The BAD AST Project - Faze II

[trackrat79]

I have a fealing your not going to like what it tells you.I know a lot of guys that have lowered thier vehicles the way you are talking about and just about all of them complain about the road manners after the change. I am sure you know that stock suspension are desined to operate at a sertain ride hight. Drop spindals dont affect this but makes wheel selection a little difficult. Lowering springs change the area of motion that the control arms operate in and change the operation of the suspension. I think you would be much happier with your original plan.

Maybe its because I don't have the referance of the body to compare to the chassi but from your renderings it looks like the rack is in front of the front axle center line. I realize that astro vans are rather cab forward but I would think that a link between the stock columb and the rack should be possable allbeit a bit verticle.

[astroracer]

Thanks for the input. I have a '95 GMC pickup I dropped 4" with spindles and springs and it drives like a slot car. I will run the stock Astro points and see what happens. I may end up building control arms anyways so, if a change to ball stud height or orientation is dictated by the program, I can do that during the build.
I'll post up some pics of the current column to rack mismatch along with some dimensions. I "probably" could get there... But I just feel uncomfortable with an intermediate shaft that doubles back on itself and then goes forward again...
Mark

[syborg tt]

Sometimes it's better to re-evaluate a project early on. The original goal with my truck was to build a light weight race truck and then i realized that i would just own another garage queen that i couldn't take out for a spin when ever i wanted.

So in the end try to figure out what your goals are for your project and build in that direction.

[astroracer]

Here are a few pics of my current "set-up". This is the stock van lower output shaft and the C5 Rack input shaft. The C5 rack is already "clocked" 20 degrees up from the C5 position.
What do you all think? It doesn't look bad at all from the front or top but the side view shows the actual orietations...
Any steering intermediate shaft guys? I MAY be able to do this with a couple of doubles and a single but is it getting stupid?
Front View

Top View

Side View (shows the actual angles...)

[trackrat79]

Would it be possable to rotate the rack so that the input spline is vertical or even tilted a bit forward to get around the fire wall. Maybe shorten the stearing shaft comming out of the columb and some kind of tunnel behind the firewall. Another Idea is to use two double jointed universal joint like rock crawlers use on thier axles. They should allow you to get aroung the angles you need.Then I think all you would need to do is maybe cut a channel in the firewall to get a little clearance and you mite be able to get the connection with one pice of rod. Aslo I would not be worried about the shaft coming back towards your feat. Take a look at some cab over semi trucks ,they have the same problem. With your design ability you could probly take the center section of the joint and make it longer if that would help. I did not start with a made double jointer but I made basicaly the same thing with two regular joints and a short piece of shaft for my budies drag car that I helped convert to rack style stearing.

[astroracer]

Rotating the rack to vertical would solve my problems. I already have it rotated 20 degrees up. Going vertical wouldn't be a problem with a manual rack but the vette racks are all P/S and I don't know if rotating the rack that far will cause a problem with bleeding the system... I have the question in to Marval so we'll see. Maybe re-plumbing the hardlines would get me there... Pressure bleeding? Don't really know.
The double joints would be about my only way out without more rack tippage. I down loaded some specs today so I can rough in the envelopes and see where I end up. I don't think I'll need to cut a channel in the firewall once I get a dbl "u" on the end of the column. That will push the joint farther forward so it should clear the tin and, if I CAN rotate the rack to vertical it will move the shaft forward quite a bit and it would lose the "switchback".
Thanks for your thoughts. It helps to know other people can understand the problem and think it through.
Mark

[FoxGranadaChuck]

Just out of curiousity, what type of rear suspension is this bad boy going to have?!

[trackrat79]

Glad to be of any kind of help. Te be fair , you make it realy easy with your diagrams and 3-d renderings. I wish I had persued mechanical drafting and auto cad futher after highschool when I had the chance. It would realy help with my projects and friends projects that I have been designated the designer and braintrust for. Nothing like having the reasponsability of making sure someone elses car is road worthy.

[astroracer]

FGC,
The plan right now is leaf springs, dbl adjustable shocks and a good sway bar. With enough adjustment designed into the spring mounts to be able to tweak things.

