Different uses/experiences with spring rubbers

[mickley.28]

[QUOTE=MasterSbilt_Racer;2177110]Not always. [/QUOTECan you please explain when adding rr spring rubbers wouldn’t loosen middle-off??? It should load the right rear harder and or quicker which unloads the left rear which would loose exit correct?

[MasterSbilt_Racer]

If the car is still translating laterally across the surface as you exit the corner, a front with good grip can overcome the RR to change the direction of the car. If the RR is pinned harder, the front tires cant do as much.

The car is almost never going "straight". At tracks with decent arcs to the "straight" it really isn't.

There is also the scenario where the rear is not at optimal grip because the LR is overloaded. Any increase of RR load would tighten a car suffering that problem.

[mickley.28]

If the car is still translating laterally across the surface as you exit the corner, a front with good grip can overcome the RR to change the direction of the car. If the RR is pinned harder, the front tires cant do as much. The car is almost never going "straight". At tracks with decent arcs to the "straight" it really isn't.There is also the scenario where the rear is not at optimal grip because the LR is overloaded. Any increase of RR load would tighten a car suffering that problem.

Won’t A car that has a left rear that’s overloaded on exit be extremely tight??? More load on left rear means it will be doing more work and providing more forward thrust than the right rear. All else being equal If left rear has more weight/thrust than right rear car will push the nose to the right when on the gas.

[Punisher88]

I would think with all these high tech spring smashers everyone is going wild to get would help get a picture of what your looking at when you install a spring rubber in various places and amounts. Speaking of pictures, i had a friend of mine make me an excel spreadsheet that layouts out the points in a graph, so you can see it more in a graphical sense. Its helps to see the progression visually. Next thing i want to work on is a program that will record the sweep like a shock dyno, and not have to stop the machine to record it. How nice would that be? Start at max spring height, press it down to ride height, and its all recorded in a nice visual output. I just need to talk to some computer dudes LOL.There was a video on FB by Booze Brothers Performance that showed a RR with a bunch of rubbers in it, very interesting to watch.

If you search in your app store penske has am app called spring machine or spring smasher, I can't remember off the top of my head but it puts in in a graph for you after you enter the info. I just screen shot it and save it to my notebook on my phone. And it will email it to you in a spreadsheet form.

[MasterSbilt_Racer]

A decent driver is going to compensate and keep that LR heavy car going in a circle. He isn't going to just plow the nose every lap. That means breaking traction. And breaking traction is easier to do when one wheel does the heavy lifting.

[billetbirdcage]

I would think with all these high tech spring smashers everyone is going wild to get would help get a picture of what your looking at when you install a spring rubber in various places and amounts.

Speaking of pictures, i had a friend of mine make me an excel spreadsheet that layouts out the points in a graph, so you can see it more in a graphical sense. Its helps to see the progression visually. Next thing i want to work on is a program that will record the sweep like a shock dyno, and not have to stop the machine to record it. How nice would that be? Start at max spring height, press it down to ride height, and its all recorded in a nice visual output. I just need to talk to some computer dudes LOL.

There was a video on FB by Booze Brothers Performance that showed a RR with a bunch of rubbers in it, very interesting to watch.

The new accuforce smashers do that.

https://www.youtube.com/watch?v=ml-V3qSCT3c&feature=youtu.be

[billetbirdcage]

mickley.28

There is lots of times stiffening the RR with tighten the car on exit, but it's extremely situational. I've done it a bunch of times in private tests where the driver had it in his head it would loosen the car (so driver had a preconceived notion what it was gonna do) and after I did it came in scratching his head, lol.

Honestly it takes experience to know when it will and when it won't and I can't say I can do that all the time.

There are several things that will give you the opposite reaction at times, another example of this is J-bar. The most common answer to raising the J-bar on the frame is it will tighten the car, but there are situations where I raise it to loosen the car especially thru the middle. I've had people pitted next to us watch me do that to someones car when about everyone is fighting a tight condition on a real heavy track and ask me: "Wasn't you guys tight too? so why are you raising the J-bar". I just answer "Yes, we was tight". They always give me a strange look and think I'm nuts, but are really confused when we win the heat race.

Some of these things I can't find a decent theory to explain it that I can't poke holes in or seems rock solid correct, but they happen and it just takes experience and a ton of testing to really get a feel for when these things happen. Only making changes at races and no testing where you get back to back examples, you're probably not going to get a good data base to sort out when this happens.

[Kromulous]

That Accuforce smasher is nice, maybe i can buy one when my ship comes in.

Until then, that APP looks nice too, or my ole spreadsheet.

[fastford]

mickley.28

There is lots of times stiffening the RR with tighten the car on exit, but it's extremely situational. I've done it a bunch of times in private tests where the driver had it in his head it would loosen the car (so driver had a preconceived notion what it was gonna do) and after I did it came in scratching his head, lol.

Honestly it takes experience to know when it will and when it won't and I can't say I can do that all the time.

There are several things that will give you the opposite reaction at times, another example of this is J-bar. The most common answer to raising the J-bar on the frame is it will tighten the car, but there are situations where I raise it to loosen the car especially thru the middle. I've had people pitted next to us watch me do that to someones car when about everyone is fighting a tight condition on a real heavy track and ask me: "Wasn't you guys tight too? so why are you raising the J-bar". I just answer "Yes, we was tight". They always give me a strange look and think I'm nuts, but are really confused when we win the heat race.

Some of these things I can't find a decent theory to explain it that I can't poke holes in or seems rock solid correct, but they happen and it just takes experience and a ton of testing to really get a feel for when these things happen. Only making changes at races and no testing where you get back to back examples, you're probably not going to get a good data base to sort out when this happens.

In theory , putting a spring rubber or a stiffer spring in rt rear will loosen car from middle off , and most of the time it will , but you guys are right , sometimes , according to driving styles and other variables , it will give a tightening effect , here is another example of going against the norm , back 15 years or so ago , we were at a track that lost all grip , the more bite you gave the car , the worse it got from middle off , after qualifying , i said what the heck , and we put reverse wedge in it , about a 100 lbs when we got home and put it on the scales , and drove around every body and won the race , this is what i like about dirt , the norm does not always win races........

[CCHIEF]

In theory , putting a spring rubber or a stiffer spring in rt rear will loosen car from middle off , and most of the time it will , but you guys are right , sometimes , according to driving styles and other variables , it will give a tightening effect , here is another example of going against the norm , back 15 years or so ago , we were at a track that lost all grip , the more bite you gave the car , the worse it got from middle off , after qualifying , i said what the heck , and we put reverse wedge in it , about a 100 lbs when we got home and put it on the scales , and drove around every body and won the race , this is what i like about dirt , the norm does not always win races........

I concur, this works very well on big sweeping corner tracks, when they go dead slick and slow down, there is corner speed to be (re)found by putting static load on the rr instead of relying on transfer. Spring rubbers are convenient, but often inconsistent. Nice to have for "adjustments" in 100 lappers. For a regular Saturday night shoot out, your far better off without. My 2 sense. YMMV