postell69 Posted September 5, 2007 Report Share Posted September 5, 2007 allright been thinking about this for few days so im going to ask i heard some drivers talking about putting a softer spring on the right rear for better bite coming off the corners on the dirt since i really dont know much about this topic im going to ask has anybody heard of this thank you all for not laughing to hard at me but was just wondering and i did hear spring not shocks Link to comment Share on other sites More sharing options...
NickHolt Posted September 5, 2007 Report Share Posted September 5, 2007 allright been thinking about this for few days so im going to ask i heard some drivers talking about putting a softer spring on the right rear for better bite coming off the corners on the dirt since i really dont know much about this topic im going to ask has anybody heard of this thank you all for not laughing to hard at me but was just wondering and i did hear spring not shocks Yes, a softer spring on the RR than on the LR will help with bite coming off the turn. BUT it will also add dynamic cross weight to the RF/LR diagonal which will also tighten the car somewhat through the entire turn. Like everything else in suspension, what you gain somewhere, you lose somewhere else... Nick Link to comment Share on other sites More sharing options...
JohnnyT66 Posted September 5, 2007 Report Share Posted September 5, 2007 so NICK,what if you ran softer on the r.r. and the right front?we are talking on dirt.......frank t Link to comment Share on other sites More sharing options...
NickHolt Posted September 5, 2007 Report Share Posted September 5, 2007 so NICK,what if you ran softer on the r.r. and the right front?we are talking on dirt.......frank t Softer right side springs will add more body roll which is great for generating side bite if the if the track is tacky (or unless it's too soft and the chassis bottoms out). But by softening the RF will remove some of the bite you achieved by softening the RR. Nick Link to comment Share on other sites More sharing options...
speed demon 7 Posted September 5, 2007 Report Share Posted September 5, 2007 Nick, while we are on the subject of springs. I am going to give you a spring set up and see what you think LF 750 RF 650 LR 350 RR 200 I have a 1.5" Sway bar and run about 2 inches of stagger. The car is a tad tight in the turns, which I like, but I am getting loose when I get back on the gas. I know that I need to ease in on the throttle more, but what can I do to get more bite. This is in a metric chassis, with no tricks on the rear suspension. I have a set of chevelle upper trailing arms, will putting them on and getting more pinion angle help? ride heights are LF 6 RF 6.25 LR 8 RR 8.25 Link to comment Share on other sites More sharing options...
NickHolt Posted September 5, 2007 Report Share Posted September 5, 2007 Arthur, First off, one possbile reason you're a bit loose coming off the turn (this car runs on asphalt, right?) is due to the slight push in the middle. Fix the slight push in the middle and you should have more than enough bite coming off the turns expecially with that big LR spring. Without knowing any of the wheel rates, motion ratios, moment arm lengths, weight distribution, and a host of other very critical variables, perhaps part of the slight push in the middle would be eliminated by reducing the strength of the LR spring. You say the car is a metric chassis. Has the natural binding in the rear trailing arms been eliminated or reduced? Nick Link to comment Share on other sites More sharing options...
speed demon 7 Posted September 5, 2007 Report Share Posted September 5, 2007 I have loosened the bolts in the upper trailing arm and they have some wore out bushings, but the natural bind is pretty much stll there. Any ideas on getting rid of the bind, no mono balls allowed. I do explore GREY areas, but I have to stay within the rules. Yes, this is my HMP Pro Stock. Link to comment Share on other sites More sharing options...
ProTree Posted September 5, 2007 Report Share Posted September 5, 2007 shocks? Link to comment Share on other sites More sharing options...
NickHolt Posted September 5, 2007 Report Share Posted September 5, 2007 Most asphalt metric chassis that have the stock rear trailing arm setup are pretty much loose in the center (where the body roll produces the most suspension bind), so having a metric that is a bit tight in the center probably means your rear suspension bind has been reduced to an acceptable level. OR.. you have front suspension bind (or horrible front suspension geometry) which more or less negates (or matches) the rear bind. I hope this is not the case. Yes, I have some ideas about how to reduce the metric rear suspension bind, but I don't discuss those sorts of things in public... Some tech official might be listenting LOL.. Nick Link to comment Share on other sites More sharing options...
poorboy Posted September 6, 2007 Report Share Posted September 6, 2007 Just from what I ran into in the past I would assume you are running very low cross weight with those springs like that. Link to comment Share on other sites More sharing options...
speed demon 7 Posted September 6, 2007 Report Share Posted September 6, 2007 My cross weight was 49.4, I am going to try to get it up to 51-51.5. Link to comment Share on other sites More sharing options...
