LR shock and spring setup

[Kromulous]

Recently been looking into nitrogen type limiters, it seems they have the ability to add in quite a bit more progressive rate than rubber, or some sort of poly / foam type pucks. Anyone running the nitrogen types?

I guess the next question is, what kind of rate are we wanting on the limiting device?

[fastford]

i saw a home made chain limiter that he used a cone style bump stop , think it was yellow , that worked well and was compact . this is what i was gone try but because we run under slung frame , i went that way.....

[King1]

Running the LR stack without the lockout is kinda useless. Setting how much wheel load the lower spring holds at ride height is make or break the whole deal

[manwplan]

Running the LR stack without the lockout is kinda useless. Setting how much wheel load the lower spring holds at ride height is make or break the whole deal

How the car rides through the pits is irrelevant hence the current deck height and nose height rules. It's all about dynamic loads

[MasterSbilt_Racer]

Running the LR stack without the lockout is kinda useless. Setting how much wheel load the lower spring holds at ride height is make or break the whole deal

I don't race at ride height. If you want to put a stop on there or something, have at it.

[King1]

Might want to be a little more open minded to that lower spring load at ride height. Im all about dynamic wheel loads too, but that lockout location is 2/3 of the LR setup. You're only using the bottom spring until the LR drops out enough to come off the lockout and both springs are utilized.
But whatever, not here to argue about deck height, just trying to help the guy out.
Ask Mccreadie about how important that lower spring load is. If it wasnt then people wouldnt spend the money on a lockout nut.

[billetbirdcage]

my real question is why would you want progressive or digressive left rears,,, i understand pro uses the bottom spring to set ride height, and top coilover is setting the extension load.... while digressive it is opposite. but still can arrive at same point. so what is the difference?? and how do you know the extension load you need to be at for a condition

You do realize that the rate the LR see's even with a single linear spring isn't linear? While it can be, typically it isn't on most cars.

[billetbirdcage]

billet , do you think the load applied to the rubber on a chain is equal , load wise , to the rear hitting the rubber on my under slung ? just wandering because this might be where something could be learned with a spring smasher and some rubber......

Forgot last night to say this:

Keep in mind you can get the bottom deal to be just like a chain but there are some inherient issues you have to over come.

1. Some cars will hit the undersling in the bell area, where the rear end meets the tube. You can be hitting with the axle tube but if you adjust the J-bar with more rake so the rear end pulls left more and then hits with the bell lessening the over all drop.

2. If it hits with one of the bolts that holds the tube in the bell, that will effect the rate of the rubber/cushion and change how it cushions and again possibly the over all travel.

3. If you adjust the bars and change steer, you may have more or less contact with the rubber and again change things like rate or overall travel. This is due to the rear end hitting farther forward or backwards on the undersling, so the cushion may need to be long front to back to hit full material all the time.

4. Just a lot more to consider on the undersling and how it contacts the rear end. Where the chain doesn't have this issues to pay attention too.

When you really look at it, the chain is less work and most likely better as you don't have to engineer it to death to make it consistent.

[billetbirdcage]

Recently been looking into nitrogen type limiters, it seems they have the ability to add in quite a bit more progressive rate than rubber, or some sort of poly / foam type pucks. Anyone running the nitrogen types?

I guess the next question is, what kind of rate are we wanting on the limiting device?

If you want my honest opinion on different limiters:

I don't really think there is a nickles difference in them, just how much lighter your wallet is.

Now I will say if you can run one that has valving to it (illegal by most sanction bodies), well I do think there is a benefit to those. Like I described earlier, the travel over time deal with different materials can be controlled/altered by having a limiter with valving, so. . . . .

[billetbirdcage]

So this all leads to something else, not talked about and maybe people don't know about them.

Position sensitive shocks

The LR valving on a std shock is linear on valving no matter where it's at on it's travel, but having a position sensitive shock allows me to control/change the valving at the point of travel it's on the limiter thus altering it or adding/subtracting valving and still meet or bypass the rules on the dampened limiter.

More things to say. . . . . hmmm.

