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Topic: Throwing your weight around Email this topic to a friend | Subscribe to this TopicReport this Topic to Moderator
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revjimk
February 12, 2018 at 05:29:22 PM
Joined: 09/14/2010
Posts: 7595
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Posted By: racefanigan on February 12 2018 at 08:39:47 AM

In all reality, it depends on where you race and how the track is. Most rules dictate between the axles for weight, and basically below the drivers lap, or below the bars that run horizontal at the top of the kick pannels. If the track gets slick, I will raise the car up, which raises the center of gravity which in turn transfers more wieght. Its like having a fishing weight on top of a 4 inch pencil and one on top of a 6 inch pencil. When you put the unwieghted side down, and move the top, there is more "Falling" force, and takes less force to get it to fall, tightening the car up.

Most people will put weight in the driver compartment of bolt lead to the diagonal rails under the headers. We used to run 1/4" steel kick pannels and floor pans when we had a high weight rule in the area.

Really, it depends on the tendancies of your track. If it usually gets slick, you will want the weight higher to get the CG higher and help tighten the car. If it usually stays pretty heavy, you will want that weight lower, to keep your CG lower and keep the car free'd up.



Thats pretty confusing to me, actually (having never set up a sprint car)

You're saying the higher the weight, the more weight transfer? (to RR tire?)

How does that make the car tighter? Are you saying more traction?

I guess I'm asking for a basic chassis setup course... if you could explain briefly, that would be cool

Embarassed to admit I'm still confused about the meaning of "tighter & looser".... tighter means harder to turn?



Murphy
February 12, 2018 at 05:38:07 PM
Joined: 05/26/2005
Posts: 3262
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Posted By: revjimk on February 12 2018 at 05:29:22 PM

Thats pretty confusing to me, actually (having never set up a sprint car)

You're saying the higher the weight, the more weight transfer? (to RR tire?)

How does that make the car tighter? Are you saying more traction?

I guess I'm asking for a basic chassis setup course... if you could explain briefly, that would be cool

Embarassed to admit I'm still confused about the meaning of "tighter & looser".... tighter means harder to turn?



     It means you don't want a girlfriend who is........I better not.



revjimk
February 12, 2018 at 05:40:51 PM
Joined: 09/14/2010
Posts: 7595
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Posted By: Murphy on February 12 2018 at 05:38:07 PM

     It means you don't want a girlfriend who is........I better not.



naughty naughty....




EasyE
February 12, 2018 at 05:47:00 PM
Joined: 10/29/2017
Posts: 384
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Posted By: Murphy on February 11 2018 at 12:35:39 PM

     A recent event since I first started this thread adds a dimension to the question. The thread about David Gravel's wreck suggests that a top bar on the rollcage bent or broke. The owner talked about maybe mandating thicker wall tubing. Someone said that would add 20# to the chassis. Really? 20#? I think if I knew I was going to have a guy the size of Rico in my car, I'd just go with thicker rollcage tubing to start with. Or, if I had a heavier driver, would 20# of safety make us lose the race?



Thicker tubing would take some flex out of the chassis which would affect handling. You would be surprised how much a chassis flexes and bends while racing. 



kossuth
February 12, 2018 at 06:11:52 PM
Joined: 11/02/2013
Posts: 529
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Posted By: EasyE on February 12 2018 at 05:47:00 PM

Thicker tubing would take some flex out of the chassis which would affect handling. You would be surprised how much a chassis flexes and bends while racing. 



Which is a very powerful discussion in itself. Some very smart people are of the opinion that you want a flexible chassis because it is a working component of the suspension.  Additionally there is a very intelligent and successful group of racers that want the chassis as stiff as can be and let the suspension itself do all the work. Interesting contrast. 



racefanigan
February 13, 2018 at 08:17:58 AM
Joined: 07/31/2007
Posts: 230
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Tighter means the car is harder to turn. If the car is loose, or free'd up, the rear end feels like it wants to slide out, which is better for heavier tracks when the car sticks better. Sometimes, when the track is so dry and blown away, you can't really get the car tight enough, you can just make it better than everyone else.

