DAVECS1

iTrader: (2)

In all reality a panhard is perfectly fine for our cars. If you have enough travel in the rear that you are experiencing unwanted axle movement in the rear, the that is probably too much.

Along with that thought if your car is setup properly and you are able to drive to the point you can feel the panhard making the rearend walk on you, that in its self is an accomplishment. I have only had this problem on one autocros track and once I understood what was happening I was able to walk the car even faster around the corner to the chagrin of my tires.

Pan hards are very effect when setup right, and suprisingly GM did a very decent job putting one in out cars. It is the correct length and with some tweaking it is easy to set at the correct height.

For all those wondering why people are questioning the panhard, basically it is the realavant motion of the bar when you draw the kinematic diagram. The bar inherently moves in a large sweeping arc. This will cause some side to side motion of the rear axle. The longer the bar the flatter the arc the better the motion. The bar on the Fbody cannot get much bigger therefor it is not a bad setup.

305TA85

The curve you can feel mainly when turning. I like to drift, so a little or some doesn't really cut it. The effect is a slingshot. Your rear end will shoot out a little more than the body, and pull back in. This leaves for a disaster around high speed corners. This is really where the independent rear is needed. And for those thinking learn how to drive. If you are cruising fastly down the street and have to make a last second turn because someone pulls in front of you, do you want your cars life to depend on you knowing how to drive against the "slingshot." There is obvious flaws with the panhard or they would not even make one with an adjustment. The adjustment is only putting a bandaid over the real issue at hand.

Greg

ghettocruiser

iTrader: (4)

Nevermind...not gonna comment.

Lets not turn this into a panhard bar dicsussion..its about his custom inboard coil over set up. I want it to stay on track so we can see how this set up performs for him!

Sorry for the hijack!!

J.

83 Crossfire TA

iTrader: (2)

I don’t think that any of us suggested that it would be easy to make it better, or that the geometry thing is just a slap it together and run it thing, we were just suggesting how this could be made functionally better.

Grrr… do the math and tell us how much that “slingshot” action is…

Screw it, I’m not going to wait for this… with 2” of travel we’re talking about something on the order of around .05”. Now if you think that .05” is something that you’re going to feel, send you flying off a corner… well, then start replacing _everything_ in your suspension, since I guarantee that everything down there gives more than that. IRS… you have to be kidding… how does that solve this? By adding more links with more deflection and less control of the tire location/alignment? Funny thing, have you noticed that a few old school American cars have showed upon the scene and are doing quite well if not dominating some events? How many of them us an IRS?

The reason that people look at things like watts links on cars like these which have relatively low suspension travel to start with has nothing to do with “more accurately locating” the rear like most people think (the “accuracy” with a PHB is more than you need) it’s to prevent some of the “jacking” effect that it has, making the suspension feel stiffer turning one way then the other.

Greg, I’d suggest that you look into kinematics and how suspensions work before spending all your effort and money.

305TA85

Wrong place

Spifz

Just a new pic and a small update, I've driven the car around in the yard and bounced it through all the holes in the dirt driveway just to give it a little bit of a workout. To keep it pretty sealed, the pushrods are running through the factory shock top foam, then through the carpet. Under heavy droop, the rocker squishes the carpet and foam down, but it doesn't come close enough to the underlying metal to cut anything. Time to get the factory plastic back in there along the sides, it should all fit with only trimming for where the main hoop goes through.

ghettocruiser

iTrader: (4)

Nice spifz!!! I saw this thread pop up and I was like...ok who bumped the tread. hehe.

Im glad to see you not only kept with the idea, but you have it basically built! Those things look great sitting back there!

You should make another video like you did back in the beginning. I just re-read the thread to freshen my memory, and I noticed the vid no longer worked. I remember it being a pretty good visual.

Still anxious to hear how those suckers work on the road for ya!

J.

Stephen

iTrader: (12)

You read faster than I do.....I was gonna mention the missing video too.

How well do the pushrods seal to the body? Not exactly a big place for bad exhaust/etc. to be coming from but.......?

