soft RF why and what.

[andy16]

good point fastford, since we are just discussing this not really addressing a problem ill play along also. with what iv learned and know to be true to myself and my driving style at the the track i ran a full season at last i can say i made more bad calls than good but learned alot also. my thoughts are a soft rf works well because your supposed to stiffen your lf also. and could if necessary soften the lr and stiffen the rr. i think this works well in the slick because it changes the shear point of the tire, the more the car is in roll the less shear pressures are on the tire. also the bumpstop is pretty much a must w this. how do you get a 400 spring and a 250 spring compress the same amount give or take, a bump stop. so when softening rf and stiffeng lf you change your lr2rf rr2lf dynamic values causing the rr and lf to get more traction earlier in the begining of weight transfer. then by the time your ready to get back to the gas your rf is on the bumpstop eliminating the spring and acting like a stiff spring / the lr has begun to hike because of body roll then hopefully your car will pull up out of the corner and str8ten up and pick up off the bumpstp down str8 and then do it all over again. but timing must be perfect for all this to work like it should. the expensive shocks help fine tune the timing and the dual stage spring is another finer adjustment of same concept. its not easy or simple and took me 3/4 of a season to learn what i wanted. im trying now to work out a chart for me so that for a given weight because latemodels can weigh anywhere from 2200 to 2450 depending on your rules a spring combo that keeps the same spring to weight ratio and front to rear and side to side ratio, im not sure its gonna work but im working it out. say a 500lf 300rf 200lr 225rr works well for a 2200lb car that doesn mean its gonna work for a 2450 lb car. something that no chassis manf. addresses . my theory is the 2450 lb car is 250 lbs heavier so i need to distribute 250lbs of more spring pressure to the 4 corners of the car assuming you keep your % the same. aprox 62lbs more spring per corner. so applying that to whats available out there the spring setup will be 550lf 350rf 250lr 275rr but if i told you i was running these springs you would say im way off and need to move them. this applys to the soft spring setup like this, for tacky start w a 550lf 400rf 200lr 225 rr = 1375 lb in springs. then for slick go to 650lf 300rf 175lr 250rr and that equals 1375lb in springs. now to me on both setups the front and rear are carrying the same amount of weight although applying it to different tires. is this a good key to a balanced setup? will this help when tuning from one track condition to the next. will this help when switching from a crate motor to a super motor or one tracks rules to another?

sorry got a little deep there.

[4bangerhotrod]

i believe your way over thinking this

[fastford]

andy , i think your on the right track, ill say this about the bump stop and the stacked spring, there are some people on this board that dislikes the bump and likes the stacked set up, and vice versa, me personally i like both in the right conditions, i like the bump stop on a super dry and smooth track, i feel better drive off the conner this way, but on a somewhat of a rough track that is heavier the stacked is better on equipment. and 4banger there is nothing simple about this, evidently you have little experience with this subject

[abe_05]

i believe your way over thinking this

Good subject, I going to answer the original question, the why and the what ? In the setup back the late 90's the lr spring moved to behide axle. The lr was getting up on bars easier and harder than ever but when rolled out of gas this made cars very loose off throttle so here came the softer front to tighting car up on entry as we all know now. That started the soft rf in my opinion but it has evolved much since then. Now attitude, roll steer, shocks, and areo are big factors today. But is the front really soft today ? Are we all really thinking? Even though rf spring is soft but really that is not the case. If you running 350 lb on bump stop how much travel are you getting before and after on bump ? We are talking rates over 4000 lb easy in some cases at full travel. So what about the ones that are running strait spring and getting a lot of travel ? Let say a 425 lb that is getting 4 to 5 inches of travel and has shocks tied down like most of us have never seen before. The rate is still up there over 2000 lb and the shock is keeping it in that range. So why are we keeping the front rolled over ? We are trying the find that magical spot were car is balanced on the front. How many cars you see picking lf up now? Not many, as rf roll over a lot the lf is increasing the load as long as car is not rolling on the rr. Point being made, set car on ground take rf spring off the car, what happens then ? Car rolls over some but the lf is carrying the all the load but right front frame doesn't touch the ground, think about it, your trying to increase loading of left front. So I do not put much into spring rates today because there is so many different ways to make car do the same thing, this is the attitude of car. Different chassis are different with this point, as the rf rolls over the first 1-2 inches the weight or loading goes up on rf and down on lf, at some point the lf loading starts to go up if rf continues to roll over. Some racers are using bump stops on lf now instead of rf (keeping rf on strait spring ) to help this method. This topic can go forever, some top guys are using tie down on both front springs and using the rear to bars run up to top to push front down and running rear percentage up. If had all the answers I would working for some big team but I am not. Just trying to shed some light. You still to have to make driver like the feel also with all the new stuff that is happening. Has everyone seen a big difference in competition in past year or so? The big teams are getting faster at a faster pace than small guys, why- they have enough time and money to go test these different setups to max balance cars.

[7uptruckracer]

I agree a bumpstop can work but you can't have variables like a bumpy track or a changing surface bump wise you have to know when your getting on the bump in the corner and stay on the bump so you know what your doing to the car. I like the dual spring not to be confused with a stack but like anything you have to test it. Everything is a compromise and each driver is different for the weekly same track racer who can test it might be easier in a way then a touring driver who has a new facility and conditions each night unless your a big boy.

[7uptruckracer]

Does everyone run 10/4 inch dual Combos? What brand Im Having a hard time finding above 650 in 10" Id like to try say a 700 10" or maybe an 8" if people are running those...Post your Ideas it would be cool to gather some more knowledge.

[7uptruckracer]

Nevermind I run 6/6 I don't know why afco suggests what they do, Someone said not to use the nylon sleeve anyone else run into this?