Shock Tech Q&A

[PenskeShocks]

Please post any shock related questions. Penske Shocks is making a big push into LateModels and our techs are here to help you with any shock related questions or comments...we will have 2 technicians in Knoxville next week, we will be working with Scott Bloomquist, come by and see us.

[37mod]

if the 5th coil shock has to an extreme amount of rebound will it cause a push on a momentum track by not letting the front settle?

[PenskeShocks]

Definitely, we typically run very little to no rebound on the 5th. Generally the 5th is a great shock to control on throttle grip.

[racin6mod]

how much to rebuild a lr gas shock mine has a ding in the shaft and a leaking seal.

[zeroracing]

What is the biggest mistake or false trend that you see late model racers doing?

i.e. Too high rebound one wheel, too low compression, vise versa, gas pressure mistakes...

[JR. MECHANIC]

Definitely, we typically run very little to no rebound on the 5th. Generally the 5th is a great shock to control on throttle grip.


Are you sure you two are talking about the same shock.... I believe he is asking about the shock on the lift arm.... Typically 3 compression, 3-7 range on rebound depending on track condition. It looks like penske is talking about the damper on top of the housing.....

[37mod]

I was referring to the shock on the lift arm.
thanks for the reply.

[stevo]

Bloomquist runs a shock on top of the rear end,feels like 90/10 but most don't so if most don't run one on top should the 5th coil be higher number rebound,if not will car not be loose?

[JR. MECHANIC]

Stevo, adding more rebound to the 5th coil shock will tighten entry. One cannot say that if you don't run a top shock, that you have to add more rebound to the 5th coil. Let the stopwatch determine that.

Brandon Dierlam
MBR (mark bush racing)
Shock guru

[stevo]

I was think they did the same thing,

[JR. MECHANIC]

Simplying adding a 90/10 will tighten entry also

[stevo]

So is this doing the same thing? Adding rebound on 5th as putting 90/10 also some say anything on rearend takes away drive,and how did Bloomquist do with these shock guys i see there not here anymore.

[JR. MECHANIC]

You see who isnt here anymore? The only way a top shock can take away drive is if there is rebound control or it is topping out under acceleration

[mab475]

I believe he is referring to Penske Shocks. They started the thread wanting questions from everybody and has only been on once since. If this is any indication of their service then I'm sure guys will just stick with what they have and the shock guys they have.

[PenskeShocks]

Guys, sorry I haven't been on lately.. At Knoxville currently. I will post back to all your questions Monday..As for the rebuild..$50 per shock, includes post Dyno, new shims, oil, and seals...

[PenskeShocks]

This is a reply for the above question about the most common mistakes. This is a tough one, when it comes to shocks, i think the biggest mis-conception when discussing shocks is using the number value when explaining damping values. A good race shock, and there are a few out there besides Penske, have so many different damping levels, both low and high speed, you can't really refer to them as a single number. When you take into account the different piston types, along with bleed, and shim combinations, you end up with a limitless variety of damping options.So the biggest mistake is thinking these really good full time racers are running standard off the shelf shocks, some might be, but the good ones, have some one custom tuning their shocks to work with their driver feel and car set-up.

[PenskeShocks]

Penske Shocks is looking at having a Seminar at PRI this year pertaining to Latemodel Chassis Set-Up. Please let us know if you will be attending PRI and if you would be interested in attending, we are thinking of having this after the show ends in one of the hotel banquet rooms. We would have dinner catered, also would have special guest speakers.

[PenskeShocks]

Stevo, there are a number of reasons we run different set-ups on the 5th. Its not the same everywhere we run. Track condition, banking, length of turn, all play factors in what you want it to do. It is a tuning device. Now obviously there are a lot of areas you can tune with on these cars, and one area will always effect another, so you can just say you should run a certain 5th coil build everywhere, believe me, if it was that easy, everyone would do it. It is like any other corner of the car. Figure out feel wise what you want your car to do. Talk to people to find out a direction, but don't just take someones word, try to figure out what they are telling you to do and why, if they can't tell you why to run a certain shock # or build, best bet is they don't know. Even if it helped them, if they don't know why it helped them, they won't know why its possibly hurting them in other areas.