I started thinking....It would be kinda cool to either be able to mount those more outwards, under the side plastics, or rebuild the plastics farther inwards, to hide them. I could see people peeking underneath..... "Ummmm....Where are your springs & shock?"

ghettocruiser

iTrader: (4)

I think the plastics will come close to fitting... Its hard to tell from the pics without a shot straight on from the back. Im sorta torn whether he should cover those suckers up though. haha. On one hand, it'd be nice and stealth. on the other...those things look sweet.

For sealing the push rods, you can look into some of those two piece rubber diaphram seals. They bolt or rivet into place, and are in halves. I think you can get them full circle also.

But they'd have some nice give to allow for movement and seal pretty nice Ide imagine.

Something like these...tho Im not sure how these particular ones would stand up to something cycling through it.

http://www.sealsit.com/firewall.asp

J.

paul_huryk

I'm going to throw this out there as I do like the idea and the possibility of what it can do...

You need to have a rock solid chassis with all the right mounting points to run a pushrod style suspension - thirdgens are not the ideal platform (in near stock form) to effectively do such a conversion and maximize its impact on handling.

What it would be awesome for is a tube chassis conversion with a thirdgen body draped over it - so you can have the chassis mounting points in the correct place and to have a structure that wont deflect under load.

LB9Iroc87

This is absoloutley amazing, how does it work on the street, on the track, and on the drag strip, is there any chance that you could possibly put these parts into production, as in the rocker and such, i see something here that some third and fourth gen racers would possibly love to have.

Stephen

iTrader: (12)

I can totally see this setup in a dropped S10 bed, with the coil-overs possibly mounted tranverse (although would limit truck-bed carrying room).


hint, hint.....

Shagwell

Wow, old thread. - AKA, "canti-lever suspension".

By having a off ratio(not 1:1) rocker it will severally effect the shocks valving. Since the shocks will not move nearly as far as the suspension travels throught the range of motion, it makes finding the proper adjustment considerably more difficult. The shorter travel range makes for a smaller range of control over the suspension's travel.

As for the roll center/CG weight that was mentioned before, you could easily mount the shocks crossways in the car, vs front to rear.

Very cool idea and makes for a inquisitive questions about the car. Just not sure it's worth the effort on a stock chassis.

Stephen

iTrader: (12)

If you had no rear seat, couldn't you lay those facing FORWARD, more towards the CG of the car?

If you had SFCs or a cage, wouldn't be good things to tie into for stiff chassis points too?

guest666

Just signing in to say Nice work. Ive been working on paper how to do this on my Nova and you helped me out alot....

tony_cogliandro

iTrader: (3)

that is so far beyond what i could do - i am amazed.
but dont let the purists see this thread - they riped me for putting up instructions on a fuel pump access door.
great job. too bad the link does not work anymore.

camarozz383

iTrader: (2)

awesome job!! nice fabrication to, i love it.

HCR13

iTrader: (5)

kudos for a great settup. I too would like to see a vid and a finished product...

Spifz

Video link:
http://gearbox.no-ip.com/wiki/suspension.avi

(Recorded with a Sony bullet cam tied to the passenger seat, into my car PC running linux and a Hauppauge 500 card. It looked better before mpeg4'ing it.)

tony_cogliandro

iTrader: (3)

off topic but how does someone who is banned still post?

and i think it was a great production fabrication job.

HCR13

iTrader: (5)

obviously its the posting fairy granting wishes...
no no...kidding. Its probably posts BEFORE they got banned. The tittle changes to junior member, senior member, banned, no matter when the posts where made...

Spifz

For any looking for the original video:
http://gearbox.no-ip.com/wiki/Keith-PushrodSusp.mpg

guest666

Where did you get the rockers cut?

HCR13

iTrader: (5)

man thats awesome!

Spifz

Kline Bros. for the laser work

Address: 10083 Allentown Blvd
Grantville, PA, 17028-8715
Phone: 717-469-0137

I drew the parts, gave them the dwg files and the specs (1/4" steel for the rockers.)
They did the rockers and the brackets in the back that hold the coilover, along with my dash and console, which also turned out great (pics coming soon.)

Stephen

iTrader: (12)

What did you do for bushings, to pivot everything mounts?

Bushings or rod ends I can see as a possibility for the rod & coil-over, but what about the rocker assembly?

You could consider building these as a "kit" to sell.......

