Conversation on Shocks

[MasterSbilt_Racer]

A traction shock has nothing to do with attitude?

If you take it off and your car looks the same, what is it doing for attitude? Shocks work by moving. They are intended to damp motion. You can build something crazy to act like a prop stick, but that isn't going to be the fastest way.

[let-r-eat]

Originally Posted by let-r-eat View Post
A traction shock has nothing to do with attitude?

MBR"If you take it off and your car looks the same, what is it doing for attitude? Shocks work by moving. They are intended to damp motion. You can build something crazy to act like a prop stick, but that isn't going to be the fastest way."


If the propstick improves aero/increases bar angles etc etc that outweigh the disadvantage of the propstick? I believe you know I'm talking about dynamically balancing the race car.

I think it's important to define what the "right shock" *goal* may be.

It's a plethora of variables. That right front hold down deal.........the traction shock........the ratcheting stuff............They all deal with attitude.

The right shock controls motion to improve traction. A prop stick isn't a shock. You can build a shock to be one but IMO that's not a shock and you must compensate for the motion somewhere else on the car.

[MasterSbilt_Racer]

Originally Posted by let-r-eat View Post
A traction shock has nothing to do with attitude?

MBR"If you take it off and your car looks the same, what is it doing for attitude? Shocks work by moving. They are intended to damp motion. You can build something crazy to act like a prop stick, but that isn't going to be the fastest way."


If the propstick improves aero/increases bar angles etc etc that outweigh the disadvantage of the propstick? I believe you know I'm talking about dynamically balancing the race car.

I think it's important to define what the "right shock" *goal* may be.

It's a plethora of variables. That right front hold down deal.........the traction shock........the ratcheting stuff............They all deal with attitude.

The right shock controls motion to improve traction. A prop stick isn't a shock. You can build a shock to be one but IMO that's not a shock and you must compensate for the motion somewhere else on the car.

I guess my point is that you can make the car be nose down lr up without any crazy shocks. And you should. No way the benefits outweigh a rigid suspension.

[Kromulous]

Stede, its sounds like you have real shock experience, so i have a question for you? Why do all the shock companies promote a digressive valved over a linear valve? I know the party line, they have more traction, and i think thats a complete load.

[MasterSbilt_Racer]

Stede, its sounds like you have real shock experience, so i have a question for you? Why do all the shock companies promote a digressive valved over a linear valve? I know the party line, they have more traction, and i think thats a complete load.

I am not Sted, but if you have ridiculous rebound at 1"/sec if will really be crazy at 10" if it isn't digressive.

[zeroracing]

Also to answer Kromulous some in the sports car or F1 type realm will tell you the opposite. That often a linear valve will produce more traction overall, but drivers will not like the feel as much and it will not control body movements as much. But for pure mechanical traction very little dampening and very light springs would be best.

Other side note, it is my understanding that the high frequency pistons that people like on dirt were originally designed for novice drivers that hit curbs on road courses to keep from upsetting the car with dampening too much on those hits.

[Kromulous]

Its already crazy rebound digressive or linear. If u were to do a linear valve you would have to scale it i would think. Also what purpose does the bleed adjustment serve on a linear valved shock? Most DA shocks only manipulate the bleed orifice is my understanding.

What is meant by "High freq" anyway, especially for a shock piston?

Why do say Drivers will not like the feel of a linear valved shock?

Thanks, Krom.

[Stede Bonnet]

Stede, its sounds like you have real shock experience, so i have a question for you? Why do all the shock companies promote a digressive valved over a linear valve? I know the party line, they have more traction, and i think thats a complete load.

Digressive is typically better for slick situations where maintaining traction is a must.
Linear or progressive would be better suited for hooked up, heavy and rough tracks.
These are general rules of thumb, driving style can't be overlooked either. If the driver doesn't like it or feel confident in whats under him it won't be an optimum situation.

[MachineMasters]

One thing to understand is that bleed has a huge effect on rebound in a digressive shock.

For example, Carrera was real big on large bleed digressive shocks. Meaning - there was little damping control at lower shock velocities (1ips - 3ips). Modern/current shocks used in DLM racing have little to no bleed which is what helps keep the car on the RF. This low/no-bleed digressive curve looks and performs entirely different at lower shock velocities. A big bleed digressive shock lets the car 'move around' and can promote weight transfer due little resistance in the shock at low velocities, but also can let the nose pop up in dirty air and give the car a sloppy feeling.

My preferred damping characteristics for each corner are:
LF - linear compression/digressive rebound (the type of curve is least important on this corner)
RF - linear compression/digressive rebound
RR - linear compression and rebound (large bleed w/stiff stack)
LRF - digressive with large bleed
LRR - digressive compression/linear rebound

[Kromulous]

Why do you like the RR set up that way, better feel st speed?

[Brian Gray]

Facts are there things available from different manufacturers that are unique to particular brands. I build them all I've worked with literately thousands of components and shocks have become a passion of mine. The characteristics of certain pistons are most definitely noticeable to the driver yet never show on our oscillator style dynos. Even on the mag I really haven't seen real definable data but driving I can tell a vdp from an mx. Fox has came out with some real good stuff but the variety of choices Penske has is very hard to beat.

Everyone in the know can agree it's not so much the brand it's the person working with you that makes the difference. But the only reason I bothered here was to answer mats question about the new Afcos. Yes they are very good they are quality wise as good as anything Penske or jri have. But along with quality comes a cost and it's on the same level. For the money though I still believe the silver/blue afco monotube shocks are much more bang for the buck . I don't know why every local team isn't on them.