OK, I'm done for the day (grins)

[Kromulous]

Yeah i was looking at the DEI Unit and you can adjust the nitrogen pressure, which affected the spring rate greatly. I made a little mount that i can add bisquits in, them nitro units are pricey.

Anyway, trying to wrap my head around with King1 is saying up there too, very interesting.

[fastford]

Running the LR stack without the lockout is kinda useless. Setting how much wheel load the lower spring holds at ride height is make or break the whole deal

now im confused , are you talking about a lock out like on a rt frt two stage ?

[MasterSbilt_Racer]

Might want to be a little more open minded to that lower spring load at ride height. Im all about dynamic wheel loads too, but that lockout location is 2/3 of the LR setup. You're only using the bottom spring until the LR drops out enough to come off the lockout and both springs are utilized.
But whatever, not here to argue about deck height, just trying to help the guy out.
Ask Mccreadie about how important that lower spring load is. If it wasnt then people wouldnt spend the money on a lockout nut.

It sounds like maybe you are saying this important point is above ride height now? This point you describe is important if the car reaches that height during racing conditions. Me, for what I need to get for load to hold the car up, and load at extension, there isn't much way to keep the stage nut in play for very long.

[racer2e]

Kent, I have been thinking about a position sensitive shock for the left rear front shock for some time. I built one years ago for a different application, but now I think you could have it with almost no damping except just before it tops out on rebound. My concern is how much it will change with bar changes. Maybe make a few of them with the port in different locations so the damping comes in at the same amount of total droop. To match a couple of bar positions you run.

[sidewinder69]

Billet can you offer more on the digressive and progressive concepts, I dont want any secrets . Just a general conversation to better enlighten

[billetbirdcage]

Kent, I have been thinking about a position sensitive shock for the left rear front shock for some time. I built one years ago for a different application, but now I think you could have it with almost no damping except just before it tops out on rebound. My concern is how much it will change with bar changes. Maybe make a few of them with the port in different locations so the damping comes in at the same amount of total droop. To match a couple of bar positions you run.

Simple, don't use the front of the birdcage for your hike down shock location. On top of the tube would allow you to use the same shock for all set ups. For some reason, you needed to change the drop or chain length just have the top mount on a screw jack. You could always keep the last 3/8 or 1/2" of the shock where the rebound goes high in the same place.

However again, back to is it worth anything? Shrugs

You can do a twin tube pretty cheap and yourself if you know how to take a shock apart. However if your wanting to do with a mono-tube, then you going to need someone to machine some stuff for you or know how to do it in other ways.

Hell, early in the 2017 racing year I drew up a position sensitive shock that at the last 1" of travel (fully compressed) it had 800# of rebound. So you just put the fat crew guy on the back of the car to smash it down and it would hold it there to go thru tech easy and once out on the track you just rock the car back and forth to get it over the high rebound and the car acted like normal just had 2" of static deck height. We all saw the writing on the wall but they eventually put the nose hieght rules that I said was needed before anyone understood it or why and what was happening. I just wasn't gonna explain it and lose the advantage that a lot of people didn't know was going on.

I guarantee I wasn't the only one that knew how to do it. Also the position sensitive stuff isn't new and been around on other corners of the car for a long time, just not many people will talk about it.

[hucktyson]

Make the right front static 10” max and check the deck height after the race on the scales like we always used to do .... That eliminates a TON of BS

[fastford]

billet , i read an article some where , i,m gone try to find it , that discussed a shock like your describing , i think they called it a variable shaft location valve or something like that.....

[Kromulous]

https://vimeo.com/103859987

https://www.youtube.com/watch?v=pyoYRSPmdwA

[billetbirdcage]

https://vimeo.com/103859987

https://www.youtube.com/watch?v=pyoYRSPmdwA

The problem with most of those bypass type shocks to make a position sensitive shock is they change both compression and rebound in those zones. So many of those styles can't just change comp or rebound without effecting the other also.

Now granted maybe you want both increased or decreased in certain places, but maybe you only want to change one direction and not both. Like I said, those been around a long long time. That style won't do what I was talking about, because you'd have high comp and rebound in that last part of the travel and less of both in the other 8" of stroke of the shock which wouldn't deal ideal in the situation I was describing as far as a LR front shock.