Shocking Questons for Jerry O or anyone.......

[Sumner]

jl222 .......  I will be running the car at Maxton so I think suspension is need there. The car is a flat bottom car and the ride height can be adjusted from 1 inch to 2 inch inch ground clearance. The way I have designed it I can run as soft or as stiff as I need. I can also lock it solid if need. The shocks are gas shocks that require no coil over springs. The ride height, compression, rebound. and spring rate are adjustable also.

Do you have any pictures of what you've done?  I'd like to see them.  I have multiple positions for my springs and separate multiple positions for my shocks that will both vary their travel and stiffness (both ends of the car)....



http://purplesagetradingpost.com/sumner/bvillecar-2/construction%20page-78.html

.....and it is getting closer to the time of ordering both.  I'm not too worried about the springs, but have concerns about picking the right shock.  I will be running about 1 to 1 1/4 inch of travel at the suspension pickup point near the wheel/tine and plan on having most of that on compression.  I don't really have the budget for $400 shocks and have been looking at some $100 QA1 shocks with a 7 inch stroke and they have all the different valving (comp./reb) numbers that I kind of understand, but don't know which to use in my application.  I know I want a stiff setting, but how stiff?  With the lever arms I have depending on where the shock is mounted with 1 inch of travel they will see 1 to 2 inches of travel (the same with the springs).  The springs will be 10 inch 1 7/8 dia..

Sounds like with your background you might know where I need to go with this.

Thanks for any help and anyone else that might have something to say, even if it is just opinion, jump in,

Sum

[JimL]

Sum....check into these:

Front wheel drive, transaxle type powertrains are a 300-400 lb. lump mounted on soft engine mounts (needed for the 4-cylinder vibration).  Due to the reaction of rough roads (like segmented concrete, here in SoCal), the powertrain can get into a cyclic "jumping mode" that shakes the whole car.  As a result, you'll find many cars have a single shock absorber mounted between the side of the engine block and the subframe. 

These shocks are designed for very short travel with zero lash before damping begins (have about 2 1/2" of available stroke).  The damping is zero-zero so there is no pump-up or pump-down.  The actual damping is so quick (since they are designed to handle very high frequency oscillation), they should do well for you.

I gave a batch of them to Mike Cook, some years back, and he may still have some around.  Those were designed for the early-mid 90's Toyota Camry 4-cylinder.  I know some of them have been run on the salt, and they worked well.

I run these on my street rod, but the damping is so strong I have to lay them down and use softer bushings.  Here's a pic below....they come with the weatherproof boot already in place.  The bottom end has a bolt on type bracket (as seen on my rear shock mount).  In the pick-a-parts they're about 5 bucks.

Regards, JimL

[Jerry O]

Sumner...... If you plan on using the QA1 shocks, I would contact them to determine what valving to use. They will need to know what spring rates you will be running and what the rocker ratio will be. I am sure they will need other info also. I too was going to use the QA1 shocks because of the cost but came across a great deal on these gas shocks that were used on a USAC midget. I think they normally cost about 500 bucks each, well over my budjet also.  Since my car is very small and not much room for any type suspension, these shocks worked out perfect. I am using a four link system on the rear and a rocker type system on the front. The front shocks are mounted rear of the front axle setting parallel to the ground plan. Much like most indy cars are. I don't use a bell crank and push rod like the Indy cars. The lower control arm is part of the rocker system. My front axle king pin to king pin center line is only 6 inches apart so I had to come up with this configuration. Really pretty simple and easy to make. I will get some photos of it to you this week end.  The QA1 shocks you plan on using, do they have external adjustments for bump and rebound. That will leave you a little room if you don't get the valving just right. When I worked on the Penske indy car team one of my many jobs where to build and maintain all the shocks for all three teams. One good thing I had at that time was a shock dyno so matching shocks was not a big deal. If you can't get any info from QA1, let me know I'm sure we can come up with something that will work for your application. I will just need to get some specific numbers from you so I can determine what your shaft/piston speeds will be.  I will be glad to help if I can............JerryO

[Sumner]

Thanks guys for taking the time to respond.  Jim I'll look into those shocks.  That might be an option to try right off the bat just to see how things work before investing more money.  I'll try and get in touch with Mike and if that doesn't work out I'll be begging some of you guys to look in some salvage yards for me since there are none near here, but I do have to go to Farmingion, NM soon and there are a couple large ones there.  If I tried those I'd have to make an adapter for the one end to work with my present shock mount system, but that could probably be done pretty easily.  Are you pretty sure about the 2 1/2 inches of travel.  I think I would need a minimum of that due to the movement range of the lever arm at the shock compared to the movement at the wheel/tire.  Maybe they would dampen too much?