Spifz

There are a pair of needle roller bearings (half sealed, half open) for the 5/8 Thompson shafting that take the load. Bronze thrust bearings are squeezed between the plates and the bearing block to take any side friction. Theoretically there is only the smallest amount of side load, not enough for roller thrust washers in my opinion; the 'Oilite' bronze bearings don't require lubrication either.

The QA1 coilovers came with what they called spherical bearings with a 1/2" hole, and there is an upgrade option to teflon or something, but I didn't buy that.

You could do poly bushings in some places I guess, I figured I'd try rod ends first round and see how long they last. (Second round might be with the lower rod ends actually protected from the elements... If you can hear suspension noise, your exhaust isn't loud enough, haha.

I'll happily share parts sources, part numbers, dimensions, math, or whatever is requested that I can do, but even after spending a lot of time putting the car into the cad software, there were adjustments on the fly that had to be made. The most 'kit like' it could be made would be a deal on the coilovers, brackets, rockers, bearings, shaft, rod ends and center bearing section. I will fab one into anyone's car/truck if they want it though, it was a lot of fun to build.

Twin_Turbo

iTrader: (25)

What is the cam ratio? From the looks of it, the longer side ratio is on the wheel side and the short one on the shock. This makes the shock & spring much less efficient. If you do it the other way around you will not need as stiff a shock & spring and the setup will be much more responsive to small deflections and spring changed/shock changes (or if adjustable the setting of the bump/rebound ****(s) )

Spifz

You are correct, the longer side is on the wheel side. The ratio is set up to use the shortest QA1 damper (bringing the longer housing travel into the operating range of the shorter damper) and 7" springs instead of what would typically be used when attached directly to the housing. Since the shorter dampers are designed for that purpose (such as when attached half way in an a-arm) I was not suprised to find out that I am right about in the middle of the adjustability of the damper. Track events may show whether I have enough resolution or range on the adjustability, but you could run into the same problem with different rocker ratios (or with a stock type suspension) where 1 click is too much or 10 clicks doesn't do anything for an application.

I don't remember the rocker ratio exactly, but it is around 1.8, making the 550 lb/in springs act like a 170 lb/in spring on the housing. A change of a 50lb/in spring is about a 15 lb/in change at the housing, so the inefficiency of the spring gives me a finer adjustibility based on what springs are available off the shelf. A rocker that would utilize a lower rate spring would also need more travel, and would probably require a 10" or 14" spring The weight difference between the longer 'lighter' (wire size) spring and the shorter 'heavier' spring is probably negligable, and there probably isn't a huge difference in the short stroke dampers over the longer ones, but if there is any, it helps offset the rocker and pushrod weights.

BTW, nice cad work, your project? Looks like it is further along than my mid engine scratch built car design, maybe I'll get back to it some day

TraviZ

iTrader: (2)

not sure what im looking at as far as benifits, but I give it props for the genious behind it. if it would make me launch 1.0 60' foots, ill buy a set!
can I see photos under the car?

Twin_Turbo

iTrader: (25)

Thanks, I once designed a pushrod IRS (double a arm) for my car too...decided to just stick the coil overs in there the old fashion way.

Spifz

Haha, got me with my own joke, posting a model and following up with the real deal That is awesome looking!! Projects like that deserve a whole forum to itself in my opinion!

TheMonster

You live close to me man. I live on the other side of Evansville, Newburgh/Paradise.

Amazing. Simply put.

RevItUpZ28

iTrader: (1)

That's sick!

I don't know how I missed this post from way back, but man that's awesome work!

Primetime91

iTrader: (15)

Sweet stuff

BMR Sales

Nice work Spifz!

iroc a 86 berli

holly shlt! i saw the first pic, and thought "just another dude day dreaming with cad" then bam, already fabbed and functioning! nice job, tuning that thing at the track is gonna be a snap.

wonder when arrow camaro is gonna chime in and bash you for not leaving it like gm designed it.

ellocojorge

iTrader: (1)

my goodness that is incredible

89_RS

Spifz,

All you need for an ARB is a bracket on each bellcrank, fab up some poly bushings & housing and weld that all to a peice of 4140 spring steel or Grade 5 Titanium bar and you could make one kickass flexture ARB.

*EDIT*: Also, how would you setup a front pushrod ARB suspension on our cars?