[hucktyson]

Penske Shocks is looking at having a Seminar at PRI this year pertaining to Latemodel Chassis Set-Up. Please let us know if you will be attending PRI and if you would be interested in attending, we are thinking of having this after the show ends in one of the hotel banquet rooms. We would have dinner catered, also would have special guest speakers.

Ill be there ... Where do I sign up ?

[PenskeShocks]

Hucktyson, if you email me at ajl@penskeshocks.com, i will send you the info once its finalized.thank you

[PenskeShocks]

Ok guys, looks like we will be having a 1hr seminar on either Thursday or Friday at PRI. Shooting for 10 o'clock. Once i have all speakers confirmed i will re-post. Right now it is Penske Shocks, and Hyper Coil Springs. Waiting on confirmation of a few more guest speakers.

[PenskeShocks]

PRI is willing to work with us and have the seminar during show hours. we will post official time and date shortly. Tentative we are looking at Friday during PRI from 10-11am. Keep an eye on their seminar schedule. i will re-post as soon as i have an official date/time.

[PenskeShocks]

Ok, here is the confirmed information on the PRI Seminar. Hope to see everyone there.Penske Shocks will be holding a seminar at PRI this year. Below is the information. This will be a Latemodel Suspension seminar. Will include representatives from Hyperco Spring, Penske Shocks, and Scott Bloomquist. Hope to see you there!Friday, December 13, 20139:00 am – 10:00 amSeminar Title – “Penske Racing Shocks Short Track/ Latemodel Technology”Meeting Room – 211

[TALON75]

do we need to sign up for this or just show up?

[HEAVY DUTY]

Are you sure that the damper was a 90/10? Could it have been a dummy shock to keep the rearend from turning over in case a liftbar broke? It might be something softer ran in conjunction with a softer liftbar shock. Everything is a combination that has to work together

[PenskeShocks]

you just have to show up. it is open to everyone. seating for 100.

[bdr.team.jacob]

in what ways do you change your base setup between 4 link and swing arm cars?

[PenskeShocks]

BDR, depends on what your trying to achieve by switching. What issues are you having with your current set/up?

[Windy]

Penske Shocks is looking at having a Seminar at PRI this year pertaining to Latemodel Chassis Set-Up. Please let us know if you will be attending PRI and if you would be interested in attending, we are thinking of having this after the show ends in one of the hotel banquet rooms. We would have dinner catered, also would have special guest speakers.

will be attending,would love to attend seminar..as a 47 year racefan/driver/crewman/crew chief..everyone has been taught and learned the standard number system because it is extra simple..racing needs as much shock help as we can get..

[PenskeShocks]

Please attend, we will have a great panel and will help you understand the shock basics and the different variables. You will easily see why a standard numbering system doesn't begin to tell you what your shocks are.

[LLOYD-XMAS]

I have a question what is to tall when talking about bump-stops on the rf of a dirt late model? What is considered to tall for the christmas tree style? Also what happens if the bump-stop is a touch to tall? Thanks

[PenskeShocks]

There isn't really a measurement that is too tall. All depends on the track and how much your RF is traveling and when you want to get into the bump stop and how much. In general, if you get into a bump stop too soon, especially in the RF, it will tend to tighten the car up. Bump stops are very tricky, if your running a bump stop set-up you have to be sure you run enough rebound to control the force produced by the bump stop.

[fastford]

I have a question what is to tall when talking about bump-stops on the rf of a dirt late model? What is considered to tall for the christmas tree style? Also what happens if the bump-stop is a touch to tall? Thanks

when i first started with the bump stops, mine were to tall, i cut them down a little at a time to get the amount of dive i wanted, then if during hot laps it was diving to much, i would shim it back up, i got all my stuff from re suspension, one thing to remember, if you cut it , it will get stiffer, but with the christmas tree type , it dont effect it much , also the more dive on rt ft, the more rear steer and the freer the car will be

[LLOYD-XMAS]

Thanks for the replies.

[xray]

The question everyone wants to know but afraid to ask, How much RF rebound @1ips for a stack combo? For a conventional 400?

How much rebound do you take out throughout the night as it slicks off?