Jerry one of the guys at QA1 told me that he would have an engineer try and help me with my car.  I just wonder if they will have the time to really think about it considering the uniqueness of the suspension setup, limited travel and our needs on the salt.  For the rear I'm hoping to keep it as soft as possible considering the travel limitations.  I've talked to more than one car owner that felt they could keep the rear hooked up with a softer suspension in the rear and that makes sense since I use to run on 14 miles of wash board gravel road everyday in Wyoming for a number of years.  I feel the front can be somewhat firmer.  The problem we have is that the track changes from smooth to rough year to year and during the week as it gets torn up.

c ya,

Sum

[JimL]

Actually, the travel is closer to 3"....I just did all my planning at the 2 1/2" stroke to be sure I'd be ok on the little T.  You'll have more suspension stroke as you lay them down, of course, and you'll probably have to.  They are intended to control over 300 pounds of "unsprung weight", so to speak. 

I had them on the original front suspension of the 797 Roadster and the damping was very strong.  Unfortunately...in a moment of total brain f**t I made a trailing arm front suspension using the lower control arm of an old pickup....great idea if you want the front wheels swinging back and forth, side to side, on the rubber control arm bushings!  It made some stupidly interesting rides at Muroc, El Mirage, and Bonneville.....the longer I learn, the less I seem to know.

One thing I'll mention....the top bushings (rubber donuts) are where you determine your initial "travel-to-damping".  The double-nut arrangement allows you to adjust that.  The tighter you tighten, the quicker the damping reaction.  On my street roadster (in the rear), I use a softer, taller cushion on the compression movement, and a harder, thinner cushion on top (for the rebound).  That seems to help when hitting a cyclic (evenly spaced) pattern of bumps at higher speed.  I do that because 65% of my cars weight (850 lbs.) is on the rear axle, so bumpy corners can get spooky.

Also, with a lower eye that does not use a Heim, the shocks will tend to bind if there is any bend sideways on the eye.  You will probably be a lot better off than my street setup, because you aren't looking for as much articulation.  On my front axle, I pressed out the original bushing and rubber, and substituted GM "repair kit" shock cushions.  That makes the axle supple (plenty of articulation, despite the split wishbones).

Hope this is helpful.  Below is a pic that might give a little better idea of the size and mounting....they are pretty well extended in the picture, because only the engine, trans, and fuel tank were mounted, and the engine has a LOT of setback (the radiator shell fits behind the front cross-member).

Sorry...get to rambling on, it seems...
Regards, JimL

[Skip Pipes]

Hi Sum,

I'm building Fuel/Gas Roadster (with rear suspension) and last November took a clue from your site and contacted QA-1 for some advise. Spoke with Reed whom I believe is a sales engineer about my suspension strategy and he felt my requirements were unique enough to require specialized attention so he referred me to Naake, Inc. http://www.naake.com in California as they specialize in custom assembles of QA1's. Worked directly with Mike Naake, who was extremely patient in listening to my shock & suspension strategy? Nonetheless, I share a similar belief in compliant compression dampening and serious rebound dampening, as I want the car to settle and stay there. My front and rear shock requirements are somewhat different as I've tucked the front coil-over’s inside the grill shell, with resulting .4 motion ratio. Therefore, I spec'd a 3/9 compression/rebound for the front and a 4/8 for the rear, which required custom valving, which required set-up on their shock dyno. I also took counsel from them and opted for double adjustable QA1’s as I'm certain my strategy is all theory and I might need some adjustability.
 
Skip Pipes

http://www.naake.com/
916-771-0109 Phone
916-771-5201 Fax

[Sumner]

Jim thanks for the additional info on the shocks and Skip I'll check that company out and give them a call. 