Raising the center of gravity on the car will make the weight want to roll more from front to back generally, this will transfer more weight from the front tires to the rear tires, helping keep the wheels from spinning on corner exit. It gives you a pretty good shot off the corner.

I for one do not like the feeling of teansfering a lot of weight over to the RR corner, as I feel like the car is binding at that point and is slows me down more than helps me, but thats just my feeling, as everyone is different. I like my car so tight that a lot of other poeple couldn't drive it. I remember Justin Henderson coming out to the shop after a night of racing and taking some measurements on my car and saying "Theres no way I could drive a car that tight."

The best cars I have ever had, have more weight over the LR, to make the LR bite harder. Everyone makes the statement of a red solo cup representing stagger, which is true, that will help you roll through the corner, but if you LR is biting harder than your RR is, it will essentially straighten the car out coming off the corner, as the LR is pushing more than the RR, and basically pushing it right. That is how I know I have a good car. The way I see it, RR drive is good for non wing racing, and LR drive is good for winged racing.

Again, this is just my personal findings in what I like in a racecar, which could be total opposites of what others like.

Theres a little crash coruse, though, there is so much more that goes into it than I could type in a post on Hoseheads. lol!




RodinCanada
MyWebsite
February 13, 2018 at 09:03:16 PM
Joined: 07/24/2016
Posts: 1720
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I would rather add weight where it is a help than plop extra weight in a seat and not have any gain


Even though I may not know you, I 
care what most of you think!

revjimk
February 14, 2018 at 01:55:03 AM
Joined: 09/14/2010
Posts: 7595
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This message was edited on February 14, 2018 at 01:46:17 PM by revjimk
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Posted By: racefanigan on February 13 2018 at 08:17:58 AM

Tighter means the car is harder to turn. If the car is loose, or free'd up, the rear end feels like it wants to slide out, which is better for heavier tracks when the car sticks better. Sometimes, when the track is so dry and blown away, you can't really get the car tight enough, you can just make it better than everyone else.

Raising the center of gravity on the car will make the weight want to roll more from front to back generally, this will transfer more weight from the front tires to the rear tires, helping keep the wheels from spinning on corner exit. It gives you a pretty good shot off the corner.

I for one do not like the feeling of teansfering a lot of weight over to the RR corner, as I feel like the car is binding at that point and is slows me down more than helps me, but thats just my feeling, as everyone is different. I like my car so tight that a lot of other poeple couldn't drive it. I remember Justin Henderson coming out to the shop after a night of racing and taking some measurements on my car and saying "Theres no way I could drive a car that tight."

The best cars I have ever had, have more weight over the LR, to make the LR bite harder. Everyone makes the statement of a red solo cup representing stagger, which is true, that will help you roll through the corner, but if you LR is biting harder than your RR is, it will essentially straighten the car out coming off the corner, as the LR is pushing more than the RR, and basically pushing it right. That is how I know I have a good car. The way I see it, RR drive is good for non wing racing, and LR drive is good for winged racing.

Again, this is just my personal findings in what I like in a racecar, which could be total opposites of what others like.

Theres a little crash coruse, though, there is so much more that goes into it than I could type in a post on Hoseheads. lol!



Thanks for the explanation! 

More bite on LR helps you straighten out... which brings up another thing I've been wondering about: do you have to steer slightly to the right to compensate for stagger on the straights?

I used to try reading those chassis geometry articles in Circle Track, confused the hell out of me, I eventually gave up. I need to be standing in front of the car, with somebody pointing out "If the weight shifts this way, car goes that way", etc...Your explanation makes sense, I think the guy who writes those articles spent too much time in Engineering school...

 



racefanigan
February 14, 2018 at 08:22:44 AM
Joined: 07/31/2007
Posts: 230
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Posted By: revjimk on February 14 2018 at 01:55:03 AM

Thanks for the explanation! 

More bite on LR helps you straighten out... which brings up another thing I've been wondering about: do you have to steer slightly to the right to compensate for stagger on the straights?