[MasterSbilt_Racer]

The question everyone wants to know but afraid to ask, How much RF rebound @1ips for a stack combo? For a conventional 400?

How much rebound do you take out throughout the night as it slicks off?

That is where the crew chief earns his money. There is no one right answer. Your stopwatch, eyes, and the driver determine that for the given track.

[PenskeShocks]

I agree with MasterSbilt. There is no right answer, depending on chassis, driver, tire choice, and other factors, it can all vary. There is definitely gains to be had when it comes to zero point rebound, the type of rebound curve being run, whether its digressive or linear. Again may things, 1" velocity is important but its usually because the amount of bleed run in the shock. The proper bleed is more important.

[xray]

I agree with MasterSbilt. There is no right answer, depending on chassis, driver, tire choice, and other factors, it can all vary. There is definitely gains to be had when it comes to zero point rebound, the type of rebound curve being run, whether its digressive or linear. Again may things, 1" velocity is important but its usually because the amount of bleed run in the shock. The proper bleed is more important.


I agree, and apologize with the vaugness of the question, But there has to be a "starting point" for weekly guy on a non glass smooth surface? I guess i hoping for an answer that i knew didn't exist.

I have been all over the map on RF rebound and cant put consistent back to back results together to get that "AHA" moment. Am I at least on the right page by taking it out in the slick to add grip?

Has anyone found out what "too much" compression in the LR front is either?

[xray]

Also by bleed do you mean in the stack or with the needle, or a combination?

Thanks for the reply!

[MasterSbilt_Racer]

Am I at least on the right page by taking it out in the slick to add grip?


Do you have so much that the front is ratcheting down? Are you on a paperclip or a momentum deal? The right adjustment on one night at one track can be completely wrong the next night at another track.

It reminds me of the early 4 link days when people argued about cheat sheets that didn't agree. One said stiffer lr spring tightens exit. The other said softer tightens exit. Guess what?, both can be right!

[xray]

Yes, full tight the rebound overcomes the spring with the bumper dyno test.

Majority of places i run are paperclip style, 1/4 miles

[JR. MECHANIC]

Penske, what's your thoughts on "critically damped"?

[PenskeShocks]

honestly, we typically never have much luck with critical damping. in theory or some simulation it should work, but in actuality, when it comes to driver feel, track conditions, tire wear, you will typically end up with a different curve. I know some engineers that live by it, some work, but majority we have seen struggle to make it work. They get so focused on critical damping, they end up tuning everything else around it.

[zeroracing]

Penske has a wide range of shocks available, what in your opinion is the best choice for a budget racer that runs one track week to week, as far as out of your line up of shocks?

[PenskeShocks]

If your running the same track week to week our 7500 non adjust is perfect. All our shocks use the same piston diameter so. internally you getting the same as our other shock, just not the adjustability. We have a lot of local guys and thats all they run, because like you said, they run the same track each week.We are finding we run a similar curve a lot of places, you could probably get away with all non-adjustables for a lot of tracks, may just need a few RF, RR, and LR options.

[PenskeShocks]

I would like to thank everyone that showed up to PRI this year and attended our seminar and stopped by our booth. The turn out was great and we had some really good discussions with some really good racers. Can't wait for 2014!

[hucktyson]

I spent a considerable amount of time talking to Penske at the PRI ... And I can say without a doubt there is an entirely different level of shock technology out there that the Penske guys operate on and the other manufactures aren't even aware it exists. I would have to be insane to not switch to Penske z

[racin6mod]

I would like to thank everyone that showed up to PRI this year and attended our seminar and stopped by our booth. The turn out was great and we had some really good discussions with some really good racers. Can't wait for 2014!

any chance you guys would be at the widwest speed expo jan 11/12 . I have a couple shocks I want revalved rl-rf

[7uptruckracer]

Penske truly is top notch and are really stepping up in the dirt world their asphalt has always been second to none. Don't rule out JRI their booth the other week was amazing and they are top notch as well you can't go wrong with either IMO. The only problem we ever had was because we ran nascar LMSC breaking shim stacks and their nascar piston (has to be approved so it is what it is) isnt the bees knees but you won't be unhappy with either