With the lever arms and multiple attach points I'm able to have quite a bit of variation in shock travel, anywhere from about 1 : 1 to 1 : 2 (wheel travel : Shock travel) in the back and almost the same in the front.  I was hoping with the longer shock travel vs. wheel travel that it would be easier to find a happy spot with a cheaper shock.

Like you Skip who knows if this is going to work until we try it.  I like the damping numbers that you came up with.

c ya,

Sum

[Rex Schimmer]

Sum,
I am sure that you know this but I want to make sure.  Because you are laying the shocks horizontally you must use some sort of "gas" shock that either has an internal or external pressurized "accumulator" that allows the shock to work in any position. The normal "double tube" shocks will not work in your laydown position.


JimL,
Like the looks of your street rod, is that a Toyota motor?. Looks similar to my roadster, I use a Ford Zetec 4 cylinder. Drop me a line and some pictures on my private E mail: rexschimmer@gmail.com

Rex

[Sumner]

Sum,
I am sure that you know this but I want to make sure.  Because you are laying the shocks horizontally you must use some sort of "gas" shock that either has an internal or external pressurized "accumulator" that allows the shock to work in any position. The normal "double tube" shocks will not work in your laydown position..............

Yes I was aware that I needed a shock that could be used in any position, but it never hurts to remind an old guy like me about anything, so I appreciate it,

Sum

[Jerry O]

Sumner       I think the shock valving direction you are looking at is a good idea, just be carefull with getting too aggressive with the rebound forces.  A problem that can accur is too much rebound stiffness and the chassis will jack itself down. This can happen when you hit a bump and the shock compresses, if the bumps are close enough and frequent enough,  your stiff rebound will not let the shock travel back to normal ride height before you reach the next bump and you start to loose ride height. Where it can be a big problem is if only one wheel hits a bump and it compresses and then fails to travel back to normal ride height fast enough, this will change your cross weight and can make for a very unstable car. You may never have a problem with this but just keep it in mind if find your car starts get weird. I used this setup on some of the nascars, before nascar got smart to it. Since nascar has a ride height rule, we would build a set of shocks on the rear that had a very stiff rebound setting. When the car went out for qualifying it would start to jack itself down in the rear, this would lower the rear and get the spoiler out of the air on the straight away's. This would give the car a few more MPH. Then when the car came back off the track for inspection, it would have time for the shocks to travel back to the origanal ride height. Worked for a while. Old technology now. JMO

[Sumner]

Sumner       I think the shock valving direction you are looking at is a good idea, just be carefull with getting too aggressive with the rebound forces.  A problem that can accur is too much rebound stiffness and the chassis will jack itself down. This can happen when you hit a bump and the shock compresses, if the bumps are close enough and frequent enough,  your stiff rebound will not let the shock travel back to normal ride height before you reach the next bump and you start to loose ride height. Where it can be a big problem is if only one wheel hits a bump and it compresses and then fails to travel back to normal ride height fast enough, this will change your cross weight and can make for a very unstable car. You may never have a problem with this but just keep it in mind if find your car starts get weird. I used this setup on some of the nascars, before nascar got smart to it. Since nascar has a ride height rule, we would build a set of shocks on the rear that had a very stiff rebound setting. When the car went out for qualifying it would start to jack itself down in the rear, this would lower the rear and get the spoiler out of the air on the straight away's. This would give the car a few more MPH. Then when the car came back off the track for inspection, it would have time for the shocks to travel back to the origanal ride height. Worked for a while. Old technology now. JMO

Some good points to think about and watch for.  I'm starting to think that I need to be looking on e-bay or some of the stock car sites for some more expensive (when new) used shocks that are adjustable.  That would make things easier than new ones that are cheaper, but would have to be re-valved.

On my pickup I use to drag the back bottoms of the front fenders when hitting dips on some of the bad roads around this area.  I put out the money and replaced the gas shocks I had with some good 50/50 Carrera shocks and it solved that problem as the truck wouldn't compress the springs as fast and as much.  The shocks I had before those didn't do much on compression, but more on rebound.  It handled much better all around after that as it also slowed body roll going into a corner.

I sent you a PM about your build pictures.

c ya,

Sum