I used to try reading those chassis geometry articles in Circle Track, confused the hell out of me, I eventually gave up. I need to be standing in front of the car, with somebody pointing out "If the weight shifts this way, car goes that way", etc...Your explanation makes sense, I think the guy who writes those articles spent too much time in Engineering school...

 



Sprint cars are an odd beast. I am not sure why it is like this but here is what I found.

Yes, during caution laps, you need to steer a bit right to compensate for the stagger wanting to turn you left, but at speed, the wheel seems like it is pointed straight. I don't know if that is due to the wing, tires spinning and having less of a plastic cup roll, or if I just don't notice that I still have to turn right lol. When the car is right, it should just turn itself into the corner, and you shouldn't have to do a whole lot of physically turning the wheel, especially on bigger tracks like Knoxville or Jackson MN. Smaller tracks you do more of it, but still, if the car is right, you shouldn't have to turn much.

The easiest asjustments to make that make a big difference, is moving the RR tire, moving the wing, and raising or lowering the car. Shocks and bar rates are big too, but in my eyes, those are finer adjustments. If anyone has ever seen a Torsion bar being dynoed, there is really only about 10-15 lbs difference in resistance between a 1000 bar and a 1025 bar.

As stated before, raising the ride height raises the center of gravity, which puts the weight of the car higher in the air making it want to fall easier, and transfer easier. Moving the RR tire in will tighten the car up, and moving the ing back will tighten the car up. Opposites of that will free the car up.

One thing that I think people have a misconception of, is putting turns in a bar. That is how you raise the car, but some call it "Preload". I do not think that is "Preloading the bar". I think people think that beacuse they see a bar twist on a dyno, and the more it twists the higher the spring rate gets. When you add turns or take out turns from a bar, it doesn't actually twist the bar, it raises the whole corner. That same 1025 bar in the RR straight off of blocks is the same 1025 bar with the same bar regardless of whether it has no turns, 1 turn, 2 turns, or what have you. The only difference is the measurement from the center of the bar to the gound will be different, while that bar has the same amount of twist. As far as I'm concerned, that bar still has the same spring rate, you simply raised the car up.

I could go on and on here, lol. They are magnificent machines and there are infinite possibilities when it comes to setups, thats why sprint cars are so facinating to me, you never stop learning!

 




Murphy
February 14, 2018 at 10:22:23 AM
Joined: 05/26/2005
Posts: 3262
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Dalton- Please do go on and on.


Where I grew up in Rapid City they used to have a big race at the end of the year that would attract a lot of foreign iron. John Stevenson usually won the sprint portion because he was nearly unbeatable when the track dried out. During the features for that race the track would get so dry slick that nearly every lap had a car spinning out. In a post race interview the track announcer complimented John for winning on such a dry slick track. John said "I didn't win the race, my set-up guy did."



cubicdollars
February 17, 2018 at 09:32:53 AM
Joined: 02/27/2005
Posts: 4443
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Posted By: racefanigan on February 14 2018 at 08:22:44 AM

Sprint cars are an odd beast. I am not sure why it is like this but here is what I found.

Yes, during caution laps, you need to steer a bit right to compensate for the stagger wanting to turn you left, but at speed, the wheel seems like it is pointed straight. I don't know if that is due to the wing, tires spinning and having less of a plastic cup roll, or if I just don't notice that I still have to turn right lol. When the car is right, it should just turn itself into the corner, and you shouldn't have to do a whole lot of physically turning the wheel, especially on bigger tracks like Knoxville or Jackson MN. Smaller tracks you do more of it, but still, if the car is right, you shouldn't have to turn much.

The easiest asjustments to make that make a big difference, is moving the RR tire, moving the wing, and raising or lowering the car. Shocks and bar rates are big too, but in my eyes, those are finer adjustments. If anyone has ever seen a Torsion bar being dynoed, there is really only about 10-15 lbs difference in resistance between a 1000 bar and a 1025 bar.