Tr79,
Being able to do all this stuff is great but sometimes I think it is more of a liability then anything else. It is too easy to "rethink" stuff rather then just go out, build it and get it done... I am doing all of this CAD work so I only have to build the suspension once but I've already junked one cradle and I can't seem to get anywhere with the design.... I guess that is part of my reasoning for re-using the stock suspension. It's already done, I know it works (to a point) and taking it apart, cleaning, painting and rebuilding is actually getting something done! I guess I'm just getting frustrated...
I'll stop whining now.
Mark

[astroracer]

I did some work this past weekend and looked at rotating the C5 rack to a more verticle orientation. After talking to a friend Saturday night I decided to go for it with the rack in this new position.
TOP VIEW...


FRONT & SIDE VIEWS...


You can see in the side view the angle is greatly improved and I think, with a little more developement it will work fine.
I am hoping it will be fine for bleeding and, if it doesn't work out, I will have to bite the bullit and purchase a one off manual rack that WILL work.
Thanks for looking.
Mark

[trackrat79]

Could you not just bleed the system with the rack not bolted up so the the bleeder valve could be as high as it needs to be and then bolt the rack in place.

[formula98]

Hey Mark,

I think you have a winner! The drawings look great and someone else corroborated the same bleeding approach! Glad to see you making progress… The angles look much better!

Keep up the great work.

Ron

[astroracer]

That's pretty sharp trackrat! Un-bolting the rack for bleeding is the saving grace here and Ron had suggested that Saturday night when we were talking on the phone.
I want to thank you guys for the help and direction! I realize this van is not your typical car build. I have come across a few engineering issues that have almost stopped me from continueing with it but, with your help, I have worked through them and feel I have a buildable, workable design. I have 5 days off over turkey break and plan to use them to get the new cradle pieces cut out and possibly tacked together.
Thanks again!
Mark

[FoxGranadaChuck]

I for one am pleased as punch that you are not working on yet another '69 Camaro PT project. Please do not misunderstand me-'69 Camaros are not bad! But they are so common on the PT scene that they have become quite boring.

An Astro van is different, but different is good!!!

[FoxGranadaChuck]

Please refresh my memory, but weren't you planning a big block carbureted Chevy back by a 700R4?! Just curious.

Also, is the tranny going to be column or floor shifted?! Or will it be paddle shifted?!

[astroracer]

Yup... BBC with a carb and a 700R4. Floor shifter. The motor position is still shifting but at this point it is 10" rearward and 5" down from the stock V6 location.
Paddle shifters would be cool but you have to have the "E" version of the trans to work. I am trying to keep the build simple as far as drivetrain goes. I do have a line on an LS2 but that is/would be a lot of work and I will probably save that for the Firebird.
Mark

[FoxGranadaChuck]

Yup... BBC with a carb and a 700R4. Floor shifter. The motor position is still shifting but at this point it is 10" rearward and 5" down from the stock V6 location.
Paddle shifters would be cool but you have to have the "E" version of the trans to work. I am trying to keep the build simple as far as drivetrain goes. I do have a line on an LS2 but that is/would be a lot of work and I will probably save that for the Firebird.
Mark

That's cool.

[trackrat79]

I was under the impresion that the 4l60E used the same casing as the 700r4 and would bolt right up to a gen1 type engine without any special parts. What would realy be cool is if you could get your hands on one of the new five speed auto's. In case you were not aware you can put paddle shift on any auto tranny it just takes a bit of extra parts to do it to a non electric tranny.

[astroracer]

Yea, 700R4_4L60_4L60E are all the same case (mostly). I was looking at the paddle shifter stuff but saw no applications for a non electronic trans... Maybe I missed something on the site?
Mark

[trackrat79]

It takes some engineering on your part. Don't try and find a kit or anything you probly wont find it. What guys do is use external solinoids to physicaly move the gear lever back and forth. Look in tranny accesories for drag racing. It can be left in drive or you can paddle shift each gear. But a 4l60e or 4l80e would be the way to go.