Danielsen Motorsports Posted September 6, 2007 Report Share Posted September 6, 2007 If its a metric chassis the first thing you must do is correct the stock upper control arms mount location so your geometry in the frontend will be consistant as you are turning. Metrics sucks really bad. The only person I recommend in your area is Fast 1 Fabricating Phil Dixon. He will put the camber caster gauge on it an show you first how bad it is and then you will want to fix it. He has a jig ready to go. Again all metric frames have this problem from the get go. Link to comment Share on other sites More sharing options...
speed demon 7 Posted September 6, 2007 Report Share Posted September 6, 2007 Moving the upper mounts is not allowed. We use tubular upper control arms, that helps quite a bit. Link to comment Share on other sites More sharing options...
Danielsen Motorsports Posted September 7, 2007 Report Share Posted September 7, 2007 it can be done without anyone being able to notice as a matter of fact probably 50% of the faster cars have it done. Plus if you get into a wreck how do you think they make repairs. Link to comment Share on other sites More sharing options...
soaker Posted September 7, 2007 Report Share Posted September 7, 2007 Arthur, I know your fast already but if you want to go faster take out the springs and throw away the metric chassis. Link to comment Share on other sites More sharing options...
speed demon 7 Posted September 7, 2007 Report Share Posted September 7, 2007 Yeah, I may have to buy that one Rookie49 likes so much!!! Link to comment Share on other sites More sharing options...
Truck99 Posted September 7, 2007 Report Share Posted September 7, 2007 My cross weight was 49.4, I am going to try to get it up to 51-51.5. I'm not sure if that would be a step in the right direction. If the increase in cross adds to your tight in the center condition, the loose off will still most likely be present. If you can make the car neutral at entry and in the center, the loose off condition will probably go away. Link to comment Share on other sites More sharing options...
NickHolt Posted September 7, 2007 Report Share Posted September 7, 2007 Arthur, First off, one possbile reason you're a bit loose coming off the turn (this car runs on asphalt, right?) is due to the slight push in the middle. Fix the slight push in the middle and you should have more than enough bite coming off the turns expecially with that big LR spring... Nick I'm not sure if that would be a step in the right direction. If the increase in cross adds to your tight in the center condition, the loose off will still most likely be present. If you can make the car neutral at entry and in the center, the loose off condition will probably go away. Is there an echo in here? LOL.. Nick Link to comment Share on other sites More sharing options...
Truck99 Posted September 7, 2007 Report Share Posted September 7, 2007 I guess so... sorry Nick. I guess I should read ALL of the posts before I say somthin'. Link to comment Share on other sites More sharing options...
NickHolt Posted September 7, 2007 Report Share Posted September 7, 2007 I guess so... sorry Nick. I guess I should read ALL of the posts before I say somthin'. Hey, no problem Chase. I just thought it cool that both of us had the same thought.. Nick Link to comment Share on other sites More sharing options...
speed demon 7 Posted September 7, 2007 Report Share Posted September 7, 2007 So what you are saying is take a little cross weight out. That is also what my book says and what I think of, but everyone keeps telling me that I need to be at over 50%. I am going to put it on the scales on Sunday and see where it is at on my scales and make some changes. Nick, can you come to HMP on the 22nd and help with my car, I will pay double your TXSZ salary to help out. Link to comment Share on other sites More sharing options...
Truck99 Posted September 7, 2007 Report Share Posted September 7, 2007 So what you are saying is take a little cross weight out. That is also what my book says and what I think of, but everyone keeps telling me that I need to be at over 50%. I am going to put it on the scales on Sunday and see where it is at on my scales and make some changes. Nick, can you come to HMP on the 22nd and help with my car, I will pay double your TXSZ salary to help out. Arthur, I have first-hand experience that a car running below 50% cross can be fast and fast on the long run. Link to comment Share on other sites More sharing options...
poorboy Posted September 8, 2007 Report Share Posted September 8, 2007 I think you should run the front springs even, 750 both sides. Go up on the right rear and up the cross but thats only an opinion. I ran 250 to 275 in the right rear. Seems to keep the left front working to take away mid turn push. Link to comment Share on other sites More sharing options...
ProTree Posted September 8, 2007 Report Share Posted September 8, 2007 what effect do your shocks play in all this?do you go softer for no bite and stiffer for bite?or are you restricted by the rules?just wondering about the crossover of straightliners to circle tracking,dealing with vector forces and what not.I help alot of guys hook up alot of HP and shocks are overlooked alot of times in our racing. Link to comment Share on other sites More sharing options...
speed demon 7 Posted September 9, 2007 Report Share Posted September 9, 2007 I honestly don't know about my shocks. I gave my shock guy the specs of the car and track, and he built them. We went 3 races where I would tell him what the car was doing and he would revalve them. They are QA-1 stock mount shocks. Link to comment Share on other sites More sharing options...
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