could have happened.

Now we are at 2006 and had a good track and at about 4 miles an hour faster (223) than we ran in 2004 Hooley hit the aero wall and spun the tires ..... resulting in this ............

http://youtube.com/watch?v=CU59SUocJoA

This is a great video of traction problems, how fast it can get out from under you and how fast you should be in getting the chute out.  We were still running the same weight as 2004/2005 (3100 lbs.).  After the spin we added weight that at least we finally had with us.  We added about 700 lbs. and that enabled us to set the record at 236 with a 241 exit speed.

In 2007 we ran good the first day, except for one small problem, forgetting to turn the cooling water on.  After working on the car we got back out Wed. and Thurs. qualified over our record, but the course was really going away.  We had added weight and were up to about 4100 lbs (about 50% -- 50%).  It helped us run a 243 exit speed, but not enough to handle the course on the back up run on Friday (see second video above).  With our current weight we need a perfect course and I think 250+ is possible, but I would like to see us add at least 800 lbs. for this year to give us a cushion if Hooley and John have time to do that.  You can't count on getting a perfect course and 800 lbs. would only get us 400 lbs. on the back for traction the rest is needed to keep the CG/CP about where it is now.

I have more of my thoughts on this on my site ..........................

http://purplesagetradingpost.com/sumner/bvillecar/bville%20-%20LSR%20Thoughts-Index.html

............. pages 3 and 4 if you aren't totally bored by this point.

One thing that seems to be agreed on is that weight will help you on the big end when you hit the aero wall where you overpower the tires trying to get the power to the ground to run the speed.  Personally I think weight can help you at the start of the run with a high power car where you are also overpowering the track.  We can only get 25% to 30% throttle in 1st and 2nd without spinning the tires.  I  think more weight will help us accelerate faster in the first couple gears by getting more HP to the ground.

c ya,

Sum

[GH]

I agree with Sumner, my car #787 weighed about 4200 lbs when I first started racing it, after the change to the turbos, it now weighs 4500 lbs. I get lots of tire spin, I am going to add 500 to 600 pounds more this winter. The car has always went nice and straight.

[4-barrel Mike]

I was recently privy to a conversation between Pete Richardson #1931 (V4/VGC record holder) and Bruce Geisler (200 MPH Club Lifetime Member).  Pete has never run any ballast in his Model A brick and it became evident at World Finals, when he ran a 109.890 qualifying run on Wednesday, and a 107.780 record run into the headwind on Thursday (both at the same RPM) that he needed ballast.

In the discussion of how much ballast and where to put it, Bruce said that they ran 1500# in the 219 Studebaker, all in the rear (contrary to normal usage, but it sure worked well for him).

Mike

[Glen]

Mike
Ask Bruce how many times his car has spun, It is a lot. We use to take bets in the timing stand on which mile.
 

[836dstr]

Jeremy,

As Pete and Sum said distribution and balance are probably more important than the amount of weight. Centered and low is where to start.

The other factor is horsepower and where and how it comes in. A blown and or fuel big block will require more ballast that a small carb'ed car.

Tom

[836dstr]

Jeremy,

I should have mentioned this in the previous post. There have been a lot of discussions on ballast/ center of pressure, etc. in the past on this Site. You just need to go back a ways.

Tom

[Stan Back]

Mike --

Don't you think the 2 mph difference might be due to the headwind against the brick coupe?  We coupled up with a Model A Roadster with a lot more horspower until about 170.

Stan

[Sumner]

I was recently ......................of how much ballast and where to put it, Bruce said that they ran 1500# in the 219 Studebaker, all in the rear (contrary to normal usage, but it sure worked well for him).

Mike

You could run a ton of ballast at the very rear of the car as long as you never spin a tire and if it keeps you from spinning then it might work, but I feel you are taking a big risk.  As soon as you break a tire loose the rear will want to start to come around, especially with a locked rear, and the weight back there is going to act like the weight at the bottom of a big pendulum and just carry the car right on around.  How many arrows with the weight up front have you seen swap ends??

For those of you like Kent that watch NASCAR all the time you see that those cars are loose (back wants to come around) at the start of a run with the weight of the gas back there and then usually tighten up as the run goes on and they burn that weight off.

So the balance ( CG/CP ) is there for when the car losses traction for whatever reason and helps the car go straight so you can recover.

My thoughts and yours might be different,

Sum  

[Sumner]

Mike --

Don't you think the 2 mph difference might be due to the headwind against the brick coupe?  We coupled up with a Model A Roadster with a lot more horsepower until about 170.

Stan

I agree, it is hard for me to believe that running in the 110 mph range would require much weight. 

This spreadsheet will figure the Drag Force on a vehicle, the HP needed to run a certain speed for that vehicle, the thrust and the weight needed on the drive wheels. for a given thrust and speed................

http://purplesagetradingpost.com/sumner/bvillecar/bville-spreadsheet-index.html#Drag%20Force%20--HP%20to%20run%20a%20Speed

........... load the Drag Force --HP to run a Speed -- Thrust -- Weight Needed on Drive Wheels one on that page,

Sum