[Matt49]

Everyone in the know can agree it's not so much the brand it's the person working with you that makes the difference.

Truer words never spoken.

[Brian Gray]

For the record, I didn't say it could not be measured. But I personally have experienced some noticeable variances between specific builds that looked nearly identical on a very high tech shock machine. .

I think that speaks volumes.

[fastford]

im on a set of blue afco,s that jerry link did for me just before leaving shy and going to afco, there the best shocks for my application ive ever had. ive talked to jerry several times since his move and im not going to tell on here all we discussed , but I personally feel after talking to him, my old blues are just as good ,for me, as the new ones. I think basically you are paying for what he was already doing and brought to the table at afco.

[fastford]

To say we, "Carrera" were big on big bleed/digressive is a little misleading, like that's all we knew how to do. We built whatever the customer wanted. For example we had an asphalt customer who wanted all his shocks(4-7 valve) on compression from 1 in/sec - 3 in/sec to all be the same, but wanted them to blow off differently. So we built them that way. We also built rear shocks for Talladega cup cars(before the rules change) to qualify that were more than 1500 @ 1 in/sec rebound climging to in excess of #3000(customer specified). Chub Frank, at that time, liked running digressive RS shocks with 5 rebound and 3 compression, but this was in line with the setups of that time and he won the Stars title running exactly that. We built a Magne-shock for the military hummer program that broke their dyno, which sounds bad but that earned us the right to move on to the next level in their trials. So you see we had a broad spectrum of what we could and did do. My main focus was R&D, developing different curves and testing different fluids and components. Carrera's didn't just come in one flavor.

In closing, I have a question for those who believe that some things can't be seen or have not been seen on the dyno. If you can't measure a given designs effect in some way, how do you prove it made a real change and isn't some placebo effect? Their are good dyno's and their are great dyno's, the great ones can tell you everything that's happening. Most "racer" dyno's just don't have the technology to do it, most only give peak velocity dampening numbers. I guarantee the shock companies that developed the parts and shocks know exactly the effects the those parts had before they left the lab and could accurately measure them on their dyno.

one thing that cant be seen on a dyno is how two identical shocks of the dyno will react to two different drivers, i would bet they will have two different opinions , i guess that would be the effect part you speak of, so to me , if the designs are identical, then you cant measure the "effects" of two different drivers.

[Ghopper]

For perspective:
- Great dynos cost ~80k (electro-magnetic). Research level, frequency sweeps, track playback, sine/square/triangle wave possibilities. There are servo hydraulic system that MTS builds for damper testing.
- Good dynos cost ~10k (sinusoidal). Production level, limited frequency input, sine wave.
- Pen dynos confirm if the shock if broke or not. You do not design shock builds with this dyno.


Ghopper

[billetbirdcage]

For perspective:
- Great dynos cost ~80k (electro-magnetic). Research level, frequency sweeps, track playback, sine/square/triangle wave possibilities. There are servo hydraulic system that MTS builds for damper testing.
- Good dynos cost ~10k (sinusoidal). Production level, limited frequency input, sine wave.
- Pen dynos confirm if the shock if broke or not. You do not design shock builds with this dyno.


Ghopper

Good to see you getting to race a little, the euro manufacturers gave you some time off or you back in the states for a little while?

[Kromulous]

What the problem with shocks is no one will share info, and i get it, its $$. Shock Builders are ok, but some i feel are out right crooks, all they do is "rebuild" and dyno a shock and want to charge you $300 bucks, thats complete crap. Most of them have no idea what different pistons do, or frequencies or anything, its just copy this, do that, and buy more stuff for more $$.

Machinemasters, is the 1st post i ever seen on any real info on shocks, something a guy can use and work from. I plan to talk to a "Shock guru" and build from there.

Reason i asked about the RR build he mentioned was, many years ago i used to build my own Modified shocks, QA1 twin tubes. Thats how i built both right sides, Linear, stiff stacks, and biggish bleeds on rebound, and those were some of the best shocks we have ever ran to this day.

[Stede Bonnet]

One thing to understand is that bleed has a huge effect on rebound in a digressive shock.

For example, Carrera was real big on large bleed digressive shocks. Meaning - there was little damping control at lower shock velocities (1ips - 3ips). Modern/current shocks used in DLM racing have little to no bleed which is what helps keep the car on the RF. This low/no-bleed digressive curve looks and performs entirely different at lower shock velocities. A big bleed digressive shock lets the car 'move around' and can promote weight transfer due little resistance in the shock at low velocities, but also can let the nose pop up in dirty air and give the car a sloppy feeling.

My preferred damping characteristics for each corner are:
LF - linear compression/digressive rebound (the type of curve is least important on this corner)
RF - linear compression/digressive rebound
RR - linear compression and rebound (large bleed w/stiff stack)
LRF - digressive with large bleed
LRR - digressive compression/linear rebound

Your critique of Carrera is a bit broad an inaccurate. We didn't just build one kind of shock, with one set of curves, it depended on several variables such as customer preference and application. For example the qualifying shocks we built for the rear of Cup cars at Talledega were similar to todays DLM RF, letting the car fall and then holding it there. We built what suited the setups of the times and customers application, they were not, "one size fits all" and not only in vanilla. Compared to our contemporaries of the times, we had the broadest selection of designs, styles, sizes and curves ahead of anyone, period. With the right equipment and knowledge you build whatever is needed, the trick is knowing whats needed. Cheers.

[7uptruckracer]

^^^^ SO very true even in todays world, they have to work with the spring packages.