As stated before, raising the ride height raises the center of gravity, which puts the weight of the car higher in the air making it want to fall easier, and transfer easier. Moving the RR tire in will tighten the car up, and moving the ing back will tighten the car up. Opposites of that will free the car up.

One thing that I think people have a misconception of, is putting turns in a bar. That is how you raise the car, but some call it "Preload". I do not think that is "Preloading the bar". I think people think that beacuse they see a bar twist on a dyno, and the more it twists the higher the spring rate gets. When you add turns or take out turns from a bar, it doesn't actually twist the bar, it raises the whole corner. That same 1025 bar in the RR straight off of blocks is the same 1025 bar with the same bar regardless of whether it has no turns, 1 turn, 2 turns, or what have you. The only difference is the measurement from the center of the bar to the gound will be different, while that bar has the same amount of twist. As far as I'm concerned, that bar still has the same spring rate, you simply raised the car up.

I could go on and on here, lol. They are magnificent machines and there are infinite possibilities when it comes to setups, thats why sprint cars are so facinating to me, you never stop learning!

 



+1


 

 

 

They don't even know how to spell sprint car much less chromoly...http://www.ycmco.com


cubicdollars
February 17, 2018 at 09:36:08 AM
Joined: 02/27/2005
Posts: 4443
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As far as the weight rule goes it is a joke. Titanium is still the name of the game. If there was a legitimate weight rule you would see a lot less titanium and a lot safer chassis.


 

 

 

They don't even know how to spell sprint car much less chromoly...http://www.ycmco.com



EasyE
February 17, 2018 at 10:21:00 AM
Joined: 10/29/2017
Posts: 384
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Posted By: revjimk on February 14 2018 at 01:55:03 AM

Thanks for the explanation! 

More bite on LR helps you straighten out... which brings up another thing I've been wondering about: do you have to steer slightly to the right to compensate for stagger on the straights?

I used to try reading those chassis geometry articles in Circle Track, confused the hell out of me, I eventually gave up. I need to be standing in front of the car, with somebody pointing out "If the weight shifts this way, car goes that way", etc...Your explanation makes sense, I think the guy who writes those articles spent too much time in Engineering school...

 



I was at Sedalia  (1/2 mile) last year when the outlaws were there. If your in the pits everyone watches at the end of turn 3 looking straight down the back straightaway. When coming out of the corner and getting on the straightaway about 1/3 of the way down nearly every car would start drifting to the inside then jerk back to the outside pretty hard. They pretty much all did this except i noticed one stayed lot straighter than everyone else. Anybody wanna guess who it was.......



alum.427
February 18, 2018 at 06:15:44 AM
Joined: 03/16/2017
Posts: 1599
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Cubic, I'm not trying to get into a p-match with you. Titanium has nothing to do with making a chassis safer. Weight is weight, and the driver is a part of that. A driver that weights in at say 170, that team, is going to buy there components with that in mind. Just as if your driver comes in at say 220. 50 pound difference. Then you may see titanium stops, wing mts, bumpers. You have to make it up a lot of extra pds. Lite weight rears have become increasingly popular. Steering gears also. I can't say and i highly doubt any team out is going to sacrifice driver safety over weight, and i am not saying you suggested that in any way. 



Murphy
February 18, 2018 at 09:02:12 AM
Joined: 05/26/2005
Posts: 3262
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Posted By: cubicdollars on February 17 2018 at 09:36:08 AM

As far as the weight rule goes it is a joke. Titanium is still the name of the game. If there was a legitimate weight rule you would see a lot less titanium and a lot safer chassis.



     What would you say a "legitimate weight rule" would look like?




blazer00
February 18, 2018 at 09:36:19 AM
Joined: 06/10/2015
Posts: 2420
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Posted By: Murphy on February 18 2018 at 09:02:12 AM

     What would you say a "legitimate weight rule" would look like?



