Visit The Dirt Forum for More Information

Author Topic:   Pendulum Effect
flywheel
Dirt Full Roller

Total posts: 28
posted July 27, 2003 12:01 PM  
Ok, I put 50 lbs 12 inches behind the axle and it raised my rear percentage to 50.3% and then I moved it to 36 inches behind the axle and it raised it to 52.4%. I like the second percentage better. Been told that a heavy car is better than a pendulum car. Any opinions?

sideways
Dirt Forum Champ
Total posts: 715
posted July 27, 2003 10:22 PM  
The pendalum effect is not a big concern at small tracks.I would do this:Get the percent you want "heavy" and with the weight like you have it.Try it both ways your driving style may compliment one more than the other.I have to make weight with 400+lbs. in the trunk hard to keep it all foward.lol Just my opinion

SLEEPY GOMEZ
Dirt Freak

Total posts: 295
posted July 27, 2003 10:25 PM  
Yes, it can make a difference but as everything on a race car is a compromise......... I think the pendulum effect on a stock car is far less important than the weight distribution gained by leveraging the weight. Where I have heard about problems of a weight pendulum effect they have been talking about exotic lightweight cars usually in a theoretical context. SLEEPY

PEDDLER
Dirt Freak

Total posts: 446
posted July 29, 2003 11:34 AM  
Interesting !!!
I was wondering just how much the effect would be on a 3500 LB car. Apparently not that much.

66jj
Dirt Forum Champ
Total posts: 823
posted July 29, 2003 05:24 PM  
well I disagree strongly.


I have raced at the same paved half mile track for 8 years. I set and lowered the track record every year. I still have the record and havent been there in 2 years, and they have opened up even more rules.

My car was faster with all the wt, right around the tranny in one big pile, 400 lbs to get to 3300.

I ran 55 ls, 48 or so rear, any more rear was too much and pushed.

I had the same amount of lead but spread over, more area, some in ls rail, some on rs rail, and some under my feet area, suffice to say putting it in one pile was the best thing in the world. it transfered weight much much better, all the way around.

anyways times went from 19.4 consistently to 19.175 officially and 19.00 unofficially in the main. all I changed was the pile of wt.

the travel on all corners was very different. I was able to drive even smoother, everything just felt free'd up.

This was a paved track big motors and used goodyear slicks.

maybe its not as big on dirt, well see, I am building 2 IMCA stock cars this winter. Both novas, and they will be like nothing I have seen since moving to Iowa.

cell placement,size, lead placement etc.

Jeff Joldersma

I hope it will be better of course.

Eljojo
Dirt Forum Champ
Total posts: 968
posted July 29, 2003 08:55 PM  
Jeff, I too have had extensive experience with paved track cars, and the set up is 110% different! My Howe coil-over late model had weight in the frame rails, under the seat, along the tranny tunnel, --all under the car! The dirt stocker I'm running now has ALL the ballast in the trunk. all as far rearward as I can get it. All up high to promote body roll and enhance "side bite" Now there's a term I never heard till I hit the dirt!
Good luck with your Nova's! Keep us posted as to how things are coming along for you.

powerglides
Dirt Freak

Total posts: 374
posted July 30, 2003 06:22 AM  
66jj, You should check the IMCA rulebook before building those Novas. I don't believe they are IMCA legal. That is probably why they would be like nothing you have seen since moving to Iowa.

[This message has been edited by powerglides (edited July 30, 2003).]

66jj
Dirt Forum Champ
Total posts: 823
posted July 30, 2003 06:11 PM  
I have the rules and novas are over the 109 wheel base limit.

I have seen one nova.

the differences will be in the wt, cell placement etc.

Eljojo, I raced dirt once 5000 to win I was 3rd fastest qualifier and was taken out by a lapped car in 2nd swapping the lead. all the wt was moved shoulder ht, but I still dont think the trunk is a good place for it....


Jeff Joldersma

zoomy#74
Dirt Full Roller

Total posts: 34
posted July 30, 2003 11:05 PM  
I'd have to check to be sure, but I believe that IMCA has a rule against using a unibody car. I think they have to be a full frame.

tilley88
Dirt Forum Champ
Total posts: 879
posted July 31, 2003 12:36 AM  
I used to race against a fella who won everywhere, grocery money for this cat. He had lead hangin all over the top of his rear bumper. No body, and I mean "nobody", could touch him. I started hangin lead as far back as I could get it, and guess what? I found out if you hang it high enuff if still rolls over. This is on dirt, wet and dry. "Asphalt is for gettin there, dirt is for racin."

66jj
Dirt Forum Champ
Total posts: 823
posted July 31, 2003 04:37 PM  
Imca has no rule against unibodys, I wouldnt have 3 novas in my yard, 9 3rd members, and 3 motors sitting here if they did, lol. I would have a Grand National late model instead, and probably for less investment.

Jeff


Back to the Archives