Conversation on Shocks

[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.

[MachineMasters]

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.

Oh yes, I know.. sorry, wasn't trying to offend. I think Carrera was ahead of its time in the market: super lightweight shocks, PTFE lined shock bodies, 4-lead threads, basevalve, floating rod guide, 48mm piston, checked bleed circuits, real digressive pistons, etc. When they incorporated the Ohlins style rebound adjuster they got even better.

Getting back to the OP, shocks nowadays are all good for the most part - there really aren't any 'bad' shock brands out there. As others have stated, it all comes down to how they're valved. With the type of racing we all do, I'd be VERY impressed if someone could feel a difference between two identical valved shocks from two different brands. On asphalt yes, on dirt, I'm skeptical.

[RCJ]

In reference to the Digressive vs linear.A linear such as a 208/72 will only be at that rate at one velocity,low speeds it is soft ,high speeds it is stiffer.A dig.will be closer to its advertised rate over a much wider range of velocitys thus able to control the inertia of the wheel and tire over a wider range.Any time you talk about shocks you have to ask what are you trying to do.Control the tire over bumps, Change the handling or balance of the car or Hold the body at a certain attitude for aerodynamics.

[Kromulous]

Were looking to get more feel in the car, currently feels disconnected to the track and like its just floating across the surface. What would you suggest to do?

Mods it seems its easier to get a better feel of the track, smaller tires and firmer sidewalls i guess.

Especially in the RR.

Like everyone else nowadays, RF pinned down, a lot of hike, traction is pretty good and the car goes FWD ok, but he keeps telling me over and over the car lacks side-bite on the RR and no feel.

[MasterSbilt_Racer]

Were looking to get more feel in the car, currently feels disconnected to the track and like its just floating across the surface. What would you suggest to do?

Mods it seems its easier to get a better feel of the track, smaller tires and firmer sidewalls i guess.

Especially in the RR.

Like everyone else nowadays, RF pinned down, a lot of hike, traction is pretty good and the car goes FWD ok, but he keeps telling me over and over the car lacks side-bite on the RR and no feel.

Put a big RR spring in there Krom.

[fastford]

In reference to the Digressive vs linear.A linear such as a 208/72 will only be at that rate at one velocity,low speeds it is soft ,high speeds it is stiffer.A dig.will be closer to its advertised rate over a much wider range of velocitys thus able to control the inertia of the wheel and tire over a wider range.Any time you talk about shocks you have to ask what are you trying to do.Control the tire over bumps, Change the handling or balance of the car or Hold the body at a certain attitude for aerodynamics.

great post RCJ, that pretty much sums it up. when i first tried the soft rt frt on a bump stop , i turned my rebound all the way up on my m2s and i could feel the rt frt hoping or almost kind of vibrating, when i explained this to my shock builder he explained the need for slow speed dampening when doing this, now im no shock expert , but it made since to me so i sent him my shock with all the info he wanted, ie: shock measurement from eye to eye at ride height, static weight on that wheel and several other things , he sent me the shock back and it was night and day , sold me.......