Thats a pretty easy answer, really. A "legitimate weight rule" to me would mean a weight rule that not only establishes the weight of the car, but a concise list of the components and materials that make up the entire car. Then, added weight to make up for the difference in driver weight and any "established weight", such as any difference declared in chassis weight due to design, etc. So as an example, 20 pounds may be needed for basic car weight, and another ? weight for driver. Yes.....similar to horse racing weight rules. Enforcement: Cheat once.....banned for 12 months!



alum.427
February 18, 2018 at 09:41:55 AM
Joined: 03/16/2017
Posts: 1599
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Murphy, as in my previous post. You take a guy Dale Blaney or Kinser. Dale is tall and probably tips the scales at 230, Kinser was a wrestler and he is by no means a small guy. Both of these teams have to take into consideration what they are bolting on to these cars because of that lone factor. For each of these 2 guys I mentioned it is going to cost them a premium to make the same weight as a team with a smaller lighter driver. 

I for one don't feel steve kinser forgot how to drive or couldn't do it anymore. I think it became a issue of he just couldn't make up for the added weight his car was competing with. I wonder if that is also a issue that hurts dale blaney in getting a ride. 

You asked, what would be a good weight for a sprint car ? You make it to high and teams are going to have to spend a lot to get it down to weight or look for a smaller driver. The rule makers had to do something, cars were getting lite, to lite. I had heard 1100 pds and that creates a safety factor #1 and #2 a high cost factor. 



Murphy
February 18, 2018 at 01:06:53 PM
Joined: 05/26/2005
Posts: 3262
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Posted By: blazer00 on February 18 2018 at 09:36:19 AM

Thats a pretty easy answer, really. A "legitimate weight rule" to me would mean a weight rule that not only establishes the weight of the car, but a concise list of the components and materials that make up the entire car. Then, added weight to make up for the difference in driver weight and any "established weight", such as any difference declared in chassis weight due to design, etc. So as an example, 20 pounds may be needed for basic car weight, and another ? weight for driver. Yes.....similar to horse racing weight rules. Enforcement: Cheat once.....banned for 12 months!



   Are you thinking specific rules such as "front axle must be steel"? That sort of thing?




Murphy
February 18, 2018 at 01:20:33 PM
Joined: 05/26/2005
Posts: 3262
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Posted By: alum.427 on February 18 2018 at 09:41:55 AM

Murphy, as in my previous post. You take a guy Dale Blaney or Kinser. Dale is tall and probably tips the scales at 230, Kinser was a wrestler and he is by no means a small guy. Both of these teams have to take into consideration what they are bolting on to these cars because of that lone factor. For each of these 2 guys I mentioned it is going to cost them a premium to make the same weight as a team with a smaller lighter driver. 

I for one don't feel steve kinser forgot how to drive or couldn't do it anymore. I think it became a issue of he just couldn't make up for the added weight his car was competing with. I wonder if that is also a issue that hurts dale blaney in getting a ride. 

You asked, what would be a good weight for a sprint car ? You make it to high and teams are going to have to spend a lot to get it down to weight or look for a smaller driver. The rule makers had to do something, cars were getting lite, to lite. I had heard 1100 pds and that creates a safety factor #1 and #2 a high cost factor. 



A Couple things:

I'm not sure I'm following why it would cost Blaney or Kinser a lot to meet the weight. When wieght rules were started, I think those two may have benefitted some.

I don't hink Kinser's weight was the issue. I recall Joey Saldana saying something like "Oh man! If Kinser could beat us before, how are we going to keep up after we add another 50# to our car?". I'd be more inclined to believe getting older was a bigger factor.

I really wasn't asking what the magic number should be. Cubicdollars mentioned "a legitimate weight rule". I wondered what he or others thought that might entail. Blazer00 above talks about what he thinks it might entail without plugging a specific number.

What do you mean by "You make it too high and teams are going to have to spend a lot to get it down to weight or look for a smaller driver."?     too high................down to wieght...........huh?



alum.427
February 18, 2018 at 01:35:14 PM
Joined: 03/16/2017
Posts: 1599
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Understand Murphy. In using blaney and kinser I just picked 2 guys that are bigger than your normal sprint car driver . As for current weight according to woo rules I don't know what it is





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