Author Topic: Weight bars  (Read 11670 times)

Offline PSweeney

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Weight bars
« on: April 24, 2017, 03:29:33 AM »
Last time I ran my car it hit the bar pretty hard, to the extent it broke the wheel.  It's 138in with SBC shorty glide close coupled.  Motor is 420in SBC injected on alky, making c 600bhp and 500ft lbs ish.  Rear gear is 3.7 and it's on 33x10's

Chassis is CDS I have a full size battery ahead of the motor and a moon tank but little else further forward. We knew we'd need weight but hoped to calm it with 3.7 gear.  Before we go back out with it, I'm making a weight bar to mount in the front axle.  Lead shot is expensive so I'm smelting lead roof flashings.  So far I've got it to 22lb and the material I have will see it total 35lb.   

Does anyone have an opinion on how much weight I'll need ?.  If I need any more I'll have to fab boxes to sit in the chassis also.

Offline rooman

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Re: Weight bars
« Reply #1 on: April 24, 2017, 05:34:14 AM »
If it is hitting the bar hard enough to break the wheel it sounds as if the bar is set too high and/or the car is hooked too well. I generally like to run the bar so that the wheel is around 1 1/2-2" off the ground but that number will vary with how rigid the bar is. I would try varying the bar height and/or the tire pressure to get a bit of wheel speed leaving and stop the car from rotating hard.

Roo
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dreracecar

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Re: Weight bars
« Reply #2 on: April 24, 2017, 08:22:01 AM »
When adding weight to set balence, it does not have to be pretty, just safe. When the proper amount is figured out then steps can be made to clean up the looks.

 I hear the Parks has some new "Lite weight" bars available--- Ti tubing filled with aluminum shot and clamps to the frame with Mag brackets  ;D

Offline Roger

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Re: Weight bars
« Reply #3 on: April 24, 2017, 08:36:13 AM »
I'm sure they could build some nice ones; all it would take is a short phone call and a lot of $$$$:)

Ponti

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Re: Weight bars
« Reply #4 on: April 24, 2017, 09:26:10 AM »
Steve Field is running about 50lb in his car, which is 148 inch, so I would try close to that best bet is have a word with him.

Offline PSweeney

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Re: Weight bars
« Reply #5 on: April 24, 2017, 10:12:18 AM »
If it is hitting the bar hard enough to break the wheel it sounds as if the bar is set too high and/or the car is hooked too well. I generally like to run the bar so that the wheel is around 1 1/2-2" off the ground but that number will vary with how rigid the bar is. I would try varying the bar height and/or the tire pressure to get a bit of wheel speed leaving and stop the car from rotating hard.

Roo

your correct Roo, it was a midnight special welded up hours before the event, bar was probably 3in off the ground and we'd run out of adjustment.  I'll get it down lower, just need to source a decent wheel for the bar

Offline PSweeney

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Re: Weight bars
« Reply #6 on: April 24, 2017, 10:26:24 AM »
Steve Field is running about 50lb in his car, which is 148 inch, so I would try close to that best bet is have a word with him.

spoke to him last year on it, and he added the weight after the mishap off the line.  I can't fit much more out front so I think it'll have to be a box in the chassis or drill and fill the front axle.




Offline Supercat

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Re: Weight bars
« Reply #7 on: April 24, 2017, 12:16:26 PM »
We use flat lead plates poured to fit in the nose cone

Offline rooman

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Re: Weight bars
« Reply #8 on: April 24, 2017, 01:30:34 PM »
When adding weight to set balence, it does not have to be pretty, just safe. When the proper amount is figured out then steps can be made to clean up the looks.

 I hear the Parks has some new "Lite weight" bars available--- Ti tubing filled with aluminum shot and clamps to the frame with Mag brackets  ;D

I watched Lee Beard bolt a weight bar to a chassis with Titanium bolts.  :o
Yeah, I am from the south--any further south and I would have been a bloody penguin.

Ponti

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Re: Weight bars
« Reply #9 on: April 25, 2017, 06:31:51 AM »

spoke to him last year on it, and he added the weight after the mishap off the line.  I can't fit much more out front so I think it'll have to be a box in the chassis or drill and fill the front axle.

 Bugger, the problem with putting it further back is you'll need even more.

 There is always a way round it :-)

Offline rooman

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Re: Weight bars
« Reply #10 on: April 25, 2017, 08:07:58 AM »

spoke to him last year on it, and he added the weight after the mishap off the line.  I can't fit much more out front so I think it'll have to be a box in the chassis or drill and fill the front axle.

 Bugger, the problem with putting it further back is you'll need even more.

 There is always a way round it :-)

The way that Brisette did it back in the day.  :P
Yeah, I am from the south--any further south and I would have been a bloody penguin.

dreracecar

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Re: Weight bars
« Reply #11 on: April 25, 2017, 09:03:36 AM »
If you run a index, and tune up & down to the number, who cares about weight. Carry over 100# on the frame behind the axle and still lifts the front wheels and buries the rear trying to drive underneath the front weight

Offline PSweeney

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Re: Weight bars
« Reply #12 on: April 25, 2017, 09:33:18 AM »
well, I had a little win today, scored 30lb of used lead for the equivalent of $12, so tonight I'm smelting more lead and going to try making shot 8) 

My axle is a 1/4in thick, anybody see an issue drilling and tapping a 3/8th hole to fill it with shot ?

Offline BK

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Re: Weight bars
« Reply #13 on: April 25, 2017, 03:05:55 PM »
I want to say whoever did my front axle used 1/4" pipe. I cant imagine 3/8" being a problem though.

Offline BK

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Re: Weight bars
« Reply #14 on: April 25, 2017, 03:10:12 PM »
When adding weight to set balence, it does not have to be pretty, just safe. When the proper amount is figured out then steps can be made to clean up the looks.

 I hear the Parks has some new "Lite weight" bars available--- Ti tubing filled with aluminum shot and clamps to the frame with Mag brackets  ;D

I watched Lee Beard bolt a weight bar to a chassis with Titanium bolts.  :o
Sort of off topic. What is strength of Ti. vs grade 8?